209 research outputs found
An outbreak of sheep-associated malignant catarrhal fever in sows
his paper describes a case of malignant catarrhal fever in a sow herd in Belgium caused by infection with ovine herpesvirus-2 (OHV-2). The 11 affected sows had high fever and 10 of them died within 3 days after the onset of clinical disease. The most prominent macroscopic lesion was a hemorrhagic to pseudo-membranous gastritis. Histopathology revealed severe infiltration and necrosis of the gastric mucosa. Neither antimicrobial treatment nor injection with anti-inflammatory drugs ameliorated the severity of the disease. As the sows and sheep were housed in the same building with the possibility of having direct nose-to-nose contact, and as PCR testing showed that the virus found in the sows was identical to that found in the sheep, it is very likely that the infection was transmitted from the subclinically infected sheep to the sows. The present case showed that OHV-2 infection should be included in the differential diagnosis when facing problems of fever followed by death, especially when pigs are housed in close contact with sheep
Settlement of Macoma balthica larvae in response to benthic diatom films
The role of multi-species benthic diatom films (BDF) in the settlement of late pediveliger larvae of the bivalve Macoma balthica was investigated in still-water bioassays and multiple choice flume experiments. Axenic diatom cultures that were isolated from a tidal mudflat inhabited by M. balthica were selected to develop BDF sediment treatments characterized by a different community structure, biomass, and amount of extracellular polymeric substances (EPS). Control sediments had no added diatoms. Although all larvae settled and initiated burrowing within the first minute after their addition in still water, regardless of treatment, only 48-52% had completely penetrated the high diatom biomass treatments after 5 min, while on average 80 and 69% of the larvae had settled and burrowed into the control sediments and BDF with a low diatom biomass (<3.5 mu g Chl a g(-1) dry sediment), respectively. The percentage of larvae settling and burrowing into the sediment was negatively correlated with the concentration of Chl a and EPS of the BDF. This suggests higher physical resistance to bivalve penetration by the BDF with higher diatom biomass and more associated sugar and protein compounds. The larval settlement rate in annular flume experiments at flow velocities of 5 and 15 cm s(-1) was distinctly lower compared to the still-water assays. Only 4.6-5.8% of the larvae were recovered from BDF and control sediments after 3 h. Nonetheless, a clear settlement preference was observed for BDF in the flume experiments; i.e., larvae settled significantly more in BDF compared to control sediments irrespective of flow speed. Comparison with the settlement of polystyrene mimics and freeze-killed larvae led to the conclusion that active selection, active secondary dispersal and, at low flow velocities (5 cm s(-1)), passive adhesion to the sediment are important mechanisms determining the settlement of M. balthica larvae in estuarine biofilms
Settlement of <i>Macoma balthica</i> larvae in response to benthic diatom films
The role of multi-species benthic diatom films (BDF) in the settlement of late pediveliger larvae of the bivalve Macoma balthica was investigated in still-water bioassays and multiple choice flume experiments. Axenic diatom cultures that were isolated from a tidal mudflat inhabited by M. balthica were selected to develop BDF sediment treatments characterized by a different community structure, biomass, and amount of extracellular polymeric substances (EPS). Control sediments had no added diatoms. Although all larvae settled and initiated burrowing within the first minute after their addition in still water, regardless of treatment, only 48-52% had completely penetrated the high diatom biomass treatments after 5 min, while on average 80 and 69% of the larvae had settled and burrowed into the control sediments and BDF with a low diatom biomass (3.5 µg Chl a g1 dry sediment), respectively. The percentage of larvae settling and burrowing into the sediment was negatively correlated with the concentration of Chl a and EPS of the BDF. This suggests higher physical resistance to bivalve penetration by the BDF with higher diatom biomass and more associated sugar and protein compounds. The larval settlement rate in annular flume experiments at flow velocities of 5 and 15cm s1 was distinctly lower compared to the still-water assays. Only 4.6-5.8% of the larvae were recovered from BDF and control sediments after 3h. Nonetheless, a clear settlement preference was observed for BDF in the flume experiments; i.e., larvae settled significantly more in BDF compared to control sediments irrespective of flow speed. Comparison with the settlement of polystyrene mimics and freeze-killed larvae led to the conclusion that active selection, active secondary dispersal and, at low flow velocities (5cm s1), passive adhesion to the sediment are important mechanisms determining the settlement of M. balthica larvae in estuarine biofilms
Viabilidade técnica e econômica da substituição de fontes convencionais de energia por biogás em assentamento rural do Estado de São Paulo.
O objetivo deste estudo foi avaliar a viabilidade econômica da implantação de dois biodigestores com uso de dejetos animais em área do Assentamento de Trabalhadores Rurais no município de Itaberá - SP, no ano de 2005; um deles para o fornecimento de energia para os domicílios e outro para as atividades produtivas. Foram avaliados os benefícios referentes ao fornecimento de energia elétrica e térmica, a partir do biogás, para cinco domicílios da agrovila do assentamento e para as atividades produtivas, comparativamente aos custos de construção e operação para produção de biogás. Os resultados mostraram a viabilidade econômica da produção de gás em ambos os biodigestores. Foram gerados benefícios no valor de R 9.080,57 por ano, nos biodigestores para os domicílios e produção, respectivamente; bem como o equivalente a R 1.218,50 em cada biodigestor. O prazo de recuperação do investimento é de 2,5 anos e 11 meses, para a produção de biogás nos domicílios e na produção, respectivamente. Os resultados podem ser utilizados para subsidiar políticas públicas direcionadas ao aproveitamento de biomassa para a produção de energia a baixos custos no segmento da agricultura familiar
Organism-sediment interactions govern post-hypoxia recovery of ecosystem functioning
Hypoxia represents one of the major causes of biodiversity and ecosystem functioning loss for coastal waters. Since eutrophication-induced hypoxic events are becoming increasingly frequent and intense, understanding the response of ecosystems to hypoxia is of primary importance to understand and predict the stability of ecosystem functioning. Such ecological stability may greatly depend on the recovery patterns of communities and the return time of the system properties associated to these patterns. Here, we have examined how the reassembly of a benthic community contributed to the recovery of ecosystem functioning following experimentally-induced hypoxia in a tidal flat. We demonstrate that organism-sediment interactions that depend on organism size and relate to mobility traits and sediment reworking capacities are generally more important than recovering species richness to set the return time of the measured sediment processes and properties. Specifically, increasing macrofauna bioturbation potential during community reassembly significantly contributed to the recovery of sediment processes and properties such as denitrification, bedload sediment transport, primary production and deep pore water ammonium concentration. Such bioturbation potential was due to the replacement of the small-sized organisms that recolonised at early stages by large-sized bioturbating organisms, which had a disproportionately stronger influence on sediment. This study suggests that the complete recovery of organism-sediment interactions is a necessary condition for ecosystem functioning recovery, and that such process requires long periods after disturbance due to the slow growth of juveniles into adult stages involved in these interactions. Consequently, repeated episodes of disturbance at intervals smaller than the time needed for the system to fully recover organism-sediment interactions may greatly impair the resilience of ecosystem functioning.
San Francisco Bay Area corporate history : a selected annotated bibliography
Human activities, among which dredging and land use change in river basins,
are altering estuarine ecosystems. These activities may result in changes in
sedimentary processes, affecting biodiversity of sediment macrofauna. As
macrofauna controls sediment chemistry and fluxes of energy and matter between
water column and sediment, changes in the structure of macrobenthic
communities could affect the functioning of an entire ecosystem. We assessed
the impact of sediment deposition on intertidal macrobenthic communities and
on rates of an important ecosystem function, i.e. sediment community oxygen
consumption (SCOC). An experiment was performed with undisturbed sediment
samples from the Scheldt river estuary (SW Netherlands). The samples were
subjected to four sedimentation regimes: one control and three with a
deposited sediment layer of 1, 2 or 5 cm. Oxygen consumption was measured
during incubation at ambient temperature. Luminophores applied at the
surface, and a seawater–bromide mixture, served as tracers for bioturbation
and bio-irrigation, respectively. After incubation, the macrofauna was
extracted, identified, and counted and then classified into functional groups
based on motility and sediment reworking capacity. Total macrofaunal
densities dropped already under the thinnest deposits. The most affected
fauna were surficial and low-motility animals, occurring at high densities in
the control. Their mortality resulted in a drop in SCOC, which decreased
steadily with increasing deposit thickness, while bio-irrigation and
bioturbation activity showed increases in the lower sediment deposition
regimes but decreases in the more extreme treatments. The initial increased
activity likely counteracted the effects of the drop in low-motility, surficial
fauna densities, resulting in a steady rather than sudden fall in oxygen
consumption. We conclude that the functional identity in terms of motility
and sediment reworking can be crucial in our understanding of the regulation
of ecosystem functioning and the impact of habitat alterations such as
sediment deposition
Energy poverty in Portugal, Italy, and Norway: awareness, short-term driving forces, and barriers in the built environment
Portugal, Italy, and Norway differ by energy performance of buildings and gross
domestic product (GDP). Portugal has significantly highest thermal discomfort with harsher
winters. In 2021, 80% of Portuguese buildings had a low energy rating, with 75% of buildings
without thermal insulation, highly contributing to the energy poverty (EP) of the country. In
Italy, despite a generally mild climate, the building stock has low thermal performance. The most
affected areas are the suburban and peri-urban ones, with an EP rate in southern regions between
13% and 20% compared to 8.8% at national level. Moreover, 65% of buildings were constructed
before the first law on energy saving criteria and a 25% of it has never undergone any work of
maintenance or improvement. Norway, despite the limited studies performs well respect to other
European Economic Area and European Union countries, in investing and using indicators to
enhance and monitor the green energies’ use. Because of energy price growth, seasonal price
fluctuations, and different energy tariffs, energy inequality is increasing. EP risk is
underestimated, masked by Norway's high GDP and regional price disparity. Energy inequality
is increasing due to energy price growth, seasonal price fluctuations, and energy prices’
geographical inequality. The barriers in reducing EP are the underestimation of risk masked by
the high GDP, and the need of homogenized prices in Norway. This study provides an overview
to discuss EP awareness and it assesses the drivers and barriers that influence building's energy
efficiency renovatio
Restoration of estuarine tidal mudflat sediments after hypoxia
Ecosystem function recovery and benthic community recovery was investigated after experimentally induced depleted oxygen bottom water concentrations in a tidal mudflat (Paulinapolder, Westerschelde estuary). Macrofauna recovery developed through different succession stages and was structured by facilitative and inhibitive interactions: early colonizers had a positive effect on subsequent colonizers, while later succession species negatively affected the stable conditions created by the early colonizing tube-builders. Transitions between different stages were related to changes in environmental characteristics and biotic-environmental interactions (e.g. exploitation competition for food). Nematode community -and biogeochemical recovery were related to macrobenthic succession. Dense polychaete tube aggregations and the development of a fresh diatom bloom, as a result of the low grazing pressure by surface deposit feeding macrofauna during the first stage, stabilized the sediment and thereby enhanced macrobenthic and nematode recruitment success. Bioturbation impact of later succession species increased oxygen input in the sediment, resulting in an enhanced nitrification, denitrification and energy use
A dataset of criteria on the use of thermal insulation solutions in building facades located in Norway, Portugal and Italy
The building sector is responsible for a significant percentage of the energy consumption in Europe. The level of thermal insulation of the building envelope leads to decrease energy consumption, thus contributing towards a sustainable and efficient built environment. As a result, the choice of the most suitable thermal insulation solution to be applied both in new construction and in retrofitting of building facades is fundamental for a satisfactory thermal performance of the building. Nevertheless, the thermal insulation solution should not be chosen considering only the thermal performance, but rather based on a set of performance parameters (i.e., water resistance, fire performance, impact on the environment and human health, among others) and climate-related requirements. This data article includes a dataset on criteria adopted in three European countries (namely Norway, Portugal, and Italy) considering a PESTE analysis (i.e., criteria related to Political, Economic, Social, Technological, and Environmental questions). The main objective was to evaluate the knowledge and perception of people living and/or working in these countries about the use and the performance of thermal insulation solutions in building facades. To this aim a questionnaire was developed within the scope of the EEA Granted EFFICACY research project (November 2022 – February 2023), whose overall objective is to create a database that serves as a reference for the choice of thermal insulation solutions to be applied in building facades for thermal and energy performances optimization. This database contributes to systemize criteria and can be extended by other researchers or professionals in the area, as well as in other countries
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