Commercialisation of agriculture in Kenya: Case study of urban bias on food availability in farm households

This study investigates the effect of cash cropping on food availability and examines the determinants of the proportion of income allocated for food expenditures in the Nyeri district in Kenya. Using a Tobit model, the results suggest that in general food expenditure allocations suffer due to cash cropping in Kenya as the lump-sum income flows from this may be used for purchases other than food. Food expenditure also suffers when remittances are irregular. On the other hand, earnings from outside employment for married women living with husbands are positively associated with food expenditure allocations. Amounts of non-cash food output as well as ownership of livestock are negatively associated with food expenditure allocations. These findings indicate that lump sum income may not lead to improved welfare of women and children. Thus, there may be social reasons for increasing non-cash food production especially by women, instead of over emphasizing cash cropping as now seems to be so in public policy.

The relationship between commercial agriculture and food availability to Kenyan farm families: A case study

This article examines the effects of agricultural commercialization and other factors on per capita food availability by means of a case study in the Nyeri district in Kenya. It was found that cash cropping has a negative influence on per capita food availability in the male-headed households. This negative influence is not apparent in the female-headed households and in fact, per capita food availability rises with increased agricultural commercialization. Households of married women seem to suffer more in terms of reduced food availability than households headed by females. Husbands have control over cash income and therefore influence food purchases. They are less likely than females to use the cash for food purchases and tend to spend the cash on themselves, thus reducing food availability to family members. This suggests that in some patriarchal societies, caution should be displayed in encouraging cash cropping especially in male-headed households. Cash cropping under such circumstances is unwise from both a food availability and food security point of view because it can result in reduced crop diversification hence increasing the risks of income food deficits for families. Other factors found to have an influence on per capita food availability are employment of the women outside households, educational level of the women and the quality of land.

Estimating Income Inequality in China Using Grouped Data and the Generalized Beta Distribution

There are two main types of data sources of income distributions in China: household survey data and grouped data. Household survey data are typically available for isolated years and individual provinces. In comparison, aggregate or grouped data are typically available more frequently and usually have national coverage. In principle, grouped data allow investigation of the change of inequality over longer, continuous periods of time, and the identification of patterns of inequality across broader regions. Nevertheless, a major limitation of grouped data is that only mean (average) income and income shares of quintile or decile groups of the population are reported. Directly using grouped data reported in this format is equivalent to assuming that all individuals in a quintile or decile group have the same income. This potentially distorts the estimate of inequality within each region. The aim of this paper is to apply an improved econometric method designed to use grouped data to study income inequality in China. A generalized beta distribution is employed to model income inequality in China at various levels and periods of time. The generalized beta distribution is more general and flexible than the lognormal distribution that has been used in past research, and also relaxes the assumption of a uniform distribution of income within quintile and decile groups of populations. The paper studies the nature and extent of inequality in rural and urban China over the period 1978 to 2002. Income inequality in the whole of China is then modeled using a mixture of province-specific distributions. The estimated results are used to study the trends in national inequality, and to discuss the empirical findings in the light of economic reforms, regional policies, and globalization of the Chinese economy.

Quasi-stationarity in populations that are subject to large-scale mortality or emigration

We shall examine a model, first studied by Brockwell et al. [Adv Appl Probab 14 (1982) 709.], which can be used to describe the longterm behaviour of populations that are subject to catastrophic mortality or emigration events. Populations can suffer dramatic declines when disease, such as an introduced virus, affects the population, or when food shortages occur, due to overgrazing or fluctuations in rainfall. However, perhaps surprisingly, such populations can survive for long periods and, although they may eventually become extinct, they can exhibit an apparently stationary regime. It is useful to be able to model this behaviour. This is particularly true of the ecological examples that motivated the present study, since, in order to properly manage these populations, it is necessary to be able to predict persistence times and to estimate the conditional probability distribution of population size. We shall see that although our model predicts eventual extinction, the time till extinction can be long and the stationary exhibited by these populations over any reasonable time scale can be explained using a quasistationary distribution. (C) 2001 Elsevier Science Ltd. All rights reserved.

Ecological distribution of mosquito larvae of the Anopheles punctulatus group on Niolam (Lihir) Island, Papua New Guinea

We surveyed the larval habitats of member,, of the Anopheles punctulatus group of mosquitoes on Niolam (Lihir) Island. Papua New Guinea. Identification of this group was undertaken by polymerase chain reaction-restriction fragment length polymorphism analysis of the amplified internal transcribed spacer unit 2 of rDNA. because morphologic separation of member species is unreliable. The most widespread malaria vector species and their most common larval habitats identified to aid source-reduction programs for malaria control. The most ubiquitous species was An. punctulatus, followed by An. farauti no. 2. then An. farauti s.s. Anopheles punctulatus has increased relative to An.farauti s.l. since the start of development projects on Lihir Island. The most common larval habitats were shallow temporary pools with clay substrate and with plants or floatage. These habitats. mostly encountered alongside poorly drained roads, may be increased by development projects.

Distribution of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia in an Australian population

Background, aim: The present study describes (i) the natural distribution of the three putative periodontopathogens Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans in an Australian population and (ii) the relationship between these organisms, pocket depths and supragingival plaque scores. Methods: Subgingival plaque was collected from the shallowest and deepest probing site in each sextant of the dentition. In total, 6030 subgingival plaque samples were collected from 504 subjects. An ELISA utilising pathogen-specific monoclonal antibodies was used to quantitate bacterial numbers. Results:: A. actinomycetemcomitans was the most frequently detected organism (22.8% of subjects) followed by P. gingivalis and P. intermedia (14.7% and 9.5% of subjects respectively). The majority of infected subjects (83%) were colonised by a single species of organism. A. actinomyceteincomitans presence was overrepresented in the youngest age group but under-represented in the older age groups. Conversely, P. gingivalis and P. intermedia presence was under-represented in the youngest age group but over-represented in the older age groups. Differing trends in the distribution of these bacteria were observed between subjects depending upon the site of the infection or whether a single or mixed infection was present; however, these differences did not reach significance. Bacterial presence was strongly associated with pocket depth for both A. actinomyceteincomitans and P. gingivalis. For A. actinomycetemcomitans, the odds of a site containing this bacterium decrease with deeper pockets. In contrast, for P. gingivalis the odds of a site being positive are almost six times greater for pockets >3 ram than for pockets less than or equal to3 nun. These odds increase further to 15.3 for pockets deeper than 5 mm. The odds of a site being P. intermedia positive were marginally greater (1.16) for pockets deeper than 3 mm. Conclusions: This cross-sectional study in a volunteer Australian population, demonstrated recognised periodontal pathogens occur as part of the flora of the subgingival plaque. Prospective longitudinal studies are needed to examine the positive relationship between pocket depth and pathogen presence with periodontal disease initiation and/or progression.