Etude de la culture en couloirs de manioc (Manihot esculenta CRANTZ) à base de Gliricidia sepium en Côte d’Ivoire

L’objectif de l’étude est de recommander aux paysans un système de production de manioc à la fois rentable et préservatrice de l’environnement. Pour atteindre cet objectif, deux systèmes améliorés de culture en couloirs (manioc amélioré Yavo/soja vert (Mung bean)/Gliricidia sepium avec un apport de fumure de fond minérale_200 kg/ha de NPK_10-18-18 ou organique_10 t/ha de fiente de poule) ont été mis en compétition avec le système traditionnel (association manioc local/arachide). Les systèmes de culture en couloirs ont bien couvert le sol comparativement au système traditionnel. Les taux moyens de débourrage du manioc ont varié de 80,15 à 82,03% pour la variété locale et de 80,11 à 75,08% pour la variété Yavo. Ces taux ont montré des interactions site x variété significatives et des interactions année x site très hautement significatifs. La culture en couloirs a enregistré un rendement moyen général en racines tubéreuses fraîches de 40 t/ha contre 13 t/ha dans le système traditionnel. Elle a permis d’augmenter le rendement du manioc de 27 t/ha. La culture en couloirs pourrait constituer une solution intéressante de remplacement du système traditionnel. Il est donc possible d’obtenir des rendements élevés à l’unité de surface grâce à la culture en couloirs de manioc.Mots-clés : manioc, Yavo, gliricidia sepium, soja vert, culture en couloirs, Côte d’Ivoire

Exploitation of trophic resources by fish under stressful estuarine conditions

Despite the high complexity and variability of estuaries, these ecosystems are very productive and play an important role in fish feeding. This paper constitutes a preliminary investigation to test how fish optimize the use of the available trophic resources, by studying trophic preference variability and feeding strategies of some pelagic and demersal fish in the Gironde estuary (southwest France). Fish and their prey were collected approximately every two months from July 2003 to June 2004 in the upstream area of the saline estuary. Stomach content analyses were realized to describe the variability of fish feeding according to their size and the time of year. Intra- and interspecific food niche overlap was evaluated using Schoener's index and a cross-calculation method was used to highlight the general fish trends in predation strategy. Stomach content results showed interspecific and intraspecific variability in fish feeding, which can be explained by their different or evolutionary ecomorphology. Their diets are composed mainly of zooplankton and hyperbenthic crustaceans with temporal variations in the consumed taxa. Optimization of the available trophic resource use, a key element in estuarine resilience, is thus possible due to the temporal adaptation of this structural trophic web. However, in spite of their temporal adaptation capacity, most fish species exhibited a specialist feeding strategy. This result was not expected, especially in the high turbidity of the Gironde estuary; the loss of one of these species could affect the fish trophic web structure and hence the resilience of the system

Effect of a legume cover crop on carbon storage and erosion in an ultisol under maize cultivation in southern Benin

Field experiment was conducted from 1988 to 1999 at an experimental farm at Agonkanmey, near Cotonou in southern Benin, to study the effect of relay-cropping maize through Mucuna pruriens (var. utilis). The relay-cropping system was compared with traditional maize cropping system without any input, and with a maize cropping system with mineral fertilizers (NPK). Special attention was given on the changes in soil C during the period of the experiment in relation to residue biomass C returned to the soil, runoff and soil erosion losses, and loss of C with erosion. The soils are classified as sandy loam Typic Kandiustult. The general properties of these soils are given. For this soil type, relay cropping of maize and mucuna was very effective in enhancing C sequestration: change in Ct (total C content) stock for 0 to 40 cm depth was 1.3 t C/ha per year over the 12-year period of the experiment, ranging among the highest rates recorded for the eco-region. This increase resulted first from the high amount of residue biomass provided by mucuna, which amounted to 10 t DM/ha per year (83% aboveground). Mucuna residues, supplying the soil with N, also favoured the production of maize biomass, and total mucuna plus maize residue biomass returned to the soil was approximately 20 t/ha per year. In contrast, non-fertilized and fertilized continuous maize cultivation resulted in -0.2 and 0.2 t C/ha per year change in Ct stock for 0 to 40 cm depth, respectively. Total residue biomass was 8 and 13 t/ha per year, including 77 and 29% by weeds, respectively. Thick mulch produced by mucuna decreased losses by runoff and erosion, which were 0.28, 0.12 and 0.08 mm/mm and 34.0, 9.0 and 3.0 t/ha per year in unfertilized, fertilized with NPK and mucuna treatments, respectively. Eroded C was estimated at 0.3, 0.1 and 1.0 t C/ha per year in unfertilized, fertilized with NPK and mucuna treatments, respectively. Through its benefits on soil organic matter management, weed suppression and erosion control, cropping systems including a legume crop may have an adverse impact from a global change standpoint

Biomedical Co-Cr-Mo Components Produced by Direct Metal Laser Sintering

Direct Metal Laser Sintering (DMLS) is an additive manufacturing technique based on a laser power source that sinters powdered materials using a 3D CAD model. The mechanical components produced by this procedure typically show higher residual porosity and poorer mechanical properties than those obtained by traditional manufacturing techniques. In this study, samples were produced by DMLS starting from a Co-Cr-Mo powder (in the \u3b3 phase) with a composition suitable for biomedical applications. Samples were submitted to hardness measurements and structural characterization. The samples showed a hardness value remarkably higher that those commonly obtained for the same cast or wrought alloys. In fact, the HRC value measured for the samples is 47 HRC, while the usual range for CAST Co-Cr-Mo is from 25 to 35 HRC. The samples microstructure was investigated by X-ray diffraction (XRD), electron microscopy (SEM and TEM) and energy dispersive microanalysis (EDX) in order to clarify the origin of this unexpected result. The laser treatment induced a melting of the metallic Co-Cr-Mo powder, generating a phase transformation from the \u3b3 (fcc) to the e (hcp) phase. The rapid cooling of the melted powder produced the formation of e (hcp) nano-lamellae inside the \u3b3 (fcc) phase. The nano-lamellae formed an intricate network responsible for the measured hardness increase. The results suggest possible innovative applications of the DMLS technique to the production of mechanical parts in the medical and dental fields, where a high degree of personalization is required

Information Needs and Concerns of Patients with Inflammatory Bowel Disease: What Can We Learn from Participants in a Bilingual Clinical Cohort?

BACKGROUND: Inflammatory Bowel Disease (IBD) patients are confronted with needs and concerns related to their disease. AIM: To explore information expectations of patients included in a national bilingual IBD cohort in Switzerland (SIBDC). METHODS: This is a mixed-methods study, comprising 1) a semi-narrative survey sent to 1506 patients from the SIBDC and 2) two focus groups conducted with 14 patients to explore and assess the relevance of the survey's findings. Data collected within the framework of the SIBDC was used to characterize survey's responders. RESULTS: 728 patients (48%) replied to the survey: 52.5% females, 56% Crohn's disease (CD), 87% secondary/tertiary level educated, 70% full/part-time employed. On average, 47% of patients sought for information, regardless of the disease stage; 27% of them were dissatisfied with information received at the time of first symptoms. During flares, 43% were concerned about drugs and therapies; in remission, 57% had concerns on research and developments; 27% searched for information linked to daily disease management. Information-seeking increased when active disease, for CD with high levels of perceived stress (OR = 2.47; p = 0.003), and for all with higher posttraumatic stress symptoms. The focus groups confirmed a perceived lack of information about general functioning, disease course, treatments and their risks, extra-intestinal symptoms and manifestations. CONCLUSIONS: Information remains insufficient for IBD patients. Lack of information in specific domains can potentially cause stress and hinder detection of symptoms. Better information should be considered as a potentially important component in improving patients' outcomes in IBD

Effects of build orientation and element partitioning on microstructure and mechanical properties of biomedical Ti-6Al-4V alloy produced by laser sintering

Direct Metal Laser Sintering (DMLS) technology was used to produce tensile and flexural samples based on the Ti-6Al-4V biomedical composition. Tensile samples were produced in three different orientations in order to investigate the effect of building direction on the mechanical behavior. On the other hand, flexural samples were submitted to thermal treatments to simulate the firing cycle commonly used to veneer metallic devices with ceramics in dental applications. Roughness and hardness measurements as well as tensile and flexural mechanical tests were performed to study the mechanical response of the alloy while X-ray diffraction (XRD), electron microscopy (SEM, TEM, STEM) techniques and microanalysis (EDX) were used to investigate sample microstructure. Results evidenced a difference in the mechanical response of tensile samples built in orthogonal directions. In terms of microstructure, samples not submitted to the firing cycle show a single phase acicular α’ (hcp) structure typical of metal parts subject to high cooling rates. After the firing cycle, samples show a reduction of hardness and strength due to the formation of laths of the β (bcc) phase at the boundaries of the primary formed α’ plates as well as to lattice parameters variation of the hcp phase. Element partitioning during the firing cycle gives rise to high concentration of V atoms (up to 20 wt%) at the plate boundaries where the β phase preferentially forms

Embedding of Cortical Representations by the Superficial Patch System

Pyramidal cells in layers 2 and 3 of the neocortex of many species collectively form a clustered system of lateral axonal projections (the superficial patch system—Lund JS, Angelucci A, Bressloff PC. 2003. Anatomical substrates for functional columns in macaque monkey primary visual cortex. Cereb Cortex. 13:15-24. or daisy architecture—Douglas RJ, Martin KAC. 2004. Neuronal circuits of the neocortex. Annu Rev Neurosci. 27:419-451.), but the function performed by this general feature of the cortical architecture remains obscure. By comparing the spatial configuration of labeled patches with the configuration of responses to drifting grating stimuli, we found the spatial organizations both of the patch system and of the cortical response to be highly conserved between cat and monkey primary visual cortex. More importantly, the configuration of the superficial patch system is directly reflected in the arrangement of function across monkey primary visual cortex. Our results indicate a close relationship between the structure of the superficial patch system and cortical responses encoding a single value across the surface of visual cortex (self-consistent states). This relationship is consistent with the spontaneous emergence of orientation response-like activity patterns during ongoing cortical activity (Kenet T, Bibitchkov D, Tsodyks M, Grinvald A, Arieli A. 2003. Spontaneously emerging cortical representations of visual attributes. Nature. 425:954-956.). We conclude that the superficial patch system is the physical encoding of self-consistent cortical states, and that a set of concurrently labeled patches participate in a network of mutually consistent representations of cortical inpu

Health utility indexes in patients with acute coronary syndromes.

BACKGROUND: Acute coronary syndromes (ACS) have been associated with lower health utilities (HUs) compared with the general population. Given the prognostic improvements after ACS with the implementation of coronary angiography (eg, percutaneous coronary intervention (PCI)), contemporary HU values derived from patient-reported outcomes are needed. METHODS: We analysed data of 1882 patients with ACS 1 year after coronary angiography in a Swiss prospective cohort. We used the EuroQol five-dimensional questionnaire (EQ-5D) and visual analogue scale (VAS) to derive HU indexes. We estimated the effects of clinical factors on HU using a linear regression model and compared the observed HU with the average values of individuals of the same sex and age in the general population. RESULTS: Mean EQ-5D HU 1-year after coronary angiography for ACS was 0.82 (±0.16) and mean VAS was 0.77 (±0.18); 40.9% of participants exhibited the highest utility values. Compared with population controls, the mean EQ-5D HU was similar (expected mean 0.82, p=0.58) in patients with ACS, but the mean VAS was slightly lower (expected mean 0.79, p<0.001). Patients with ACS who are younger than 60 years had lower HU than the general population (<0.001). In patients with ACS, significant differences were found according to the gender, education and employment status, diabetes, obesity, heart failure, recurrent ischaemic or incident bleeding event and participation in cardiac rehabilitation (p<0.01). CONCLUSIONS: At 1 year, patients with ACS with coronary angiography had HU indexes similar to a control population. Subgroup analyses based on patients' characteristics and further disease-specific instruments could provide better sensitivity for detecting smaller variations in health-related quality of life

Social and cultural aspects of 'malaria' and its control in central Côte d'Ivoire

Background. A sound local understanding of preventive measures and health-seeking behaviour is important for the effective control of malaria. The purpose of this study was to assess the knowledge, attitudes, practices and beliefs of 'malaria' and its control in two rural communities of central Côte d'Ivoire, and to examine associations between 'malaria' and the households' socioeconomic status. Methods. A cross-sectional household survey was carried out, using a combination of qualitative and quantitative methods. People's socioeconomic status was estimated, employing a household asset-based approach. Results. Malaria was identified as djèkouadjo, the local folk name of the disease. Although people were aware of malaria-related symptoms and their association with mosquitoes, folk perceptions were common. In terms of treatment, a wide array of modern and traditional remedies was employed, often in combination. Individuals with a sound knowledge of the causes and symptoms of malaria continued to use traditional treatments and only a few people sleep under bed nets, whereas folk beliefs did not necessarily translate into refusal of modern treatments. Perceived causes of malaria were linked to the household's socioeconomic status with wealthier individuals reporting mosquitoes more frequently than poorer households. Bed nets were more frequently used in wealthier social strata, whereas other protective measures - perceived to be cheaper - were more prominent among the poorest. Conclusion. Equitable access to resources at household, community and health system levels are essential in order to enable community members to prevent and treat malaria. There is a need for community-based approaches that match health care services with poor people's needs and resources