Assessing the recovery of species diversity and composition after major disturbance is key to understanding the resilience of tropical forests through successional processes, and its importance for biodiversity conservation. Despite the specifi c abiotic environment and ecological processes of tropical dry forests, secondary succession has received less attention in this biome than others and changes in species diversity and composition have never been synthesised in a systematic and quantitative review. Th is study aims to assess in tropical dry forests 1) the directionality of change in species richness and evenness during secondary succession, 2) the convergence of species composition towards that of old-growth forest and 3) the importance of the previous land use, precipitation regime and water availability in infl uencing the direction and rate of change. We conducted meta-analyses of the rate of change in species richness, evenness and composition indices with succession in 13 tropical dry forest chronosequences. Species richness increased with succession, showing a gradual accumulation of species, as did Shannon evenness index. Th e similarity in species composition of successional forests with old-growth forests increased with succession, yet at a low rate. Tropical dry forests therefore do show resilience of species composition but it may never reach that of old-growth forests. We found no signifi cant diff erences in rates of change between diff erent previous land uses, precipitation regimes or water availability. Our results show high resilience of tropical dry forests in term of species richness but a slow recovery of species composition. Th ey highlight the need for further research on secondary succession in this biome and better understanding of impacts of previous land-use and landscape-scale patterns.Succession has been a major focus of plant community ecology for more than a century (McIntosh 1999), yet the processes underlying assembly of secondary forests continue to be actively researched (Norden et al. 2015). Th e early view of Clements (1916) (monoclimax hypothesis) and initial fl oristic composition model of Egler (1954) were further formalized by the three models of Connell and Slatyer (1977). Th ese deterministic models are all based on the idea that tradeoff s between traits promote success in diff erent stages of succession (Huston and Smith 1987). However, none of these models accounts for stochastic events or historical contingencies (Young et al. 2005). Lawton (1987) proposed a model of succession based only on random survival of established species and colonization by new species, paving the way for the neutral theory of community assembly (Hubbell 2001). Although deterministic niche-based and neutral models of succession have often been treated as mutually exclusive explanations for empirical patterns, a growing body of literature evidences the importance of the integration of the two (Chave 2004, Gravel et al. 2006, Tilman 2004. A major focus of research is now to assess the res...

Chronology of tropical dry forest regeneration in Santa Rosa, Guanacaste, Costa Rica. I. Edaphic characteristics. We characterized soil chemical and physical properties in eight tropical dry forest (TDF) successional sites along a time sequence (10, 15, 20, 40, 60 and >100 years) in Santa Rosa, Costa Rica. Seventeen soils were identified, described, and classified in six orders. Most soils were classified as Entisols and Vertisols, but Mollisols, Alfisols, Inceptisols and Ultisols were also present. All soils showed good fertility that did not constrain species richness. High edaphic variation seemed the result of complex interactions among the pyroclastic origin of Santa Rosa ignimbritic plateau (SRIP), the lithological composition and acidity of ignimbritic rocks, the strong seasonality in rainfall, intense hydric and aeolic erosion, topographic variations within the SRIP, and past human intervention. Correlations performed on soils classified as Entisols (<60 cm deep) showed a depletion of soil cations (Ca, Mg, K, Na and CEC) during the first 20 years of forest regeneration, that later recovered in mature TDF sites. Organic matter content did not change significantly along the TDF chrono-sequence. Substantial increments in macro-pores and soil hydraulic conductivity were observed, probably resulting from higher root biomass and turnover in older successional sites. Soil available water and meso-pore abundance were negatively correlated with TDF successional age. Our results indicate that edaphic chan ges observed along TDF regeneration might have been due to annual fires in pastures and young TDF sites, addition of decaying litter and fine roots as regeneration progressed, milder microclimate conditions during late regeneration in mature TDF sites, increased nutrient cycling, and the predominance of sandy loam textures among the soils examined. These changes in the soil environment with succession may have physiological and phenological consequences on the species appearing at different stages of TDF regeneration. Rev. Biol. Trop. 57 (3): 801-815. Epub 2009 September, 30. Keywords: Santa Rosa National Park, soils, chemical properties, physical properties, seasonally dry tropical forests, pastures, forest succession.Los bosques tropicales estacionalmente secos (BTS) de Meso América contienen una alta riqueza estructural y funcional (Murphy & Lugo 1986, Medina 1995, proveen numerosos servicios ambientales (Maas et al. 2005), y constituyen un modelo para la restauración ecológica y el estudio de la regeneración de los ecosistemas tropicales (Janzen 2000). Estas zonas de vida han sido las predilectas para el desarrollo de importantes asentamientos humanos a través del tiempo, lo que ha causado enormes perturbaciones ecológicas; los BTS son actualmente un mosaico de fragmentos de bosques sucesionales secundarios (Kramer 1997). En la actualidad, los BTS continúan sometidos a presiones superiores a las enfrentadas por sus contrapartes, los bosques tropicales lluviosos (Janzen 1986), y el éxito de los ...

No abstract

Resumen A partir de la evidencia del fenómeno migratorio en Chile, se examina la situación de los estudiantes inmigrantes extranjeros, tomando como referencia la normativa del sistema escolar y la perspectiva del dilema redistribución o reconocimiento. En particular, el texto pretende mostrar las consecuencias de la comprensión generada por dicho dilema en relación con la dialéctica igualdad/diversidad, para explicar los efectos del discurso inclusivo sobre la situación de los estudiantes inmigrantes, considerados como paradigma de grupo minoritario. Con este propósito, se distingue y analiza un particular corpus legislativo que se extiende entre los años 2009-2015, el cual se caracteriza por introducir masivamente la idea de una política educativa inclusiva como ideario a perseguir por el sistema escolar.

BACKGROUND: Most patients with severe traumatic brain injury (sTBI) in low-or-middleincome countries and surprisingly many in high-income countries are managed without intracranial pressure (ICP) monitoring. The impact of the first published protocol (Imaging and Clinical Examination [ICE] protocol) is untested against nonprotocol management. OBJECTIVE: To determine whether patients treated in intensive care units (ICUs) using the ICE protocol have lower mortality and better neurobehavioral functioning than those treated in ICUs using no protocol. METHODS: This study involved nineteen mostly public South American hospitals. This is a prospective cohort study, enrolling patients older than 13 years with sTBI presenting within 24 h of injury (January 2014-July 2015) with 6-mo postinjury follow-up. Five hospitals treated all sTBI cases using the ICE protocol; 14 used no protocol. Primary outcome was prespecified composite of mortality, orientation, functional outcome, and neuropsychological measures. RESULTS: A total of 414 patients (89% male, mean age 34.8 years) enrolled; 81% had 6 months of follow-up. All participants included in composite outcome analysis: average percentile (SD) = 46.8 (24.0) nonprotocol, 56.9 (24.5) protocol. Generalized estimating equation (GEE) used to account for center effects (confounder-adjusted difference [95% CI] = 12.2 [4.6, 19.8], P = .002). Kaplan-Meier 6-month mortality (95% CI) = 36% (30%, 43%) nonprotocol, 25% (19%, 31%) protocol (GEE and confounder-adjusted hazard ratio [95% CI] = .69 [.43, 1.10], P = .118). Sixmonth Extended Glasgow Outcome Scale for 332 participants: average Extended Glasgow Outcome Scale score (SD) = 3.6 (2.6) nonprotocol, 4.7 (2.8) protocol (GEE and confounderadjusted and lost to follow-up-adjusted difference [95% CI] = 1.36 [.55, 2.17], P = .001). CONCLUSION: ICUs managing patients with sTBI using the ICE protocol had better functional outcome than those not using a protocol. ICUs treating patients with sTBI without ICP monitoring should consider protocolization. The ICE protocol, tested here and previously, is 1 option.