308 research outputs found
Dry matter and area partitioning, radiation interception and radiation-use efficiency in open-field bell pepper
The objective of this study was to determine some key components of a model for bell pepper growth and
yield under non-limiting water and nutrient conditions using data from field trials conducted in
Southern Portugal. DM partitioning, at least before fruiting, and specific area indices for leaves, stems
and fruits were conservative in relation to normalized thermal time. The interception model had a good
performance. It was based on the exponential extinction of radiation on the area covered by the plants,
the ellipsoidal leaf-angle distributionmodel (X-parameter 2.48 and 2.89), and absorptivities of the leaves
for PAR and NIR, 0.8 and 0.2, respectively. Radiation-use efficiency (RUE) was determined and presented
in four different forms. RUE did not change substantially throughout the growing season. RUE of irrigated
pepper crops grown in our experiments was around 1.6 g MJ 1 of intercepted PAR. The models and
parameter values presented in this study may be useful to simulate the development and growth of fieldgrown
pepper cro
Life cycle assessment of a vanadium flow battery
The 6th International Conference on Energy and Environment Research, July 22–25, 2019, University of Aveiro, PortugalBattery storage technologies have been showing great potential to address the vulnerability of renewable electricity generation systems. Among the various options, vanadium redox flow batteries are one of the most promising in the energy storage market. In this work, a life cycle assessment of a 5 kW vanadium redox flow battery is performed on a cradle-to-gate approach with focus on the vanadium electrolytes, since they determine the battery’s storage capacity and can be readjusted and reused indefinitely. The functional unit is 1 kWh stored by the battery. The initial results show that the environmental hotspots reside mainly in the structural and material components of the battery, evidencing the need for alternative or recycled materials, preferably produced locally. Since the quantity of electrolytes determine the amount of storable electricity, an analysis was conducted on the variation of the impacts with the increase of storage capacity. An alternative scenario with reused electrolytes was also performed. Results show that with the increase of storage capacity, the contribution of the electrolytes to the impacts decrease significantly by stored kWh. In the reused electrolytes scenario, impacts were reduced mainly for the Acidification and Mineral, fossil and renewable resource depletion categories.This work was financial supported by projects “SunStorage – Harvesting and storage of solar energy”, with reference POCI-01-0145-FEDER-016387, funded by European Regional Development Fund (ERDF), through COMPETE 2020 – Operational Programme for Competitiveness and Internationalization (OPCI), and to FCT — Fundação para a Ciência e a Tecnologia, Portugal I.P., project IF/01093/2014/CP1249/CT0003, research grants IF/01093/2014 and SFRH/BPD/112003/2015. Support from POCI-01-0145-FEDER-006939 (Laboratory for Process Engineering, Environment, Biotechnology and Energy — LEPABE, UID/EQU/00511/2019) funded by FEDER, Spain through COMPETE2020-POCI and by national funds through FCT/MCTES (PIDDAC), Portugal.info:eu-repo/semantics/publishedVersio
Initial in vitro evaluations of antibacterial activities of glucosinolate enzymatic hydrolysis products against plant pathogenic bacteria
Aims: The aim of the study was to evaluate the in vitro antibacterial effects of
glucosinolate hydrolysis products (GHP) against plant pathogenic micro-organisms
namely Agrobacterium tumefaciens, Erwinia chrysanthemi, Pseudomonas
cichorii, Pseudomonas tomato, Xanthomonas campestris and Xanthomonas
juglandis.
Methods and Results: Using a disc diffusion assay, seven different doses of 10
GHP were tested against each bacteria. The results showed that the isothiocyanates
were potent antibacterials, whilst the other GHP were much less efficient.
Moreover, the antibacterial effects were dose-dependent, increasing with the
dose applied; 2-phenylethylisothiocyanate and sulforaphane showed the strongest
inhibitory effects. The overall results show a great potential for using the
isothiocyanates as an alternative tool to control undesired bacterial growth in
plants.
Conclusions: Glucosinolate hydrolysis products and more specifically the
isothiocyanates: benzylisothiocyanate, 2-phenylethylisothiocyanate, the isothiocyanate
Mix and sulforaphane, were effective phytochemicals against the in vitro
growth of the phytopathogenic bacteria. The antibacterial activity exhibited by
these phytochemicals reinforces their potential as alternatives to the traditional
chemical control of phytopathogenic bacteria.
Significance and Impact of the Study: This current in vitro study is the first
providing comparative data on GHP as potential control agents for plant
pathogenic bacteria. However, more studies are needed to determine their
possible allelopathic impacts e.g. inhibition of plant growth and negative effects
on beneficial soil bacteria and fungi (mycorrhizae
Membrane-associated proteins of ejaculated sperm from Morada Nova rams
AbstractThe objective was to describe the profile of membrane proteins from sperm of tropically adapted Morada Nova rams (N = 5). Samples from protein-enriched fractions of ejaculated sperm (containing 400 μg of protein) were separated by two-dimensional electrophoresis and respective maps analyzed using PDQuest software (version 7.3.0; Bio-Rad). Proteins were identified using tandem mass spectrometry. Also, membrane proteins were incubated with antibodies against binder of sperm protein (BSP) 1 and bodhesin 2 (Bdh-2), components of vesicular gland secretion. For membrane proteins of ejaculated sperm, an average of 133 ± 4.6 spots were detected per gel, of which, 107 spots were consistently present on all gels. Sixty-eight spots and 37 proteins were identified using mass spectrometry, corresponding to 71.6% of the intensity of all spots detected. Three major spots identified as ram seminal vesicle protein (RSVP) 14 represented approximately 30% of the intensity of all spots. Two of the most intense spots in the gel reacted against anti-BSP1, at 14 kDa. In addition, four low molecular weight spots reacted with anti-Bdh-2 antibodies. Proteins RSVP and Bdh-2 belong to the BSP and spermadhesin families, respectively, and were previously reported as major components of ram seminal proteins. Additional proteins identified in the sperm membrane two-dimensional maps included alpha-2-heparan sulfate-glycoprotein, plasma glutamate carboxypeptidase, arylsulfatase A, cathelicidin, heat shock protein 70 kDa, angiotensin-converting enzyme, leucine aminopeptidase, and clusterin. Some proteins were present as multiple isoforms, such as tubulin (12), alpha-2-heparan sulfate-glycoprotein (5), ATP synthase (5), Bdh-2 (4) and RSVP14 (3). Based on gene ontology analysis, the most common biological processes associated with the membrane proteins were cellular processes (34%), response to stimulus (14%), and metabolic processes (11%). Binding (37%) and catalytic activity (32%) corresponded to the most frequent molecular functions for those proteins. In conclusion, we identified a diverse cohort of components of membrane proteins in ram sperm. Major proteins previously reported in seminal plasma, such as RSVP14 and Bdh-2, were also extracted from sperm membranes. Knowledge of sperm proteins is crucial for elucidating mechanisms underlying their association with sperm function
O epitélio respiratório em ratos Wistar após 48 horas de exposição contínua ao ruído de baixa frequência
ABSTRACTPrevious studies show that exposure to low frequency noise (LFN) (≤500Hz, including infrasound) produces irreversible lesions in Wistar rat respiratory epithelia. Recovery periods for LFN-induced lesions have thus become an object of interest. Changes in the respiratory epithelia of Wistar rats after continuous short-term exposure to LFN are described. Twelve rats were exposed to continuous LFN for 48hrs, and 10 age-matched rats were kept in silence. Animals were treated in accordance with 86/609/CE. After exposure ceased, two rodents were sacrificed immediately, and another two after 6, 12, 24, 48hrs, and 7 days of post-exposure silence. Respiratory epithelial fragments were prepared for light and scanning/ transmission electron microscopy. Six hours after exposure, intense and irregular cellular tumefaction was visible and rosetta structures, formed by secretory cells (SC) centered on a brush cell (BC), were identifiable. Cilia were shorter and shaggy. BC microvilli tended to group, losing the uniform distribution seen in controls. Twelve hours after exposure, cell balooning was still present, BC shape was highly irregular and microvilli were grouped. SC microvilli were still shorter than controls. Seven days after exposure, controls and exposed were indistinguishable. LFN-induced epithelial lesions seem to be reversible if recovery periods are respected.REV PORT PNEUMOL 2003; IX (6): 473-47
A quadtree-polygon-based scaled boundary finite element method for image-based mesoscale fracture modelling in concrete
A quadtree-polygon scaled boundary finite element-based approach for image-based modelling of concrete fracture at the mesoscale is developed. Digital images representing the two-phase mesostructure of concrete, which comprises of coarse aggregates and mortar are either generated using a take-and-place algorithm with a user-defined aggregate volume ratio or obtained from X-ray computed tomography as an input. The digital images are automatically discretised for analysis by applying a balanced quadtree decomposition in combination with a smoothing operation. The scaled boundary finite element method is applied to model the constituents in the concrete mesostructure. A quadtree formulation within the framework of the scaled boundary finite element method is advantageous in that the displacement compatibility between the cells are automatically preserved even in the presence of hanging nodes. Moreover, the geometric flexibility of the scaled boundary finite element method facilitates the use of arbitrary sided polygons, allowing better representation of the aggregate boundaries. The computational burden is significantly reduced as there are only finite number of cell types in a balanced quadtree mesh. The cells in the mesh are connected to each other using cohesive interface elements with appropriate softening laws to model the fracture of the mesostructure. Parametric studies are carried out on concrete specimens subjected to uniaxial tension to investigate the effects of various parameters e.g. aggregate size distribution, porosity and aggregate volume ratio on the fracture of concrete at the meso-scale. Mesoscale fracture of concrete specimens obtained from X-ray computed tomography scans are carried out to demonstrate its feasibility
Generalised Schwarzschild metric from double copy of point-like charge solution in Born-Infeld theory
We discuss possible application of the classical double copy procedure to construction of a generalisation of the Schwarzschild metric starting from an -corrected open string analogue of the Coulomb solution. The latter is approximated by a point-like charge solution of the Born-Infeld action, which represents the open string effective action for an abelian vector field in the limit when derivatives of the field strength are small. The Born-Infeld solution has a regular electric field which is constant near the origin suggesting that corrections from the derivative terms in the open string effective action may be small there. The generalization of the Schwarschild metric obtained by the double copy construction from the Born-Infeld solution looks non-singular but the corresponding curvature invariants still blow up at . We discuss the origin of this singularity and comment on possible generalizations
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