Anisotropic electrical resistivity of LaFeAsO: evidence for electronic nematicity

Single crystals of LaFeAsO were successfully grown out of KI flux. Temperature dependent electrical resistivity was measured with current flow along the basal plane, \rho_perpend(T), as well as with current flow along the crystallographic c-axis, \rho_parallel(T), the latter one utilizing electron beam lithography and argon ion beam milling. The anisotropy ratio was found to lie between \rho_parallel/\rho_perpend = 20 - 200. The measurement of \rho_perpend(T) was performed with current flow along the tetragonal [1 0 0] direction and along the [1 1 0] direction and revealed a clear in-plane anisotropy already at T \leq 175 K. This is significantly above the orthorhombic distortion at T_0 = 147 K and indicates the formation of an electron nematic phase. Magnetic susceptibility and electrical resistivity give evidence for a change of the magnetic structure of the iron atoms from antiferromagnetic to ferromagnetic arrangement along the c-axis at T^\ast = 11 K.Comment: 10 pages, 6 figures, minor change

Holographic Kondo and Fano Resonances

We use holography to study a $(1+1)$-dimensional Conformal Field Theory (CFT) coupled to an impurity. The CFT is an $SU(N)$ gauge theory at large $N$, with strong gauge interactions. The impurity is an $SU(N)$ spin. We trigger an impurity Renormalization Group (RG) flow via a Kondo coupling. The Kondo effect occurs only below the critical temperature of a large-$N$ mean-field transition. We show that at all temperatures $T$, impurity spectral functions exhibit a Fano resonance, which in the low-$T$ phase is a large-$N$ manifestation of the Kondo resonance. We thus provide an example in which the Kondo resonance survives strong correlations, and uncover a novel mechanism for generating Fano resonances, via RG flows between $(0 + 1)$-dimensional fixed pointsComment: 5 pages + references, 6 figures; v2: discussion clarified, references added; as accepted by PR

Caring for a loved one with a malignant fungating wound

Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch)Purpose: Caring for a loved one with a malignant fungating wound is very challenging and causes extreme physical and psychological distress. The aim of this study was to explore the experiences of carers who care for a loved one with a fungating breast wound. Method: To explore the lived experiences of carers, a methodological framework using Heideggerian hermeneutic phenomenology and semi-structured interviews was used. Seven carers were interviewed from January until November 2009. Results: Having to deal with a situation of a loved one with a visible cancer was hard for all the carers. The visibility of the cancer was one of the most shocking aspects to deal with from the perspective of the patient and the carer. The presence of the visible wound and a cancer at an advanced stage contributed to a change in the relationship and extreme suffering for both the patient and the carer. Despite many problems such as wound odour and copious discharge from the wound, which was difficult to control, carers did their best to help their loved one with the wound. Gradually, the wound became the centre of the patient and carer’s life, and a great deal of time was spent trying to control the wound symptoms. All carers managed the wound on their own without help and advice from health care practitioners. For all of them, it was a major burden and they felt isolated. Conclusion: This study contributes to an understanding that the care of women and their carers needs strategies that are integrated in palliative wound care that takes a holistic and empathic approach that responds to patients’ and carers’ psychosocial and emotional needs and a practical need for information to help carers assist in managing the wound-related symptoms

Alfalfa: Back to Basics

In the past, many university research trials and on-farm demonstrations have determined a range of cutting intervals for alfalfa. Most researchers have agreed that the optimum harvest frequency is about every 35 days to ensure top yields, without sacrificing too much in the way of forage quality and stand persistence. Others use a strategy of harvesting at 10% bloom

Superconductivity at 17 K in Yttrium Metal under Nearly Hydrostatic Pressures to 89 GPa

In an experiment in a diamond anvil cell utilizing helium pressure medium, yttrium metal displays a superconducting transition temperature which increases monotonically from Tc ? 3.5 K at 30 GPa to 17 K at 89.3 GPa, one of the highest transition temperatures for any elemental superconductor. The pressure dependence of Tc differs substantially from that observed in previous studies under quasihydrostatic pressure to 30 GPa. Remarkably, the dependence of Tc on relative volume V/Vo is linear over the entire pressure range above 33 GPa, implying that higher values of Tc are likely at higher pressures. For the trivalent metals Sc, Y, La, Lu there appears to be some correlation between Tc and the ratio of the Wigner-Seitz radius to the ion core radius.Comment: submitted for publicatio