Frustrated multiband superconductivity

We show that a clean multiband superconductor may display one or several phase transitions with increasing temperature from or to frustrated configurations of the relative phases of the superconducting order parameters. These transitions may occur when more than two bands are involved in the formation of the superconducting phase and when the number of repulsive interband interactions is odd. These transitions are signalled by slope changes in the temperature dependence of the superconducting gaps.Comment: 5 pages, 3 figure

Sorbent coatings for solid-phase microextraction targeted towards the analysis of death-related polar analytes coupled to comprehensive two-dimensional gas chromatography: comparison of zwitterionic polymeric ionic liquids versus commercial coatings

Decomposition of bodies generates several types of polar volatile organic compounds (VOCs), whose types, patterns and ratios change during the various stages of decomposition and, therefore, their determination has huge potential to provide useful information to disclose events related to the time of death, or body surrounding environment. As sample preparation is a mandatory key-point in a method development, this research aims to develop a simple, accurate and rapid approach to study death-related polar VOCs based on headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography-time of flight mass spectrometry (GC × GC-ToFMS) analysis. The performance of zwitterionic PIL-based fibers (containing a [VIm+C9COO−] monomer and a [(VIm)2C122+]-2Br− crosslinker), tailored for polar compounds, was evaluated for a set of 19 analytes associated with the unique odour created by decomposing bodies, and it was compared to the commercially-available fibers: divinylbenzene/carboxen/poly(dimethylsiloxane) – DVB/CAR/PDMS, poly(dimethylsiloxane)/divinylbenzene – PDMS/DVB and polyacrylate (PA). Fibers with absorptive-type mechanism, such as PA and PIL, showed the best results in the balance of the parameters studied, being able to detect analytes at ng level and providing a profile representative of the headspace composition, thus they may represent a useful tool to respond to current challenges in forensic taphonomy. The reproducibility (with relative standard deviation lower than 18%, depending on the analyte) and relative recoveries (higher than 99.1%) were similar and acceptable for both fibers. The zwitterionic PIL, with ca. 4 times smaller film thickness than PA, still has potential to have the best performance, supported by the efforts to obtain thicker sorbent coatings.publishe

Non-equilibrium Phase Transitions with Long-Range Interactions

This review article gives an overview of recent progress in the field of non-equilibrium phase transitions into absorbing states with long-range interactions. It focuses on two possible types of long-range interactions. The first one is to replace nearest-neighbor couplings by unrestricted Levy flights with a power-law distribution P(r) ~ r^(-d-sigma) controlled by an exponent sigma. Similarly, the temporal evolution can be modified by introducing waiting times Dt between subsequent moves which are distributed algebraically as P(Dt)~ (Dt)^(-1-kappa). It turns out that such systems with Levy-distributed long-range interactions still exhibit a continuous phase transition with critical exponents varying continuously with sigma and/or kappa in certain ranges of the parameter space. In a field-theoretical framework such algebraically distributed long-range interactions can be accounted for by replacing the differential operators nabla^2 and d/dt with fractional derivatives nabla^sigma and (d/dt)^kappa. As another possibility, one may introduce algebraically decaying long-range interactions which cannot exceed the actual distance to the nearest particle. Such interactions are motivated by studies of non-equilibrium growth processes and may be interpreted as Levy flights cut off at the actual distance to the nearest particle. In the continuum limit such truncated Levy flights can be described to leading order by terms involving fractional powers of the density field while the differential operators remain short-ranged.Comment: LaTeX, 39 pages, 13 figures, minor revision

The role of temperature on the impact of remediated water towards marine organisms

Marine organisms are frequently exposed to pollutants, including trace metals, derived from natural and anthropogenic activities. In order to prevent environmental pollution, di erent approaches have been applied to remove pollutants from waste water and avoid their discharge into aquatic systems. However, organisms in their natural aquatic environments are also exposed to physico-chemical changes derived from climate change-related factors, including temperature increase. According to recent studies, warming has a negative impact on marine wildlife, with known e ects on organisms physiological and biochemical performance. Recently, a material based on graphene oxide (GO) functionalized with polyethyleneimine (PEI) proved to be e ective in the remediation of mercury (Hg) contaminated water. Nevertheless, no information is available on the toxic impacts of such remediated water towards aquatic systems, neither under actual nor predicted temperature conditions. For this, the present study assessed the toxicity of seawater, previously contaminated with Hg and remediated by GO-PEI, using the clam species Ruditapes philippinarum exposed to actual and a predicted temperature conditions. The results obtained demonstrated that seawater contaminated with Hg and/or Hg+GO-PEI induced higher toxicity in clams exposed to 17 and 22 C compared to organisms exposed to remediated seawater at the same temperatures. Moreover, similar histological and biochemical results were observed between organisms exposed to control and remediated seawater, independently of the temperatures (17 and 21 C), highlighting the potential use of GO-PEI to remediate Hg from seawater without significant toxicity issues to the selected marine species.publishe

Highly sensitive optical fibre long period grating biosensor anchored with silica core gold shell nanoparticles

An optical fibre long period grating (LPG), modified with a coating of silica core gold shell (SiO2:Au) nanoparticles (NPs) deposited using the layer-by-layer method, was employed for the development of a biosensor. The SiO2:Au NPs were electrostatically assembled onto the LPG with the aid of a poly(allylamine hydrochloride) (PAH) polycation layer. The LPG sensor operates at the phase matching turning point to provide the highest sensitivity. The SiO2:Au NPs were modified with biotin, which was used as a ligand for streptavidin (SV) detection. The sensing mechanism is based on the measurement of the refractive index change induced by the binding of the SV to the biotin. The effect on sensitivity of increasing the surface area by virtue of the SiO2:Au nanoparticles’ diameter and film thickness was studied. The lowest measured concentration of SV was 2.5 nM, achieved using an LPG modified with a 3 layer (PAH/SiO2:Au) thin film composed of SiO2 NPs of 300 nm diameter with a binding constant o

Phenotypic and genotypic monitoring of Schistosoma mansoni in Tanzanian schoolchildren five years into a preventative chemotherapy national control programme

We conducted combined in vitro PZQ efficacy testing with population genetic analyses of S. mansoni collected from children from two schools in 2010, five years after the introduction of a National Control Programme. Children at one school had received four annual PZQ treatments and the other school had received two mass treatments in total. We compared genetic differentiation, indices of genetic diversity, and estimated adult worm burden from parasites collected in 2010 with samples collected in 2005 (before the control programme began) and in 2006 (six months after the first PZQ treatment). Using 2010 larval samples, we also compared the genetic similarity of those with high and low in vitro sensitivity to PZQ

Scaling predictions for radii of weakly bound triatomic molecules

The mean-square radii of the molecules $^4$He$_3$, $^4$He$_2-^6$Li, $^4$He$_2-^7$Li and $^4$He$_2-^{23}$Na are calculated using a three-body model with contact interactions. They are obtained from a universal scaling function calculated within a renormalized scheme for three particles interacting through pairwise Dirac-delta interaction. The root-mean-square distance between two atoms of mass $m_A$ in a triatomic molecule are estimated to be of de order of ${\cal C}\sqrt{\hbar^2/[m_A(E_3-E_2)]}$, where $E_2$ is the dimer and $E_3$ the trimer binding energies, and ${\cal C}$ is a constant (varying from $\sim 0.6$ to $\sim 1$) that depends on the ratio between $E_2$ and $E_3$. Considering previous estimates for the trimer energies, we also predict the sizes of Rubidium and Sodium trimers in atomic traps.Comment: 7 pages, 2 figure

Jorge A. Swieca's contributions to quantum field theory in the 60s and 70s and their relevance in present research

After revisiting some high points of particle physics and QFT of the two decades from 1960 to 1980, I comment on the work by Jorge Andre Swieca. I explain how it fits into the quantum field theory during these two decades and draw attention to its relevance to the ongoing particle physics research. A particular aim of this article is to direct thr readers mindfulness to the relevance of what at the time of Swieca was called "the Schwinger Higgs screening mechanism". which, together with recent ideas which generalize the concept of gauge theories, has all the ingredients to revolutionize the issue of gauge theories and the standard model.Comment: 49 pages, expansion and actualization of text, improvement of formulations and addition of many references to be published in EPJH - Historical Perspectives on Contemporary Physic

Adaptação da escala de homofobia implítica e explícita ao contexto brasileiro

The great number of aggressive attitudes and discriminatory behavior reported toward homosexuals has been widely discussed. Recent studies have shown that the prejudice has changed, becoming more subtle. However, the researches that try to emphasize this change in relation to the prejudice toward these minority groups are insufficient. Therefore, this study aimed at adapting the Explicit and Implicit Homophobia Scale to the Brazilian context. A sample of 231 university students participated in this research, ages varying from 17 to 55 years old (M = 24.0; SD = 5.38), mostly males (51.5%). They have answered the above-mentioned scale as well as socio-demographic questions. The results of the confirmatory factor analysis corroborated the bi-factorial structure of the instrument. The measure has also presented a satisfactory internal consistency (Cronbach's Alpha = .87).O grande número de atitudes agressivas e comportamentos discriminatórios reportados com relação aos homossexuais tem sido amplamente discutido. Estudos recentes têm mostrado que o preconceito se modificou, tornando-se mais sutil. No entanto, são escassos os estudos que procuram enfatizar essa modificação no que diz respeito ao preconceito frente a estes grupos minoritários. Assim, o objetivo deste estudo foi adaptar a Escala de Homofobia Implícita e Explícita para o contexto brasileiro. Participaram desta pesquisa 231 estudantes universitários, com idade variando de 17 a 55 anos (M = 24,0; DP = 5,38), sendo a maioria (51,5%) do sexo masculino. Estes responderam à escala mencionada e questões sócio-demográficas. Os resultados da análise fatorial confirmatória corroboraram a estrutura bi-fatorial da medida. Conjuntamente, o instrumento apresentou consistência interna (alfa de Cronbach = 0,87), mostrando-se uma medida fidedigna para utilização neste contexto