Land use determinants of small mammals abundance and distribution in a plague endemic area of Lushoto District, Tanzania

Small mammals are considered to be involved in the transmission cycle of bubonic plague, still occurring in different parts of the world, including the Lushoto district in Tanzania. The objective of this study was to determine the relationship between land use types and practices and small mammal abundance and distribution. A field survey was used to collect data in three landscapes differing in plague incidences. Data collection was done both in the wet season (April-June 2012) and dry season (August-October 2012). Analysis of variance and Boosted Regression Trees (BRT) modelling technique were used to establish the relationship between land use and small mammal abundance and distribution. Significant variations (p ≤ 0.05) of small mammal abundance among land use types were identified. Plantation forest with farming, natural forest and fallow had higher populations of small mammals than the other aggregated land use types. The influence of individual land use types on small mammal abundance level showed that, in both dry and wet seasons, miraba and fallow tended to favour small mammals’ habitation whereas land tillage practices had the opposite effect. In addition, during the wet season crop types such as potato and maize appeared to positively influence the distribution and abundance of small mammals which was attributed to both shelter and food availability. Based on the findings from this study it is recommended that future efforts to predict and map spatial and temporal human plague infection risk at fine scale should consider the role played by land use and associated human activities on small mammal abundance and distribution

A combined first and second order variational approach for image reconstruction

In this paper we study a variational problem in the space of functions of bounded Hessian. Our model constitutes a straightforward higher-order extension of the well known ROF functional (total variation minimisation) to which we add a non-smooth second order regulariser. It combines convex functions of the total variation and the total variation of the first derivatives. In what follows, we prove existence and uniqueness of minimisers of the combined model and present the numerical solution of the corresponding discretised problem by employing the split Bregman method. The paper is furnished with applications of our model to image denoising, deblurring as well as image inpainting. The obtained numerical results are compared with results obtained from total generalised variation (TGV), infimal convolution and Euler's elastica, three other state of the art higher-order models. The numerical discussion confirms that the proposed higher-order model competes with models of its kind in avoiding the creation of undesirable artifacts and blocky-like structures in the reconstructed images -- a known disadvantage of the ROF model -- while being simple and efficiently numerically solvable.Comment: 34 pages, 89 figure

ADI splitting schemes for a fourth-order nonlinear partial differential equation from image processing

We present directional operator splitting schemes for the numerical solution of a fourth-order, nonlinear partial differential evolution equation which arises in image processing. This equation constitutes the H−1-gradient flow of the total variation and represents a prototype of higher-order equations of similar type which are popular in imaging for denoising, deblurring and inpainting problems. The efficient numerical solution of this equation is very challenging due to the stiffness of most numerical schemes. We show that the combination of directional splitting schemes with implicit time-stepping provides a stable and computationally cheap numerical realisation of the equation

On a coupled PDE model for image restoration

In this paper, we consider a new coupled PDE model for image restoration. Both the image and the edge variables are incorporated by coupling them into two different PDEs. It is shown that the initial-boundary value problem has global in time dissipative solutions (in a sense going back to P.-L. Lions), and several properties of these solutions are established. This is a rough draft, and the final version of the paper will contain a modelling part and numerical experiments

The effect of preparation methods on fenthion residues in sprayed quelea birds for human consumption

Research Article published by International Research Journals Vol. 5(1) February 2016The aim of this study was to assess the different local methods that are used by the communities to prepare quelea birds collected after spray with Queleatox for human consumption. It was conducted in order to compare their effects in reduction of fenthion residues. The assessment of various local preparation techniques was done through social survey where by a questionnaire was administered to enumerate 34 respondents and data was collected. This study was conducted at Ikonda village in Shinyanga region with coordinates 03o 54'.097''S and 27o.033'. 035'E' and at Basotu village in Arusha regions with 04° 31'.658''S and 036° 12'.921"E coordinates. Both areas are famous for the production of three common cereal crops of rice, wheat and barley in Tanzania where by aerial spray of Queleatox to control quelea birds are done as an annual event. This social survey was conducted two days before spray operations in both sites after which samples of sprayed birds were randomly collected for fenthion residues analysis in laboratory. Residues analysis was done in Tropical Pesticides Research Laboratory (TPRI) by using Gas Chromatography with Mass Spectrometry (GC-MS). Results from general social survey showed that the mostly used preparation methods are frying in oil, boiling and grilling after washing. Results from fenthion residues analysis showed washing and cooking had significant effects in reduction of residues to below detection limit by GC-MS compared to raw sprayed samples which demonstrated some residues content

Health risks of pesticides to non target species and ecosystem due to control of migrant pests in Tanzania

Research Article published by International Research Journals Vol. 4(2), December 2015This report is a review of impacts of pesticides on non taget species and the ecosystem in Tanzania. The use of pesticides in Agriculture and other activities has increased rapidly in the past decades in developing countries following expansion of new areas of production and need to increase productivity per given area in order to meet demand to feed the increasing populations in developing countries. Although the largest quantities of pesticides are still consumed by western countries, many cases of pesticide poisoning occurred in developing countries. This is due to lack of knowledge on proper handling of pesticides, widespread ignorance of risks involved, lack of reinforcement of legislation governing pesticides and inadequate extension services especially in rural areas. Other factors are like lack or minimun use of full protective clothing, poor disporsal methods and mis handling of empty pesticides containers accounts for increased risks of pesticides poisoning to the agricultural workers, general public and the environmental pullution. The purpose of this review is to focus on health effects of pesticides that are used to control migrant agricultural pests to non target organisms and the ecosystem in Tanzania