Minimum Action Path theory reveals the details of stochastic biochemical transitions out of oscillatory cellular states

Cell state determination is the outcome of intrinsically stochastic biochemical reactions. Tran- sitions between such states are studied as noise-driven escape problems in the chemical species space. Escape can occur via multiple possible multidimensional paths, with probabilities depending non-locally on the noise. Here we characterize the escape from an oscillatory biochemical state by minimizing the Freidlin-Wentzell action, deriving from it the stochastic spiral exit path from the limit cycle. We also use the minimized action to infer the escape time probability density function

Uso de circuitos equivalentes y teoría de filtros para el diseño de superficies selectivas en frecuencia

Frequency selective surfaces (FSS) and reflect/trasmitarrays are mostly designed on the basis ot optimization using an electromagnetic simulator. That is a time consuming method and some decisions have to be taken using simply intuition. The use of equivalent circuits of the scatterers selected for the design allows the substitution of the intuition and most part of the optimization process by the application of the classic rules of filter design. This communication presents all the steps necessary to obtain the equivalent circuit of different square scatterers in a periodic lattice and to implement the desired FSS frequency behaviour calculating the number of layers and the dimensions of the periodic cells. Several examples are included to evaluate the results

Achieving Consensus for the Design and Delivery of an Online Intervention to Support Midwives in Work-Related Psychological Distress: Results From a Delphi Study

Background Some midwives are known to experience both professional and organizational sources of psychological distress, which can manifest as a result of the emotionally demanding midwifery work, and the traumatic work environments they endure. An online intervention may be one option midwives may engage with in pursuit of effective support. However, the priorities for the development of an online intervention to effectively support midwives in work-related psychological distress have yet to be explored. Objective The aim of this study was to explore priorities in the development of an online intervention to support midwives in work-related psychological distress. Methods A two-round online Delphi study was conducted. This study invited both qualitative and quantitative data from experts recruited via a scoping literature search and social media channels. Results In total, 185 experts were invited to participate in this Delphi study. Of all participants invited to contribute, 35.7% (66/185) completed Round 1 and of those who participated in this first round, 67% (44/66) continued to complete Round 2. Out of 39 questions posed over two rounds, 18 statements (46%) achieved consensus, 21 (54%) did not. Participants were given the opportunity to write any additional comments as free text. In total, 1604 free text responses were collected and categorized into 2446 separate statements of opinion, creating a total of 442 themes. Overall, participants agreed that in order to effectively support midwives in work-related psychological distress, online interventions should make confidentiality and anonymity a high priority, along with 24-hour mobile access, effective moderation, an online discussion forum, and additional legal, educational, and therapeutic components. It was also agreed that midwives should be offered a simple user assessment to identify those people deemed to be at risk of either causing harm to others or experiencing harm themselves, and direct them to appropriate support. Conclusions This study has identified priorities for the development of online interventions to effectively support midwives in work-related psychological distress. The impact of any future intervention of this type will be optimized by utilizing these findings in the development process. </jats:sec

Quasinormal resonances of near-extremal Kerr-Newman black holes

We study analytically the fundamental resonances of near-extremal, slowly rotating Kerr-Newman black holes. We find a simple analytic expression for these black-hole quasinormal frequencies in terms of the black-hole physical parameters: omega=m Omega-2i pi T(l+1+n), where T and Omega are the temperature and angular velocity of the black hole. The mode parameters l and m are the spheroidal harmonic index and the azimuthal harmonic index of a co-rotating mode, respectively. This analytical formula is valid in the regime Im omega << Re omega <<1/M, where M is the black-hole mass.Comment: 4 page

Exchange Bias Induced by the Fe3O4 Verwey transition

We present a study of the exchange bias in different configurations of V2O3 thin films with ferromagnetic layers. The exchange bias is accompanied by a large vertical shift in the magnetization. These effects are only observed when V2O3 is grown on top of Ni80Fe20 permalloy. The magnitude of the vertical shift is as large as 60% of the total magnetization which has never been reported in any system. X-Ray diffraction studies show that the growth conditions promote the formation of a ferrimagnetic Fe3O4 interlayer. The change in the easy magnetization axis of Fe3O4 across the Verwey transition at 120 K is correlated with the appearance of exchange bias and vertical shift in magnetization. Both phenomena disappear above 120 K, indicating for the first time a direct relationship between the magnetic signature of the Verwey transition and exchange bias.Comment: Accepted for publication Physical Review

Swift/XRT monitoring of the Supergiant Fast X-ray Transient IGR J18483-0311 for an entire orbital period

IGR J18483-0311 is an X-ray pulsar with transient X-ray activity, belonging to the new class of High Mass X-ray Binaries called Supergiant Fast X-ray Transients. This system is one of the two members of this class, together with IGR J11215-5952, where both the orbital (18.52d) and spin period (21s) are known. We report on the first complete monitoring of the X-ray activity along an entire orbital period of a Supergiant Fast X-ray Transient. These Swift observations, lasting 28d, cover more than one entire orbital phase consecutively. They are a unique data-set, which allows us to constrain the different mechanisms proposed to explain the nature of this new class of X-ray transients. We applied the new clumpy wind model for blue supergiants developed by Ducci et al. (2009), to the observed X-ray light curve. Assuming an eccentricity of e=0.4, the X-ray emission from this source can be explained in terms of the accretion from a spherically symmetric clumpy wind, composed of clumps with different masses, ranging from 10^{18}g to 5x 10^{21}g.Comment: Accepted for publication in MNRAS. 7 pages, 7 figures, 2 table

The XMM-SSC survey of hard-spectrum XMM-Newton sources 1: optically bright sources

We present optical and X-ray data for a sample of serendipitous XMM-Newton sources that are selected to have 0.5-2 keV vs 2-4.5 keV X-ray hardness ratios which are harder than the X-ray background. The sources have 2-4.5 keV X-ray flux >= 10^-14 cgs, and in this paper we examine a subsample of 42 optically bright (r < 21) sources; this subsample is 100 per cent spectroscopically identified. All but one of the optical counterparts are extragalactic, and we argue that the single exception, a Galactic M star, is probably a coincidental association. The X-ray spectra are consistent with heavily absorbed power laws (21.8 < log NH < 23.4), and all of them appear to be absorbed AGN. The majority of the sources show only narrow emission lines in their optical spectra, implying that they are type-2 AGN. Only a small fraction of the sources (7/42) show broad optical emission lines, and all of these have NH < 10^23 cm^-2. This implies that ratios of X-ray absorption to optical/UV extinction equivalent to > 100 times the Galactic gas-to-dust ratio are rare in AGN absorbers (at most a few percent of the population), and may be restricted to broad absorption-line QSOs. Seven objects appear to have an additional soft X-ray component in addition to the heavily absorbed power law. We consider the implications of our results in the light of the AGN unified scheme. We find that the soft components in narrow-line objects are consistent with the unified scheme provided that > 4 per cent of broad-line AGN have ionised absorbers that attenuate their soft X-ray flux by >50 per cent. In at least one of the X-ray absorbed, broad-line AGN in our sample the X-ray spectrum requires an ionised absorber, consistent with this picture.Comment: accepted for publication in MNRA

Sobre el diseño de una antena moderna (o por qué un ingeniero debe poseer ciertos conocimientos básicos))

El diseño de una antena complicada, como las que se usan en los sistemas de comunicaciones embarcados en satélites, exige el uso masivo de cálculo numérico, basado en un software adecuado, en general comercial. Pero el manejo eficaz de estas herramientas exige conocimientos básicos, que muchas veces el diseñador utiliza incluso de forma inconsciente. En ausencia de tales conocimientos las posibilidades de éxito son muy bajas. Mas aún, el ordenador es capaz de optimizar, a veces muy eficazmente, las dimensiones de una estructura que le haya sido suministrada por el usuario, pero no es capaz, en general, de decidir su topología. Es aquí donde los conocimientos básicos muestran su carácter de imprescindibles. El caso de las antenas del tipo reflect/transmit-array, que se presenta en esta conferencia, constituye un ejemplo claro de la veracidad de esta afirmaciónUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech