Topological insight into the non-Arrhenius mode hopping of semiconductor ring lasers

We investigate both theoretically and experimentally the stochastic switching between two counter-propagating lasing modes of a semiconductor ring laser. Experimentally, the residence time distribution cannot be described by a simple one parameter Arrhenius exponential law and reveals the presence of two different mode-hop scenarios with distinct time scales. In order to elucidate the origin of these two time scales, we propose a topological approach based on a two-dimensional dynamical system.Comment: 4 pages, 3 figure

HABITAT ASSOCIATIONS OF LAND BIRDS IN FERNANDO DE NORONHA, BRAZIL

ABSTRACT Fernando de Noronha is one of few archipelagos of Brazil. These islands harbor five species of land birds: two introduced species (House Sparrow, Passer domesticus, and Cattle Egret, Bubulcus ibis), one widespread dove (Eared Dove, Zenaida auriculata) and two endemic passerines. The two endemic species, Noronha Vireo (Vireo gracilirostris) and Noronha Elaenia (Elaenia ridleyana), have been classified as ‘Near Threatened’ and ‘Vulnerable’, respectively. Here, we quantified the abundance of land birds and correlated it to habitat features to assess potential habitat preferences. We carried out 120 five‐minute point counts in October 2009, and correlated bird abundance with percentages of woodland, bushes, low herbs, bare ground, and man‐made habitats in each sample. The abundance of Noronha Vireo and Noronha Elaenia was positively correlated with woodland and bushes cover. The Eared Dove was associated to sites with bare ground, the House Sparrow with man‐made habitats, and the Cattle Egret with low vegetation sites. Abundances of Noronha Vireo and Noronha Elaenia were significantly higher in sites with natural vegetation than in human‐influenced areas. The association between these species and areas with high native vegetation cover highlights their potential vulnerability to human disturbance. RESUMO ∙ Associações entre os ambientes e as aves terrestres de Fernando de Noronha, BrasilFernando de Noronha é um dos poucos arquipélagos do Brasil. Estas ilhas abrigam cinco espécies de aves terrestres: duas espécies introduzidas (Passer domesticus e Bubulcus ibis), uma pomba com ampla distribuição (Zenaida auriculata) e duas espécies de passeriformes endêmicos (Vireo gracilirostris e Elaenia ridleyana). Estas duas espécies são classificadas como “quase ameaçada” (V. gracilirostris) e “vulnerável” (E. ridleyana). Neste estudo, quantificamos a abundancia das aves terrestres e correlacionamos com as características de habitat do arquipélago de Fernando de Noronha. Fizemos 120 pontos de escuta de cinco minutos em outubro de 2009, comparamos a abundancia de aves com a porcentagem de ambientes contendo vegetação árvobórea, arbustos, vegetação rasteira, solo aberto e construções amostradas em um raio de 25m. A abundancia de V. gracilirostris e de E. ridleyana é positivamente correlacionada com porcentagem de cobertura de árvores e arbustos. A abundancia de Z. auriculata está positivamente correlacionada com a porcentagem de solo aberto, a abundancia de P. domesticus com construções e de B. ibis com a porcentagem de vegetação rasteira. As abundancias de V. gracilirostris e E. ridleyana são significativamente maiores em locais com vegetação conservada, distante das vilas. As associações entre as es

Tile decoration with greener technologies: spray pyrolysis and solution combustion synthesis for alternative colorations

Ponència presentada al V Congreso Hispano-Luso y LVI Congreso de la Sociedad Española de Cerámica y Vidrio, Barcelona, 8-10 October 2018The great concern about environmental impacts of different industries if forcing the research in more nature-friendly processes. In the case of ceramic tiles manufacture, decoration stage consumes pigments or frits for special effects whose manufacture requires great amounts of energy. Our group has investigated alternative ways to obtain pigments and decorative effects

Performance assessment of polymer based electrodes for in vitro electrophysiological sensing: the role of the electrode impedance

Conducting polymer electrodes based on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) are used to record extracellular signals from autonomous cardiac contractile cells and glioma cell cultures. The performance of these conducting polymer electrodes is compared with Au electrodes. A small-signal impedance analysis shows that in the presence of an electrolyte, both Au and polymer electrodes establish high capacitive double-layers. However, the polymer/electrolyte interfacial resistance is 3 orders of magnitude lower than the resistance of the metal/electrolyte interface. The polymer low interfacial resistance minimizes the intrinsic thermal noise and increases the system sensitivity. However, when measurements are carried out in current mode a low interfacial resistance partially acts as a short circuit of the interfacial capacitance, this affects the signal shape

Quantum Electrodynamics at Extremely Small Distances

The asymptotics of the Gell-Mann - Low function in QED can be determined exactly, \beta(g)= g at g\to\infty, where g=e^2 is the running fine structure constant. It solves the problem of pure QED at small distances L and gives the behavior g\sim L^{-2}.Comment: Latex, 6 pages, 1 figure include

Scintillating double beta decay bolometers

We present the results obtained in the development of scintillating Double Beta Decay bolometers. Several Mo and Cd based crystals were tested with the bolometric technique. The scintillation light was measured through a second independent bolometer. A 140 g CdWO_4 crystal was run in a 417 h live time measurement. Thanks to the scintillation light, the alpha background is easily discriminated resulting in zero counts above the 2615 keV gamma line of Thallium 208. These results, combined with an extremely easy light detector operation, represent the first tangible proof demonstrating the feasibility of this kind of technique.Comment: 15 pages, 8 figure

A modeling domain-specific language for IoT-enabled operating systems

With the increased complexity of low-end devices in the Internet of Things (IoT), mainly due to the connectivity and interoperability requirements, the development and configuration of embedded operating systems (OSes) for such devices is not straight forward. The complexity of the communication requirements is usually mitigated by the OS, e.g., the Contiki-OS, as it already incorporates an IoT-compliant network stack. Yet, the configuration of such stack requires major knowledge on the code structure, leading to additional development time, particularly when the network comprises several wireless nodes and individual configurations with subsequent firmware that needs to be generated. Based on a developed software modeling domain-specific language, this paper presents the EL4IoT framework. It aims to reduce and ease the development time by promoting a design automation tool that can configure, and automatically generate code (ready to compile) for low-end IoT devices running the Contiki-OS. Although leveraging the whole Contiki-OS modeling, this work only refactored and modeled the network stack while approaching the OS itself as one big building block or component. The proposed approach can be extended to other IoT-enabled OSes as well as integrated in other design automation tools.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT - Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013. Tiago Gomes is supported by FCT PhD grant SFRH/BD/90162/2012

Multivariable analysis to determine risk factors associated with early pregnancy loss in thoroughbred broodmares

Early pregnancy loss (EPL) between days 15–65 after breeding has been shown to occur in 7.9% of equine pregnancies with substantial economical, welfare and safety implications. Whilst maternal age has been recognised as an important risk factor in relation to the incidence of EPL, few other risk factors have been conclusively identified. Further, multivariable data analysis of risk factors for EPL is sparse. A prospective cohort investigation of thoroughbred broodmares in the United Kingdom was conducted over the 2013 and 2014 breeding seasons. Information relating to 28 factors including mare, stallion, pregnancy and therapeutic interventions was collected using questionnaires and entered into a custom-designed Microsoft Access database. Mixed effects logistic regression was used to determine risk factors for EPL, including ‘mare’ as a random effect to account for repeat pregnancies in the same mare. Stallion, stud and veterinarian were also evaluated as random effects. Variables with a p-value of <0.25 in univariable analysis were taken forward for consideration in the multivariable model which was built using a forward stepwise approach. Data were collected on 2245 pregnancies in 1753 mares. Increasing mare age (OR = 1.11, 95% confidence interval (CI) = 1.04, 1.18, p = 0.001), having had one previous foal (OR = 3.52, 95% CI = 1.56, 7.95, p = 0.002) and presence of uterine cysts (OR = 1.76, 95% CI = 1.07, 2.91, p = 0.03) were all associated with increased odds of EPL following multivariable analysis. Increasing day 15/16 scan vesicle size (OR = 0.24, 95% CI = 0.16, 0.38, p < 0.001) and the use of ovulatory induction agents (OR = 0.31, 95% CI = 0.17, 0.55, p < 0.001) were negatively associated with EPL. Stallion, stud and veterinarian were not significantly associated with EPL. Analysis of a subpopulation of 344 multiple (twin and triplet) pregnancies found that the use of flunixin meglumine at the time of manual reduction of a multiple pregnancy resulted in reduced odds of EPL (OR = 0.34, 95% CI = 0.14, 0.84, p = 0.02). Results from this study can be used by stud farm personnel when assessing their broodmare population and by clinicians when deciding upon therapeutic strategies. Additional work can be focused around these risk factors to further our understanding of the pathophysiology of EPL