1,389 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
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
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
Robotic vs laparoscopic total mesorectal excision for rectal cancers: has a paradigm change occurred? A systematic review by updated meta-analysis
Aim The debate about the oncological adequacy, safety and efficiency of robotic vs laparoscopic total mesorectal excision for rectal cancers continues. Therefore, an updated, traditional and cumulative meta-analysis was performed with the aim of assessing the new evidence on this topic. Method A systematic search of the literature for data pertaining to the last 25 years was performed. Fixed- and random-effects models were used to cumulatively assess the accumulation of evidence over time. Results Patients with a significantly higher body mass index (BMI), tumours located approximately 1 cm further distally and more patients undergoing neoadjuvant therapy were included in the robotic total mesorectal excision (RTME) cohort compared with those in the laparoscopic total mesorectal excision (LTME) cohort [RTME, mean difference (MD) = 0.22 (0.07, 0.36), P = 0.005; LTME, MD = -0.97 (-1.57, 0.36), P < 0.002; OR = 1.47 (1.11, 1.93), P = 0.006]. Significantly lower conversion rates to open surgery were observed in the RTME cohort than in the LTME cohort [OR = 0.33 (0.24, 0.46), P < 0.001]. Operative time in the LTME cohort was significantly reduced (by 50 min) compared with the RTME cohort. Subgroup analysis of the three randomized controlled trials (RCTs) challenged all the significant results of the main analysis and demonstrated nonsignificant differences between the RTME cohort and LTME cohort. Conclusion Although the RTME cohort included patients with a significantly higher BMI, more distal tumours and more patients undergoing neoadjuvant therapy, this cohort demonstrated lower conversion rates to open surgery when compared with the LTME cohort. However, subgroup analysis of the RCTs demonstrated nonsignificant differences between the two procedures
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
The role of diet in the aetiopathogenesis of inflammatory bowel disease
Crohn’s disease and ulcerative colitis, collectively known as IBD, are chronic inflammatory disorders of the gastrointestinal tract. Although the aetiopathogenesis of IBD is largely unknown, it is widely thought that diet has a crucial role in the development and progression of IBD. Indeed, epidemiological and genetic association studies have identified a number of promising dietary and genetic risk factors for IBD. These preliminary studies have led to major interest in investigating the complex interaction between diet, host genetics, the gut microbiota and immune function in the pathogenesis of IBD. In this Review, we discuss the recent epidemiological, gene–environment interaction, microbiome and animal studies that have explored the relationship between diet and the risk of IBD. In addition, we highlight the limitations of these prior studies, in part by explaining their contradictory findings, and review future directions
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