Magnetization reversal and magnetic anisotropy in Co network nanostructures

The magnetization reversal and magnetic anisotropy in Co network structures have been studied using magneto-optic Kerr effect (MOKE). An enhancement of the coercivity is observed in the network structures and is attributed to the pinning of domain walls by the hole edges in the vicinity of which the demagnetizing field spatially varies. We find that the magnetization reversal process is dominated by the intrinsic unaxial anisotropy (2K(u)/M(s)approximate to 200 Oe) in spite of the shape anisotropy induced by the hole edges. The influence of the cross-junction on the competition between the intrinsic uniaxial anisotropy and the induced shape anisotropy is discussed using micromagnetic simulations

Breast milk iodine and perchlorate concentrations in lactating Boston-area women

Context: Breastfed infants rely on adequate maternal dietary iodine intake. Objective: Our objective was to measure breast milk iodine and perchlorate, an inhibitor of iodide transport into the thyroid and potentially into breast milk, in Boston-area women. Participants: The study included 57 lactating healthy volunteers in the Boston area. Measurements: Breast milk iodine and perchlorate concentrations and urine iodine, perchlorate, and cotinine concentrations were measured. For comparison, iodine and perchlorate levels in infant formulae were also measured. Results: Median breast milk iodine content in 57 samples was 155 μg/liter (range, 2.7-1968 μg/liter). Median urine iodine was 114 μg/liter (range, 25-920 μg/liter). Perchlorate was detectable in all 49 breast milk samples (range, 1.3-411 μg/liter), all 56 urine samples (range, 0.37-127 μg/liter), and all 17 infant formula samples (range, 0.22-4.1 μg/liter) measured. Breast milk iodine content was significantly correlated with urinary iodine per gram creatinine and urinary cotinine but was not significantly correlated with breast milk or urinary perchlorate. Conclusions: Perchlorate exposure was not significantly correlated with breast milk iodine concentrations. Perchlorate was detectable in infant formula but at lower levels than in breast milk. Forty-seven percent of women sampled may have been providing breast milk with insufficient iodine to meet infants' requirements. Copyright © 2007 by The Endocrine Society

Rms-flux relation in the optical fast variability data of BL Lacertae object S5 0716+714

The possibility that BL Lac S5 0716+714 exhibits a linear root mean square (rms)-flux relation in its IntraDay Variability (IDV) is analysed. The results may be used as an argument in the existing debate regarding the source of optical IDV in Active Galactic Nuclei. 63 time series in different optical bands were used. A linear rms-flux relation at a confidence level higher than 65% was recovered for less than 8% of the cases. We were able to check if the magnitude is log-normally distributed for eight timeseries and found, with a confidence > 95%, that this is not the case.Comment: Accepted by Astrophysics and Space Scienc

Experimental Implementation of the Quantum Random-Walk Algorithm

The quantum random walk is a possible approach to construct new quantum algorithms. Several groups have investigated the quantum random walk and experimental schemes were proposed. In this paper we present the experimental implementation of the quantum random walk algorithm on a nuclear magnetic resonance quantum computer. We observe that the quantum walk is in sharp contrast to its classical counterpart. In particular, the properties of the quantum walk strongly depends on the quantum entanglement.Comment: 5 pages, 4 figures, published versio

Can a CPT Violating Ether Solve ALL Electron (Anti)Neutrino Puzzles?

Assuming that CPT is violated in the neutrino sector seems to be a viable alternative to sterile neutrinos when it comes to reconciling the LSND anomaly with the remainder of the neutrino data. There are different (distinguishable) ways of incorporating CPT violation into the standard model, including postulating m different from \bar{m}. Here, I investigate the possibility of introducing CPT violation via Lorentz-invariance violating effective operators (``Ether'' potentials) which modify neutrino oscillation patterns like ordinary matter effects. I argue that, within a simplified two-flavor like oscillation analysis, one cannot solve the solar neutrino puzzle and LSND anomaly while still respecting constraints imposed by other neutrino experiments, and comment on whether significant improvements should be expected from a three-flavor analysis. If one turns the picture upside down, some of the most severe constrains on such CPT violating terms can already be obtained from the current neutrino data, while much more severe constraints can arise from future neutrino oscillation experiments.Comment: 10 pages, 1 eps figure; version to appear in PRD. Comment added, mistake corrected, results and conclusions unchange

Biochemical parameters of silver catfish (Rhamdia quelen) after transport with eugenol or essential oil of Lippia alba added to the water

The transport of live fish is a routine practice in aquaculture and constitutes a considerable source of stress to the animals. The addition of anesthetic to the water used for fish transport can prevent or mitigate the deleterious effects of transport stress. This study investigated the effects of the addition of eugenol (EUG) (1.5 or 3.0 mu L L-1) and essential oil of Lippia alba (EOL) (10 or 20 mu L L-1) on metabolic parameters (glycogen, lactate and total protein levels) in liver and muscle, acetylcholinesterase activity (AChE) in muscle and brain, and the levels of protein carbonyl (PC), thiobarbituric acid reactive substances (TBARS) and nonprotein thiol groups (NPSH) and activity of glutathione-S-transferase in the liver of silver catfish (Rhamdia quelen; Quoy and Gaimard, 1824) transported for four hours in plastic bags (loading density of 169.2 g L-1). The addition of various concentrations of EUG (1.5 or 3.0 mu L L-1) and EOL (10 or 20 mu L L-1) to the transport water is advisable for the transportation of silver catfish, since both concentrations of these substances increased the levels of NPSH antioxidant and decreased the TBARS levels in the liver. In addition, the lower liver levels of glycogen and lactate in these groups and lower AChE activity in the brain (EOL 10 or 20 mu L L-1) compared to the control group indicate that the energetic metabolism and neurotransmission were lower after administration of anesthetics, contributing to the maintenance of homeostasis and sedation status.Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul (FAPERGS/PRONEX) [10/0016-8]; Conselho Nacional de Pesquisa e Desenvolvimento Cientifico (CNPq) [470964/2009-0]; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES); CNPqinfo:eu-repo/semantics/publishedVersio

Magnetism in Dense Quark Matter

We review the mechanisms via which an external magnetic field can affect the ground state of cold and dense quark matter. In the absence of a magnetic field, at asymptotically high densities, cold quark matter is in the Color-Flavor-Locked (CFL) phase of color superconductivity characterized by three scales: the superconducting gap, the gluon Meissner mass, and the baryonic chemical potential. When an applied magnetic field becomes comparable with each of these scales, new phases and/or condensates may emerge. They include the magnetic CFL (MCFL) phase that becomes relevant for fields of the order of the gap scale; the paramagnetic CFL, important when the field is of the order of the Meissner mass, and a spin-one condensate associated to the magnetic moment of the Cooper pairs, significant at fields of the order of the chemical potential. We discuss the equation of state (EoS) of MCFL matter for a large range of field values and consider possible applications of the magnetic effects on dense quark matter to the astrophysics of compact stars.Comment: To appear in Lect. Notes Phys. "Strongly interacting matter in magnetic fields" (Springer), edited by D. Kharzeev, K. Landsteiner, A. Schmitt, H.-U. Ye

A CHIME/FRB Study of Burst Rate and Morphological Evolution of the Periodically Repeating FRB 20180916B

FRB 20180916B is a repeating fast radio burst (FRB) with a 16.3 day periodicity in its activity. In this study, we present morphological properties of 60 FRB 20180916B bursts detected by CHIME/FRB between 2018 August and 2021 December. We recorded raw voltage data for 45 of these bursts, enabling microseconds time resolution in some cases. We studied variation of spectro-temporal properties with time and activity phase. We find that the variation in dispersion measure (DM) is ≲1 pc cm−3 and that there is burst-to-burst variation in scattering time estimates ranging from ∼0.16 to over 2 ms, with no discernible trend with activity phase for either property. Furthermore, we find no DM and scattering variability corresponding to the recent change in rotation measure from the source, which has implications for the immediate environment of the source. We find that FRB 20180916B has thus far shown no epochs of heightened activity as have been seen in other active repeaters by CHIME/FRB, with its burst count consistent with originating from a Poissonian process. We also observe no change in the value of the activity period over the duration of our observations and set a 1σ upper limit of 1.5 × 10−4 day day−1 on the absolute period derivative. Finally, we discuss constraints on progenitor models yielded by our results, noting that our upper limits on changes in scattering and DM as a function of phase do not support models invoking a massive binary companion star as the origin of the 16.3 day periodicity.</p