Farmer experience of pluralistic agricultural extension, Malawi

Purpose: Malawi’s current extension policy supports pluralism and advocates responsiveness to farmer demand. We investigate whether smallholder farmers’ experience supports the assumption that access to multiple service providers leads to extension and advisory services that respond to the needs of farmers. Design/methodology/approach: Within a case study approach, two villages were purposively selected for in-depth qualitative analysis of available services and farmers’ experiences. Focus group discussions were held separately with male and female farmers in each village, followed by semi-structured interviews with 12 key informants selected through snowball sampling. Transcripts were analysed by themes and summaries of themes were made from cross case analysis. Findings: Farmers appreciate having access to a variety of sources of technical advice and enterprise specific technology. However, most service providers continue to dominate and dictate what they will offer. Market access remains a challenge, as providers still emphasize pushing a particular technology to increase farm productivity rather than addressing farmers’ expressed needs. Although farmers work in groups, providers do not seek to strengthen these to enable active interaction and to link them to input and produce markets. This limits farmers’ capacity to continue with innovations after service providers pull out. Poor coordination between providers limits exploitation of potential synergies amongst actors. Practical implications: Services providers can adapt their approach to engage farmers in discussion of their needs and work collaboratively to address them. At a system level, institutions that have a coordination function can play a more dynamic role in brokering interaction between providers and farmers to ensure coverage and responsiveness. Originality/value: The study provides a new farmer perspective on the implementation of extension reforms.

Olive leaf phenolics and cardiovascular risk reduction: Physiological effects and mechanisms of action

Olive oil, an important component of the Mediterranean diet, is rich in polyphenols and is known to possess positive health effects relative to other dietary fats. In addition, the leaves of the olive plant (Olea europaea) contain similar phenolics (oleuropein, luteolin-7-glucoside, apigenin-7-glucoside, verbascoside and hydroxytyrosol) to those of olives and olive oil, although at higher concentrations. For example, the most abundant is the secoiridoid, oleuropein, representing 1–14% of olive leaf weight vs. 0.005–0.12% in olive oil. Although currently considered a waste product of the olive oil industry, recent research has suggested beneficial effects of phenolic-rich olive leaf extracts (OLE) in modifying cardiovascular risk biomarkers such as blood pressure, hyperglycaemia, oxidative stress and inflammation, as well as improving vascular function and lipid profiles. Despite this, data regarding the biological actions of OLE has mostly derived from animal, in vitro and ex vivo studies, with limited evidence deriving from human trials. Although the absorption and metabolism of olive oil phenolics has been investigated, less is known about the bioavailability of phenolics from OLE, limiting the interpretation of existing in vitro and ex vivo data. The current review will begin by describing the phenolic composition of olive leaves in comparison with that of the better studied olive oil. It will then review the effects of OLE on cardiovascular risk factors, covering both animal and human studies and will end by considering potential mechanisms of action

Demand, supply and willingness-to-pay for extension services in an emerging-market setting

Although it may be wholly inappropriate to generalize, the most important resource available to a subsistence household is the total amount of time that its members have available to spend in productive enterprises. In this context, services that minimize the time that it takes to perform productive activities are valuable to the household. Consequently the household is willing to relinquish quantities of other resources in exchange for quantities of the time-saving service. These simple observations motivate a search for the values that subsistence households place on time-saving services. This search is especially important when it is realized that extension services promote productivity, enhance the surplus-generating potential of the household and can, as a consequence, promote immersion into markets that are currently constrained by thinness and instability. In this capacity, extension visitation has the potential to overcome one of the principal impediments to economic development, namely lack of density of market participation. In this article, we consider this issue in the context of a rich data set on milk-market participation by small-holder dairy producers in the Ethiopian highlands.

The influence of powdery mildew infection on photosynthesis, chlorophyll fluorescence, leaf chlorophyll and carotenoid content of three woody plant species

The effect of powdery mildew development on photosynthesis, chlorophyll fluorescence, leaf chlorophyll and carotenoid concentrations on three woody plants frequently planted in urban environments was studied. Rates of photosynthetic CO2 fixation were rapidly reduced in two of the three genotypes tested prior to visible signs of infection. Effects on chlorophyll fluorescence (Fo, Fv/Fo, Fv/Fm), leaf chlorophyll and carotenoid content were not manifest until >25 per cent of the leaf area was observed to be covered by mycelial growth indicating reduced photo-synthetic rates during the early stages of infection were not due to degradation of the leaf chloroplast structure. Observation of the fluorescence transient (OJIP curves) showed powdery mildew infection impairs photosynthetic electron transport system by reducing the size but not heterogeneity of the plastoquninone pool, effecting both the acceptor and donor side of photosystem II. Impairment of the photosynthetic electron transport system was reflected by reduced values of a performance index used in this investigation as a measure of photochemical events within photosystem II electron transport. In addition interpretation of the fluorescence data indicated powdery mildew infection may impair the photo-protective process that facilitates the dissipation of excess energy within leaf tissue.

Can valuation factors be prescribed? The case of collective enfranchisement and leasehold extension of flats in England and Wales

Recent concerns over the valuation process in collective leasehold enfranchisement and lease extension cases have culminated in new legislation. To underpin this, the Government (Department of Environment Transport and the Regions (DETR)) commissioned new research, which examined whether the valuation of the freehold in such cases could be simplified through the prescription of either yield or marriage value/relativity. This paper, which is based on that research, examines whether it is possible or desirable to prescribe such factors in the valuation process. Market, settlement and Local Valuation Tribunal (LVT) decisions are analysed, and the basis of 'relativity charts' used in practice is critically examined. Ultimately the imperfect nature of the market in freehold investment sales and leasehold vacant possession sales means that recommendations must rest on an analysis of LVT data. New relativity curves are developed from this data and used in conjunction with an alternative approach to valuation yields (based on other investment assets). However, the paper concludes that although the prescription of yields and relativity is possible, it is not fully defensible because of problems in determining risk premia; that the evidential basis for relativity consists of LVT decisions; and that a formula approach would tend to 'lead' the market as a whole.

Tackling regional climate change by leaf albedo bio-geoengineering

The likelihood that continuing greenhouse-gas emissions will lead to an unmanageable degree of climate change [1] has stimulated the search for planetary-scale technological solutions for reducing global warming [2] (“geoengineering”), typically characterized by the necessity for costly new infrastructures and industries [3]. We suggest that the existing global infrastructure associated with arable agriculture can help, given that crop plants exert an important influence over the climatic energy budget 4 and 5 because of differences in their albedo (solar reflectivity) compared to soils and to natural vegetation [6]. Specifically, we propose a “bio-geoengineering” approach to mitigate surface warming, in which crop varieties having specific leaf glossiness and/or canopy morphological traits are specifically chosen to maximize solar reflectivity. We quantify this by modifying the canopy albedo of vegetation in prescribed cropland areas in a global-climate model, and thereby estimate the near-term potential for bio-geoengineering to be a summertime cooling of more than 1°C throughout much of central North America and midlatitude Eurasia, equivalent to seasonally offsetting approximately one-fifth of regional warming due to doubling of atmospheric CO2[7]. Ultimately, genetic modification of plant leaf waxes or canopy structure could achieve greater temperature reductions, although better characterization of existing intraspecies variability is needed first.

Evidence of a universal scaling relationship for leaf CO2 drawdown along an aridity gradient

The leaf carbon isotope ratio (δ13C) of C3 plants is inversely related to the drawdown of CO2 concentration during photosynthesis, which increases towards drier environments. We aimed to discriminate between the hypothesis of universal scaling, which predicts between-species responses of δ13C to aridity similar to within-species responses, and biotic homoeostasis, which predicts offsets in the δ13C of species occupying adjacent ranges. The Northeast China Transect spans 130–900 mm annual precipitation within a narrow latitude and temperature range. Leaves of 171 species were sampled at 33 sites along the transect (18 at ≥ 5 sites) for dry matter, carbon (C) and nitrogen (N) content, specific leaf area (SLA) and δ13C. The δ13C of species generally followed a common relationship with the climatic moisture index (MI). Offsets between adjacent species were not observed. Trees and forbs diverged slightly at high MI. In C3 plants, δ13C predicted N per unit leaf area (Narea) better than MI. The δ13C of C4 plants was invariant with MI. SLA declined and Narea increased towards low MI in both C3 and C4 plants. The data are consistent with optimal stomatal regulation with respect to atmospheric dryness. They provide evidence for universal scaling of CO2 drawdown with aridity in C3 plants.

Relative values: residential leasehold reform in England and Wales - valuation of lease extension and enfranchisement

This research report was commissioned by the DETR and examines valuation issues relating to leasehold enfanchisement and lease extension - the right for flat owners to collectively purchase the freehold or buy a longer lease. The two factors examined examined in detail are the yield to be applied when capitalising the ground rent and the relative value of leases with a relatively short period left to run as against the value of the freehold or a new long lease, which determines the level of 'marriage level'. The research report will be of interest to all those involved in the valuation of residential leasehold property and those with an interest in legislative proposals for leasehold reform.

Elevated atmospheric CO2 and humidity delay leaf fall in Betula pendula, but not in Alnus glutinosa or Populus tremula × tremuloides

Context: Anthropogenic activity has increased the level of atmospheric CO2, which is driving an increase of global temperatures and associated changes in precipitation patterns. At Northern latitudes, one of the likely consequences of global warming is increased precipitation and air humidity. Aims: In this work, the effects of both elevated atmospheric CO2 and increased air humidity on trees commonly growing in northern European forests were assessed. Methods: The work was carried out under field conditions by using Free Air Carbon dioxide Enrichment (FACE) and Free Air Humidity Manipulation (FAHM) systems. Leaf litter fall was measured over 4 years (FACE) or 5 years (FAHM) to determine the effects of FACE and FAHM on leaf phenology. Results: Increasing air humidity delayed leaf litter fall in Betula pendula, but not in Populus tremula × tremuloides. Similarly, under elevated atmospheric CO2, leaf litter fall was delayed in Betula pendula, but not in Alnus glutinosa. Increased CO2 appeared to interact with periods of low precipitation in summer and high ozone levels during these periods to effect leaf fall. Conclusions: This work shows that increased CO2 and humidity delay leaf fall, but this effect is species specific.

Use of mutants to dissect the role of ethylene signalling in organ senescence and the regulation of yield in Arabidopsis thaliana

The role of ethylene in regulating organ senescence in Arabidopsis has been investigated by studying the development of mutants that have an attenu- ated capacity to perceive the gas. The onset of leaf senescence and floral organ abscission was delayed in the ethylene-insensitive mutant etr1. The photosynthetic life span of rosette leaves was similarly extended in the gain- of-function mutant ers2, and this mutant also exhibited a delay in the timing of pod dehiscence primarily as a con- sequence of an extension in the final stages of senescence. A detailed analysis of yield revealed that whilst thousand grain weight was increased, by as much as 20 %, in etr1, ein4, and the loss-of-function mutant etr2, only the latter showed a significant increase in total weight of seeds produced per plant. The other studied mutants exhibited a reduction in total seed yield of almost 40 %. These observations are discussed in the context of the possible role of ethylene in regulating organ senescence and their significance in the breeding of crop plants with enhanced phenotypic characteristics.

Extension of the TAMSAT satellite-based rainfall monitoring over Africa and from 1983 to present

Tropical Applications of Meteorology Using Satellite Data and Ground-Based Observations (TAMSAT) rainfall monitoring products have been extended to provide spatially contiguous rainfall estimates across Africa. This has been achieved through a new, climatology-based calibration, which varies in both space and time. As a result, cumulative estimates of rainfall are now issued at the end of each 10-day period (dekad) at 4-km spatial resolution with pan-African coverage. The utility of the products for decision making is improved by the routine provision of validation reports, for which the 10-day (dekadal) TAMSAT rainfall estimates are compared with independent gauge observations. This paper describes the methodology by which the TAMSAT method has been applied to generate the pan-African rainfall monitoring products. It is demonstrated through comparison with gauge measurements that the method provides skillful estimates, although with a systematic dry bias. This study illustrates TAMSAT’s value as a complementary method of estimating rainfall through examples of successful operational application.

Preliminary leaf area index estimates from airborne small footprint full-waveform LiDAR data

This study has compared preliminary estimates of effective leaf area index (LAI) derived from fish-eye lens photographs to those estimated from airborne full-waveform small-footprint LiDAR data for a forest dataset in Australia. The full-waveform data was decomposed and optimized using a trust-region-reflective algorithm to extract denser point clouds. LAI LiDAR estimates were derived in two ways (1) from the probability of discrete pulses reaching the ground without being intercepted (point method) and (2) from raw waveform canopy height profile processing adapted to small-footprint laser altimetry (waveform method) accounting for reflectance ratio between vegetation and ground. The best results, that matched hemispherical photography estimates, were achieved for the waveform method with a study area-adjusted reflectance ratio of 0.4 (RMSE of 0.15 and 0.03 at plot and site level, respectively). The point method generally overestimated, whereas the waveform method with an arbitrary reflectance ratio of 0.5 underestimated the fish-eye lens LAI estimates.

K-Surfer: a KNIME extension for the management and analysis of Human brain MRI FreeSurfer/FSL data

Human brain imaging techniques, such as Magnetic Resonance Imaging (MRI) or Diffusion Tensor Imaging (DTI), have been established as scientific and diagnostic tools and their adoption is growing in popularity. Statistical methods, machine learning and data mining algorithms have successfully been adopted to extract predictive and descriptive models from neuroimage data. However, the knowledge discovery process typically requires also the adoption of pre-processing, post-processing and visualisation techniques in complex data workflows. Currently, a main problem for the integrated preprocessing and mining of MRI data is the lack of comprehensive platforms able to avoid the manual invocation of preprocessing and mining tools, that yields to an error-prone and inefficient process. In this work we present K-Surfer, a novel plug-in of the Konstanz Information Miner (KNIME) workbench, that automatizes the preprocessing of brain images and leverages the mining capabilities of KNIME in an integrated way. K-Surfer supports the importing, filtering, merging and pre-processing of neuroimage data from FreeSurfer, a tool for human brain MRI feature extraction and interpretation. K-Surfer automatizes the steps for importing FreeSurfer data, reducing time costs, eliminating human errors and enabling the design of complex analytics workflow for neuroimage data by leveraging the rich functionalities available in the KNIME workbench.