Signatures of quantum criticality in hole-doped and chemically pressurized EuFe_2As_2 single crystals

We study the effect of hole-doping and chemical pressure (isovalent doping) in single crystals of K$_x$Eu$_{1-x}$Fe$_2$As$_2$ and EuFe$_2$(As$_{1-y}$P$_y$)$_2$, respectively, by measurements of the thermopower, $S(T)$, and electrical resistivity, $\rho(T)$. The evolution of $S(T)$ upon doping indicates drastic changes of the electronic configuration at critical values $x_{\mathrm{cr}}=0.3$ and $y_{\mathrm{cr}}=0.21$, respectively, as the spin-density-wave transition is completely suppressed and superconductivity (SC) emerges. For the case of chemical pressure, the comparison with published ARPES measurements indicates a Lifshitz transition at $y_{cr}$. The temperature dependences $S(T)/T\propto \log T$ and $\Delta\rho\propto T$ observed in the normal state above the SC transition suggest quantum criticality in both systems.Comment: PRB accepte

Environmental occurrence of the Whipple's disease bacterium (Tropheryma whippelii).

Whipple's disease is a systemic disorder in which a gram-positive rod-shaped bacterium is constantly present in infected tissues. After numerous unsuccessful attempts to culture this bacterium, it was eventually characterized by 16S rRNA gene analysis to be a member of the actinomycetes. The name Tropheryma whippelii was proposed. Until now, the bacterium has only been found in infected human tissues, but there is no evidence for human-to-human transmission. Here we report the detection of DNA specific for the Whipple's disease bacterium in 25 of 38 wastewater samples from five different sewage treatment plants in the area of Heidelberg, Germany. These findings provide the first evidence that T. whippelii occurs in the environment, within a polymicrobial community. This is in accordance with the phylogenetic relationship of this bacterium as well as with known epidemiological aspects of Whipple's disease. Our data argue for an environmental source for infection with the Whipple's disease bacterium

Is flow velocity a significant parameter in flood damage modelling?

Flow velocity is generally presumed to influence flood damage. However, this influence is hardly quantified and virtually no damage models take it into account. Therefore, the influences of flow velocity, water depth and combinations of these two impact parameters on various types of flood damage were investigated in five communities affected by the Elbe catchment flood in Germany in 2002. 2-D hydraulic models with high to medium spatial resolutions were used to calculate the impact parameters at the sites in which damage occurred. A significant influence of flow velocity on structural damage, particularly on roads, could be shown in contrast to a minor influence on monetary losses and business interruption. Forecasts of structural damage to road infrastructure should be based on flow velocity alone. The energy head is suggested as a suitable flood impact parameter for reliable forecasting of structural damage to residential buildings above a critical impact level of 2 m of energy head or water depth. However, general consideration of flow velocity in flood damage modelling, particularly for estimating monetary loss, cannot be recommended

Upper critical magnetic field in K0.83Fe1.83Se2 and Eu0.5K0.5Fe2As2 single crystals

The H-T phase diagrams of single crystalline electron-doped K0.83Fe1.83Se2 (KFS1), K0.8Fe2Se2 (KFS2) and hole-doped Eu0.5K0.5Fe2As2 (EKFA) have been deduced from tunnel diode oscillator-based contactless measurements in pulsed magnetic fields up to 57 T for the inter-plane (H//c) and in-plane (H//ab) directions. The temperature dependence of the upper critical magnetic field Hc2(T) relevant to EFKA is accounted for by the Pauli model including an anisotropic Pauli paramagnetic contribution (\mu_BHp=114 T for H//ab and 86 T for H//c). This is also the case of KFS1 and KFS2 for H//ab whereas a significant upward curvature, accounted for by a two-gap model, is observed for H//c. Despite the presence of antiferromagnetic lattice order within the superconducting state of the studied compounds, no influence of magnetic ordering on the temperature dependence of Hc2(T) is observed.Comment: 9 pages, 5 figures. arXiv admin note: text overlap with arXiv:1104.561

Persistent detwinning of iron pnictides by small magnetic fields

Our comprehensive study on EuFe$_2$As$_2$ reveals a dramatic reduction of magnetic detwinning fields compared to other AFe$_2$As$_2$ (A = Ba, Sr, Ca) iron pnictides by indirect magneto-elastic coupling of the Eu$^{2+}$ ions. We find that only 0.1T are sufficient for persistent detwinning below the local Eu$^{2+}$ ordering; above $T_\text{Eu}$ = 19K, higher fields are necessary. Even after the field is switched off, a significant imbalance of twin domains remains constant up to the structural and electronic phase transition (190K). This persistent detwinning provides the unique possibility to study the low temperature electronic in-plane anisotropy of iron pnictides without applying any symmetrybreaking external force.Comment: accepted by Physical Review Letter

Gewisse morphologische, physiognomische und antropologische Merkmale bei einwohnern eines jugoslawischen Küstengebiets

Autori su obavili analizu nalaza 498 ispitanika obaju spolova djece starosjedilaca (najmanje jedna generacija) u Solinu i Kaštelima. Ispitivanja su provedena kod djece stare 10—14 godina, s namjerom da se pridonese prikupljanju podataka nacionalnih obilježja. Ispitivanja su po karakteru sondažna. Problematika se je sastojala u tome da se utvrdi postoje li signifikantni nalazi i njihove međusobne korelacije. Ispitivanja su obavljena u području identične geografske širine, u kojoj je obavljao ispitivanja i Francuz Pont30, s namjerom da se ustanovi da li utvrđeni indeks odgovara onom spomenutog autora. Mjerenja, su izvedena standardnim instrumentarijem, a vršila ih je ekipa od triju članova, koautora ovog rada, koja je prethodno prošla blind test, konstruiran za ispitivanja te vrsti. Unošenje i obrada podataka učinjeno je na obrascima za ortodontske sistematske preglede (rubno bušene kartice br. 1226/038). Rezultati su komparirani s nalazima stranih autora. Utvrđeno je između ostalog da je SI i parametar Zy-Zy veći kod muških ispitanika. PŠ i SŠ su u cijelosti veće kod ispitanika bez anomalija. Usporedbene vrijednosti dobivenog indeksa za PŠ i SŠ vrlo su blizu mjerama po Pontu30, što potvrđuje pretpostavku, da se je radilo o ispitanicima sa širokim čeljustima. Statistička obrada vlastitih podataka prikazana je na tab. 1., dok ostale tablice prikazuju rezultate stranih autora. Tab. 2 i 4 sadrže i vlastite rezultate zbog preglednije komparacije. Autori se kritički osvrću na pomanjkanje standardne metodike u ispitivanjima te vrsti u nacionalnoj stomatološkoj literaturi Njemačke i Jugoslavije.The authors published an analysis of the findings in 498 test subjects of both sexes, children of the indigenes (at least one generation) of Solin and Kaštela. The testing was carried out in children aged between 10 to 14 for the purpose of contributing to the collection of data on national characteristics. The tests had a probing character and were meant to investigate the problem whether there existed any significant findings and to establish their mutual correlation. Testings were carried out in a region of identical geographical latitude to that in which the Frenchman Pont made his investigations (30). The aim was to establish whether the index obtained corresponded to that of the mentioned author. Measuring was carried out by means of standard instruments and a team consisting of three members, coauthors of this paper, was engaged in the task. The team had previously undergone the blind test for investigations of that kind. The elaboration and entry of data was made on forms for ortodontic systematic examinations (punch cards no. 1226/038). The results were compared1 to^ the findings of the foreign authors. It was ascertained that the width of the upper incisors and the distance Zy-Zy were higher in boys. Anterior and posterior widths of the upper dental arch were higher in subjects without malocclusions. The obtained values for both widths of the dental arch were very close to those of Pont, thus confirming the hypothesis that the test subjects had wide jaws. The statistical elaboration of our own data is shown in Table 1, while the other tables show the results of foreign authors. Table 2 and 4 contain also our own results for easier comparison. The authors point out at the lack of standard methods in investigations of that kind in the national German and Yugoslav dental literature.Die Autoren haben eine Befunderhebung bei 498 Kindern beiderlei Geschlechts von Alteingesessenen in Solin und Kaštela auf gewisse Merkmale, durchgeführt. Die Untersuchungen wurden an Kindern im Alter von 10 bis 14 Jahren gemacht, mit der Absicht Beiträge für nationale Merkmale zu sammeln. Es sollte festgestellt werden ob deutliche Befunde erhoben werden können, und ihre gegen seitigen Zusammenhänge geprüft werden. Die Untersuchungen wurden in Gebieten der gleichen geographischen Breite durchgeführt, in welchen auch der Franzose Pont seine Untersuchungen anstellte, mit der Absicht festzustellen ob der erhaltene Index dem Pontschen-Index gleich ist. Die Messungen wurden von den drei Koautoren dieser Arbeit mit standardisierten Methoden ausgeführt. Die Resultate wurden mit Befunden anderer Autoren verglichen. Unter Anderem wurde festgestellt, dass die Sl und der Parameter Zy-Zy bei männlichen Probanaen grösser ist. Die vordere und die hintere obere Zahn bogen breite ist im Ganzen grösser bei Untersuchten die keine Anomalien aufwiesen. Der Vergleichswert der erhaltenen Indexe für die angeführten Breiten sind den Pont - Werten sehr nahe, was die Vorraussetzung bestätigt, dass es sich um Probanden mit breiten Kiefern handelt. Die statistische Bearbeitung der eigenen Befunde ist auf Tabelle 1 dargestellt, während die übrigen Tabellen Resultate anderer Autoren zeigen. Die Tabellen 2 und 4 behalten auch eigene Resultate, wegen besserer Übersicht bei der Vergleichung. Die Autoren beanständen das Fehlen einer Standard- -Methode für Untersuchungen dieser Art in der nationalen stomatologischen Literatur Deutschlands und Jugoslawiens

Effects of closed-loop automatic control of the inspiratory fraction of oxygen (FiO(2)-C) on outcome of extremely preterm infants - study protocol of a randomized controlled parallel group multicenter trial for safety and efficacy

Background: Most extremely low gestational age neonates (ELGANS, postmenstrual age at birth (PMA) < 28 completed weeks) require supplemental oxygen and experience frequent intermittent hypoxemic and hyperoxemic episodes. Hypoxemic episodes and exposure to inadequately high concentrations of oxygen are associated with an increased risk of retinopathy of prematurity (ROP), chronic lung disease of prematurity (BPD), necrotizing enterocolitis (NEC), neurodevelopmental impairment (NDI), and death beyond 36 weeks PMA. Closed-loop automated control of the inspiratory fraction of oxygen (FiO2-C) reduces time outside the hemoglobin oxygen saturation (SpO2) target range, number and duration of hypo- and hyperoxemic episodes and caregivers’ workload. Effects on clinically important outcomes in ELGANs such as ROP, BPD, NEC, NDI and mortality have not yet been studied. Methods: An outcome-assessor-blinded, randomized controlled, parallel-group trial was designed and powered to study the effect of FiO2-C (in addition to routine manual control (RMC) of FiO2), compared to RMC only, on death and severe complications related to hypoxemia and/or hyperoxemia. 2340 ELGANS with a GA of 23 + 0/7 to 27 + 6/ 7 weeks will be recruited in approximately 75 European tertiary care neonatal centers. Study participants are randomly assigned to RMC (control-group) or FiO2-C in addition to RMC (intervention-group). Central randomization is stratified for center, gender and PMA at birth (< 26 weeks and ≥ 26 weeks). FiO2-C is provided by commercially available and CE-marked ventilators with an FiO2-C algorithm intended for use in newborn infants. The primary outcome variable (composite of death, severe ROP, BPD or NEC) is assessed at 36 weeks PMA (or, in case of ROP, until complete vascularization of the retina, respectively). The co-primary outcome variable (composite outcome of death, language/cognitive delay, motor impairment, severe visual impairment or hearing impairment) is assessed at 24 months corrected age. Discussion: Short-term studies on FiO2-C showed improved time ELGANs spent within their assigned SpO2 target range, but effects of FiO2-C on clinical outcomes are yet unknown and will be addressed in the FiO2-C trial. This will ensure an appropriate assessment of safety and efficacy before FiO2-C may be implemented as standard therap

Beurteilung der hämodynamischen Wirksamkeit von Extrasystolen mittels Impedanzkardiographie und peripherer Pulswellenanalyse

In der klinischen Routine ist gegenwärtig das Langzeit-EKG zur Beurteilung der klinischen Relevanz von Arrhythmien und Extrasystolen Mittel der Wahl. Obwohl bekannt ist, daß ventrikuläre (VES) und auch supraventrikuläre (SVES) Extrasystolen sowohl ein normales, ein reduziertes und teilweise überhaupt kein Schlagvolumen besitzen können, wird gegenwärtig die hämodynamische Wirksamkeit von arrhythmogenen Schlägen in der klinischen Routine wenig beachtet. Nachfolgend wird eine Methode vorgestellt, die eine quantitative Einschätzung der hämodynamischen Wirksamkeit von SVES und VES gestattet

Spatially-resolved potential measurement with ion crystals

We present a method to measure potentials over an extended region using one-dimensional ion crystals in a radio frequency (RF) ion trap. The equilibrium spacings of the ions within the crystal allow the determination of the external forces acting at each point. From this the overall potential, and also potentials due to specific trap features, are calculated. The method can be used to probe potentials near proximal objects in real time, and can be generalized to higher dimensions.Comment: 7 pages (double spaced), 3 figure

Linkage between scattering rates and superconductivity in doped ferropnictides

We report an angle-resolved photoemission study of a series of hole- and electron-doped iron-based superconductors, their parent compound BaFe$_{2}$As$_{2}$, and their cousins BaCr$_{2}$As$_{2}$ and BaCo$_{2}$As$_{2}$. We focus on the inner hole pocket, which is the hot spot in these compounds. More specifically, we determine the energy (E)-dependent scattering rate (E) as a function of the 3d count. Moreover, for the compounds K$_{0.4}$Ba$_{0.6}$Fe$_{2}$As$_{2}$ and BaCr$_{2}$As$_{2}$, we derive the energy dependence of the renormalization function Z(E) and the imaginary part of the self-energy function Im(E). We obtain a non-Fermi liquidlike linear in energy scattering rate (E>>k$_{B}$T ), independent of the dopant concentration. The main result is that the slope β = (E>>k$_{B}$T )/E reaches its maxima near optimal doping and scales with the superconducting transition temperature. This supports the spin fluctuation model for superconductivity for these materials. In the optimally hole-doped compound, the slope of the scattering rate of the inner hole pocket is about three times bigger than the Planckian limit T(E)/E ≈ 1. This result, together with the energy dependence of the renormalization function Z(E), signals very incoherent charge carriers in the normal state which transform at low temperatures to a coherent unconventional superconducting state