Adolescent smoking: behavioural risk factors and health beliefs

The study extends previous research on adults by assessing the role of cognitive factors of smoking behaviour in 885 teenagers

xPand: An algorithm for perturbing homogeneous cosmologies

In this paper, we develop in detail a fully geometrical method for deriving perturbation equations about a spatially homogeneous background. This method relies on the 3+1 splitting of the background space-time and does not use any particular set of coordinates: it is implemented in terms of geometrical quantities only, using the tensor algebra package xTensor in the xAct distribution along with the extension for perturbations xPert. Our algorithm allows one to obtain the perturbation equations for all types of homogeneous cosmologies, up to any order and in all possible gauges. As applications, we recover the well-known perturbed Einstein equations for Friedmann-Lemaitre-Robertson-Walker cosmologies up to second order and for Bianchi I cosmologies at first order. This work paves the way to the study of these models at higher order and to that of any other perturbed Bianchi cosmologies, by circumventing the usually too cumbersome derivation of the perturbed equations.Comment: 21 pages, 2 figure

Farm Management Dividends in a Friendly Policy Environment: The Case of Cassava Industry in Nigeria

Following the radical reorientation of agricultural policy during the SAP years, beginning in the mid-1980's, cassava emerged as an important crop in the national effort to replace imported foods with domestic production. The policy direction of the Nigerian government has encouraged cassava development leading to a new orientation in research-extension-farmers linkage, especially in the IFAD-assisted Cassava Multiplication Programme (CMP). This study evaluated farm management dividends in a friendly policy environment: the case of cassava industry in Nigeria. Data were collected from randomly sampled 360 cassava farmers in Benue State, Nigeria using a structured questionnaire. The data were analyzed using the stochastic frontier production function. The findings of the study indicated that the elasticity of mean value of cassava output with respect to farm size (1.39) was of increasing function while labour cost (0.19), family labour (0.90), cassava stems (0.95) and fertilized (0.01) were of decreasing function. Moreover, the coefficients on the variables: labour cost, X1(-0.19), farm size, X3 (1.39), cassava stems, X4 (0.95) and fertilizer, X5 (0.01) were statistically significant at the 1% level while family labour,X2 (-0.09) was not significant. The sum of the coefficients on the significant variables of the stochastic frontier production model (2.63) was higher than unity. The estimated coefficient of cassava variety planted (-0.18) and the estimated coefficient of processing technology available (-0.1) were negative and significant at 1% level, suggesting that technical inefficiency effects declined with the planting of improved cassava varieties and the use of improved cassava processing technology. The estimated sigma squared, á2 (0.16), was significantly different from zero at 1% level. This indicates a good fit and the correctness of the specified distributional assumption of the composite error term. In addition the magnitude of the variance ratio, was estimated to be high at 0.96, suggesting that the systematic influences that are unexplained by the production function are the dominant sources of errors. Thus, given the specifications of the Cobb-Douglas frontier production function, the Cobb-Douglas frontier is an adequate representation of the model for the farm data collected on the cassava farmers in Benue State of Nigeria. Majority of the respondents (63.61%) operated closer to their frontier production function while predicted technical efficiencies varied widely among farms, ranging between 31% and 100%, and a mean technical efficiency of 89%. It is recommended that adequate financial assistance and credit facilities should be made available to the farmers to enable them increase their production. Since there are potentials for cassava growth in the study area, the cassava farmers in Benue State should expand their production because they would obtain more output in the long run. Technical efficiency in cassava production in Benue State could be increased through better use of available resources via improved farm-specific factors, which include access to improved cassava planting material, access to improved cassava processing technology, access to available cassava markets and access to improved extension services.Crop Production/Industries,

PREFERENCE DIFFERENTIALS FOR AGRO-ENTREPRENEURSHIP AMONG YOUTHS IN EBONYI STATE, NIGERIA

The study analyzed the Preference Differentials for agro-entrepreneurship among youths in Ebonyi State, Nigeria. A multi-stage sampling technique was adopted in the selection of 180 youth agro-entrepreneurs and data collectedusing structured questionnaire. The study employed descriptive statistics and Principal Component Factor for analyses of data. Results show that the major agro-entrepreneurship activities of the youths were farm production (crop and livestock production), farm input supply, agro-processing, and marketing/distribution. The study identified high profit motive, technical qualification, good market potential, previous experience, ambition to become agro-entrepreneur, desire to be self-employed, government support, family agro-entrepreneurial history, economic needs, and support from donor agencies etc as the important factors influencing the youth’s agro-entrepreneurship preference. Lack of credit facilities, corruption, high interest rate, high capital demand, poor transportation facilities, limited access to improved technologies, insufficient information, challenges of market accessibility, poor enabling environment, inconsistent government policies, multiple taxation were the major constraints to agro-entrepreneurship development among the youths. State and private information and communication agencies should be encouraged to convey information on existing government and other small and medium scale business funding support platforms that are accessible to youth agro-entrepreneurs

Technical Efficiency Analysis of Nigerian Cassava Farmers: A Guide for Food Security Policy

This study analyzed relationship between techn ical efficiency and socio-economic variables of cassava farmers in Nigeria. Data were collected from randomly sampled 360 cassava farmers in Nigeria using a structured questionnaire. The data were analyzed using descriptive statistics comprising mean, minimum value, maximum value and standard deviation, as well as inferential statistics, which comprised correlation and regression. The findings of the s tudy indicated that a significant relationship exists between technical efficiency and cassava output (0.542), farm income (0.612), processing cost (- 0.414), gari yield (0.608), gross margin (0.483), farming experience (0.278), education (0.699) and extension contact (0.585) of the sampled cassava farmers in Nigeria. Multiple regression result showed that variation in technical efficiency is explained by variations in annual farm income (2.718E-06), annual processing cost (- 1.542E-05), annual gross margin (9.383E-07) farming experience (3.825E-03), education (0.191) and extension contact (6.562E-02). Hence, policy that would enable cassava farmers in Nigeria increase farm income, gross margin and have access to quality education and extension services will lead to the enhancement of technical efficiency of cassava production. Furthermore, policy that would encourage experienced farmers in cassava production and ensure that cost effective improved cassava processing technology is available to the cassava farmers will enhance technical efficiency in cassava production in Nigeria. Policy that would further raise the current level of technical efficiency in cassava production in Nigeria is strongly recommended for the enhancement of the welfare of the cassava farmers in Nigeria.technical efficiency, Nigerian cassava farmers, food security policy, Crop Production/Industries, Food Security and Poverty, Productivity Analysis,

Comparative Analysis of the Impact of World Bank Root and Tuber Expansion Programme on Poverty Alleviation of Peri-Urban and Rural Communities in Benue State, Nigeria

This study examined in 2005 t he impact of World Bank Expanded Programme for Root and Tuber Production (RTEP) on the poverty alleviation of peri-urban and rural communities in Benue State, Nigeria. It aimed at delineating causal effect disparity in poverty alleviation of two major producer communities. Data were collected from two hundred and eight (208) respondent s randomly drawn from ten (10) typically rural and ten (10) peri-urban communities. Simple descriptive statistics (percentages) and discriminant function analysis were used to analyze the collected data. The discriminant function was fitted on the poverty alleviation score to analyze causal and effect relationship. The study found disparities in valued output, quality of life, income and a homogeneous non-significant age disparity in both rural and peri-urban root and tuber crops producer communities. Major contributors to t he poverty alleviation were: Income realized from market able surplus (X3), distance in kilometers to the nearest urban market of best sales (X1), the kilometer distance traveled to evacuate produce (X2), with 5 5%, 15% and 10% contributions respectively in that sequence to the tot al discriminant score(Z) of 87%. Other contributory indicators were average revenue receipt per unit of root and tuber in the best market (X4), quality of life score (X5) and mobility score (X6). The study recommends that developing nations should re-focus their policy framework to provide better markets and marketing opportunities as well as improved transportation and communication infrastructures for the typically rural to accelerate poverty alleviation.World Bank, Poverty Reduction programme valued output, Discriminant Function, Crop Production/Industries, Food Security and Poverty,

The art of building a smooth cosmic distance ladder in a perturbed universe

How does a smooth cosmic distance ladder emerge from observations made from a single location in a lumpy Universe? Distances to Type Ia supernovae in the Hubble flow are anchored on local distance measurements to sources that are very nearby. We described how this configuration could be built in a perturbed universe where lumpiness is described as small perturbations on top of a flat Friedmann-Lema{\i}tre Robertson-Walker spacetime. We show that there is a non-negligible modification (about 11\%) to the background Friedmann-Lema{\i}tre Robertson-Walker area distance due to the presence of inhomogeneities in the immediate neighbourhood of an observer. We find that the modification is sourced by the electric part of the Weyl tensor indicating a tidal deformation of the local spacetime of the observer. We show in detail how it could impact the calibration of the Type Ia supernova absolute magnitude in the Hubble flow. We show that it could potentially resolve the Type Ia supernova absolute magnitude and Hubble tensions simultaneously without the need for early or late dark energy.Comment: Version accepted for publication by JCA

Emergence of smooth distance and apparent magnitude in a lumpy Universe

The standard interpretation of observations such as the peak apparent magnitude of Type Ia supernova made from one location in a lumpy Universe is based on the idealised Friedmann-Lema\^itre Robertson-Walker spacetime. All possible corrections to this model due to inhomogeneities are usually neglected. Here, we use the result from the recent concise derivation of the area distance in an inhomogeneous universe to study the monopole and Hubble residual of the apparent magnitude of Type Ia supernovae. We find that at low redshifts, the background FLRW spacetime model of the apparent magnitude receives corrections due to relative velocity perturbation in the observed redshift. We show how this velocity perturbation could contribute to a variance in the Hubble residual and how it could impact the calibration of the absolute magnitude of the Type Ia supernova in the Hubble flow. We also show that it could resolve the tension in the determination of the Hubble rate from the baryon acoustic oscillation and local measurements.Comment: Version accepted for publication by CQ

Cosmological evolution of the gravitational entropy of the large-scale structure

We consider the entropy associated with the large-scale structure of the Universe in the linear regime, where the Universe can be described by a perturbed Friedmann-Lema\^itre spacetime. In particular, we compare two different definitions proposed in the literature for the entropy using a spatial averaging prescription. For one definition, the entropy of the large-scale structure for a given comoving volume always grows with time, both for a CDM and a $\Lambda$CDM model. In particular, while it diverges for a CDM model, it saturates to a constant value in the presence of a cosmological constant. The use of a light-cone averaging prescription in the context of the evaluation of the entropy is also discussed.Comment: 10 pages, 4 figures. Presentation improved, typos corrected, previous subsection III.B merged with subsection II.C, comments, clarifications and a reference added. Version accepted for publication in GR