5,658 research outputs found
Towards an integrated stratigraphy of the Gramame Formation (Maastrichtian), CIPASA quarry, Pernambuco-ParaÃba Basin, NE Brazil
This study presents the integrated biostratigraphic (calcareous nannofossils and foraminifera), petrographic, geochemical and ichnological analyzes of the Gramame Formation (Maastrichtian) at the CIPASA Quarry section, in the Pernambuco-ParaÃba Basin, northeastern Brazil. A high resolution calcareous nannofossil biostratigraphic study has been carried out, allowing to subdivide the studied section into three subzones of Maastrichtian age: CC25A, CC25B, and CC25C. Each biostratigraphic unit was further characterized by petrographic, geochemical and ichnological parameters. During the Maastrichtian the area was characterized by a dry and warm climate with low influx of terrigenous sediments. These conditions were fundamental to the widespread development of a carbonate ramp system in an outer neritic to bathyal setting, with deposition of alternating calcareous mudstones and argillaceous mudstones of the Gramame Formation. The Gramame Formation belongs to the transgressive system tract of second-order type, characteristic of a Passive Margin Sequence. The studied section consists of part of a third order deposicional cycle, which is arranged in a transgressive systems tract and a highstand systems tract. The lowstand systems tract was not characterized
Cleavages of photochromic compounds derived from heterocycles under electrospray tandem mass spectrometry : study of the influence of the heteroatom in fragmentation mechanisms
In this paper we report the fragmentation pathways of chromenes derived from carbazole, dibenzofuran and dibenzothiophene, under ESI-MS/MS experimental conditions, and their relationship with structural features, specially focused on the heteroatom’s effect on the fragmentation mechanisms.Fundação para a Ciência e Tecnologia (FCT
Innovative structural systems for industrial buildings using fiber reinforced concrete and material nonlinear FEM-Based models
Fibre Reinforced Concrete (FRC) can be very effective in precast pre-stressed
high strength concrete structures, since shear reinforcement and passive longitudinal bars
can be totally replaced by fibre reinforcement. To simulate adequately the fibre
reinforcement benefits, material constitutive models, able of capturing the crack initiation
and crack propagation need to be used, under the frame-work of FEM-based analysis. In
the present work, the use of FRC was explored for the development of innovative
structural systems for industrial buildings. The connections between structural precast
elements were also simulated. The numerical simulations are described and the results are
analyzed and discussed
Development of a metric of aquatic invertebrates for volunteers (MAIV): a simple and friendly biotic metric to assess ecological quality of streams
Citizen science activities, involving local people in volunteer-supported and sustainable
monitoring programs, are common. In this context, the objective of the present work was to develop a
simple Metric of Aquatic Invertebrates for Volunteers (MAIV), including a user-friendly tool that can
be easily accessed by volunteers, and to evaluate the e ciency of a volunteer monitoring program
following an audit procedure. To obtain MAIV values, macroinvertebrate communities were reduced
to 18 surrogate taxa, which represented an acceptable compromise between simplicity, e ciency, and
reproducibility of the data, compared to the regular Water Framework Directive monitoring. When
compared to results obtained with the National Classification System of Portugal, MAIV accurately
detected moderate, poor, and bad ecological status. Thus, MAIV can be used by volunteers as a
complement to the o cial monitoring program, as well as a prospective early warning tool for
local problems related to ecological quality. Volunteers were students supervised by their teachers.
Results obtained by volunteers were compared to results obtained by experts on macroinvertebrate
identification to measure the e ciency of the procedure, by counting gains and losses on sorting,
and identification. Characteristics of groups of volunteers (age and school level) did not influence
significantly the e ciency of the procedure, and generally results of volunteers and experts matched.info:eu-repo/semantics/publishedVersio
Development of new analytical tools for monitoring of cardiovascular disease markers – towards the detection of homocysteine-thiolactone
Poster presented at the 4th International Conference on Bio-Sensing Technology, 10-13 May 2015, Lisbon, Portuga
New PON1-based biosensor for the detection of homocysteine-thiolactone in human plasma
Poster presented at the XXIII International Symposium on Bioelectrochemistry and Bioenergetics, 14-18 June 2015, Malmo, Sweden
Chaetomellic acid A treatment improves oxidative stress in rats with renal mass reduction
Chaetomellic acid A (CA) is a potent and highly specific inhibitor of Ras farnesyl-protein
transferase that has shown to decrease oxidative stress in rats with brain damage.
Oxidative stress has been suggested to play an important role in the pathogenesis of
chronic renal disease. Thus, the aim of this work was to evaluate the effect of chronic
treatment with CA on oxidative stress in a model of renal mass reduction. Male Wistar
rats were subjected to 5/6 nephrectomy (RMR) or sham-operated (SO). One week after
surgery, rats have been placed in four experimental groups: RMR rats without
treatment (n=12); RMR rats treated with CA (n=8); SO rats without treatment (n=13);
SO rats treated with CA (n=13). CA was intraperitoneally administered in a dose of
0.23 μg/Kg three times a week for six months. To evaluate the effect of CA on renal
redox potential, the status of oxidative stress in renal tissues was determined. RMR
was accompanied by a significant reduction in catalase and glutathione reductase (GR)
activity, and a decrease in reduced glutathione (GSH)/oxidized glutathione (GSSG)
ratio. CA administration significantly increased catalase and GR activity (p<0.05), and
increased GSH/GSSG ratio, but no significant difference between the treated and no
treated groups was found in this ratio. These data suggest that CA can attenuate 5/6
RMR-induced oxidative stress and therefore, contribute to prevention of progressive
renal failure in chronic renal disease
A flexible decision support tool for maintenance float systems: a simulation approach
This paper is concerned with the use of simulation as a decision support tool in maintenance systems, specifically in MFS (Maintenance Float Systems). For this purpose and due to its high complexity, in this paper the authors explore and present a way to develop a flexible MFS model, for any number of machines in the workstation, spare machines and maintenance crews, using Arena simulation language. Also in this paper, some of the most common performance measures are identified, calculated and analysed. Nevertheless this paper would concentrate on the two most important performance measures in maintenance systems: system availability and maintenance total cost. As far as these two indicators are concerned, it was then quite clear that they assumed different behaviour patterns, especially when using extreme values for periodic overhauls rates. In this respect, system availability proved to be a more sensitive parameter.This work was funded by the "Programa Operacional Fatores de Competitividade - COMPETE" and by the FCT - Fundação para a Ciência e Tecnologia in the scope of the project: FCOMP-01-0124-FEDER-022674
Thermal and structural analysis of 4,5,6-trimethoxyisatin
4,5,6-Trimethoxyisatin was crystallized from water to give dark red needles that were characterized by NMR and IR spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), single-crystal X-ray diffraction (XRD) and hot-stage microscopy.Fundação para a Ciência e a Tecnologia (FCT) - POCTISFA-3-686Fundo Europeu de Desenvolvimento Regional (FEDER
Diversity of plant growth-promoting bacteria associated with sugarcane
The sugarcane (Saccharum spp) presents economic importance, mainly for tropical regions, being an important Brazilian commodity. However, this crop is strongly dependent on fertilizers, mainly nitrogen (N). This study assessed the plant growth-promoting bacteria (PGPB) associated with sugarcane that could be used as a potential inoculant to the crop. We evaluated the genetic diversity of PGPB in the plant tissue of sugarcane varieties (RB 867515, RB 1011, and RB 92579). The primer BOX-A1R was used to differentiate the similar isolated and further sequencing 16S rRNA ribosomal gene. The 16S rRNA gene showed the presence of seven different genera distributed into four groups, the genus Bacillus, followed by Paenibacillus (20%), Burkholderia (14%), Herbaspirillum (6%), Pseudomonas (6%), Methylobacterium (6%), and Brevibacillus (3%). The molecular characterization of endophytic isolates from sugarcane revealed a diversity of bacteria colonizing this plant, with a possible biotechnological potential to be used as inoculant and biofertilizers
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