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

Anisotropic rare-earth spin ensemble strongly coupled to a superconducting resonator

Interfacing photonic and solid-state qubits within a hybrid quantum architecture offers a promising route towards large scale distributed quantum computing. Ideal candidates for coherent qubit interconversion are optically active spins magnetically coupled to a superconducting resonator. We report on a cavity QED experiment with magnetically anisotropic Er3+:Y2SiO5 crystals and demonstrate strong coupling of rare-earth spins to a lumped element resonator. In addition, the electron spin resonance and relaxation dynamics of the erbium spins are detected via direct microwave absorption, without aid of a cavity

Pressure-Induced Superconductivity in Sc to 74 GPa

Using a diamond anvil cell with nearly hydrostatic helium pressure medium we have significantly extended the superconducting phase diagram Tc(P) of Sc, the lightest of all transition metals. We find that superconductivity is induced in Sc under pressure, Tc increasing monotonically to 8.2 K at 74.2 GPa. The Tc(P) dependences of the trivalent d-electron metals Sc, Y, La, and Lu are compared and discussed within a simple s-d charge transfer framework.Comment: to be published in Phys. Rev. B (Brief Reports

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

Kinetic-energy release in Coulomb explosion of metastable C3H52+

C3H52+, formed by electron impact ionization of propane, undergoes metastable decay into C2H2++CH3+. We have monitored this reaction in a magnetic mass spectrometer of reversed geometry that is equipped with two electric sectors (BEE geometry). Three different techniques were applied to identify the fragment ions and determine the kinetic-energy release (KER) of spontaneous Coulomb explosion of C3H52+ in the second and third field free regions of the mass spectrometer. The KER distribution is very narrow, with a width of about 3% [root-mean square standard deviation]. An average KER of 4.58+/-0.15 eV is derived from the distribution. High level ab initio quantum-chemical calculations of the structure and energetics of C3H52+ are reported. The activation barrier of the reverse reaction, CH3++C2H2+ (vinylidene), is computed. The value closely agrees with the experimental average KER, thus indicating that essentially all energy available in the reaction is partitioned into kinetic energy. (C) 2003 American Institute of Physics

Sainfoin – New Data on Anthelmintic Effects and Production in Sheep and Goats

Gastrointestinal nematodes (GIN) are one of the most important problems affecting health and therefore performance and welfare in small ruminant husbandry. The control of these parasites in the past strongly relied on the repeated use of anthelmintic drugs. This has led to nematode populations which are resistant to most of the currently available anthelmintics. Furthermore customer’s demands for organic and residue free animal products are increasing. The aforementioned problems have given a strong impetus for the development of new non-chemical strategies to control GIN. Previous research has pointed out the anthelmintic potential of sainfoin (Onobrychis viciifolia) and other tanniferous (CT) feed sources in goats and lambs infected with GIN. A recent Swiss experiment focussed on the use of sainfoin and field bean (Vicia faba, cv. Scirocco) as single CT sources as well as in combination for additional synergic effects, to reduce periparturient GIN egg rise of ewes in late gestation and early lactation. Another experiment with Alpine goats concentrated on the influence of sainfoin on milk performance and cheese quality. The results of these experiments will be presented and discussed in connection with previous knowledge on (i) anthelmintic effects of sainfoin and (ii) the influence of sainfoin administration on performance

Aluminium-oxide wires for superconducting high kinetic inductance circuits

We investigate thin films of conducting aluminium-oxide, also known as granular aluminium, as a material for superconducting high quality, high kinetic inductance circuits. The films are deposited by an optimised reactive DC magnetron sputter process and characterised using microwave measurement techniques at milli-Kelvin temperatures. We show that, by precise control of the reactive sputter conditions, a high room temperature sheet resistance and therefore high kinetic inductance at low temperatures can be obtained. For a coplanar waveguide resonator with 1.5\,k$\Omega$ sheet resistance and a kinetic inductance fraction close to unity, we measure a quality factor in the order of 700\,000 at 20\,mK. Furthermore, we observe a sheet resistance reduction by gentle heat treatment in air. This behaviour is exploited to study the kinetic inductance change using the microwave response of a coplanar wave guide resonator. We find the correlation between the kinetic inductance and the sheet resistance to be in good agreement with theoretical expectations.Comment: 16 pages, 7 figure

Formation of even-numbered hydrogen cluster cations in ultracold helium droplets

Neutral hydrogen clusters are grown in ultracold helium nanodroplets by successive pickup of hydrogen molecules. Even-numbered hydrogen cluster cations are observed upon electron-impact ionization with and without attached helium atoms and in addition to the familiar odd-numbered H(n)(+). The helium matrix affects the fragmentation dynamics that usually lead to the formation of overwhelmingly odd-numbered H(n)(+). The use of high-resolution mass spectrometry allows the unambiguous identification of even-numbered H(n)(+) up to n congruent to 120 by their mass excess that distinguishes them from He(n)(+), mixed He(m)H(n)(+), and background ions. The large range in size of these hydrogen cluster ions is unprecedented, as is the accuracy of their definition. Apart from the previously observed magic number n = 6, pronounced drops in the abundance of even-numbered cluster ions are seen at n = 30 and 114, which suggest icosahedral shell closures at H(6)(+)(H(2))(12) and H(6)(+)(H(2))(54). Possible isomers of H(6)(+) are identified at the quadratic configuration interaction with inclusion of single and double excitations (QCISD)/aug-cc-pVTZ level of theory (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3035833

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