Seasonal changes in soil organic matter after a decade of nutrient addition in a lowland tropical forest

© 2015, US Government. Soil organic matter is an important pool of carbon and nutrients in tropical forests. The majority of this pool is assumed to be relatively stable and to turn over slowly over decades to centuries, although changes in nutrient status can influence soil organic matter on shorter timescales. We measured carbon, nitrogen, and phosphorus concentrations in soil organic matter and leaf litter over an annual cycle in a long-term nutrient addition experiment in lowland tropical rain forest in the Republic of Panama. Total soil carbon was not affected by a decade of factorial combinations of nitrogen, phosphorus, or potassium. Nitrogen addition increased leaf litter nitrogen concentration by 7 % but did not affect total soil nitrogen. Phosphorus addition doubled the leaf litter phosphorus concentration and increased soil organic phosphorus by 50 %. Surprisingly, concentrations of carbon, nitrogen, and phosphorus in soil organic matter declined markedly during the four-month dry season, and then recovered rapidly during the following wet season. Between the end of the wet season and the late dry season, total soil carbon declined by 16 %, total nitrogen by 9 %, and organic phosphorus by between 19 % in control plots and 25 % in phosphorus addition plots. The decline in carbon and nitrogen was too great to be explained by changes in litter fall, bulk density, or the soil microbial biomass. However, a major proportion of the dry-season decline in soil organic phosphorus was explained by a corresponding decline in the soil microbial biomass. These results have important implications for our understanding of the stability and turnover of organic matter in tropical forest soils, because they demonstrate that a considerable fraction of the soil organic matter is seasonally transient, despite the overall pool being relatively insensitive to long-term changes in nutrient status

Casimir type effects for scalar fields interacting with material slabs

We study the field theoretical model of a scalar field in presence of spacial inhomogeneities in form of one and two finite width mirrors (material slabs). The interaction of the scalar field with the defect is described with position-dependent mass term. For the single layer system we develop a rigorous calculation method and derive explicitly the propagator of the theory, S-matrix elements and the Casimir self-energy of the slab. Detailed investigation of particular limits of self-energy is presented, and connection to know cases is discussed. The calculation method is found applicable to the two mirrors case as well. By means of it we derive the corresponding Casimir energy and analyze it. For particular values of the parameters of the model the obtained results recover the Lifshitz formula. We also propose a procedure to obtain unambiguously the finite Casimir \textit{self}-energy of a single slab without reference to any renormalizations. We hope that our approach can be applied to calculation of Casimir self-energies in other demanded cases (such as dielectric ball, etc.)Comment: 22 pages, 3 figures, published version, significant changes in Section 4.

Historia de los medios de comunicación de Misiones: LT 85 TV Canal 12, el canal de TV de los Misioneros. 16H295

Actividades desarrolladas durante el período: avance en la búsqueda de información respecto de documentación y de fuentes orales de información sobre la historia del Canal 12; rescate testimonios fotográficos y de cintas fílmicas de los primeros años del Canal 12 que están en poder de particulares; rescate de material fílmico existente en el Canal; desgravaciones de las entrevistas realizadas para la entrega posterior a los informantes. Sistematización de la organización de las fotografías que han sido facilitadas para la construcción de la investigación

Plant responses to fertilization experiments in lowland, species-rich, tropical forests.

We present a meta-analysis of plant responses to fertilization experiments conducted in lowland, species-rich, tropical forests. We also update a key result and present the first species-level analyses of tree growth rates for a 15-yr factorial nitrogen (N), phosphorus (P), and potassium (K) experiment conducted in central Panama. The update concerns community-level tree growth rates, which responded significantly to the addition of N and K together after 10 yr of fertilization but not after 15 yr. Our experimental soils are infertile for the region, and species whose regional distributions are strongly associated with low soil P availability dominate the local tree flora. Under these circumstances, we expect muted responses to fertilization, and we predicted species associated with low-P soils would respond most slowly. The data did not support this prediction, species-level tree growth responses to P addition were unrelated to species-level soil P associations. The meta-analysis demonstrated that nutrient limitation is widespread in lowland tropical forests and evaluated two directional hypotheses concerning plant responses to N addition and to P addition. The meta-analysis supported the hypothesis that tree (or biomass) growth rate responses to fertilization are weaker in old growth forests and stronger in secondary forests, where rapid biomass accumulation provides a nutrient sink. The meta-analysis found no support for the long-standing hypothesis that plant responses are stronger for P addition and weaker for N addition. We do not advocate discarding the latter hypothesis. There are only 14 fertilization experiments from lowland, species-rich, tropical forests, 13 of the 14 experiments added nutrients for five or fewer years, and responses vary widely among experiments. Potential fertilization responses should be muted when the species present are well adapted to nutrient-poor soils, as is the case in our experiment, and when pest pressure increases with fertilization, as it does in our experiment. The statistical power and especially the duration of fertilization experiments conducted in old growth, tropical forests might be insufficient to detect the slow, modest growth responses that are to be expected

Normal and Lateral Casimir Forces between Deformed Plates

The Casimir force between macroscopic bodies depends strongly on their shape and orientation. To study this geometry dependence in the case of two deformed metal plates, we use a path integral quantization of the electromagnetic field which properly treats the many-body nature of the interaction, going beyond the commonly used pairwise summation (PWS) of van der Waals forces. For arbitrary deformations we provide an analytical result for the deformation induced change in Casimir energy, which is exact to second order in the deformation amplitude. For the specific case of sinusoidally corrugated plates, we calculate both the normal and the lateral Casimir forces. The deformation induced change in the Casimir interaction of a flat and a corrugated plate shows an interesting crossover as a function of the ratio of the mean platedistance H to the corrugation length \lambda: For \lambda \ll H we find a slower decay \sim H^{-4}, compared to the H^{-5} behavior predicted by PWS which we show to be valid only for \lambda \gg H. The amplitude of the lateral force between two corrugated plates which are out of registry is shown to have a maximum at an optimal wavelength of \lambda \approx 2.5 H. With increasing H/\lambda \gtrsim 0.3 the PWS approach becomes a progressively worse description of the lateral force due to many-body effects. These results may be of relevance for the design and operation of novel microelectromechanical systems (MEMS) and other nanoscale devices.Comment: 20 pages, 5 figure

Evaluation of the indicators of inflammation in the diagnosis of ovine mastitis

O objetivo do presente trabalho foi avaliar diferentes indicadores inflamatórios no diagnóstico da mamite em ovinos da raça Santa Inês. Após a realização do exame físico das mamas e a prova de fundo escuro, foram coletadas e analisadas 390 amostras de leite, sendo as metades mamárias divididas de acordo com o exame bacteriológico e a prova de fundo escuro, resultando em 290 amostras negativas em ambos os exames, 90 amostras negativas à prova de fundo escuro e positivas na cultura bacteriológica, 5 amostras positivas à prova de fundo escuro e negativas ao exame bacteriológico e 3 amostras positivas em ambos os testes. Nestas amostras foram realizadas a contagem automática de células somáticas (CCS), o California Mastitis Test (CMT), a determinação da concentração hidrogeniônica (pH) e dos teores de cloreto e lactose, e ainda a avaliação do índice de cloreto-lactose. Os maiores valores preditivos foram observados para a CCS, CMT e teor de cloreto; o pH, o teor de lactose e o índice cloreto-lactose apresentaram-se como marcadores inflamatórios menos sensíveis, onde se considerou o resultado da cultura bacteriológica como padrão ouro. O exame físico não se mostrou como método diagnóstico seguro quando utilizado isoladamente, exaltando a importância da associação de outros meios diagnósticos indiretosThe aim of this trial was to evaluate distinct indictors of inflammation in the diagnosis of mastitis in Santa Ines ewes. The physical examination and the dark bottom cup test were performed. Afterwards, the bacteriologic samples of 390 milk samples were analyzed. The samples were divided according to the bacteriological examination and the dark cup bottom test, resulting in 290 samples negative in both tests, 90 samples positive in the bacteriological examination and negative in the dark cup bottom test, 5 samples positive in the dark cup bottom test and negative in bacteriological culture, and 3 samples positive in both tests. The automatic somatic cell count (SSC), the California mastitis test (CMT), the pH, the chloride and lactose content, and the chloride-lactose number were established. Then, their predictive value as a indicator of inflammation was calculated assuming the bacteriologic examination as the gold standard test. The CCS, CMT and chloride content proved to be the best predictors, while the pH, the lactose content and chloride-lactose number were the least sensitive tests. The physical examination was revealed to be a nonsensitive diagnostic procedure when used as the only procedure to detect the disease, showing that other diagnostics tests are requiredFAPESPCNP

Interaction of convective organisation with monsoon precipitation, atmosphere, surface and sea: the 2016 INCOMPASS field campaign in India

The INCOMPASS field campaign combines airborne and ground measurements of the 2016 Indian monsoon, towards the ultimate goal of better predicting monsoon rainfall. The monsoon supplies the majority of water in South Asia, but forecasting from days to the season ahead is limited by large, rapidly developing errors in model parametrizations. The lack of detailed observations prevents thorough understanding of the monsoon circulation and its interaction with the land surface: a process governed by boundary‐layer and convective‐cloud dynamics. INCOMPASS used the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe‐146 aircraft for the first project of this scale in India, to accrue almost 100 h of observations in June and July 2016. Flights from Lucknow in the northern plains sampled the dramatic contrast in surface and boundary‐layer structures between dry desert air in the west and the humid environment over the northern Bay of Bengal. These flights were repeated in pre‐monsoon and monsoon conditions. Flights from a second base at Bengaluru in southern India measured atmospheric contrasts from the Arabian Sea, over the Western Ghats mountains, to the rain shadow of southeast India and the south Bay of Bengal. Flight planning was aided by forecasts from bespoke 4 km convection‐permitting limited‐area models at the Met Office and India's NCMRWF. On the ground, INCOMPASS installed eddy‐covariance flux towers on a range of surface types, to provide detailed measurements of surface fluxes and their modulation by diurnal and seasonal cycles. These data will be used to better quantify the impacts of the atmosphere on the land surface, and vice versa. INCOMPASS also installed ground instrumentation supersites at Kanpur and Bhubaneswar. Here we motivate and describe the INCOMPASS field campaign. We use examples from two flights to illustrate contrasts in atmospheric structure, in particular the retreating mid‐level dry intrusion during the monsoon onset

Interaction of convective organisation with monsoon precipitation, atmosphere, surface and sea: the 2016 INCOMPASS field campaign in India

The INCOMPASS field campaign combines airborne and ground measurements of the 2016 Indian monsoon, towards the ultimate goal of better predicting monsoon rainfall. The monsoon supplies the majority of water in South Asia, but forecasting from days to the season ahead is limited by large, rapidly developing errors in model parametrizations. The lack of detailed observations prevents thorough understanding of the monsoon circulation and its interaction with the land surface: a process governed by boundary-layer and convective-cloud dynamics. INCOMPASS used the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 aircraft for the first project of this scale in India, to accrue almost 100 hours of observations in June and July 2016. Flights from Lucknow in the northern plains sampled the dramatic contrast in surface and boundary layer structures between dry desert air in the west and the humid environment over the northern Bay of Bengal. These flights were repeated in pre-monsoon and monsoon conditions. Flights from a second base at Bengaluru in southern India measured atmospheric contrasts from the Arabian Sea, over the Western Ghats mountains, to the rain shadow of southeast India and the south Bay of Bengal. Flight planning was aided by forecasts from bespoke 4km convection-permitting limited-area models at the Met Office and India's NCMRWF. On the ground, INCOMPASS installed eddy-covariance flux towers on a range of surface types, to provide detailed measurements of surface fluxes and their modulation by diurnal and seasonal cycles. These data will be used to better quantify the impacts of the atmosphere on the land surface, and vice versa. INCOMPASS also installed ground instrumentation supersites at Kanpur and Bhubaneswar. Here we motivate and describe the INCOMPASS field campaign. We use examples from two flights to illustrate contrasts in atmospheric structure, in particular the retreating mid-level dry intrusion during the monsoon onset

Simple to be Useful: Ecosystem Base for Coastal Management

Os processos de Gerenciamento Costeiro (GC) nas últimas décadas vêm evoluindo, apresentando diferentes métodos de gestão, sendo que uma nova fronteira se encontra na Gestão com Base Ecossistêmica (GBE). No entanto, para colocar em prática a GBE, a qual leva em consideração as funções, os processos e os serviços ecossistêmicos dos ambientes costeiros e marinhos, entendendo-os como um conjunto de ecossistemas compostos por elementos ecológicos (naturais), econômicos e sociais, se faz necessária a base de informação ecossistêmica. O presente trabalho propõe, apresentando resultados aplicados, um roteiro metodológico de seis etapas: 1. Identificar os ecossistemas como “Unidades de Gestão”; 2. Mapear, modelar e simular os ecossistemas; 3. Identificar e classificar os serviços ecossistêmicos; 4. Definir os valores e a qualidade dos serviços; 5. Identificar os espaços de gestão; e 6. Integrar com políticas e demais instrumentos de gestão e legais. As aplicações práticas apresentadas vão desde trabalhos acadêmicos de identificação e caracterização de ambientes costeiros e marinhos a aplicações nos processos de gestão ambiental portuários, passando também pelo desenvolvimento de Zoneamentos Ecológico-Econômicos (ZEEs) em nível regional, por exemplo. Na apreciação integral do conjunto de exemplos e iniciativas para todas as etapas do modelo, depreende-se que a sua aplicação é ampla, variada e consideravelmente simples. Da mesma forma, a multiplicidade de possíveis aplicações do modelo em ações voltadas ao suporte de uma GBE sugere que seu uso pode crescer e buscar iniciativas inovadoras. A expectativa dos autores é de que tal ferramenta possa, de fato, delinear e estimular pesquisas e aplicações com base ecossistêmica na busca da sustentabilidade da costa e do bem-estar de seus atores sociais.In the last decades Coastal Management (CM) processes have been evolving, presenting different management methods, and the new frontier is at the so-called Ecosystem Based Management (EBM). However, to put into practice EBM, which takes into account ecosystem functions, processes and services of coastal and marine environments, understanding them as a set of ecosystems composed of ecological (natural), economic and social elements, it is necessary an ecosystem-based information. The present work proposes, presenting practical results, a methodological path of six stages: 1. Identification of ecosystems as "Management Units"; 2. Mapping, modeling and simulating ecosystems and their connections; 3. Identification and classification of ecosystem services; 4. Definition of values and quality of services; 5. Identification of related management procedures; and 6. Integration with policies and other management and legal tools. The concrete applications range from academic studies of identification and characterization of coastal and marine environments, to port’s environmental management processes, and the development of ecological-economic zoning at regional level, for example. In the full appreciation of the set of examples and initiatives for all stages of the model, it can be concluded that its application is wide, varied and considerably simple. Likewise, the multiplicity of possible applications of the model in practical actions aimed to support of an EBM, suggests that its use can grow and pursue innovative initiatives. The authors' expectation is that such a tool may, in fact, delineate and stimulate research and applications based on ecosystems in the quest for the sustainability of the coast and the well-being of its social actors