Gender differentials on productivity of rice farmers in south western Nigeria: An Oaxaca-Blinder decomposition approach.

Gender differences in productivity are one of the major obstacles impeding the development of agriculture in Africa and Nigerian particularly. With the Oaxaca-Blinder (OB) and exogenous switching treatment regression (ESTER) models, this study investigates the causes of the productivity differences among 360 sampled rice farmers in Nigeria as well as gender inequality in agricultural productivity. The findings showed that there is an inequalities between men and women, which contributes to a gender productivity gap of almost 29 % in favour of men. As a result, plots managed by women are 29 % less productive than plots handled by men. The analysis of the factors influencing gender variations in production reveals that the endowment component, which accounts for 15 % of the productivity gap, is significantly influenced by marital status, education, farm size, and access to market information. Similarly, the ESTER results show that the rice yield of FHHs would have decreased by 25.41 kg/ha (a 1.02 % reduction) if they had been assigned the same returns to the observed features of MHHs. This difference is significant at the 1 % level. Thus, the findings imply that the FHHs are not at a yield disadvantage when compared to the MHHs. Therefore, it can be said that there are gender productivity disparities in the Nigerian agricultural industry. As such, policy interventions aimed at empowering women must take these disparities into consideration as well as the causes that contribute to them. Overall, the results demonstrate that although policymakers and their development partners can use improved technologies to increase MHH and FHH yields, reducing the difference in market linkages is necessary to close the gender gap in rice productivity and provide FHHs with equal access to the market.

Understanding the Determinants of Food Security among Rural Farming Households in Rwanda.

Despite Rwanda's impressive economic success over the last decade, household food insecurity persists, particularly in rural areas. Empirical evidence is therefore deemed necessary to inform policies addressing food insecurity, hunger and poverty in general. This study examines household food security and its determinants in the rural areas of Southern and Northern provinces of Rwanda. Using cross-sectional data collected from 534 farming households, we estimated household food security status by Food Consumption Score (FCS) and Food Insecurity Experience Scale (FIES) and applied ordered Probit model to identify drivers of household food security. The results indicate that a significant proportion (74.4%) of households had an acceptable FCS, but 36.52% of the farming households experienced moderate and severe food insecurity when assessed with FIES. Ownership of livestock was identified as a key determinant of food security using both metrics, which affirms the importance of combating hunger and food insecurity in Rwanda through their 'one cow per household policy' and recommends that this policy be strengthened.

Climate change adaptation strategies by smallholder farmers in Nigeria: does non-farm employment play any role?

Non-farm employment in agrarian communities in developing countries has received a lot of attention. However, its role in implementing climate change adaptation strategies is rarely discussed. This study employs a cross-sectional data to examine whether rural households in Southwest Nigeria are increasing the extent of climate change adaptation practices through their participation in non-farm employment. To account for selectivity bias, the study used endogenous treatment effect for count data model (precisely Poisson) augmented with the inverse probability-weighted-regression-adjustment (IPWRA) estimator. Both estimators found that rural non-farm jobs increase smallholder farmers' adaptive capacities and that participants would have used less adaptation techniques if they had not participated in non-farm work. Efforts to boost rural development must provide more employment opportunities for farmers, particularly during the off-cropping time. This will help farmers improve their ability to adopt more climate change adaptation strategies and, consequently increase farm productivity.

Adoption of soil and water conservation technology and its effect on the productivity of smallholder rice farmers in Southwest Nigeria.

This study estimated the effect of the adoption of soil and water conservation (SWC) on the productivity of 360 smallholder rice farmers in Southwest Nigeria. An endogenous switching regression model (ESRM) was employed to estimate the productivities of adopter and non-adopters of SWC. A doubly robust inverse-probability-weighted regression adjustment (IPWRA) was used as a credible remedy for potentially biased estimates of average treatment on the treated (ATT) and potential outcome mean (POM) of the endogenous treatment model. Significant variables, such as farmers' locations, gender, marital status, annual temperature, annual precipitation, log of fertiliser and membership in farm-based organisation (FBO), were factors influencing the adoption of SWC among smallholder rice farmers. Factors such as age, marital status, rice experience, farm size, formal education, access to extension and labour in man-days significantly influenced the rice productivity of smallholder farmers who adopted SWC technology, while location, marital status, rice experience, farm size, formal education, access to extension and labour in man-days were the determinants of rice productivity among smallholder farmers who did not adopt SWC technology. The result from the inverse-probability-weighted regression adjustment estimation indicates that the adoption of SWC technology to mitigate the adverse effects of climate change improves the productivity of rice in the study area. To ensure effective dissemination and the adoption of new conservation technologies, government and stakeholders in rice production could take the lead in promotion and dissemination in the initial stages and, in the process, create an enabling environment for the effective participation of other stakeholders in rice production.

Gender differentials in technical efficiency of Ghanaian cocoa farms.

This study considers the presence of a gender gap in technical efficiency in Ghana's cocoa production sector. The two-stage double bootstrap data envelopment analysis (DEA) procedure was applied to estimate the bias-corrected technical efficiency scores for male and female cocoa farm managers. The results indicate that there is a potential for male and female cocoa farm managers to increase output without altering the quantities of inputs employed. Applying the extended version of the Blinder-Oaxaca (B-O) decomposition approach, the findings suggest that female plot managers are, on average, less technically efficient compared to their male counterparts. This gap could be linked to differences in their resource endowments. Nevertheless, there are still significant unobservable factors that contribute to the gender efficiency gap. A comprehensive decomposition examination indicates that differences in educational attainment, engagement in non-farm activities, and farm size may contribute to the unexplained technical efficiency gap. The study recommends that female-sensitive programmes that seek to encourage the participation of non-farm activities and provide access to education and land utilization are essential in reducing the gender gap in technical efficiency.

UV photodecomposition of zinc acetate for the growth of ZnO nanowires.

The thermal annealing of zinc precursors to form suitable seed layers for the growth of ZnO nanowires is common. However, the process is relatively long and involves high temperatures which limit substrate choice. In this study the use of a low temperature, ultra-violet (UV) exposure is demonstrated for photodecomposition of zinc acetate precursors to form suitable seed layers. Comparisons are made between ZnO nanowire growth performed on seed layers produced through thermal annealing and exposure to UV. The dependence of growth density and nanowire diameter on UV exposure time is investigated. Growth quality is confirmed with energy dispersive x-ray (EDX) and x-ray diffraction analyses. The chemical composition of the exposed layers is investigated with EDX and x-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) is utilized to investigate morphological changes with respect to UV exposure. The diameter and density of the resultant growth was found to be strongly dependent on the UV exposure time. UV exposure times of only 25-30 s led to maximum density of growth and minimum diameter, significantly faster than thermal annealing. EDX, XPS and AFM analyses of the seed layers confirmed decomposition of the zinc precursor and morphological changes which influenced the growth.

Flexographic printing-assisted fabrication of ZnO nanowire devices.

In this study, the use of flexographic printing was investigated for low cost, high volume production of devices incorporating nanowires through the printing of zinc acetate precursors on a substrate used to form zinc oxide (ZnO) seeds for the growth of nanowires using a hydrothermal growth technique. The printing of precursors allows the selective area growth of ZnO nanowires, which has implications in high-yield production of devices incorporating ZnO nanowires. The work presented here achieved printed line widths of <60 µm with low edge distortion (<3 µm) using a printing plate with a line width of 50 µm. The hydrothermally grown ZnO nanowires show uniform density of growth over the printed area with nanowire diameters between 40 and 60 nm on both silicon and polyimide substrates. Energy-dispersive x-ray spectra showed contamination-free crystals with a 1:1 (zinc to oxygen) stoichiometry. Crystal orientation is along the c-axis with high quality crystalline structure shown using x-ray diffraction spectroscopy and high resolution transmission electron microscopy. A ZnO nanowire gas sensor, fabricated using the flexographic printing technique, is demonstrated. Such a printing-assisted fabrication offers low cost, high volume production of devices incorporating ZnO nanowires, ranging from gas sensors to field emission devices.

Inter-neonatal intensive care unit variation in discharge timing: influence of apnea and feeding management.

BACKGROUND: Premature infants need to attain both medical stability and maturational milestones (specifically, independent thermoregulation, resolution of apnea of prematurity, and the ability to feed by mouth) before safe discharge to home. Current practice also requires premature infants to be observed in hospital before discharge for several days (margin of safety) after physiologic maturity is recognized. OBJECTIVE: To compare postmenstrual age (PMA) at discharge in a homogeneous population of premature infants cared for in different neonatal intensive care units (NICUs) and to assess the impact on hospital stay of the recognition and recording of physiologic maturity and the required margin of safety. METHODS: We studied premature infants delivered at 30 to 34 6/7 weeks gestational age (GA), free of significant medical or surgical complications. Medical records of 30 eligible infants consecutively discharged from the hospital before July 1997 from each of 15 NICUs in Massachusetts (9 level 2 and 6 level 3) were reviewed. RESULTS: A total of 435 infants were included in the study sample. Mean (+/- standard deviation) GA and birth weight of the study population were 33.2 +/- 1.2 weeks and 2024 +/- 389 g, respectively. Infants were discharged at a similar PMA regardless of GA at birth. Considerable variation in the PMA at discharge between hospital sites was observed (range, 35.2 +/- 0.5 weeks to 36.5 +/- 1.2 weeks). Despite the homogeneous study population, hospitals in which infants had the latest PMA at discharge also recorded mature cardiorespiratory and feeding behavior at an older age. Longer duration of pulse oximetry use was associated with later resolution of apnea. Differences in the duration of the margin of safety between sites did not contribute to variation in hospital stay. CONCLUSION: NICUs vary widely in length of hospital stay for healthy premature infants. We speculate that this variation results in part from differences in monitoring for and documentation of apnea of prematurity and feeding behavior.

A model to assess the infection potential of jet injectors used in mass immunisation.

Jet injectors are needleless injectors that penetrate skin with high-pressure fluid. They have potential advantages over needles and syringes in mass immunisation programs, but concerns over their capacity to transfer blood-borne viruses have been a barrier to acceptance. Hepatitis B infection can transmit in 10 pl of blood; detection of such low volumes presents severe difficulties to such assessments. A model to assess jet injector safety was developed using injection of an inert buffer into calves and assaying the next injector discharge, representing the next dose of vaccine, for blood using a highly sensitive ELISA. Four injectors were tested: two with reusable heads and direct skin contact, one with single-use injector heads and one where the injector head discharged at a distance from the skin. All injectors tested transmitted significant (over 10 pl) volumes of blood; the volumes and frequency of contamination varied with injector. The source of the contamination was consistent with contamination by efflux of injected fluid and blood from the pressurised pocket in tissue that is formed during injection. This insight should inform the design of safe jet injectors.

Auto-disable syringes for immunization: issues in technology transfer

It reviews issues in technology transfer for the use of auto-disable syringes for immunization. Document in pdf format; Acrobat Reader required.

Specific detection of DNA and RNA targets using a novel isothermal nucleic acid amplification assay based on the formation of a three-way junction structure.

The formation of DNA three-way junction (3WJ) structures has been utilised to develop a novel isothermal nucleic acid amplification assay (SMART) for the detection of specific DNA or RNA targets. The assay consists of two oligonucleotide probes that hybridise to a specific target sequence and, only then, to each other forming a 3WJ structure. One probe (template for the RNA signal) contains a non-functional single-stranded T7 RNA polymerase promoter sequence. This promoter sequence is made double-stranded (hence functional) by DNA polymerase, allowing T7 RNA polymerase to generate a target-dependent RNA signal which is measured by an enzyme-linked oligosorbent assay (ELOSA). The sequence of the RNA signal is always the same, regardless of the original target sequence. The SMART assay was successfully tested in model systems with several single-stranded synthetic targets, both DNA and RNA. The assay could also detect specific target sequences in both genomic DNA and total RNA from Escherichia coli. It was also possible to generate signal from E.coli samples without prior extraction of nucleic acid, showing that for some targets, sample purification may not be required. The assay is simple to perform and easily adaptable to different targets.

Heterologous expression of soluble methane monooxygenase genes in methanotrophs containing only particulate methane monooxygenase.

The methanotrophs Methylococcus capsulatus (Bath) and Methylosinus trichosporium OB3b contain particulate methane monooxygenase (pMMO) and soluble methane monooxygenase (sMMO) genes. Other methanotrophs such as Methylomicrobium album BG8 and Methylocystis parvus OBBP contain only pMMO genes. Although molecular genetic techniques are poorly developed in methanotrophs, sMMO genes were expressed in methanotrophs normally containing only pMMO genes. This was achieved by conjugation using broad-host-range plasmids containing the native promoter and sMMO genes from Mc. capsulatus (Bath) and Ms. trichosporium OB3b. sMMO genes derived from Ms. trichosporium OB3b were expressed in an active form in Mcy. parvus OBBP and in Mm. album BG8. Therefore, all of the genes required for active sMMO synthesis were contained on the broad-host-range plasmids and were expressed in the heterologous hosts. Constitutive synthesis of pMMO was observed in Mm. album BG8 when grown at high and low copper-to-biomass ratios, while transcription of the recombinant sMMO genes was only observed under growth conditions of low copper-to-biomass ratios. Therefore, the regulatory protein(s) for sMMO synthesis was also present on the plasmid used, or the heterologous host contained a regulatory system for sMMO. Expression of sMMO genes in methanotrophs containing only pMMO will assist further investigations on the expression and regulation of MMO genes in methanotrophs.

Heterologous expression of alkene monooxygenase from Rhodococcus rhodochrous B-276.

Alkene monooxygenase (AMO) from Rhodococcus rhodochrous (formerly Nocardia corallina) B-276 is a three-component enzyme system encoded by the four-gene operon amoABCD. AMO catalyses the stereoselective epoxygenation of aliphatic alkenes, yielding primarily R enantiomers. The presumed site of alkene oxygenation is a dinuclear iron centre similar to that in the soluble methane monooxygenases of methanotrophic bacteria, to which AMO exhibits a significant degree of amino acid sequence identity. The AMO complex was not expressed in Escherichia coli, at least partly because that host did not produce all of the AMO polypeptides. Expression of AMO was achieved in Streptomyces lividans by cloning the AMO genes into the thiostrepton-inducible expression plasmid pIJ6021. No background of AMO activity was detected in S. lividans cells without amoABCD and expression of AMO activity, at a level comparable to that from wild-type R. rhodochrous B-276, coincided with appearance of the AMO subunits. Recombinant AMO activity in cell-free extracts of S. lividans was stimulated by the addition of NADH and produced R-epoxypropane with comparable enantiomeric excess to AMO purified from the original organism. Although the whole AMO complex could not be expressed in E. coli, the functional coupling protein (AmoB) and reductase (AmoD) were expressed individually in E. coli as fusions with glutathione S-transferase. The expression systems described here now allow structure/function studies on AMO to be carried out by site-directed mutagenesis.

Auto-disable syringes for immunization: issues in technology transfer.

WHO and its partners recommend the use of auto-disable syringes, "bundled" with the supply of vaccines when donor dollars are used, in all mass immunization campaigns, and also strongly advocate their use in routine immunization programmes. Because of the relatively high price of auto-disable syringes, WHO's Technical Network for Logistics in Health recommends that activities be initiated to encourage the transfer of production technology for these syringes as a means of promoting their use and enhancing access to the technology. The present article examines factors influencing technology transfer, including feasibility, corporate interest, cost, quality assurance, intellectual property considerations, and probable time frames for implementation. Technology transfer activities are likely to be complex and difficult, and may not result in lower prices for syringes. Guidelines are offered on technology transfer initiatives for auto-disable syringes to ensure the quality of the product, the reliability of the supply, and the feasibility of the technology transfer activity itself.

PIP: This article examines the factors influencing technology transfer, including feasibility, corporate interest, cost, quality assurance, intellectual property considerations, and probable time frames for implementing the use of auto-disable (AD) syringes. WHO and its partners recommend the use of AD syringes, "bundled" with a supply of vaccines when donor dollars are used in all mass immunization campaigns, and also strongly advocate their use in routine immunization programs. Due to the relatively high price of AD syringes, WHO's Technical Network for Logistics in Health recommends that activities must be initiated to encourage the transfer of production technology for these syringes as a means of promoting their use and enhancing its access to it. Technology transfer activities are likely to be complex and difficult and may not result in lower prices for syringes. Guidelines are offered on technology transfer initiatives for AD syringes to ensure the quality of the product, the reliability of the supply, and the feasibility of the technology transfer activity.

Inactivation of the regulatory protein B of soluble methane monooxygenase from Methylococcus capsulatus (Bath) by proteolysis can be overcome by a Gly to Gln modification.

The regulatory protein B of soluble methane monooxygenase (sMMO) from Methylococcus capsulatus (Bath), exists as a mixture of the full-length active form and truncated forms, B' and B". Electrospray ionisation mass spectrometry (ESI-MS) was used to identify a cleavage site between Met12 and Gly13, such that 12 amino acids were lost from the N-terminus of protein B. This truncate was designated B' and molecular masses were assigned to proteins B and B' of 15,852.6+/-0.4 Da and 14,629.5+/-0.3 Da, respectively. A cleavage site between Gln29 and Val30 was also identified such that 29 amino acids were lost from the N-terminus of protein B. This truncate was designated B" and had a molecular mass of 12,709.93+/-0.02 Da. Proteins B' and B" were found to be inactive in the sMMO system. Addition of protease inhibitors or the heterologous expression of protein B in various strains of lon-deficient or ompT-deficient Escherichia coli, did not inhibit B' formation. Expression of protein B as a glutathione S-transferase fusion protein and subsequent purification of protein B from E. coli using affinity chromatography resulted in preparations of protein B with higher enzyme activities than that of wild-type protein B. However, ESI-MS confirmed that protein B' was still present. Alteration of the Met12-Gly13 cleavage site to Met12-Gln13 revealed that the stability of G13Q at 20 degrees C and 37 degrees C was higher than that of wild-type preparations. ESI-MS indicated that protein B' was absent and could only be identified after prolonged incubation at room temperature. The amount of active protein B present in the cell may be controlled by protein B cleavage, thereby regulating electron transfer. Alternatively, it may allow protein B to maintain a certain conformation necessary for enzyme activity and this may control the activity of sMMO in response to the supply of methane to the cell.

Developmental transitions in the myosin heavy chain phenotype of human respiratory muscle.

We studied the expression of myosin heavy chain (MHC) isoforms in the costal diaphragm (DIA) and the genioglossus (GG) muscles from 16 to 42 weeks gestation in the human using Western blotting techniques. Embryonic/neonatal MHC (MHCemb/neo) was the predominant isoform expressed in the DIA and GG at 16-24 weeks gestation. Subsequently, MHCemb/neo expression declined and the expression of MHCslow and MHC2A increased. At term, the DIA MHC phenotype was a composite of MHCemb/neo (15% of the total MHC complement), MHCslow (32%), MHC2A (47%), and MHC2B (6%); whereas, the GG was largely comprised of MHC2A (74%). We conclude that human DIA and GG demonstrate temporally dependent changes in MHC expression during gestation- and muscle-specific MHC phenotypes as they approach term.

Bringing reality to the job hunt process. Interview by Barbara J. Linney.

A substantial percentage of the positions that open in medical management are filled through the use of recruitment firms. This is especially true of more senior positions, but it applies across the full spectrum of openings. If the working arrangement between the recruitment firm and the potential candidate is to be effective, certain key ingredients are necessary. The author interviewed a selection of principals of recruitment firms that operate extensively or exclusively in the medical management sector of executive recruitment. What she discovered about their "wish lists" for candidates' characteristics and levels of job hunting sophistication are summarized in the following statements.