1,687 research outputs found
{\it Ab initio} calculations of magnetic structure and lattice dynamics of Fe/Pt multilayers
The magnetization distribution, its energetic characterization by the
interlayer coupling constants and lattice dynamics of (001)-oriented Fe/Pt
multilayers are investigated using density functional theory combined with the
direct method to determine phonon frequencies. It is found that ferromagnetic
order between consecutive Fe layers is favoured, with the enhanced magnetic
moments at the interface. The bilinear and biquadratic coupling coefficients
between Fe layers are shown to saturate fast with increasing thickness of
nonmagnetic Pt layers which separate them. The phonon calculations demonstrate
a rather strong dependence of partial iron phonon densities of states on the
actual position of Fe monolayer in the multilayer structure.Comment: 7 pages, 8 figure
Dopant-dependent impact of Mn-site doping on the critical-state manganites: R0.6Sr0.4MnO3 (R=La, Nd, Sm, and Gd)
Versatile features of impurity doping effects on perovskite manganites,
SrMnO, have been investigated with varying the doing
species as well as the -dependent one-electron bandwidth. In
ferromagnetic-metallic manganites (=La, Nd, and Sm), a few percent of Fe
substitution dramatically decreases the ferromagnetic transition temperature,
leading to a spin glass insulating state with short-range charge-orbital
correlation. For each species, the phase diagram as a function of Fe
concentration is closely similar to that for SrMnO
obtained by decreasing the ionic radius of site, indicating that Fe doping
in the phase-competing region weakens the ferromagnetic double-exchange
interaction, relatively to the charge-orbital ordering instability. We have
also found a contrastive impact of Cr (or Ru) doping on a spin-glass insulating
manganite (=Gd). There, the impurity-induced ferromagnetic magnetization is
observed at low temperatures as a consequence of the collapse of the inherent
short-range charge-orbital ordering, while Fe doping plays only a minor role.
The observed opposite nature of impurity doping may be attributed to the
difference in magnitude of the antiferromagnetic interaction between the doped
ions.Comment: 7 pages, 6 figure
The alimentary impact of the hemp seed
Hemp seed and hemp seed oil can supply us with many important substances. Their essential fatty acid compositions are favourable, but they may contain non-psychotropic cannabinoids. Emerging data show that these components can influence the health status of the population beneficially. Some data also showed trace amounts of tetrahydrocannabinol in seed oils, the main psychotropic cannabinoid that is contraindicated.Our aim was to examine cannabinoids and fatty acid composition as well as metal and non-metal element compositions in products, like hemp seed oil and chopped hemp seed capsule.The cannabinoids were separated by thin layer chromatography. Fatty acid composition was determined with gas chromatography, and elements (Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Si, Sn, Sr, V, and Zn) were measured by inductively coupled plasma optical emission spectrometric method. Selenium was determined with polarographic analyser.Cannabinoids were not detectable by thin layer chromatography, so hemp seed oil, as well as the capsule, have no psychotropic adverse effect. Our data showed that hemp seed contains essential fatty acids close to the recommended ratio. The B and Se concentrations of the oils and the P concentration of the capsule are also relevant
Microalgae production in fresh market wastewater and its utilization as a protein substitute in formulated fish feed for oreochromis spp.
Rapid growing of human population has led to increasing demand of aquaculture production. Oreochromis niloticus or known as tilapia is one of the most globally cultured freshwater fish due to its great adaptation towards extreme environment. Besides, farming of tilapia not only involves small scales farming for local consumption but also larger scales for international market which contributes to a foreign currency earning. Extensive use of fishmeal as feed for fish and for other animals indirectly caused an increasing depletion of the natural resource and may consequently cause economic and environmental unstable. Microalgae biomass seems to be a promising feedstock in aquaculture industry. It can be used for many purposes such as live food for fish larvae and dried microalgae to substitute protein material in fish feed. The microalgae replacement in fish feed formulation as protein alternative seem potentially beneficial for long term aqua-business sustainability. The present chapter discussed the potential of microalgae as an alternative nutrition in fish feed formulations, specifically Tilapia
Measurement of the Charged Multiplicities in b, c and Light Quark Events from Z0 Decays
Average charged multiplicities have been measured separately in , and
light quark () events from decays measured in the SLD experiment.
Impact parameters of charged tracks were used to select enriched samples of
and light quark events, and reconstructed charmed mesons were used to select
quark events. We measured the charged multiplicities:
,
, from
which we derived the differences between the total average charged
multiplicities of or quark events and light quark events: and . We compared
these measurements with those at lower center-of-mass energies and with
perturbative QCD predictions. These combined results are in agreement with the
QCD expectations and disfavor the hypothesis of flavor-independent
fragmentation.Comment: 19 pages LaTex, 4 EPS figures, to appear in Physics Letters
A Search for Jet Handedness in Hadronic Decays
We have searched for signatures of polarization in hadronic jets from decays using the ``jet handedness'' method. The polar angle
asymmetry induced by the high SLC electron-beam polarization was used to
separate quark jets from antiquark jets, expected to be left- and
right-polarized, respectively. We find no evidence for jet handedness in our
global sample or in a sample of light quark jets and we set upper limits at the
95% C.L. of 0.063 and 0.099 respectively on the magnitude of the analyzing
power of the method proposed by Efremov {\it et al.}Comment: Revtex, 8 pages, 2 figure
Vegan diets : practical advice for athletes and exercisers.
With the growth of social media as a platform to share information, veganism is becoming more visible, and could be becoming more accepted in sports and in the health and fitness industry. However, to date, there appears to be a lack of literature that discusses how to manage vegan diets for athletic purposes. This article attempted to review literature in order to provide recommendations for how to construct a vegan diet for athletes and exercisers. While little data could be found in the sports nutrition literature specifically, it was revealed elsewhere that veganism creates challenges that need to be accounted for when designing a nutritious diet. This included the sufficiency of energy and protein; the adequacy of vitamin B12, iron, zinc, calcium, iodine and vitamin D; and the lack of the long-chain n-3 fatty acids EPA and DHA in most plant-based sources. However, via the strategic management of food and appropriate supplementation, it is the contention of this article that a nutritive vegan diet can be designed to achieve the dietary needs of most athletes satisfactorily. Further, it was suggested here that creatine and β-alanine supplementation might be of particular use to vegan athletes, owing to vegetarian diets promoting lower muscle creatine and lower muscle carnosine levels in consumers. Empirical research is needed to examine the effects of vegan diets in athletic populations however, especially if this movement grows in popularity, to ensure that the health and performance of athletic vegans is optimised in accordance with developments in sports nutrition knowledge
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Effect of n-3 fatty acids on immune function in broiler chickens
There is interest in the enrichment of poultry meat with long-chain n-3 polyunsaturated fatty acids in order to increase the consumption of these fatty acids by humans. However, there is concern that high levels of n-3 polyunsaturated fatty acids may have detrimental effects on immune function in chickens. The effect of feeding increasing levels of fish oil (FO) on immune function was investigated in broiler chickens. Three-week-old broilers were fed 1 of 4 wheat-soybean basal diets that contained 0, 30, 50, or 60 g/kg of FO until slaughter. At slaughter, samples of blood, bursa of Fabricius, spleen, and thymus were collected from each bird. A range of immune parameters, including immune tissue weight, immuno-phenotyping, phagocytosis, and cell proliferation, were assessed. The pattern of fatty acid incorporation reflected the fatty acid composition of the diet. The FO did not affect the weight of the spleen, but it did increase thymus weight when fed at 50 g/kg (P < 0.001). Fish oil also lowered bursal weights when fed at 50 or 60 g/kg (P < 0.001). There was no significant effect of FO on immune cell phenotypes in the spleen, thymus, bursa, or blood. Feeding 60 g/kg of FO significantly decreased the percentage of monocytes engaged in phagocytosis, but it increased their mean fluorescence intensity relative to that of broilers fed 50 g/kg of FO. Lymphocyte proliferation was significantly decreased after feeding broiler chickens diets rich in FO when expressed as division index or proliferation index, although there was no significant effect of FO on the percentage of divided cells. In conclusion, dietary n-3 polyunsaturated fatty acids decrease phagocytosis and lymphocyte proliferation in broiler chickens, highlighting the need for the poultry industry to consider the health status of poultry when poultry meat is being enriched with FO
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