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This article briefly describes the policy of subsidies through electricity rates has been implemented in Mexico in the period 2000-2014, and the negative impact it has had on public finances. It also suggests a theoretical analysis by the application of a pricing policy based on Long Term Marginal Cost considering criteria of equity and income distribution leading to a situation of financial viability to the company supplying electricity in the country., Este artigo descreve brevemente a política de subsídios através de tarifas elétricas que tem sido realizada no México no período 2000-2014, bem como o impacto negativo que teve sobre as finanças públicas. Também sugere uma análise teórica com a aplicação de uma Política de Preços baseado em Custos Marginais de Longo Prazo, considerando critérios de equidade e de distribuição de renda que levam a uma situação de viabilidade financeira a empresa fornecedora de energia elétrica do país., Este artículo describe brevemente la política de subsidios vía tarifas eléctricas que ha sido implementada en México en el periodo 2000-2014, así como el impacto negativo que ha tenido en las finanzas públicas. Asimismo sugiere mediante un análisis teórico la aplicación de una Política de Precios basada en Costos Marginales de Largo Plazo considerando criterios de equidad y distribución del ingreso que lleven a una situación de viabilidad financiera a la empresa suministradora de energía eléctrica del país.

Air pollution induces systemic inflammation, as well as respiratory, myocardial and brain inflammation in children. Peak bone mass is influenced by environmental factors. We tested the hypothesis that six-year-olds with lifetime exposures to urban air pollution will have alterations in inflammatory markers and bone mineral density (BMD) as opposed to low-polluted city residents when matched for BMI, breast feeding history, skin phototype, age, sex and socioeconomic status. This pilot study included 20 children from Mexico City (MC) (6.17 years ± 0.63 years) and 15 controls (6.27 years ± 0.76 years). We performed full paediatric examinations, a history of outdoor exposures, seven-day dietary recalls, serum inflammatory markers and dual-energy X-ray absorptiometry (DXA). Children in MC had significantly higher concentrations of IL-6 (p=0.001), marked reductions in total blood neutrophils (p=0.0002) and an increase in monocytes (p=0.005). MC children also had an insufficient Vitamin D intake and spent less time outdoors than controls (p<0.001) in an environment characterized by decreased UV light, with ozone and fine particulates concentrations above standard values. There were no significant differences between the cohorts in DXA Z scores. The impact of systemic inflammation, vitamin D insufficiency, air pollution, urban violence and poverty may have long-term bone detrimental outcomes in exposed paediatric populations as they grow older, increasing the risk of low bone mass and osteoporosis. The selection of reference populations for DXA must take into account air pollution exposures., Onečišćenje zraka uzrokuje sistemsku upalu, kao i respiratorne, miokardijalne i moždane upale kod djece. Čimbenici iz okoliša utječu na vršnu koštanu masu. Ispitali smo hipotezu da šestogodišnjaci s cjeloživotnom izloženosti gradskom onečišćenju zraka imaju drugačije upalne pokazatelje i mineralnu gustoću kostiju (BMD) od djece iz gradova s niskom razinom onečišćenja kada usporedimo tjelesni indeks mase, povijest dojenja, fototip kože, dob, spol i društveno-ekonomski položaj. Ova pilot-studija uključuje dvadesetero djece iz glavnoga grada Méxica (6,17 ± 0,63) godina i petnaestero kontrolne djece (6,27 ± 0,76) godina. Obavili smo cjelovite pedijatrijske preglede, prikupili povijesti vanjske izloženosti, sedmodnevne analize prehrane, serumske razine upalnih pokazatelja i dvoenergetsku apsorpciometriju X-zraka (DXA). Djeca iz Méxica imala su značajno više koncentracije IL-6 (p=0,001), izrazito smanjen ukupni broj krvnih neutrofila (p=0,0002) i povećan broj monocita (p=0,005). Djeca iz Méxica također su unosila nedovoljnu količinu vitamina D i provodila manje vremena na otvorenome od kontrolnih ispitanika (p<0,001), i to u okružju obilježenom smanjenom UV svjetlošću te koncentracijama ozona i čestične materije iznad standardnih vrijednosti. Nije bilo značajnih razlika između kohorta u Z-vrijednostima DXA. Učinci sistemske upale, insufi cijencije vitamina D, onečišćenja zraka, gradskog nasilja i siromaštva mogu imati dugoročne štetne posljedice na kosti u izloženim pedijatrijskim populacijama kako one odrastaju, povećavajući tako njihov rizik od smanjenja koštane mase i osteoporoze. Pri odabiru referentne populacije za DXA bi se ubuduće trebala uzimati u obzir i izloženost onečišćenom zraku.

Forest structure and dynamics vary across the Amazon Basin in an east-west gradient coincident with variations in soil fertility and geology. This has resulted in the hypothesis that soil fertility may play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates. Soil samples were collected in a total of 59 different forest plots across the Amazon Basin and analysed for exchangeable cations, carbon, nitrogen and pH, with several phosphorus fractions of likely different plant availability also quantified. Physical properties were additionally examined and an index of soil physical quality developed. Bivariate relationships of soil and climatic properties with above-ground wood productivity, stand-level tree turnover rates, above-ground wood biomass and wood density were first examined with multivariate regression models then applied. Both forms of analysis were undertaken with and without considerations regarding the underlying spatial structure of the dataset. Despite the presence of autocorrelated spatial structures complicating many analyses, forest structure and dynamics were found to be strongly and quantitatively related to edaphic as well as climatic conditions. Basin-wide differences in stand-level turnover rates are mostly influenced by soil physical properties with variations in rates of coarse wood production mostly related to soil phosphorus status. Total soil P was a better predictor of wood production rates than any of the fractionated organic- or inorganic-P pools. This suggests that it is not only the immediately available P forms, but probably the entire soil phosphorus pool that is interacting with forest growth on longer timescales. A role for soil potassium in modulating Amazon forest dynamics through its effects on stand-level wood density was also detected. Taking this into account, otherwise enigmatic variations in stand-level biomass across the Basin were then accounted for through the interactin

Aboveground tropical tree biomass and carbon storage estimates commonly ignore tree height (H). We estimate the effect of incorporating H on tropics-wide forest biomass estimates in 327 plots across four continents using 42 656 H and diameter measurements and harvested trees from 20 sites to answer the following questions: 1. What is the best H-model form and geographic unit to include in biomass models to minimise site-level uncertainty in estimates of destructive biomass? 2. To what extent does including H estimates derived in (1) reduce uncertainty in biomass estimates across all 327 plots? 3. What effect does accounting for H have on plot- and continental-scale forest biomass estimates? The mean relative error in biomass estimates of destructively harvested trees when including H (mean 0.06), was half that when excluding H (mean 0.13). Power- andWeibull-H models provided the greatest reduction in uncertainty, with regional Weibull-H models preferred because they reduce uncertainty in smaller-diameter classes (?40 cm D) that store about one-third of biomass per hectare in most forests. Propagating the relationships from destructively harvested tree biomass to each of the 327 plots from across the tropics shows that including H reduces errors from 41.8Mgha?1 (range 6.6 to 112.4) to 8.0Mgha?1 (?2.5 to 23.0). For all plots, aboveground live biomass was ?52.2 Mgha?1 (?82.0 to ?20.3 bootstrapped 95%CI), or 13%, lower when including H estimates, with the greatest relative reductions in estimated biomass in forests of the Brazilian Shield, east Africa, and Australia, and relatively little change in the Guiana Shield, central Africa and southeast Asia. Appreciably different stand structure was observed among regions across the tropical continents, with some storing significantly more biomass in small diameter stems, which affects selection of the best height models to reduce uncertainty and biomass reductions due to H. After accounting for variation in H, total biomass p

Aboveground tropical tree biomass and carbon storage estimates commonly ignore tree height (H). We estimate the effect of incorporating H on tropics-wide forest biomass estimates in 327 plots across four continents using 42 656 H and diameter measurements and harvested trees from 20 sites to answer the following questions: 1. What is the best H-model form and geographic unit to include in biomass models to minimise site-level uncertainty in estimates of destructive biomass? 2. To what extent does including H estimates derived in (1) reduce uncertainty in biomass estimates across all 327 plots? 3. What effect does accounting for H have on plot- and continental-scale forest biomass estimates? The mean relative error in biomass estimates of destructively harvested trees when including H (mean 0.06), was half that when excluding H (mean 0.13). Power- andWeibull-H models provided the greatest reduction in uncertainty, with regional Weibull-H models preferred because they reduce uncertainty in smaller-diameter classes (?40 cm D) that store about one-third of biomass per hectare in most forests. Propagating the relationships from destructively harvested tree biomass to each of the 327 plots from across the tropics shows that including H reduces errors from 41.8Mgha?1 (range 6.6 to 112.4) to 8.0Mgha?1 (?2.5 to 23.0). For all plots, aboveground live biomass was ?52.2 Mgha?1 (?82.0 to ?20.3 bootstrapped 95%CI), or 13%, lower when including H estimates, with the greatest relative reductions in estimated biomass in forests of the Brazilian Shield, east Africa, and Australia, and relatively little change in the Guiana Shield, central Africa and southeast Asia. Appreciably different stand structure was observed among regions across the tropical continents, with some storing significantly more biomass in small diameter stems, which affects selection of the best height models to reduce uncertainty and biomass reductions due to H. After accounting for variation in H, total biomass p

Forest structure and dynamics vary across the Amazon Basin in an east-west gradient coincident with variations in soil fertility and geology. This has resulted in the hypothesis that soil fertility may play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates. Soil samples were collected in a total of 59 different forest plots across the Amazon Basin and analysed for exchangeable cations, carbon, nitrogen and pH, with several phosphorus fractions of likely different plant availability also quantified. Physical properties were additionally examined and an index of soil physical quality developed. Bivariate relationships of soil and climatic properties with above-ground wood productivity, stand-level tree turnover rates, above-ground wood biomass and wood density were first examined with multivariate regression models then applied. Both forms of analysis were undertaken with and without considerations regarding the underlying spatial structure of the dataset. Despite the presence of autocorrelated spatial structures complicating many analyses, forest structure and dynamics were found to be strongly and quantitatively related to edaphic as well as climatic conditions. Basin-wide differences in stand-level turnover rates are mostly influenced by soil physical properties with variations in rates of coarse wood production mostly related to soil phosphorus status. Total soil P was a better predictor of wood production rates than any of the fractionated organic- or inorganic-P pools. This suggests that it is not only the immediately available P forms, but probably the entire soil phosphorus pool that is interacting with forest growth on longer timescales. A role for soil potassium in modulating Amazon forest dynamics through its effects on stand-level wood density was also detected. Taking this into account, otherwise enigmatic variations in stand-level biomass across the Basin were then accounted for through the interactin

Este trabajo describe los modelosde gobierno universitarios más destacados en el mundo, haciendo énfasis en el caso de los gobiernos universitarios latinoamericanosdonde se distinguen cuatro modelos degobierno: el burocrático, el colegial, el empresarial y el híbrido. Este trabajo reflexiona sobre las estrategias que se pueden implementar en cada modelo, especialmente analizando ydescribiendo el caso mexicano.

The bus rapid transit systems (BRT) have been implemented in many cities around the world, but there are few studies that analyze and compare the planning processes and consensus reached among the affected transport operators and government officials responsible for implementing these systems. In this study, it was decided to analyze and compare the procedures of planning and consensus reached in the implementation of the Metrobús in Ciudad de México and Mexibús in Estado de México. This is a cualitative study and used the case method, as well as semi-structured interviews with experts in the field and government officials. Among the findings, there is evidence of the lack of importance in BRT planning models to the consensus established between these two key players mentioned, as well as the findings shows the development of various technical studies and projects in the case of Metrobús and the absence of them to Mexibús case, although agreements in question were very similar between them., O ônibus sistemas de trânsito rápido (BRT) foram implementada em muitas cidades ao redor do mundo; No entanto, poucos estudos têm testado e comparado processos de planejamento e do consenso alcançado entre licenciados afetados e autoridades governamentais implementadores desses sistemas. Nesta estudo, optamos por analisar e comparar os procedimentos planejamento e do consenso acordado na implementação de Metrobus na Cidade do México e do Estado Mexibús México. Este estudo é de pequenos documentários e usado o método caso, além de entrevistas estruturadas com especialistas no campo e autoridades governamentais. Entre as descobertas encontraram evidências, de pouca importância nos modelos BRT planejamento para o consenso estabelecido entre estes dois jogadores-chave mencionadas, bem como o desenvolvimento vários estudos técnicos e projetos, no caso de Metrobus ea falta dela no caso de Mexibús, embora em questão de acordos muito similares., Los sistemas autobuses de tránsito rápido (BRT) han sido implementados en numerosas ciudades de todo el mundo; sin embargo, existen pocos estudios que analicen y comparen los procesos de planeación y los consensos alcanzados entre los concesionarios afectados y las autoridades de gobierno encargados de la implementación de estos sistemas. En este estudio, se decidió analizar y comparar los procedimientos de planeación y consensos pactados en la instrumentación del Metrobús de la Ciudad de México y del Mexibús del Estado de México. Este estudio es de corte documental y utilizó el método de casos, además de entrevistas semiestructuradas con expertos en el campo y autoridades gubernamentales. Entre los hallazgos encontrados, se evidencia la escasa importancia en los modelos de planeación de BRT hacia los consensos establecidos entre estos dos actores claves mencionados, además de la elaboración de diversos estudios técnicos y proyectos ejecutivos en el caso de Metrobús y la ausencia de ellos para el caso de Mexibús, aunque en cuestión de acuerdos muy similares entre sí.

Este trabajo describe los modelosde gobierno universitarios más destacados en el mundo, haciendo énfasis en el caso de los gobiernos universitarios latinoamericanosdonde se distinguen cuatro modelos degobierno: el burocrático, el colegial, el empresarial y el híbrido. Este trabajo reflexiona sobre las estrategias que se pueden implementar en cada modelo, especialmente analizando ydescribiendo el caso mexicano.

The bus rapid transit systems (BRT) have been implemented in many cities around the world, but there are few studies that analyze and compare the planning processes and consensus reached among the affected transport operators and government officials responsible for implementing these systems. In this study, it was decided to analyze and compare the procedures of planning and consensus reached in the implementation of the Metrobús in Ciudad de México and Mexibús in Estado de México. This is a cualitative study and used the case method, as well as semi-structured interviews with experts in the field and government officials. Among the findings, there is evidence of the lack of importance in BRT planning models to the consensus established between these two key players mentioned, as well as the findings shows the development of various technical studies and projects in the case of Metrobús and the absence of them to Mexibús case, although agreements in question were very similar between them., O ônibus sistemas de trânsito rápido (BRT) foram implementada em muitas cidades ao redor do mundo; No entanto, poucos estudos têm testado e comparado processos de planejamento e do consenso alcançado entre licenciados afetados e autoridades governamentais implementadores desses sistemas. Nesta estudo, optamos por analisar e comparar os procedimentos planejamento e do consenso acordado na implementação de Metrobus na Cidade do México e do Estado Mexibús México. Este estudo é de pequenos documentários e usado o método caso, além de entrevistas estruturadas com especialistas no campo e autoridades governamentais. Entre as descobertas encontraram evidências, de pouca importância nos modelos BRT planejamento para o consenso estabelecido entre estes dois jogadores-chave mencionadas, bem como o desenvolvimento vários estudos técnicos e projetos, no caso de Metrobus ea falta dela no caso de Mexibús, embora em questão de acordos muito similares., Los sistemas autobuses de tránsito rápido (BRT) han sido implementados en numerosas ciudades de todo el mundo; sin embargo, existen pocos estudios que analicen y comparen los procesos de planeación y los consensos alcanzados entre los concesionarios afectados y las autoridades de gobierno encargados de la implementación de estos sistemas. En este estudio, se decidió analizar y comparar los procedimientos de planeación y consensos pactados en la instrumentación del Metrobús de la Ciudad de México y del Mexibús del Estado de México. Este estudio es de corte documental y utilizó el método de casos, además de entrevistas semiestructuradas con expertos en el campo y autoridades gubernamentales. Entre los hallazgos encontrados, se evidencia la escasa importancia en los modelos de planeación de BRT hacia los consensos establecidos entre estos dos actores claves mencionados, además de la elaboración de diversos estudios técnicos y proyectos ejecutivos en el caso de Metrobús y la ausencia de ellos para el caso de Mexibús, aunque en cuestión de acuerdos muy similares entre sí.

•The rich ecology of tropical forests is intimately tied to their moisture status. Multi-site syntheses can provide a macro-scale view of these linkages and their susceptibility to changing climates. Here, we report pan-tropical and regional-scale analyses of tree vulnerability to drought. •We assembled available data on tropical forest tree stem mortality before, during, and after recent drought events, from 119 monitoring plots in 10 countries concentrated in Amazonia and Borneo. •In most sites, larger trees are disproportionately at risk. At least within Amazonia, low wood density trees are also at greater risk of drought-associated mortality, independent of size. For comparable drought intensities, trees in Borneo are more vulnerable than trees in the Amazon. There is some evidence for lagged impacts of drought, with mortality rates remaining elevated 2 yr after the meteorological event is over. •These findings indicate that repeated droughts would shift the functional composition of tropical forests toward smaller, denser-wooded trees. At very high drought intensities, the linear relationship between tree mortality and moisture stress apparently breaks down, suggesting the existence of moisture stress thresholds beyond which some tropical forests would suffer catastrophic tree mortality.

Executives must walk in a fine line between two ends: by a part, the arbitrary decision making without a rigorous study of the problematic situation, being based on hunches or intuition; on the other hand, to lean too much in rational and quantitative analyses. The decisions generally are not taken by a single executive, requires of the participation of certain groups involved in the problematic one and in this social sense, it is doubtless that, sometimes, conflict of interests coexists frustating the participating and collaborative context on the solution and implantation have arisen from decisions; whereas on the other hand, contexts arise where the collaboration is converted in consensus solutions., Los ejecutivos deben caminar en una fina línea entre dos extremos: por una parte, la toma de decisiones arbitrarias sin un estudio riguroso de la situación problemática, basándose en corazonadas o intuición; por otra parte, apoyarse demasiado en análisis racionales y cuantitativos. Las decisiones por lo general no las toma un solo ejecutivo, requiere de la participación de determinados grupos involucrados en la problemática y en ciertos casos, entre organizaciones, coexistiendo por un lado, conflicto de intereses que frustran la colaboración o bien, por otra parte, soluciones consensuadas bajo un contexto participativo y colaborativo.

•The rich ecology of tropical forests is intimately tied to their moisture status. Multi-site syntheses can provide a macro-scale view of these linkages and their susceptibility to changing climates. Here, we report pan-tropical and regional-scale analyses of tree vulnerability to drought. •We assembled available data on tropical forest tree stem mortality before, during, and after recent drought events, from 119 monitoring plots in 10 countries concentrated in Amazonia and Borneo. •In most sites, larger trees are disproportionately at risk. At least within Amazonia, low wood density trees are also at greater risk of drought-associated mortality, independent of size. For comparable drought intensities, trees in Borneo are more vulnerable than trees in the Amazon. There is some evidence for lagged impacts of drought, with mortality rates remaining elevated 2 yr after the meteorological event is over. •These findings indicate that repeated droughts would shift the functional composition of tropical forests toward smaller, denser-wooded trees. At very high drought intensities, the linear relationship between tree mortality and moisture stress apparently breaks down, suggesting the existence of moisture stress thresholds beyond which some tropical forests would suffer catastrophic tree mortality.

Executives must walk in a fine line between two ends: by a part, the arbitrary decision making without a rigorous study of the problematic situation, being based on hunches or intuition; on the other hand, to lean too much in rational and quantitative analyses. The decisions generally are not taken by a single executive, requires of the participation of certain groups involved in the problematic one and in this social sense, it is doubtless that, sometimes, conflict of interests coexists frustating the participating and collaborative context on the solution and implantation have arisen from decisions; whereas on the other hand, contexts arise where the collaboration is converted in consensus solutions., Los ejecutivos deben caminar en una fina línea entre dos extremos: por una parte, la toma de decisiones arbitrarias sin un estudio riguroso de la situación problemática, basándose en corazonadas o intuición; por otra parte, apoyarse demasiado en análisis racionales y cuantitativos. Las decisiones por lo general no las toma un solo ejecutivo, requiere de la participación de determinados grupos involucrados en la problemática y en ciertos casos, entre organizaciones, coexistiendo por un lado, conflicto de intereses que frustran la colaboración o bien, por otra parte, soluciones consensuadas bajo un contexto participativo y colaborativo.

•The rich ecology of tropical forests is intimately tied to their moisture status. Multi-site syntheses can provide a macro-scale view of these linkages and their susceptibility to changing climates. Here, we report pan-tropical and regional-scale analyses of tree vulnerability to drought. •We assembled available data on tropical forest tree stem mortality before, during, and after recent drought events, from 119 monitoring plots in 10 countries concentrated in Amazonia and Borneo. •In most sites, larger trees are disproportionately at risk. At least within Amazonia, low wood density trees are also at greater risk of drought-associated mortality, independent of size. For comparable drought intensities, trees in Borneo are more vulnerable than trees in the Amazon. There is some evidence for lagged impacts of drought, with mortality rates remaining elevated 2 yr after the meteorological event is over. •These findings indicate that repeated droughts would shift the functional composition of tropical forests toward smaller, denser-wooded trees. At very high drought intensities, the linear relationship between tree mortality and moisture stress apparently breaks down, suggesting the existence of moisture stress thresholds beyond which some tropical forests would suffer catastrophic tree mortality.

Xylem density is a physical property of wood that varies between individuals, species and environments. It reflects the physiological strategies of trees that lead to growth, survival and reproduction. Measurements of branch xylem density, ρx, were made for 1653 trees representing 598 species, sampled from 87 sites across the Amazon basin. Measured values ranged from 218 kg m−3 for a Cordia sagotii (Boraginaceae) from Mountagne de Tortue, French Guiana to 1130 kg m−3 for an Aiouea sp. (Lauraceae) from Caxiuana, Central Pará, Brazil. Analysis of variance showed significant differences in average ρx across regions and sampled plots as well as significant differences between families, genera and species. A partitioning of the total variance in the dataset showed that species identity (family, genera and species) accounted for 33% with environment (geographic location and plot) accounting for an additional 26%; the remaining "residual" variance accounted for 41% of the total variance. Variations in plot means, were, however, not only accountable by differences in species composition because xylem density of the most widely distributed species in our dataset varied systematically from plot to plot. Thus, as well as having a genetic component, branch xylem density is a plastic trait that, for any given species, varies according to where the tree is growing in a predictable manner. Within the analysed taxa, exceptions to this general rule seem to be pioneer species belonging for example to the Urticaceae whose branch xylem density is more constrained than most species sampled in this study. These patterns of variation of branch xylem density across Amazonia suggest a large functional diversity amongst Amazonian trees which is not well understood.

Xylem density is a physical property of wood that varies between individuals, species and environments. It reflects the physiological options of trees that lead to growth, survival and reproduction. Measurements of branch xylem density, ρx, were made for 1653 trees representing 598 species, sampled from 87 sites across the Amazon basin. Measured values ranged from 218 kg m-3 for a Cordia sagotii (Boraginaceae) from Mountaigne de Tortue, French Guiana to 1130 kg m-3 for an Aiouea sp. (Lauraceae) from Caxiuana, Central Pará, Brazil. Analysis of variance showed significant differences in average ρx across regions and sampled plots as well as significant differences between families, genera and species. A partitioning of the total variance in the dataset showed that species identity (family, genera and species) accounted for 33 % with environment (geographic location and plot) accounting for an additional 26 %; the remaining “residual” variance accounted for 41 %. Variations in plot means, were, however, not only accountable by differences in species composition because xylem density of the most widely distributed species in our dataset varied systematically from plot to plot. Thus, as well as having a genetic component branch xylem density is a plastic trait that, for any given species, varies according to where the tree is growing and in a predictable manner. Within the analysed taxa, exceptions to this general rule seem to be some pioneer species belonging for example to Urticaceae and Vochysiaceae whose branch xylem density is more constrained than most species sampled in this study. Variation of branch xylem density across Amazonia suggests a large functional diversity among Amazonian trees which is not well understood.

Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. Affected forest lost biomass, reversing a large long-term carbon sink, with the greatest impacts observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 x 10(15) to 1.6 x 10(15) grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change.

Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. Affected forest lost biomass, reversing a large long-term carbon sink, with the greatest impacts observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 x 10(15) to 1.6 x 10(15) grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change.

Positive aboveground biomass trends have been reported from old-growth forests across the Amazon basin and hypothesized to reflect a large-scale response to exterior forcing. The result could, however, be an artefact due to a sampling bias induced by the nature of forest growth dynamics. Here, we characterize statistically the disturbance process in Amazon old-growth forests as recorded in 135 forest plots of the RAINFOR network up to 2006, and other independent research programmes, and explore the consequences of sampling artefacts using a data-based stochastic simulator. Over the observed range of annual aboveground biomass losses, standard statistical tests show that the distribution of biomass losses through mortality follow an exponential or near-identical Weibull probability distribution and not a power law as assumed by others. The simulator was parameterized using both an exponential disturbance probability distribution as well as a mixed exponential–power law distribution to account for potential large-scale blowdown events. In both cases, sampling biases turn out to be too small to explain the gains detected by the extended RAINFOR plot network. This result lends further support to the notion that currently observed biomass gains for intact forests across the Amazon are actually occurring over large scales at the current time, presumably as a response to climate change.

Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. Affected forest lost biomass, reversing a large long-term carbon sink, with the greatest impacts observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 × 1015 to 1.6 × 1015 grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change

Forest structure and dynamics have been noted to vary across the Amazon Basin in an east-west gradient in a pattern which coincides with variations in soil fertility and geology. This has resulted in the hypothesis that soil fertility may play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates. To test this hypothesis and assess the importance of edaphic properties in affect forest structure and dynamics, soil and plant samples were collected in a total of 59 different forest plots across the Amazon Basin. Samples were analysed for exchangeable cations, C, N, pH with various Pfractions also determined. Physical properties were also examined and an index of soil physical quality developed. Overall, forest structure and dynamics were found to be strongly and quantitatively related to edaphic conditions. Tree turnover rates emerged to be mostly influenced by soil physical properties whereas forest growth rates were mainly related to a measure of available soil phosphorus, although also dependent on rainfall amount and distribution. On the other hand, large scale variations in forest biomass could not be explained by any of the edaphic properties measured, nor by variation in climate. A new hypothesis of self-maintaining forest dynamic feedback mechanisms initiated by edaphic conditions is proposed. It is further suggested that this is a major factor determining forest disturbance levels, species composition and forest productivity on a Basin wide scale.

Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. Affected forest lost biomass, reversing a large long-term carbon sink, with the greatest impacts observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 × 1015 to 1.6 × 1015 grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change

Forest structure and dynamics have been noted to vary across the Amazon Basin in an east-west gradient in a pattern which coincides with variations in soil fertility and geology. This has resulted in the hypothesis that soil fertility may play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates. To test this hypothesis and assess the importance of edaphic properties in affect forest structure and dynamics, soil and plant samples were collected in a total of 59 different forest plots across the Amazon Basin. Samples were analysed for exchangeable cations, C, N, pH with various Pfractions also determined. Physical properties were also examined and an index of soil physical quality developed. Overall, forest structure and dynamics were found to be strongly and quantitatively related to edaphic conditions. Tree turnover rates emerged to be mostly influenced by soil physical properties whereas forest growth rates were mainly related to a measure of available soil phosphorus, although also dependent on rainfall amount and distribution. On the other hand, large scale variations in forest biomass could not be explained by any of the edaphic properties measured, nor by variation in climate. A new hypothesis of self-maintaining forest dynamic feedback mechanisms initiated by edaphic conditions is proposed. It is further suggested that this is a major factor determining forest disturbance levels, species composition and forest productivity on a Basin wide scale.

Positive aboveground biomass trends have been reported from old-growth forests across the Amazon basin and hypothesized to reflect a large-scale response to exterior forcing. The result could, however, be an artefact due to a sampling bias induced by the nature of forest growth dynamics. Here, we characterize statistically the disturbance process in Amazon old-growth forests as recorded in 135 forest plots of the RAINFOR network up to 2006, and other independent research programmes, and explore the consequences of sampling artefacts using a data-based stochastic simulator. Over the observed range of annual aboveground biomass losses, standard statistical tests show that the distribution of biomass losses through mortality follow an exponential or near-identical Weibull probability distribution and not a power law as assumed by others. The simulator was parameterized using both an exponential disturbance probability distribution as well as a mixed exponential–power law distribution to account for potential large-scale blowdown events. In both cases, sampling biases turn out to be too small to explain the gains detected by the extended RAINFOR plot network. This result lends further support to the notion that currently observed biomass gains for intact forests across the Amazon are actually occurring over large scales at the current time, presumably as a response to climate change.

Na capa consta: Cómo se engaña a la naturaleza, cómo se venga la naturaleza, Tradución de: Les Défaitistes de l'amour. Étude anecdotique, médicale et historique sur les égarements de l'instinct et la stérilité volontaire, No pé de imprenta da capa anterior consta: Ediciones Jason ; e na capa posterior "Ancha, 13, entresuelo, Barcelona"

Na portada.: Versos recomendados no concurso de "El primer libro" aberto en 1911 pola Academia de la Poesía Española, Na capa: Renacimiento, Mención de ed. tomada da capa

Huecograbado Arte imprime ca. 1947, Probablemente impreso en la primera mitad del s. XX

El presente escrito es un trabajo autoetnográfico, en el que se usan algunas estrategias de investigación con el fin de describir y analizar mi experiencia, como autor e investigador, para comprender el conjunto de eventos y fenómenos, personales y culturales, bajo los cuales se ha desarrollado mi formación como flautista. De igual forma, no sólo se hace un registro sistemático de hechos pasados de mi vida, sino que se realiza el mismo proceso de registro de información de experiencias presentes, que se dan durante el proceso de investigación y construcción del escrito.