In tropical agroecosystems, limited N availability remains a major impediment to increasing yield. A 15N-recovery experiment was conducted in 13 diverse tropical agroecosystems. The objectives were to determine the total recovery of one single 15N application of inorganic or organic N during three to six growing seasons and to establish whether the losses of N are governed by universal principles. Between 7 and 58% (average of 21%) of crop N uptake duringthe first growing season was derived from fertilizer. On average, 79% of crop N was derived from the soil. When 15N-labeled residues were applied, in the first growing season 4% of crop N was derived from the residues. Average recoveries of 15N-labeled fertilizer and residue in crops after the first growing season were 33 and 7%, respectively. Corresponding recoveries in the soil were 38 and 71 %. An additional 6% of the fertilizer and 9.1 % of the residue was recovered by crops during subsequent growing seasons. There were no significant differences in total 15N recovery (average 54%) between N from fertilizer and N from residue. After five growing seasons, more residue N (40%) than fertilizer N (18%) was recovered in the soil, better sustaining the soil organic matter N content. Long-term total recoveries of 15N-labeled fertilizer or residue in the crop and soil were similar. Soil N remained the primary source of N for crops. As higher rainfall and temperature tend to cause higher N losses, management practices to improve N use efficiency and reduce losses in wet tropical regions will remain a challenge.

We assessed serologic responses to an oral, killed whole-cell enterotoxigenic Escherichia coli plus cholera toxin B-subunit (ETEC-rCTB) vaccine in 73 Egyptian adults, 105 schoolchildren, and 93 preschool children. Each subject received two doses of vaccine or placebo 2 weeks apart, giving blood before immunization and 7 days after each dose. Plasma antibodies to rCTB and four vaccine-shared colonization factors (CFs) were measured by enzyme-linked immunosorbent assay. Immunoglobulin A (IgA) antibodies to rCTB and CFA/I were measured in all subjects, and those against CS1, CS2, and CS4 were measured in all children plus a subset of 33 adults. IgG antibodies to these five antigens were measured in a subset of 30 to 33 subjects in each cohort. Seroconversion was defined as a >2-fold increase in titer after vaccination. IgA and IgG seroconversion to rCTB was observed in 94 to 95% of adult vaccinees, with titer increases as robust as those previously reported for these two pediatric cohorts. The proportion showing IgA seroconversion to each CF antigen among vaccinated children (range, 70 to 96%) and adults (31 to 69%), as well as IgG seroconversion in children (44 to 75%) and adults (25 to 81%), was significantly higher than the corresponding proportion in placebo recipients, except for IgA responses to CS2 in adults. IgA anti-CF titers peaked after one dose in children, whereas in all age groups IgG antibodies rose incrementally after each dose. Independently, both preimmunization IgA titer and age were inversely related to the magnitude of IgA responses. In conclusion, serologic responses to the ETEC-rCTB vaccine may serve as practical immune outcome measures in future pediatric trials in areas where ETEC is endemic.

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Background: Asthma is a chronic and complex lung disease that is not completely understood. It involves airway inflammation, reversible airflow obstruction, and bronchial hyperresponsiveness. The most common symptoms are recurrent wheezing, chest tightness, shortness of breath, and coughing.Objective: The Asthma Insights and Management study gathered information on the burden of asthma in the Gulf region (United Arab Emirates, Kuwait, Saudi Arabia) and Russia.Methods: This was a cross-sectional, multinational, noninterventional, two-phase study that collected data from patients ages Ն 12 years, through interviews and a survey questionnaire. Phase 1 consisted of survey questions focused on estimating the asthma prevalence in the community. Phase 2 was designed to assess the level of asthma control, asthma-related perceptions and behaviors, and presentation patterns. Data were summarized by using descriptive analyses.Results: Analysis of data of 711 patients revealed that the prevalence of asthma among patients who lived in the community was 7.9% and that 66% subjectively perceived their asthma as being controlled. However, 97% of the patients' asthma were partially controlled or uncontrolled based on the Global initiative for Asthma control classification. Troubling symptoms were daytime coughing (33.3%) and shortness of breath (20.3%). With respect to medications for asthma, 76.2% of the patients reported the use of quick relief medication and 80.8% of maintenance medication during the past 4 weeks. Asthma exacerbation in the past year was reported by 40% of adults and adolescents in the study. Conclusion:The results showed that a significant proportion of the patients experienced bothersome symptoms and that many had a lack of knowledge about asthma control and treatment recommendations, which indicated that there is a need for improvements in patient education and asthma care in the Gulf and Russia regions.

The use of biofertilizers has become a great hope for Egyptian agriculture, particularly in the field of production of medicinal plants, especially when the economic and environmental points of view are considered, since they reduce the environmental pollution and production costs, in addition to improving the quality. Therefore, the influence of using locally isolated nitrogen fixing bacteria as biofertilizers were studied. The isolates used were three representative strains of either Azotobacter and Azospirillum (two isolates of Azotobacter out of 60 isolates, these isolates were Az.NP7-Az.PR1, and one isolate of Azospirillum out of 60 isolates, this isolate was As.Pp1 ) which were screened for their activity in nitrogen fixing and stimulation effect by used root exudates of black-cumin plants and used for further inoculation studies as biofertilizers. These isolates were isolated at random from rhizosphere and rhizoplane of black-cumin, parsley and fenugreek cultivars at the different stages of growth. The effect of inoculation with N2-fixing bacteria ( biofertilizer ) on growth plant characteristics of tested medicinal plants ( Nigella sativa, Trigonella foenum-graecum and Petroselinum sativum ) plants were studied. Inoculation was conjugated with the application of four doses of mineral N, i.e. 0, 50%, 75% and one full dose ( 100% ) from the recommended doses. Results obtained showed that the application of biofertilizers ( N2-fixers ) produced better growth and reduced the N requirement in many medicinal plants such as Nigella sativa, Trigonella foenum and Petroselinum sativum compared with untreated plants.