1,605 research outputs found
Uniqueness of Bessel models: the archimedean case
In the archimedean case, we prove uniqueness of Bessel models for general
linear groups, unitary groups and orthogonal groups.Comment: 22 page
Spatial changes of beach profiles for a small tidal inlet (Currumbin Creek, Australia)
Many tidal inlets are actively monitored to investigate the change in flood or ebb shoals, as these sand deposits can have a major influence on the sediment budget of the adjacent coast. However, here it is hypothesized that the shores of the back barrier area can also act as a source of sediment to be considered in the sediment budget. Therefore, profile changes around Currumbin Creek tidal inlet were considered to identify the extent of such a contribution on the surrounding beach and the overall evolution of the inlet system. The results of 16 weeks survey showed that in general, the shores of the back barrier lagoon had a very marginal effect in the provision of material to the sand budget, although the gorge area is highly vulnerable and dynamic. Even an intense storm event and heavy rainfall during the data collection period, resulting in erosion of the surrounding beaches, showed no significant influence on the shore face of the lagoon
Virial mass in DGP brane cosmology
We study the virial mass discrepancy in the context of a DPG brane-world
scenario and show that such a framework can offer viable explanations to
account for the mass discrepancy problem. This is done by defining a
geometrical mass that we prove to be proportional to the virial
mass. Estimating using observational data, we show that it
behaves linearly with and has a value of the order of , pointing
to a possible resolution of the virial mass discrepancy. We also obtain the
radial velocity dispersion of galaxy clusters and show that it is compatible
with the radial velocity dispersion profile of such clusters. This velocity
dispersion profile can be used to differentiate various models predicting the
virial mass.Comment: 12 pages, 1 figure, to appear in CQ
Modelling of flow around hexagonal and textured cylinders
The flow regime around a hexagonal polygon with low Reynolds numbers Re<200 is numerically investigated in two different orientations namely face-oriented and corner-oriented. The basic flow characteristics, including drag coefficient, lift coefficient, Strouhal number and critical Reynolds number of the hexagonal cylinders, are calculated using 2D transient numerical analysis. Within the studied range of Re, the predicted lift coefficient and Strouhal number of the face-oriented hexagon were higher than those of the corner-oriented hexagon. In contrast, the predicted drag coefficient and critical Reynolds number of the corner-oriented hexagon were greater than those of the face-oriented. Flow characteristics of a novel textured geometry are also studied using 3D transient analysis. The Strouhal number St of the textured geometry was found to be in between the St of both the hexagonal cylinders, and its lift coefficient is lower than that of the hexagonal cylinders
Hardness Phenomenon in Beach Pea (Lethyrus Maritimus L.)
Beach pea is mostly grown on seashores and it contains higher amount of protein than other legumes. However, the pea has several undesirable attributes, such as long cooking time and hard to germinate (imbibitions) that limited its use as food. The present investigation aimed to study the physico-chemical properties, cooking characteristics and hull crude fibre structure of beach pea as compare to other similar legumes. Standard methods of processing pulses were used for present study. Beach pea seeds contained very low grain weight, density, hydration capacity, hydration index, swelling capacity and swelling index than the green pea and field pea. Beach pea had higher amount of crude protein, ash, crude fibre and polyphenols, but lower in starch content than the green pea and field pea. Without any treatment to beach pea seeds the water uptake capacity was very low. Mechanical treatment to beach pea seeds increasedthe water uptake percentage. The recovery of hull was 3 to 6 times higher in beach pea than that of green pea and field pea. The crude protein content in beach pea hull was 2-5% higher than others. The beach pea hull, dhal and whole seeds were good source of macro- and micro- minerals than that of the other two peas. The electron microscopic structure of beach pea hull crude fibre showed a very close and compact structure than green pea and field pea hull crude fibre structure. Lowering the hardness of beach pea seeds with mechanical or chemical treatments will give more scope for their utilization in the human nutrition
The role of intratidal oscillations in sediment resuspension in a diurnal, partially mixed estuary
Using detailed observations of the mean and turbulent properties of flow, salinity and turbidity that spanned 2001/02, we examined the physical mechanisms underpinning sediment resuspension in the low-energy Swan River estuary, Western Australia. In this diurnal tidally-dominated estuary, the presence of intratidal oscillations, a tidal inequality lasting 2 to 3 hours on the flood tide, generated by interactions of the four main diurnal and semidiurnal astronomical constituents, K₁, O₁, M₂, and S₂, played a major role in modifying vertical stratification and mixing. These intratidal oscillations are controlled by phase differences between the tropic and synodic months rather than being temporally-fixed by bed friction, as occurs in semidiurnal estuaries. Intratidal oscillations are largest, at around 0.1 m, near to the Austral solstice when the lunar and solar declination are in-phase. Despite the seemingly small change in water level, shear-induced interfacial mixing caused destratification of the water column with the top-to-bottom salinity (ΔS) difference of 3.5 present early in the flood tide eroded to less than 0.3 by the end of the intratidal oscillation. High turbidity peaks, of 250 nephelometric turbidity units, coincided with these intratidal oscillations and could not be explained by bed friction since shear stress from mean flow did not exceed threshold criteria. High Reynolds stresses of ∼1 Nm⁻² did, however, exceed τcr and together with negative Reynolds fluxes indicate a net downward transport of material. Destratification of the water column induced by shear instabilities resulted in large overturns capable of moving in situ material towards the bed during intratidal oscillations and these turbidities were ∼10 times greater than those from bed-generated resuspension observed later during the flood tide
Health promoting potential of herbal teas and tinctures from Artemisia campestris subsp maritima: from traditional remedies to prospective products
This work explored the biotechnological potential of the medicinal halophyte Artemisia campestris subsp. maritima (dune wormwood) as a source of health promoting commodities. For that purpose, infusions, decoctions and tinctures were prepared from roots and aerial-organs and evaluated for in vitro antioxidant, anti-diabetic and tyrosinase-inhibitory potential, and also for polyphenolic and mineral contents and toxicity. The dune wormwood extracts had high polyphenolic content and several phenolics were identified by ultra-high performance liquid chromatography-photodiode array-mass-spectrometry (UHPLC-PDA-MS). The main compounds were quinic, chlorogenic and caffeic acids, coumarin sulfates and dicaffeoylquinic acids; several of the identified phytoconstituents are here firstly reported in this A. campestris subspecies. Results obtained with this plant's extracts point to nutritional applications as mineral supplementary source, safe for human consumption, as suggested by the moderate to low toxicity of the extracts towards mammalian cell lines. The dune wormwood extracts had in general high antioxidant activity and also the capacity to inhibit a-glucosidase and tyrosinase. In summary, dune wormwood extracts are a significant source of polyphenolic and mineral constituents, antioxidants and a-glucosidase and tyrosinase inhibitors, and thus, relevant for different commercial segments like the pharmaceutical, cosmetic and/or food industries.FCT - Foundation for Science and Technology [CCMAR/Multi/04326/2013]; Portuguese National Budget; FCT [IF/00049/2012, SFRH/BD/94407/2013]; Research Foundation - Flanders (FWO) [12M8315N]info:eu-repo/semantics/publishedVersio
Nile red fluorescence screening facilitating neutral lipid phenotype determination in budding yeast, Saccharomyces cerevisiae, and the fission yeast Schizosaccharomyces pombe.
Investigation of yeast neutral lipid accumulation is important for biotechnology and also for modelling aberrant lipid metabolism in human disease. The Nile red (NR) method has been extensively utilised to determine lipid phenotypes of yeast cells via microscopic means. NR assays have been used to differentiate lipid accumulation and relative amounts of lipid in oleaginous species but have not been thoroughly validated for phenotype determination arising from genetic modification. A modified NR assay, first described by Sitepu et al. (J Microbiol Methods 91:321-328, 2012), was able to detect neutral lipid changes in Saccharomyces cerevisiae deletion mutants with sensitivity similar to more advanced methodology. We have also be able to, for the first time, successfully apply the NR assay to the well characterised fission yeast Schizosaccharomyces pombe, an increasingly important organism in biotechnology. The described NR fluorescence assay is suitable for increased throughput and rapid screening of genetically modified strains in both the biotechnology industry and for modelling ectopic lipid production for a variety of human diseases. This ultimately negates the need for labour intensive and time consuming lipid analyses of samples that may not yield a desirable lipid phenotype, whilst genetic modifications impacting significantly on the cellular lipid phenotype can be further promoted for more in depth analyses
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Antioxidant activity, total phenolics and flavonoids contents: should we ban in vitro screening methods?
As many studies are exploring the association between ingestion of bioactive compounds and decreased risk of non-communicable diseases, the scientific community continues to show considerable interest in these compounds. In addition, as many non-nutrients with putative health benefits are reducing agents, hydrogen donors, singlet oxygen quenchers or metal chelators, measurement of antioxidant activity using in vitro assays has become very popular over recent decades. Measuring concentrations of total phenolics, flavonoids, and other compound (sub)classes using UV/Vis spectrophotometry offers a rapid chemical index, but chromatographic techniques are necessary to establish structure-activity. For bioactive purposes, in vivo models are required or, at the very least, methods that employ distinct mechanisms of action (i.e., single electron transfer, transition metal chelating ability, and hydrogen atom transfer). In this regard, better understanding and application of in vitro screening methods should help design of future research studies on ‘bioactive compounds’
Antioxidant Activity of the Phenolic Leaf Extracts from Monechma ciliatum in Stabilization of Corn Oil
The total phenolic content and the antioxidan potential of methanolic extract (ME), ethyl acetate extract (EAE), and hexane extract (HE) from Monechma ciliatum leaves (MCL) were evaluated. The Folin-Ciocalteu, b-carotene bleaching, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and the accelerated oxidation methods were used for evaluation. Both the extraction yield and the antioxidant activity (AOA) were strongly dependent on the solvent. Among the extracts, ME exhibited highest total phenolic compounds (TPC) and IC50 values for DPPH, followed by EAE and HE, respectively. Peroxide value (PV), anisidine value (AV) conjugated dienes (CD), and thiobarbituric acid reactive substances (TBARS) were taken as the parameters for evaluation of stabilization efficacy of MCL extracts and results revealed MCL to be a potent antioxidant for the stabilization of corn oil. As a general trend, increased AOA was observed for increased extract concentration. The predominant phenolic compounds identified by HPLC-DAD in MCL extracts were p-coumaric acid, vanillin and ferulic acid
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