Preliminary studies of pest constraints to cotton seedlings in a direct seeding mulch-based system in Cameroon

The present study evaluated the pest constraints of an innovative crop management system in Cameroon involving conservation tillage and direct seeding mulch-based strategies. We hypothesized that the presence of mulch (i) would support a higher density of phytophagous arthropods particularly millipedes as well as pathogenic fungi that cause severe damage to cotton seedlings and (ii) would reduce early aphid infestations. The impact of two cover-crop mulches Calopogonium mucunoides and Brachiaria ruziziensis on the vigour of seedling cotton stands and arthropod damage was assessed in two independent field experiments conducted in 2001 and 2002 respectively. In both experiments the presence of mulch negatively affected cotton seedling stand by 13–14% compared to non-mulched plots and the proportion of damaged seedlings was higher in mulched than in non-mulched plots supporting the hypothesis that mulch favoured soil pest damage. In both experiments insecticidal seed dressing increased the seedling stand and the number of dead millipedes collected and fungicide had little or no effect on seedling stand and vigour. It was however observed in 2002 that the fungicide seed dressing had a positive effect on seedling stand in non-mulched plots but not in mulched plots suggesting that fungi may have been naturally inhibited by B. ruziziensis mulch. The dynamics of aphid colonization was not influenced by the presence of mulch. In 2001 taller seedlings were found in mulched than non-mulched plots probably due to greater water and nutrient availability in C. mucunoides-mulched plots than in non-mulched plot

Caractérisation de la fertilité du sol en fonction des mauvaises herbes présentes

Soil Fertility Characterization Based on Present Weed Specie. In order to determine the soil fertility level using weed indicators, a study was conducted in 4 villages in northern Cameroon. It was based on farmers' interviews and fi eld surveys. It appears that the soil fertility status can be determined by using two groups of weeds: "guide" weeds, orienting the diagnosis according to their relative importance; "indicator" weeds, used to discriminate the two soil types (fertile/ degraded). Presence or absence of the identifi ed species allows farmers to determine whether the plot is fertile or degraded. He can then decide to use the fi eld or not

Climate changes and farmers’ endogenous adaptation strategies: Socio economic analysis of the dynamic use of agricultural lands in central region of Benin

There is an increasing consensus that in the next decades climate changes will generate yield decrease in low income countries. So will it be in Benin. It has been claimed that climate changes impact studies often assumecertain adaptations and little explicit examination of how, when, why, and under what conditions they occur. This research aims at analysing the endogenous strategies developed by farmers in agricultural land and crop management. With random stratified sampling, 70 farmers of two villages were selected according to their level of vulnerability. Actors based mapping and R-coefficients of Ruthenberg were used to analyse the evolution of existing farming systems. This paper shows that poor farmers of the central region of Benin are developing many endogenous coping strategies: adopting new crops and cultivating more waterlogged ecologies. Though, adaptation options are determined by vulnerability level of farmers. Management and valorisation skills of farmers in low land are to be enhanced for a sustainable agriculture in the future

Conjugate 18cm OH Satellite Lines at a Cosmological Distance

We have detected the two 18cm OH satellite lines from the $z \sim 0.247$ source PKS1413+135, the 1720 MHz line in emission and the 1612 MHz line in absorption. The 1720 MHz luminosity is $L_{\rm OH} \sim 354 L_\odot$, more than an order of magnitude larger than that of any other known 1720 MHz maser. The profiles of the two satellite lines are conjugate, implying that they arise in the same gas. This allows us to test for any changes in the values of fundamental constants, without being affected by systematic uncertainties arising from relative motions between the gas clouds in which the different lines arise. Our data constrain changes in $G \equiv g_p [\alpha^2/y]^{1.849}$, where $y \equiv m_e/m_p$; we find $\Delta G/G = 2.2 \pm 3.8 \times 10^{-5}$, consistent with no changes in $\alpha$, $g_p$ and $y$.Comment: 5 pages, 1 figure. Minor changes to match published versio

Key ethical issues discussed at CDC-sponsored international, regional meetings to explore cultural perspectives and contexts on pandemic influenza preparedness and response

Background: Recognizing the importance of having a broad exploration of how cultural perspectives may shape thinking about ethical considerations, the Centers for Disease Control and Prevention (CDC) funded four regional meetings in Africa, Asia, Latin America, and the Eastern Mediterranean to explore these perspectives relevant to pandemic influenza preparedness and response. The meetings were attended by 168 health professionals, scientists, academics, ethicists, religious leaders, and other community members representing 40 countries in these regions. Methods: We reviewed the meeting reports, notes and stories and mapped outcomes to the key ethical challenges for pandemic influenza response described in the World Health Organization’s (WHO’s) guidance, Ethical Considerations in Developing a Public Health Response to Pandemic Influenza: transparency and public engagement, allocation of resources, social distancing, obligations to and of healthcare workers, and international collaboration. Results: The important role of transparency and public engagement were widely accepted among participants. However, there was general agreement that no “one size fits all” approach to allocating resources can address the variety of economic, cultural and other contextual factors that must be taken into account. The importance of social distancing as a tool to limit disease transmission was also recognized, but the difficulties associated with this measure were acknowledged. There was agreement that healthcare workers often have competing obligations and that government has a responsibility to assist healthcare workers in doing their job by providing appropriate training and equipment. Finally, there was agreement about the importance of international collaboration for combating global health threats. Conclusion: Although some cultural differences in the values that frame pandemic preparedness and response efforts were observed, participants generally agreed on the key ethical principles discussed in the WHO’s guidance. Most significantly the input gathered from these regional meetings pointed to the important role that procedural ethics can play in bringing people and countries together to respond to the shared health threat posed by a pandemic influenza despite the existence of cultural differences

The Role of Pressure in GMC Formation II: The H_2 - Pressure Relation

We show that the ratio of molecular to atomic gas in galaxies is determined by hydrostatic pressure and that the relation between the two is nearly linear. The pressure relation is shown to be good over three orders of magnitude for 14 galaxies including dwarfs, HI-rich, and H_2-rich galaxies as well as the Milky Way. The sample spans a factor of five in mean metallicity. The rms scatter of individual points of the relation is only about a factor of two for all the galaxies, though some show much more scatter than others. Using these results, we propose a modified star formation prescription based on pressure determining the degree to which the ISM is molecular. The formulation is different in high and low pressure regimes defined by whether the gas is primarily atomic or primarily molecular. This formulation can be implemented in simulations and provides a more appropriate treatment of the outer regions of spiral galaxies and molecule-poor systems such as dwarf irregulars and damped Lyman-alpha systems.Comment: 14 pages, 7 figures, Accepted to the Astrophysical Journa

CLIMATE CHANGES AND FARMERS\u2019 ENDOGENOUS ADAPTATION STRATEGIES: SOCIO ECONOMIC ANALYSIS OF THE DYNAMIC USE OF AGRICULTURAL LANDS IN CENTRAL REGION oF BENIN

There is an increasing consensus that in the next decades climate changes will generate yield decrease in low income countries. So will it be in Benin. It has been claimed that climate changes impact studies often assume certain adaptations and little explicit examination of how, when, why, and under what conditions they occur. This research aims at analysing the endogenous strategies developed by farmers in agricultural land and crop management. With random stratified sampling, 70 farmers of two villages were selected according to their level of vulnerability. Actors based mapping and R-coefficients of Ruthenberg were used to analyse the evolution of existing farming systems. This paper shows that poor farmers of the central region of Benin are developing many endogenous coping strategies: adopting new crops and cultivating more waterlogged ecologies. Though, adaptation options are determined by vulnerability level of farmers. Management and valorisation skills of farmers in low land are to be enhanced for a sustainable agriculture in the future.Il y a un consensus croissant dans la litt\ue9rature scientifique sur le fait que dans les prochaines d\ue9cennies, les changements climatiques vont faire chuter les r\ue9coltes dans les pays \ue0 faibles revenus. Le B\ue9nin ne fera pas exception. Les \ue9tudes sur les impacts des changements climatiques r\ue9pertorient certaines mesures d\u2019adaptation, mais peu examinent comment, quand, pourquoi et sous quelles conditions elles sont intervenues. Cette \ue9tude a eu pour objectif d\u2019analyser les strat\ue9gies d\u2019adaptation d\ue9velopp\ue9es par les producteurs dans la gestion des terres et des cultures. A partir d\u2019un \ue9chantillonnage al\ue9atoire stratifi\ue9, 70 producteurs ont \ue9t\ue9 s\ue9lectionn\ue9s dans deux villages. Les cartes \ue0 dires d\u2019acteurs et le coefficient R de Ruthenberg ont \ue9t\ue9 utilis\ue9s pour analyser l\u2019\ue9volution des syst\ue8mes de culture. Cette \ue9tude r\ue9v\ue8le que les producteurs du centre B\ue9nin d\ue9veloppent de nombreuses strat\ue9gies endog\ue8nes d\u2019adaptation comme : l\u2019adoption de nouvelles cultures et l\u2019exploitation des bas fonds. Mais les options d\u2019adaptation sont d\ue9termin\ue9es par le niveau de vuln\ue9rabilit\ue9s. Le renforcement des capacit\ue9s des producteurs, pour am\ue9nager ces bas fonds, doit \ueatre envisag\ue9 pour une agriculture plus durable