Structural disorder versus chiral magnetism in Cr1/3_{1/3}NbS2_2

The crystal structure of a disordered form of Cr$_{1/3}$NbS$_2$ has been characterized using diffraction and inelastic scattering of synchrotron radiation. In contrast to the previously reported symmetry (P6$_3$22), the crystal can be described by a regular twinning of an average P6$_3$ structure with three disordered positions of the Cr ions. Short-range correlations of the occupational disorder result in a quite intense and structured diffuse scattering; a static nature of the disorder was unambiguously attributed by the inelastic x-ray scattering. The diffuse scattering has been modeled using a reverse Monte-Carlo algorithm assuming a disorder of the Cr sub-lattice only. The observed correlated disorder of the Cr sub-lattice reduces the temperature of the magnetic ordering from 130 K to 88 K and drastically modifies the field dependence of the magnetization as it is evidenced by the SQUID magnetometery. We conclude, that in contrast to the helicoidal spin structure assumed for P6$_3$22 form, the compound under study is ferromagnetically ordered with a pronounced in-plane anisotropy

Quality of life of school and university students with acne

Acne may have severe negative impact on different aspects of patient health-related quality of life (HRQoL). Prevalence of acne in university and school students is high, and the HRQoL of students with acne from different countries was studied. There is a lack of studies on direct comparison of HRQoL impairment of university and school students with acne. The Cardiff Acne Disability Index (CADI) was used to assess the HRQOL in university and school students with self-assessed acne. The CADI results from 159 university and 99 school students with self-reported acne were obtained. Mean age of university and school students was 20.99±1.47 (mean ± Standard Deviation) and 14.10±0.51 years, respectively. Reported impact on QoL of university students was significantly higher (3.33±2.26 and 2.76±2.42, P&lt;0.05). Total CADI scores negatively correlated with the age of university students (r=-0.16; P&lt;0.05). Analysis of gender differences of university students showed that negative correlation of HRQoL with age was present in women (r=-0.22; P&lt;0.05) but absent in male students (r=0.05; P=0.77). Female university students reported more severe impact of acne on their life (2.55±2.31 in male and 3.59±2.20 in female students, P&lt;0.01). Our results showed that university students experience higher impact of acne on their life than school students. The highest is the impact on young female university students. We recommend paying more attention to the psychological aspects of young female students with acne during consultations. </p

Quality of life of school and university students with acne

Acne may have severe negative impact on different aspects of patient health-related quality of life (HRQoL). Prevalence of acne in university and school students is high, and the HRQoL of students with acne from different countries was studied. There is a lack of studies on direct comparison of HRQoL impairment of university and school students with acne. The Cardiff Acne Disability Index (CADI) was used to assess the HRQOL in university and school students with self-assessed acne. The CADI results from 159 university and 99 school students with self-reported acne were obtained. Mean age of university and school students was 20.99±1.47 (mean ± Standard Deviation) and 14.10±0.51 years, respectively. Reported impact on QoL of university students was significantly higher (3.33±2.26 and 2.76±2.42, P&lt;0.05). Total CADI scores negatively correlated with the age of university students (r=-0.16; P&lt;0.05). Analysis of gender differences of university students showed that negative correlation of HRQoL with age was present in women (r=-0.22; P&lt;0.05) but absent in male students (r=0.05; P=0.77). Female university students reported more severe impact of acne on their life (2.55±2.31 in male and 3.59±2.20 in female students, P&lt;0.01). Our results showed that university students experience higher impact of acne on their life than school students. The highest is the impact on young female university students. We recommend paying more attention to the psychological aspects of young female students with acne during consultations. </p

The Fundamental Plane of Gamma-ray Globular Clusters

We have investigated the properties of a group of $\gamma$-ray emitting globular clusters (GCs) which have recently been uncovered in our Galaxy. By correlating the observed $\gamma$-ray luminosities $L_{\gamma}$ with various cluster properties, we probe the origin of the high energy photons from these GCs. We report $L_{\gamma}$ is positively correlated with the encounter rate $\Gamma_{c}$ and the metalicity $\left[{\rm Fe/H}\right]$ which place an intimate link between the gamma-ray emission and the millisecond pulsar population. We also find a tendency that $L_{\gamma}$ increase with the energy densities of the soft photon at the cluster location. Furthermore, the two-dimensional regression analysis suggests that $L_{\gamma}$, soft photon densities, and $\Gamma_{c}$/$\left[{\rm Fe/H}\right]$ possibly span fundamental planes which potentially provide better predictions for the $\gamma$-ray properties of GCs.Comment: 17 pages, 4 figures, 3 tables, published in Ap

Optically switched magnetism in photovoltaic perovskite CH3_3NH3_3(Mn:Pb)I3_3

The demand for ever-increasing density of information storage and speed of manipulation boosts an intense search for new magnetic materials and novel ways of controlling the magnetic bit. Here, we report the synthesis of a ferromagnetic photovoltaic CH$_3$NH$_3$(Mn:Pb)I$_3$ material in which the photo-excited electrons rapidly melt the local magnetic order through the Ruderman-Kittel-Kasuya-Yosida interactions without heating up the spin system. Our finding offers an alternative, very simple and efficient way of optical spin control, and opens an avenue for applications in low power, light controlling magnetic devices

GaMnAs-based hybrid multiferroic memory device

A rapidly developing field of spintronics is based on the premise that substituting charge with spin as a carrier of information can lead to new devices with lower power consumption, non-volatility and high operational speed. Despite efficient magnetization detection, magnetization manipulation is primarily performed by current-generated local magnetic fields and is very inefficient. Here we report a novel non-volatile hybrid multiferroic memory cell with electrostatic control of magnetization based on strain-coupled GaMnAs ferromagnetic semiconductor and a piezoelectric material. We use the crystalline anisotropy of GaMnAs to store information in the orientation of the magnetization along one of the two easy axes, which is monitored via transverse anisotropic magnetoresistance. The magnetization orientation is switched by applying voltage to the piezoelectric material and tuning magnetic anisotropy of GaMnAs via the resulting stress field.Comment: 4 pages, 5 figure

Observing two dark accelerators around the Galactic Centre with Fermi Large Area Telescope

We report the results from a detailed $\gamma-$ray investigation in the field of two "dark accelerators", HESS J1745-303 and HESS J1741-302, with $6.9$ years of data obtained by the Fermi Large Area Telescope. For HESS J1745-303, we found that its MeV-GeV emission is mainly originated from the "Region A" of the TeV feature. Its $\gamma-$ray spectrum can be modeled with a single power-law with a photon index of $\Gamma\sim2.5$ from few hundreds MeV to TeV. Moreover, an elongated feature, which extends from "Region A" toward northwest for $\sim1.3^{\circ}$, is discovered for the first time. The orientation of this feature is similar to that of a large scale atomic/molecular gas distribution. For HESS J1741-302, our analysis does not yield any MeV-GeV counterpart for this unidentified TeV source. On the other hand, we have detected a new point source, Fermi J1740.1-3013, serendipitously. Its spectrum is apparently curved which resembles that of a $\gamma-$ray pulsar. This makes it possibly associated with PSR B1737-20 or PSR J1739-3023.Comment: 11 pages, 7 figures, 2 tables, accepted for publication in MNRA