Spin Freezing in the Spin Liquid Compound FeAl2O4

Spin freezing in the $A$-site spinel FeAl$_2$O$_4$ which is a spin liquid candidate is studied using remnant magnetization and nonlinear magnetic susceptibility and isofield cooling and heating protocols. The remnant magnetization behavior of FeAl$_2$O$_4$ differs significantly from that of a canonical spin glass which is also supported by analysis of the nonlinear magnetic susceptibility term $\chi_3 (T)$. Through the power-law analysis of $\chi_3 (T)$, a spin-freezing temperature, $T_g$ = 11.4$\pm$0.9~K and critical exponent, $\gamma$ = 1.48$\pm$0.59 are obtained. Cole-Cole analysis of magnetic susceptibility shows the presence of broad spin relaxation times in FeAl$_2$O$_4$, however, the irreversible dc susceptibility plot discourages an interpretation based on conventional spin glass features. The magnetization measured using the cooling-and-heating-in-unequal-fields protocol brings more insight to the magnetic nature of this frustrated magnet and reveals unconventional glassy behaviour. Combining our results, we arrive at the conclusion that the present sample of FeAl$_2$O$_4$ consists of a majority spin liquid phase with "glassy" regions embedded.Comment: 5 pages, 6 figs, 2-column, Accepted to Phys. Rev.

Electron hydrodynamics dilemma: whirlpools or no whirlpools

In highly viscous electron systems such as, for example, high quality graphene above liquid nitrogen temperature, a linear response to applied electric current becomes essentially nonlocal, which can give rise to a number of new and counterintuitive phenomena including negative nonlocal resistance and current whirlpools. It has also been shown that, although both effects originate from high electron viscosity, a negative voltage drop does not principally require current backflow. In this work, we study the role of geometry on viscous flow and show that confinement effects and relative positions of injector and collector contacts play a pivotal role in the occurrence of whirlpools. Certain geometries may exhibit backflow at arbitrarily small values of the electron viscosity, whereas others require a specific threshold value for whirlpools to emerge

Cytotoxic Complexes of Sodium Oleate with β-Lactoglobulin

pre-printA complex of α-lactalbumin and oleic acid has previously been shown to induce apoptosis in cancer cells in a number of in vitro and in vivo trials. This complex is called HAMLET or BAMLET, depending on the origin of α-la (human/bovine alpha-lactalbumin made lethal to tumour cells). In the current study, it was shown that bovine β-lactoglobulin (β-lg), upon binding sodium oleate (NaOle), the salt of oleic acid, also acquires cytotoxicity towards tumour cells (human monocytic cells U937), analogously to HAMLET/BAMLET complexes. The properties of the complex were characterized using FIR spectroscopy, HPLC and SDS-PAGE. It was shown that the level of covalent oligomerization (dimers and trimers) of β-lg increased with increasing the molar ratio of sodium oleate NaOle:β-lg in the preparation procedure. At the same time, increasing the molar ratio of NaOle:β-lg increased the cytotoxicity of the complex. The increase in cytotoxicity appeared to be dependent on the amount of bound NaOle in the complex, but not on the content of multimeric forms of β-lg. The NaOle/β-lg complex also showed similarity with BAMLET in penetrating the cell membrane and co-localizing with the cell nucleus. Furthermore, DNA fragmentation studies suggested that tumour cells (U937) treated with the complex died by apoptosis, as in the case of BAMLET, and healthy cells appeared to be less affected by treatment, as shown with model rat adrenal pheochromocytoma cells PC12. In conclusion, β-lg and NaOle can form complexes with apoptosis-inducing qualities comparable to those of BAMLET.The work was funded by the Irish Dairy Research Trust and The Department of Agriculture (Food Institutional Research Measure – FIRM project 08RDTMFRC650) under the National Development Plan 2007-2013. K. Lišková was funded under the TeagascWalsh Fellowship Scheme

Is Fitspiration Truly an Inspiration? Relationships between Fitspiration, Exercise, and Body Image

Young adults across the United States struggle to meet physical activity recommendations and consume healthy diets, and they often suffer from issues related to body image. Social media influencers dedicated to fitspiration (i.e., fitness inspiration) are purported to have a goal of inspiring others to lead healthier lifestyles. The purpose of this study was to explore the relationships between fitspiration and exercise and body image perceptions amongst college students. Participants (n = 361, mean age = 20.2 years, 78% female) completed surveys that included sociodemographic information, social media usage, fitspiration content engagement, exercise, and body satisfaction. An independent samples t-test assessed differences in exercise by fitspiration viewership, and a chi-square analysis determined relationships between fitspiration and body satisfaction. Participants were routinely active on social media (91% use it for \u3e 1 hour per day), and 61.5% were exposed to fitspiration content. Approximately 41% of respondents have followed exercise advice from fitspiration influencers, though only 11% reported having purchased products. No relationships were reported between following fitspiration and days per week of exercise (M∆ = .02(.20), p = .91). Participants that followed fitspiration were more likely to be dissatisfied with their bodies, X2 (1, n = 316) =7.77, p = .005, compared to participants who did not. Findings demonstrate fitspiration was not related to exercise and was related to poorer body image perceptions among college students. These results are supported by previous findings and indicate a critical misalignment between the purported purpose of fitspiration and the outcome of its viewing

A Fast Algorithm For Sparse Multichannel Blind Deconvolution

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We have addressed blind deconvolution in a multichannel framework. Recently, a robust solution to this problem based on a Bayesian approach called sparse multichannel blind deconvolution (SMBD) was proposed in the literature with interesting results. However, its computational complexity can be high. We have proposed a fast algorithm based on the minimum entropy deconvolution, which is considerably less expensive. We designed the deconvolution filter to minimize a normalized version of the hybrid l(1)/l(2)-norm loss function. This is in contrast to the SMBD, in which the hybrid l(1)/l(2)-norm function is used as a regularization term to directly determine the deconvolved signal. Results with synthetic data determined that the performance of the obtained deconvolution filter was similar to the one obtained in a supervised framework. Similar results were also obtained in a real marine data set for both techniques.811V7V16CAPESCNPqPetrobrasCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq