Numerous theories have been developed and tested to explain the high botanical diversity in tropical forests, ranging from nonequilibrium theories emphasizing the importance of chance to equilibrium theories depicting highly specialized species occupying narrow ecological niches. Niche-based theories have most often evaluated species adaptation to different light environments, but some studies have evaluated the importance of edaphic attributes in controlling species distributions. We evaluated the role of edaphic factors in controlling the distribution of African mahogany in the genus Entandrophragma on a 100-ha plot in the Dzanga-Sangha Dense Forest Reserve, Central African Republic. This study went beyond simple characterization of edaphic conditions in topographic or other classes to test for specific associations with chemical and physical soil parameters known to be important to plant growth. Trees Ն30 cm dbh of the four species of Entandrophragma evaluated were nonrandomly distributed in the forest. Torus translation tests indicated that none of the species exhibited any topographic preferences. However, three of the four species had significant associations with at least two soil chemical attributes. Randomization tests evaluating links between soil chemical and physical properties and topographic position underscored the complexity of the relationship and suggest that inferring edaphic attributes from broadly and simply defined habitat classes may significantly underestimate the importance of soil heterogeneity in contributing to species coexistence.

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BackgroundAsthma was the most common co-morbidity among patients hospitalized with pandemic influenza A(H1N1)pdm09 [pH1N1] infection. The objective was to compare characteristics of hospitalized pH1N1 patients with and without asthma and assess factors associated with severity among asthma patients.MethodsPatient data were derived from two 2009 pandemic case-series of U.S. pH1N1 hospitalizations. A case was defined as a person ≥ 2 years old hospitalized with laboratory-confirmed pH1N1. Asthma status was determined through chart review.ResultsAmong 473 cases, 29% had asthma. Persons with asthma were more likely to be 2–17 years old (39% vs. 30%, p = 0.04) and black (29% vs. 18%, p < 0.01), and have chronic obstructive pulmonary disease (13% vs. 9%, p = 0.04) but less likely to have pneumonia (37% vs. 47%, p = 0.05), need mechanical ventilation (13% vs. 23%, p = 0.02), and die (4% vs. 10%, p = 0.04) than those without asthma. Among patients with asthma, those admitted to an intensive care unit (ICU) or who died (n = 38) compared with survivors not admitted to an ICU (n = 99) were more likely to have pneumonia on admission (60% vs. 27%, p < 0.01) or acute respiratory distress syndrome (24% vs. 0%, p < 0.01) and less likely to receive influenza antiviral agents ≤ 2 days of admission (73% vs. 92%, p = 0.02).ConclusionsThe majority of persons with asthma had an uncomplicated course; however, severe disease, including ICU admission and death, occurred in asthma patients who presented with pneumonia. Influenza antiviral agents should be started early in hospitalized patients with suspected influenza, including those with asthma.

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B/I221V cocirculated with B/WT in North Carolina and South Carolina during 2010-2011. I221V did not alter illness severity but may have reduced oseltamivir effectiveness. Thus, global surveillance for I221V is important.