1,720,987 research outputs found
Cellular and cytokinic patterns in nasal lavage fluids of children with seasonal rhino-comjunctivitis
No full textShallow groundwater nitrogen and denitrification in a newly afforested, subirrigated riparian buffer
No full text1. The EU ‘Nitrates Directive’ (Directive 91⁄ 676 ⁄EEC) and the WFD (Water Framework Direc-
tive 2000⁄ 60⁄EEC) introduced a series of measures designed to reduce and prevent water pollution
caused or induced by nitrates from agricultural sources. Therefore, there is an urgent requirement
to control the nitrate concentration in freshwater. The objective of this paper was to verify the
potential capacity of a specifically designed afforested riparian zone in removing the excess of nitro-
gen from river water.
2. A buffer zone was set with irrigation ditches, to produce a subsurface water flow carrying water
from the study river through the buffer strip to drainage ditches. This experimental system enables
the co-occurrence of two main processes: vegetation⁄microbial nitrogen uptake and denitrification.
Both in situ denitrification and denitrification potential were measured at different soil depths, and
nitrogen removal of water passing through the buffer system was measured.
3. After the first year, high removal rates (63–64%) of total nitrogen in water were recorded. The
lowest rate of denitrification took place in the upper soil layer, while maximum denitrification
occurred in the medium layer (40–55 cm). Denitrification occurred mainly in the first few metres of
the irrigation ditches leading away from the river. The denitrification rates clearly increased from
the second to the third year, with highest rates in summer and autumn. Denitrification potential
indicated that carbon availability was the most limiting factor.
4. Synthesis and applications. This study has demonstrated that nitrogen levels can be reduced in
rivers by forcing water to circulate through afforested buffers. Nitrogen was removed both by plants
and by microbial denitrification. Such activity can be supported by promoting anoxic conditions
through appropriate water flow management. This could be achieved by creating semi-natural
floodplains where water flows can be efficiently managed as in a drained wetland
Microbial diversity and denitrification in a wooded riparian strip
No full textThis study is part of a project aimed at verifying the potential of a specifically assessed wooded riparian zone in removing excess of combined nitrogen from the Zero river flow for the reduction of nutrient input into Venice Lagoon. General objectives of this project were to increase knowledge on the processes which allow the riparian strips to act as a buffer and to identify the most appropriate management strategies in order to maximize the efficiency of these systems in supporting the microbial activities involved in the process. For this purpose, specific objectives were pursued to determine seasonal fluctuations of the microbial populations in the soil/water of the wooded riparian strip. The bacterial communities were determined by combined approaches involving cultivation, microscopic approaches and DNA bases techniques to characterize both colturable and total microbial community inside and outside the riparian strip.
ARDRA and DGGE analyses of soil, collected at different depths, showed a clear decrease of the microbial diversity in deeper horizons as compared to the medium depth and surface ones. A comparison between this soil and that collected from an undisturbed zone external to the riparian strip, indicated that this effect can be also observed in the external area, although higher microbial diversity was always present in the internal soil. DGGE cluster analysis and PCA of both genetic and chemical properties of water samples, indicated that the bacterial populations present at the drainage ditches are rich in denitrifiers as a result of a mixing of bacterial communities carried by the Zero river flux and those already present in the soil of the riparian strip.
Taken together, the overall results confirm what it was demonstrated by other chemical-physical analysis: the wooded riparian buffer zone assessed for water remediation (nitrogen removal from the river) is effectively working as a result of the special conditions there produced to support the work of specific microbial populations. The microbiological analysis here accomplished can also contribute to understand the bacterial population dynamic of an agricultural soil when transformed in a wooded strip and to provide key indications for the management of a phytoremediation site
TIPIZZAZIONE CELLULARE E CITOCHINICA NEL LIQUIDO DI LAVAGGIO NASALE IN BAMBINI ATOPICI CON RINITE ALLERGICA E INFETTIVA
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Preliminary assessment on flood mitigation potential via managed aquifer recharge in the Brenta megafan (Italy)
No full textManaged aquifer recharge (MAR) design and operation must incorporate the expected long-term performance from a water quantity perspective to sustainably mitigate hydrologic impacts of groundwater overexploitation. Gravity driven infiltration ditches are one of many MAR schemes that could augment the available water resources. In the present study, an infiltration system (IS) consisting of 8 ditches was monitored to determine its hydrologic performance over time and its possible export to similar areas of the Brenta Megafan (Northern Italy). The IS displayed an almost constant capacity to infiltrate the diverted water with a total amount of 0.8 Mm3/ha/y. The good results suggest to promote this technique in other areas that suffer from groundwater resources depletion
Ecosystem services evaluation of nature-based solutions with the help of citizen scientists
Full text linkEcosystem services are increasingly being considered in decision-making with respect to mitigating future climate impacts. In this respect, there is a clear need to identify how nature-based solutions (NBS) can benefit specific ecosystem services, in particular within the complex spatial and temporal dynamics that characterize most river catchments. To capture these changes, ecosystem models require spatially explicit data that are often difficult to obtain for model development and validation. Citizen science allows for the participation of trained citizen volunteers in research or regulatory activities, resulting in increased data collection and increased participation of the general public in resource management. Despite the increasing experience in citizen science, these approaches have seldom been used in the modeling of provisioning ecosystem services. In the present study, we examined the temporal and spatial drivers in nutrient delivery in a major Italian river catchment and under different NBS scenarios. Information on climate, land use, soil and river conditions, as well as future climate scenarios, were used to explore future (2050) benefits of NBS on local and catchment scale nutrient loads and nutrient export. We estimate the benefits of a reduction in nitrogen and phosphorus export to the river and the receiving waters (Adriatic Sea) with respect to the costs associated with individual and combined NBS approaches related to river restoration and catchment reforestation
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
The use of nirK gene for the evaluation of a buffer strip assessed for enhancing denitrification
No full textSpecific soil microbial populations and activities could be promoted by suitable manipulation of the
environment they live in. If correctly applied such an approach could become a very effective way
to remediate excess of chemicals. The concentration of nitrogen, especially nitrate deriving from
agricultural managements, is generally found to increase in water flow. Therefore, by forcing the
water flow through a buffer strip specifically designed and possibly afforested with suitable plant
species, may result effective in reducing high nitrogen contents. The management of a riparian
buffer may definitely affect the soil microbial activities, including denitrification, as well as the
composition of the community.
The present study reports on the changes occurred in terms of denitrifying microbial community
composition, as compared to that of a neighbouring agricultural area, as a consequence of hydraulic
management coupled to the suspension of farming practices and to the development of the woody
and herbaceous vegetation.
With this aim, denitrification was constantly measured and the data obtained were related to those
deriving from a specific analysis of the soil community composition performed both as a general
bacterial population survey and as a direct determination of specific bacterial groups involved in
denitrification. nirK, encoding for nitrite reductase, an enzyme essential for the conversion of nitrite
to nitric oxide and considered the key step in the denitrification process, was choosen as the target
gene
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