Neutron Transfer reactions induced by 8Li on 9Be

Angular distributions for the elastic scattering of 8Li on 9Be and the neutron transfer reactions 9Be(8Li,7Li)10Be and 9Be(8Li,9Li)8Be have been measured with a 27 MeV 8Li radioactive nuclear beam. Spectroscopic factors for 8Li|n=9Li and 7Li|n=8Li bound systems were obtained from the comparison between the experimental differential cross section and finite-range DWBA calculations with the code FRESCO. The spectroscopic factors obtained are compared to shell model calculations and to other experimental values from (d,p) reactions. Using the present values for the spectroscopic factor, cross sections for the direct neutron-capture reactions 7Li(n,g)8Li and 8Li(n,g)9Li were calculated in the framework of a potential model.Comment: 24 pages, 8 Figures, submitted as regular article to PR

Recent developments of the Hierarchical Reference Theory of Fluids and its relation to the Renormalization Group

The Hierarchical Reference Theory (HRT) of fluids is a general framework for the description of phase transitions in microscopic models of classical and quantum statistical physics. The foundations of HRT are briefly reviewed in a self-consistent formulation which includes both the original sharp cut-off procedure and the smooth cut-off implementation, which has been recently investigated. The critical properties of HRT are summarized, together with the behavior of the theory at first order phase transitions. However, the emphasis of this presentation is on the close relationship between HRT and non perturbative renormalization group methods, as well as on recent generalizations of HRT to microscopic models of interest in soft matter and quantum many body physics.Comment: 17 pages, 5 figures. Review paper to appear in Molecular Physic

Fine-Scale in Situ Measurement of Riverbed Nitrate Production and Consumption in an Armored Permeable Riverbed

Alteration of the global nitrogen cycle by man has increased nitrogen loading in waterways considerably, often with harmful consequences for aquatic ecosystems. Dynamic redox conditions within riverbeds support a variety of nitrogen transformations, some of which can attenuate this burden. In reality, however, assessing the importance of processes besides perhaps denitrification is difficult, due to a sparseness of data, especially in situ, where sediment structure and hydrologic pathways are intact. Here we show in situ within a permeable riverbed, through injections of 15N-labeled substrates, that nitrate can be either consumed through denitrification or produced through nitrification, at a previously unresolved fine (centimeter) scale. Nitrification and denitrification occupy different niches in the riverbed, with denitrification occurring across a broad chemical gradient while nitrification is restricted to more oxic sediments. The narrow niche width for nitrification is in effect a break point, with the switch from activity “on” to activity “off” regulated by interactions between subsurface chemistry and hydrology. Although maxima for denitrification and nitrification occur at opposing ends of a chemical gradient, high potentials for both nitrate production and consumption can overlap when groundwater upwelling is strong

One sixth of Amazonian tree diversity is dependent on river floodplains

Amazonia's floodplain system is the largest and most biodiverse on Earth. Although forests are crucial to the ecological integrity of floodplains, our understanding of their species composition and how this may differ from surrounding forest types is still far too limited, particularly as changing inundation regimes begin to reshape floodplain tree communities and the critical ecosystem functions they underpin. Here we address this gap by taking a spatially explicit look at Amazonia-wide patterns of tree-species turnover and ecological specialization of the region's floodplain forests. We show that the majority of Amazonian tree species can inhabit floodplains, and about a sixth of Amazonian tree diversity is ecologically specialized on floodplains. The degree of specialization in floodplain communities is driven by regional flood patterns, with the most compositionally differentiated floodplain forests located centrally within the fluvial network and contingent on the most extraordinary flood magnitudes regionally. Our results provide a spatially explicit view of ecological specialization of floodplain forest communities and expose the need for whole-basin hydrological integrity to protect the Amazon's tree diversity and its function.Naturali

Avaliação da cv. Isabel sobre dois porta-enxertos em três sistemas de condução sob condições de clima tropical.

A produção de suco de uva e de vinhos de mesa está concentrada no sul do Brasil, com base na cv. Isabel. Devido à possibilidade de colheitas sucessivas e processamento da uva ao longo do ano, têm surgido iniciativas empresariais visando à elaboração destes produtos também em regiões tropicais. O objetivo deste trabalho foi avaliar o comportamento da cv. Isabel sob condições de clima tropical

Caracterização química na fase de maturação da variedade apirênica BRS Linda na Região do Apodi, CE.

A qualidade dos frutos é um atributo resultante de diversos fatores edafo-climáticos que atuam simultaneamente ao longo do processo de desenvolvimento e amadurecimento. São estritamente relacionadas e podem responder pela maior ou menor aceitação pelo consumidor. As alterações químicas são mais expostas durante o processo de maturação quando proporcionam mudanças acentuadas no teor de sólidos solúveis totais (SST), açucares totais, na acidez titulável (ATT) e pH, principalmente quando ocorrem em regiões ou épocas mais quentes

Estabelecimento de bactérias diazotróficas endofíticas inoculadas em cana-de-açúcar cultivadas em diferentes regiões do Brasil.

Made available in DSpace on 2011-04-09T14:12:09Z (GMT). No. of bitstreams: 1 Estabelecimentodebacteriasdiazotroficasendofiticasinoculadas.pdf: 73494 bytes, checksum: 2e7bceede145349706f34194523917ec (MD5) Previous issue date: 2011-02-04201

Decentralised treatment solutions for on-site faecal sludge: quantifying the removal efficiencies of two novel systems in an East African city

Pit latrines, leach-tanks and septic tanks are on-site sanitation systems used by approximately 2.7 billion people. For these systems to be safe, the faecal sludge needs to be safely contained or removed and treated off-site. In lower-income countries, affordable and efficient treatment systems are frequently non-existent. One promising treatment technology for faecal sludge is decentralised mesophilic anaerobic digestion, which can operate without energy or chemical inputs. This study presents the first thorough evaluation of loading, rainfall and operational performance of two novel faecal sludge treatment plants (FSTP). The plants serviced approximately 3000 households in urban Dar es Salaam, Tanzania. The faecal sludge was extracted from latrine back-ends and transported to the plants which had loading capacities of 4 m3 d−1 for system 1 and 5 m3 d−1 for system 2. Systems were monitored for 14 consecutive weeks for physical, chemical and microbiological parameter removal through the treatment stages. Overall increased rainfall was not linked to emptying requests from households. System 1 was consistently overloaded while system 2 was under-loaded, due to an operator preference and demand. Overloading for system 1 was correlated with increased TSS in the effluent. Notably, both systems showed significant removal of total suspended solids (TSS), free-ammonia nitrogen (FAN) and E. coli from raw faecal sludge. However, only system 1 recorded significant removal for chemical oxygen demand (COD). As a new technology the standards required for effluent discharged to ground are not clear. However, the digested and dried faecal sludge from system 1 had E. coli concentrations of 2.5 × 106 cfu g−1 and was not recommended for unrestricted agricultural use based on the WHO guidelines. With more consistent operational loading practices, the FSTP evaluated present two sustainable treatment systems for lower-income urban settings. © 2023 The Royal Society of Chemistr