Analysis of the interactions of shade trees on coffee leaf diseases and coffee yield in complex agroforestry systems

In complex coffee-based agroforestry, quantifying interactions within the agrosystem that impact on coffee disease regulation and on coffee yield is a major stake to design sustainable cropping systems. To this end, we analyzed the interaction network between shade trees, coffee trees (Catimor variety), coffee foliar diseases complex (CFDC; majority of Mycena citricolor) and soil characteristics. The system is characterized by 40 variables measured in 60 plots spread on three farms (monitored for 2 years) in Nicaragua. We used Partial Least Square Path Modeling (PLSPM) to study the network interaction. We built 6 blocks with the more significant variables of each component: shade trees (shade percentage, species), soil (Cation Exchange Capacity, P), CFDC (incidence, severity), coffee trees age and size, coffee growth and coffee yield. The second part of the PLSPM was performed between blocks. Shade trees, mostly the shade percentage, had direct positive effects on CFDC and soil quality, and negative effects on coffee growth and yield. Shade had also an indirect negative effect on coffee trees by increasing CFDC, which impedes coffee growth and yield. Soil variables being negatively related to CFDC, shade had an indirect effect on coffee trees. Reducing excessive shade cover seems to be a solution to enhance positive impacts of shade trees on coffee yield. Overall, shade management requires an analysis of trade-offs between soil quality, diseases regulation and yield gains

Catharine Macaulay's influence on Mary Wollstonecraft

Although they were never to meet and corresponded only briefly, Catharine Macaulay and Mary Wollstonecraft shared a mutual admiration and a strong intellectual bond. Macaulay’s work had a profound and lasting effect on Wollstonecraft, and she developed and expanded on many of Macaulay’s ideas. While she often took these in a different direction, there remains a great synergy between their ideas to the extent that we can understand Wollstonecraft’s own feminist arguments by approaching them through the frameworks and ideas that Macaulay provided. These included the principles of classical republicanism, particularly in its understanding of the values of freedom, equality and virtue, and an understanding of reason as grounded in immutable principles that apply equally to both sexes. On the question of women’s freedom and social equality with men, I argue that though Macaulay sets up the problem in far richer and more detailed philosophical terms, in the end it is Wollstonecraft that has the more compelling account of its far-reaching social implications and of how this might be addressed

Molecular Genetic Diversity Study of Forest Coffee Tree (Coffea arabica L.) Populations in Ethiopia: Implications for Conservation and Breeding

Coffee provides one of the most widely drunk beverages in the world, and is a very important source of foreign exchange income for many countries. Coffea arabica, which contributes over 70 percent of the world's coffee productions, is characterized by a low genetic diversity, attributed to its allopolyploidy origin, reproductive biology and evolution. C. arabica has originated in the southwest rain forests of Ethiopia, where it is grown under four different systems, namely forest coffee, small holders coffee, semi plantation coffee and plantation coffee. Genetic diversity of the forest coffee (C. arabica) gene pool in Ethiopia is being lost at an alarming rate because of habitat destruction (deforestation), competition from other cash crops and replacement by invariable disease resistant coffee cultivars. This study focused on molecular genetic diversity study of forest coffee populations in Ethiopia using PCR based DNA markers such as random amplified polymorphic DNA (RAPD), inverse sequence-tagged repeat (ISTR), inter-simple sequence repeats (ISSR) and simple sequence repeat (SSR) or microsatellites. The objectives of the study are to estimate the extent and distribution of molecular genetic diversity of forest coffee and to design conservation strategies for it’s sustainable use in future coffee breeding. In this study, considerable samples of forest coffee collected from four coffee growing regions (provinces) of Ethiopia were analysed. The results indicate that moderate genetic diversity exists within and among few forest coffee populations, which need due attention from a conservation and breeding point of view. The cluster analysis revealed that most of the samples from the same region (province) were grouped together which could be attributed to presence of substantial gene flow between adjacent populations in each region in the form of young coffee plants through transplantation by man. In addition wild animals such as monkeys also play a significant role in coffee trees gene flow between adjacent populations. The overall variation of the forest coffee is found to reside in few populations from each region. Therefore, considering few populations from each region for either in situ or ex situ conservation may preserve most of the variation within the species. For instance, Welega-2, Ilubabor-2, Jima-2 and Bench Maji-2 populations should be given higher priority. In addition, some populations or genotypes have displayed unique amplification profiles particularly for RAPD and ISTR markers. Whether these unique bands are linked to any of the important agronomic traits and serve in marker assisted selections in future coffee breeding requires further investigations

A Radical Revolution in Thought: Frederick Douglass on the Slave’s Perspective on Republican Freedom

While the image of the slave as the antithesis of the freeman is central to republican freedom, it is striking to note that slaves themselves have not contributed to how this condition is understood. The result is a one-sided conception of both freedom and slavery, which leaves republicanism unable to provide an equal and robust protection for historically outcast people. I draw on the work of Frederick Douglass – long overlooked as a significant contributor to republican theory – to show one way why this is so. Focusing the American Revolution, the subsequent republican government established new political institutions to maintain the collective interests of the whole population. The political revolution was held in place by processes of public reason that reflected the values and ideas of the people that had rebelled. The black population, however, had not been part of this revolution. After emancipation, black Americans were required to accept terms of citizenship that had already been defined, leaving them socially dominated, subject to the prejudices and biases within the prevailing ideas of public discourse. Douglass argued that republican freedom under law is always dependent on a more fundamental revolution, that he calls a ‘radical revolution in thought’, in which the entire system of social norms and practices are reworked together by members of all constituent social groups – women and men, black and white, rich and poor – so that it reflects a genuinely collaborative achievement. Only then can we begin the republican project of contestatory freedom as independence or non-domination that today’s republicans take for granted

Coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae: Scolytinae) removal in coffee plantations: a pest control service provided by birds

Coffee is one of the most important crops in tropical regions of the world, where areas suited for its production are usually immersed within important biodiversity conservation regions. Studies in these agricultural systems have proven its conservation value, particularly for bird species which provide us with an array of ecosystem services including seed dispersal, pollination, and pest control. Regulating ecosystem services such as pest control (MEA 2005) are especially important to quantify because their benefits can be perceived at smaller scales and directly by coffee growers. Positive effects of bird species in the removal of insects in coffee systems have already been established however fewer studies have focused specifically on the effect of bird species in the control of the coffee berry borer (cbb), one of the most damaging pests affecting coffee production worldwide. In order to assess this effect on January 2013 we set up an exclosure experiment in a Costa Rican coffee plantation where we randomly selected two coffee shrubs at ten different coffee plots, one of the coffee shrubs was then isolated from bird foraging activity by a plastic mesh preventing the entrance of birds but allowing insects to fly in and out. Brocap traps were installed at each one of the ten coffee plots to monitored cbb flights/availability, bird community was evaluated via point counts and mistnetting and direct evidence of predation was obtained through the identification of cbb DNA in fecal and emesis samples. Results show that 25% out of 117 bird species detected within our sampling units are exclusively insectivorous birds while 55% include invertebrates as part of their diet. Trapping of cbb indicated several episodes of flights/availability of the pest throughout the year. Coffee berry borer infestation rates were significantly higher in coffee shrubs excluded in comparison with coffee shrubs exposed to bird foraging activity (F=23.40, p=0.0019). Preliminary DNA analysis shows evidence of insectivorous bird species predating on the genus Hypothenemus. Our findings provide further evidence on the potential contribution of insectivorous bird species in the removal and control of the coffee berry borer in coffee systems and highlight the importance of further studies using molecular biology techniques that allow to quantify the amount of cbb consumed by birds on a given moment as well as the economic importance of this service. (Texte intégral

Impact of consumer behavior on furan and furan-derivative exposure during coffee consumption : a comparison between brewing methods and drinking preferences

This study examined the influence of consumer behavior on furan, 2-methylfuran, 3-methylfuran, 2,5-dimethylfuran and 2,3-dimethylfuran exposure in coffee. Coffees brewed using a filter, fully automatic, capsule machine or reconstituted instant coffee were found to have a significant different cup concentrations of furan derivatives. Coffee brewed with the fully automatic machine contained the highest furan and furan derivative concentrations (99.05 µg/L furan, 263.91 µg/L 2-methylfuran, 13.15 µg/L 3-methylfuran and 8.44 µg/L 2,5-dimethylfuran) whereas soluble coffee did not contain detectable levels, thereby contributing least to a consumer’s dietary exposure. Furan and furan derivative concentrations were found to decrease significantly upon cooling, reducing consumer exposure by 8.0-17.2% on average once the coffee reached drinking temperature 55-60°C, in ceramic cups. Serving coffee in a ceramic or disposable cup were found to influence the cooling dynamics of the coffee but did not statistically influence the consumers exposure at a given temperature

Coffee consumption and prostate cancer risk: further evidence for inverse relationship

<p>Abstract</p> <p>Background</p> <p>Higher consumption of coffee intake has recently been linked with reduced risk of aggressive prostate cancer (PC) incidence, although meta-analysis of other studies that examine the association between coffee consumption and overall PC risk remains inconclusive. Only one recent study investigated the association between coffee intake and grade-specific incidence of PC, further evidence is required to understand the aetiology of aggressive PCs. Therefore, we conducted a prospective study to examine the relationship between coffee intake and overall as well as grade-specific PC risk.</p> <p>Methods</p> <p>We conducted a prospective cohort study of 6017 men who were enrolled in the Collaborative cohort study in the UK between 1970 and 1973 and followed up to 31st December 2007. Cox Proportional Hazards Models were used to evaluate the association between coffee consumption and overall, as well as Gleason grade-specific, PC incidence.</p> <p>Results</p> <p>Higher coffee consumption was inversely associated with risk of high grade but not with overall risk of PC. Men consuming 3 or more cups of coffee per day experienced 55% lower risk of high Gleason grade disease compared with non-coffee drinkers in analysis adjusted for age and social class (HR 0.45, 95% CI 0.23-0.90, p value for trend 0.01). This association changed a little after additional adjustment for Body Mass Index, smoking, cholesterol level, systolic blood pressure, tea intake and alcohol consumption.</p> <p>Conclusion</p> <p>Coffee consumption reduces the risk of aggressive PC but not the overall risk.</p

Nitrogen fixing shade trees in coffee agroforestry: Quantification of nitrogen transfer to the coffee plant

Nitrogen-fixing shade trees in coffee agroforestry systems are assumed to provide an alternative nitrogen source for the coffee crop when fertilizer applications are low, but the transfer of nitrogen from shade trees to the coffee crop has not yet been quantified directly. We present a case study for coffee agroforestry systems with Erythrina poeppigiana as a shade tree. The transfer of nitrogen from the N2 fixing tree to coffee plants was measured through a stable isotope pulse and chase experiment. Shade trees that had been labelled with a 15N-enriched nitrate solution, were pruned, and the prunings were subsequently laid out below coffee crops under conventional or organic management. Significant fractions of nitrogen ended up in the coffee plants 5 months after the deposition of 15N labelled prunings on the plantation floor (figure 1). More nitrogen from prunings was found in the soil under organic management than under conventional management. This finding was associated with higher macrofauna abundance, particularly earthworms, in the organic system. Coppicing of the shade tree and subsequent decomposition of the pruned material was the dominant mechanism for nitrogen transfer to the coffee plant, while other mechanisms only affected coffee plants directly neighbouring the tree. In conclusion, the pruning of shade trees in coffee agroforestry systems is an important pathway for the transfer of fixed N to the coffee plants and seems to be essential in organic systems