Anomalous expansion and phonon damping due to the Co spin-state transition in RCoO_3 with R = La, Pr, Nd and Eu

We present a combined study of the thermal expansion and the thermal conductivity of the perovskite series RCoO_3 with R = La, Nd, Pr and Eu. The well-known spin-state transition in LaCoO_3 is strongly affected by the exchange of the R ions due to their different ionic radii, i.e. chemical pressure. This can be monitored in detail by measurements of the thermal expansion, which is a highly sensitive probe for detecting spin-state transitions. The Co ions in the higher spin state act as additional scattering centers for phonons, therefore suppressing the phonon thermal conductivity. Based on the analysis of the interplay between spin-state transition and heat transport, we present a quantitative model of the thermal conductivity for the entire series. In PrCoO_3, an additional scattering effect is active at low temperatures. This effect arises from the crystal field splitting of the 4f multiplet, which allows for resonant scattering of phonons between the various 4f levels.Comment: 15 pages including 5 figure

Path integral quantization of electrodynamics in dielectric media

In the present paper we study the Faddeev-Popov path integral quantization of electrodynamics in an inhomogenious dielectric medium. We quantize all polarizations of the photons and introduce the corresponding ghost fields. Using the heat kernel technique, we express the heat kernel coefficients in terms of the dielectricity $\epsilon (x)$ and calculate the ultra violet divergent terms in the effective action. No cancellation between ghosts and "non-physical" degrees of freedom of the photon is observed.Comment: 10 pages, Latex, submitted to J.Phys.A, revised (a misprint in the bibliography

Strong damping of phononic heat current by magnetic excitations in SrCu_2(BO_3)_2

Measurements of the thermal conductivity as a function of temperature and magnetic field in the 2D dimer spin system SrCu$_2$(BO$_3$)$_2$ are presented. In zero magnetic field the thermal conductivity along and perpendicular to the magnetic planes shows a pronounced double-peak structure as a function of temperature. The low-temperature maximum is drastically suppressed with increasing magnetic field. Our quantitative analysis reveals that the heat current is due to phonons and that the double-peak structure arises from pronounced resonant scattering of phonons by magnetic excitations.Comment: a bit more than 4 pages, 2 figures included; minor changes to improve the clarity of the presentatio

Dilatonic current-carrying cosmic strings

We investigate the nature of ordinary cosmic vortices in some scalar-tensor extensions of gravity. We find solutions for which the dilaton field condenses inside the vortex core. These solutions can be interpreted as raising the degeneracy between the eigenvalues of the effective stress-energy tensor, namely the energy per unit length U and the tension T, by picking a privileged spacelike or timelike coordinate direction; in the latter case, a phase frequency threshold occurs that is similar to what is found in ordinary neutral current-carrying cosmic strings. We find that the dilaton contribution for the equation of state, once averaged along the string worldsheet, vanishes, leading to an effective Nambu-Goto behavior of such a string network in cosmology, i.e. on very large scales. It is found also that on small scales, the energy per unit length and tension depend on the string internal coordinates in such a way as to permit the existence of centrifugally supported equilibrium configuration, also known as vortons, whose stability, depending on the very short distance (unknown) physics, can lead to catastrophic consequences on the evolution of the Universe.Comment: 10 pages, ReVTeX, 2 figures, minor typos corrected. This version to appear in Phys. Rev.

Genetic variants of Anaplasma phagocytophilum from 14 equine granulocytic anaplasmosis cases

<p>Abstract</p> <p>Background</p> <p>Equine Granulocytic Anaplasmosis (EGA) is caused by <it>Anaplasma phagocytophilum</it>, a tick-transmitted, obligate intracellular bacterium. In Europe, it is transmitted by <it>Ixodes ricinus</it>. A large number of genetic variants of <it>A. phagocytophilum </it>circulate in nature and have been found in ticks and different animals. Attempts have been made to assign certain genetic variants to certain host species or pathologies, but have not been successful so far. The purpose of this study was to investigate the causing agent <it>A. phagocytophilum </it>of 14 cases of EGA in naturally infected horses with molecular methods on the basis of 4 partial genes (<it>16S rRNA</it>, <it>groEL</it>, <it>msp2</it>, and <it>msp4</it>).</p> <p>Results</p> <p>All DNA extracts of EDTA-blood samples of the horses gave bands of the correct nucleotide size in all four genotyping PCRs. Sequence analysis revealed 4 different variants in the partial <it>16S rRNA</it>, <it>groEL </it>gene and <it>msp2 </it>genes, and 3 in the <it>msp4 </it>gene. One <it>16S rRNA </it>gene variant involved in 11 of the 14 cases was identical to the "prototype" variant causing disease in humans in the amplified part [GenBank: <ext-link ext-link-id="U02521" ext-link-type="gen">U02521</ext-link>]. Phylogenetic analysis revealed as expected for the <it>groEL </it>gene that sequences from horses clustered separately from roe deer. Sequences of the partial <it>msp2 </it>gene from this study formed a separate cluster from ruminant variants in Europe and from all US variants.</p> <p>Conclusions</p> <p>The results show that more than one variant of <it>A. phagocytophilum </it>seems to be involved in EGA in Germany. The comparative genetic analysis of the variants involved points towards different natural cycles in the epidemiology of <it>A. phagocytophilum</it>, possibly involving different reservoir hosts or host adaptation, rather than a strict species separation.</p

Confounding conventional wisdom: political not principled differences in the transatlantic regulatory relationship

The transatlantic complaints over hormone-treated beef and genetically modified organisms before the World Trade Organisation (WTO) seem to confirm two separate but related conventional wisdoms about the transatlantic economic relationship: that it is highly conflictual and that many of the conflicts are rooted in profoundly different approaches to regulation. This article argues that neither of the two conventional wisdoms is accurate. Rather, it contends that they are products of two, compounding analytical shortcomings: one methodological, one empirical. The methodological shortcoming takes the form of an implicit selection bias. While WTO complaints are high profile they are rare and extreme examples; it is, therefore, unsound to generalise from them to the regulatory relationship as a whole. The empirical shortcoming has to do with neither the beef hormones nor the GMO dispute demonstrating what it is purported to. The article thus serves as a cautionary tale about the dangers of relying on obvious cases and the need to question whether evidence really does support a prevailing popular narrative

Conceptualizing pathways linking women's empowerment and prematurity in developing countries.

BackgroundGlobally, prematurity is the leading cause of death in children under the age of 5. Many efforts have focused on clinical approaches to improve the survival of premature babies. There is a need, however, to explore psychosocial, sociocultural, economic, and other factors as potential mechanisms to reduce the burden of prematurity. Women's empowerment may be a catalyst for moving the needle in this direction. The goal of this paper is to examine links between women's empowerment and prematurity in developing settings. We propose a conceptual model that shows pathways by which women's empowerment can affect prematurity and review and summarize the literature supporting the relationships we posit. We also suggest future directions for research on women's empowerment and prematurity.MethodsThe key words we used for empowerment in the search were "empowerment," "women's status," "autonomy," and "decision-making," and for prematurity we used "preterm," "premature," and "prematurity." We did not use date, language, and regional restrictions. The search was done in PubMed, Population Information Online (POPLINE), and Web of Science. We selected intervening factors-factors that could potentially mediate the relationship between empowerment and prematurity-based on reviews of the risk factors and interventions to address prematurity and the determinants of those factors.ResultsThere is limited evidence supporting a direct link between women's empowerment and prematurity. However, there is evidence linking several dimensions of empowerment to factors known to be associated with prematurity and outcomes for premature babies. Our review of the literature shows that women's empowerment may reduce prematurity by (1) preventing early marriage and promoting family planning, which will delay age at first pregnancy and increase interpregnancy intervals; (2) improving women's nutritional status; (3) reducing domestic violence and other stressors to improve psychological health; and (4) improving access to and receipt of recommended health services during pregnancy and delivery to help prevent prematurity and improve survival of premature babies.ConclusionsWomen's empowerment is an important distal factor that affects prematurity through several intervening factors. Improving women's empowerment will help prevent prematurity and improve survival of preterm babies. Research to empirically show the links between women's empowerment and prematurity is however needed

Developing assessments for child exposure to intimate partner violence in Switzerland – A study of medico-legal reports in clinical settings

Purpose: Evidence to inform assessment of needs of children exposed to intimate partner violence (IPV) in health settings is limited. A Swiss hospital-based medico-legal consultation for adult victims of violence also detects children’s exposure to IPV and refers cases to the Pediatrics Child Abuse and Neglect Team. Based on a conceptual ecological framework, this study examined the nature and circumstances of children’s exposure to IPV described in accounts collected by nurses in consultations with adult IPV victims. Methods: From 2011-2014, 438 parents (88% female) of 668 children aged 0 to 18 sought medico-legal care from the Violence Medical Unit in Lausanne Switzerland, following assaults by intimate partners (85% male). As part of the consultation, nurses completed a semi-structured questionnaire with victimized parents, recording their answers in the patient file. Victims’ statements about the abuse, their personal, family and social contexts, and their children’s exposure to IPV were analyzed. Descriptive statistics and qualitative thematic content analyses were conducted to identify, from the victimized parents’ accounts, elements useful to understand the nature and circumstances of children’s exposure and involvement during violent events. Results: Parent statements on specific violent events described children being present in 75% of the cases. Children were said to be exposed to, and responded to, severe physical violence, serious threats and insults, in the context of repeated assaults and coercive control. Families, especially mothers, were often coping with additional socio-economic vulnerabilities. Conclusions: Implications for further developing assessments of children living with IPV, especially in health settings were identified