Competition of local-moment ferromagnetism and superconductivity in Co-substituted EuFe2As2

In contrast to SrFe2As2, where only the iron possesses a magnetic moment, in EuFe2As2 an additional large, local magnetic moment is carried by Eu2+. Like SrFe2As2, EuFe2As2 exhibits a spin-density wave transition at high temperatures, but in addition the magnetic moments of the Eu2+ order at around 20 K. The interplay of pressure-induced superconductivity and the Eu2+ order leads to a behavior which is reminiscent of re-entrant superconductivity as it was observed, for example, in the ternary Chevrel phases or in the rare-earth nickel borocarbides. Here, we study the delicate interplay of the ordering of the Eu2+ moments and superconductivity in EuFe1.9Co0.1As2, where application of external pressure makes it possible to sensitively tune the ratio of the magnetic (T_C) and the superconducting (T_{c,onset}) critical temperatures. We find that superconductivity disappears once T_C > T_{c,onset}.Comment: 4 pages, 4 figures, submitted to the proceedings of SCES201

Effects Of Infusion Of Penicillen In The Bovine Mammary Gland

Veterinarians have waited anxiously and patiently for the time when penicillin could be released for animal therapy. Practitioners and research men have had many conditions in mind which might be expected to respond to treatment with penicillin upon the basis of its known antibiotic activity. Foremost among these conditions was bovine mastitis. It has been fervently hoped that penicillin would be a valuable drug in the treatment of streptococcic and staphylococcic mastitis. Reports to date and the experience of many practitioners prove that we have not hoped entirely in vain. We know that a large proportion of streptococcic and stapylococcic mastitis can be cured by proper treatment with penicillin. We are also acutely aware of the fact that the optimum dosage and frequency for a given case of mastitis is not known as yet. A knowledge of the physiologic behavior of this antibiotic when introduced into the mammary gland is essential for a scientific application of the drug in therapy

Roughness correction to the Casimir force at short separations: Contact distance and extreme value statistics

So far there has been no reliable method to calculate the Casimir force at separations comparable to the root-mean-square of the height fluctuations of the surfaces. Statistical analysis of rough gold samples has revealed the presence of peaks considerably higher than the root-mean-square roughness. These peaks redefine the minimum separation distance between the bodies and can be described by extreme value statistics. Here we show that the contribution of the high peaks to the Casimir force can be calculated with a pairwise additive summation, while the contribution of asperities with normal height can be evaluated perturbatively. This method provides a reliable estimate of the Casimir force at short distances, and it solves the significant, so far unexplained discrepancy between measurements of the Casimir force between rough surfaces and the results of perturbation theory. Furthermore, we illustrate the importance of our results in a technologically relevant situation.Comment: 29 pages, 11 figures, to appear in Phys. Rev.

A quantum phase transition from triangular to stripe charge order in NbSe2_{2}

The competition between proximate electronic phases produces a complex phenomenology in strongly correlated systems. In particular, fluctuations associated with periodic charge or spin modulations, known as density waves, may lead to exotic superconductivity in several correlated materials. However, density waves have been difficult to isolate in the presence of chemical disorder, and the suspected causal link between competing density wave orders and high temperature superconductivity is not understood. Here we use scanning tunneling microscopy to image a previously unknown unidirectional (stripe) charge density wave (CDW) smoothly interfacing with the familiar tri-directional (triangular) CDW on the surface of the stoichiometric superconductor NbSe$_2$. Our low temperature measurements rule out thermal fluctuations, and point to local strain as the tuning parameter for this quantum phase transition. We use this discovery to resolve two longstanding debates about the anomalous spectroscopic gap and the role of Fermi surface nesting in the CDW phase of NbSe$_2$. Our results highlight the importance of local strain in governing phase transitions and competing phenomena, and suggest a new direction of inquiry for resolving similarly longstanding debates in cuprate superconductors and other strongly correlated materials.Comment: PNAS in pres

Nationale Citymarketing Monitor 2010

Inleiding Citymarketing is volop in beweging. In het begin van de jaren tachtig was het aantal gemeenten met een citymarketingbeleid nog relatief klein; inmiddels doen veel meer gemeenten aan citymarketing1. Anno 2010 is citymarketing één van de gemeentelijke beleidsterreinen. Citymarketing komt terug in collegeakkoorden, er zijn wethouders met citymarketing in de portefeuille en er zijn ambtenaren belast met het ontwikkelen, coördineren en uitvoeren van citymarketing . Ook zien we op meerdere plaatsen externe – vaak deels door de gemeente gesubsidieerde - partijen die een belangrijke rol vervullen in de citymarketing. Soms hebben deze externe organisaties vooral uitvoeringstaken, maar er zijn ook externe organisaties die verantwoordelijk zijn voor het ontwikkelen en coördineren van het citymarketingbeleid. We kunnen ook spreken van een beroepsgroep van citymarketeers. Een goed voorbeeld hiervan is dat er veel professionals lid zijn van de Linked In groep voor citymarketing. Ook kunnen we zeggen dat de aard en omvang van citymarketingactiviteiten in de afgelopen decennia is veranderd. Zo was city branding nauwelijks aan de orde in de jaren tachtig en negentig. Vanaf de millenniumwisseling is de belangstelling voor het gebruik van branding toegenomen

Perceived Impact of the Youth Enterprise Development Fund on the Youth Towards the Establishment of Small Scale Rural Enterprises in Turbo Division, Uasin-gishu County, Kenya

The inception of the Youth Enterprise Development Fund has seen the rise of youth groups in rural areas. This paper is thus aimed at understanding the impact of the fund towards the youth establishment of small scale enterprises in Turbo Division. A descriptive research design was used in this paper. Data was collected using focused group discussion and self-administered questionnaires thus they were administered to the selected youth groups found in selected parts of the Turbo Division. Purposive technique was used in the specific youth of aged bracket 18 year to 35 years. Further, purposive and stratified sampling techniques were used in targeted youth groups. The sample size used was 147 drawn from Turbo Division. The salient findings of the study are that indeed the youth joined the small scale enterprises to obtain benefits through collaborative efforts, to gain and obtain skills and experiences, obtaining start-up capital and finally due to the unemployment. Moreover, impact made by the fund on individual life included; promoting togetherness, promoting income and sustained livelihoods thus improved economic statues, and eventually enhanced skills and experience that led to acquiring of more skills by joining polytechnics. Furthermore the fund had enhanced group development and participation. It is recommended that there should be enhanced youth group sustainability towards proper utilization of the fund

The chiral phase transition in charge ordered 1T-TiSe2

It was recently discovered that the low temperature, charge ordered phase of 1T-TiSe2 has a chiral character. This unexpected chirality in a system described by a scalar order parameter could be explained in a model where the emergence of relative phase shifts between three charge density wave components breaks the inversion symmetry of the lattice. Here, we present experimental evidence for the sequence of phase transitions predicted by that theory, going from disorder to non-chiral and finally to chiral charge order. Employing X-ray diffraction, specific heat, and electrical transport measurements, we find that a novel phase transition occurs ~7 K below the main charge ordering transition in TiSe2, in agreement with the predicted hierarchy of charge ordered phases.Comment: 5 pages, 3 figures; includes additional experimental and theoretical results; fixed typo