Maize response to macronutrients and potential for profitability in sub-Saharan Africa

The final publication is available at Springer via http://dx.doi.org/10.1007/s10705-015-9717-2Sub-Saharan Africa (SSA) is plagued by low productivity and little research is available on the attainable responses and profitability to applied nutrients under variable environments. The objective of this study was to determine the attainable maize grain response to and potential of profitability of N, P and K application in SSA using boundary line approaches. Data from experiments conducted in SSA under AfSIS project (2009–2012) and from FAO trials database (1969–1996) in 15 countries and constituting over 375 different experimental locations and 6600 data points are used. Both response to fertilizer and value cost ratio (VCR) are highly variable and no more than 61 % cases for N, 43 % for P and 25 % for K attain VCR of 2 or more. Also, based on the recent AfSIS data, VCR exceeds 1 in just 67 % (N), 57 % (P) and 40 % (K) of the cases, even when best management practices are applied on a research farm, and interest rates are zero. Chances for profitability are highest when soil organic carbon is 1–2 % and control maize grain yield is 1–3 t ha−1 but also depends on relatively static soil properties (primarily texture and mineralogy) that are not under farmer control. We conclude that return on investment of macronutrient fertilizer is highly variable and can be substantially increased by helping farmers decide where to apply the fertilizers. Consequently, farmers need access to information on factors influencing economic returns of fertilizer use in order to make the right decisions

Incidence, Clinical Outcome and Risk Factors of Intensive Care Unit Infections in the Lagos University Teaching Hospital (LUTH), Lagos, Nigeria

<div><p>Background</p><p>Infections are common complications in critically ill patients with associated significant morbidity and mortality.</p><p>Aim</p><p>This study determined the prevalence, risk factors, clinical outcome and microbiological profile of hospital-acquired infections in the intensive care unit of a Nigerian tertiary hospital.</p><p>Materials and Methods</p><p>This was a prospective cohort study, patients were recruited and followed up between September 2011 and July 2012 until they were either discharged from the ICU or died. Antimicrobial susceptibility testing of isolates was done using CLSI guidelines.</p><p>Results</p><p>Seventy-one patients were recruited with a 45% healthcare associated infection rate representing an incidence rate of 79/1000 patient-days in the intensive care unit. Bloodstream infections (BSI) 49.0% (22/71) and urinary tract infections (UTI) 35.6% (16/71) were the most common infections with incidence rates of 162.9/1000 patient-days and 161.6/1000 patient-days respectively. <i>Staphylococcus aureus</i> was the most common cause of BSIs, responsible for 18.2% of cases, while Candida spp. was the commonest cause of urinary tract infections, contributing 25.0% of cases. Eighty percent (8/10) of the Staphylococcus isolates were methicillin-resistant. Gram-negative multidrug bacteria accounted for 57.1% of organisms isolated though they were not ESBL-producing. Use of antibiotics (OR = 2.98; p = 0.03) and surgery (OR = 3.15, p< 0.05) in the month preceding ICU admission as well as urethral catheterization (OR = 5.38; p<0.05) and endotracheal intubation (OR = 5.78; p< 0.05) were risk factors for infection.</p><p>Conclusion</p><p>Our findings demonstrate that healthcare associated infections is a significant risk factor for ICU-mortality and morbidity even after adjusting for APACHE II score.</p></div

Final logistic regression model.

<p>Final logistic regression model.</p

Distribution of Causative microorganisms by the sites of Intensive Care Unit–acquired infections in Lagos University Teaching Hospital, Lagos.

<p>KEY: RTI = Respiratory tract infections; SSTs = Skin-soft tissue infections; UTI = Urinary tract infections; BSI = Blood stream infections; CoNS = Coagulase negative staphylococcus.</p

Distribution of reported cases of histoplasmosis in Nigeria in relation to vegetation (A) and soil types (B).

<p>Distribution of reported cases of histoplasmosis in Nigeria in relation to vegetation (A) and soil types (B).</p

Result of Univariate and Multivariate regression analysis of risk factors for ICU mortality.

<p>Result of Univariate and Multivariate regression analysis of risk factors for ICU mortality.</p

Distribution of Intensive Care Unit-acquired infections in Lagos University Teaching Hospital, Lagos.

<p>Bloodstream infection (48.9%); Urinary tract infection (35.6%); Skin-soft tissue infection (8.9%); Respiratory tract infection (6.7%).</p

Resistance profile of Gram negative isolates from Intensive Care Unit infections in Lagos University Teaching Hospital, Lagos.

<p>Resistance profile of Gram negative isolates from Intensive Care Unit infections in Lagos University Teaching Hospital, Lagos.</p

Univariate analysis of risk factors for Intensive Care Unit-acquired infections in Lagos University Teaching Hospital, Lagos.

<p>Univariate analysis of risk factors for Intensive Care Unit-acquired infections in Lagos University Teaching Hospital, Lagos.</p

Admitting diagnosis of Patients in Intensive Care Unit of Lagos University Teaching Hospital, Lagos.

<p>“Others” as a group of admitting diagnosis included: post-surgical patients, patients with chronic renal failure and malignancies.</p