Transmission spectroscopy is a proven technique for studying a transiting exoplanet’s atmosphere. However, stellar surface inhomogeneities – spots and faculae – alter the observed transmission ...spectra: the stellar contamination effect. The variable nature of the stellar activity also makes it difficult to stitch together multi-epoch observations and evaluate any potential variability in the exoplanet’s atmosphere. This paper introduces SAGE , a tool that corrects for the time-dependent impact of stellar activity on transmission spectra. It uses a pixelation approach to model the stellar surface with spots and faculae, while fully accounting for limb-darkening and rotational line-broadening. The current version is designed for low- to medium-resolution spectra. We used SAGE to evaluate stellar contamination for F- to M-type hosts, testing various spot sizes and locations, and quantify the impact of limb-darkening. We find that limb-darkening enhances the importance of the spot location on the stellar disc, with spots close to the disc centre impacting the transmission spectra more strongly than spots near the limb. Moreover, due to the chromaticity of limb-darkening, the shape of the contamination spectrum is also altered. Additionally, SAGE can be used to retrieve the properties and distribution of active regions on the stellar surface from photometric monitoring. We demonstrate this for WASP-69 using TESS data, finding that two spots at midlatitudes and a combined coverage fraction of ~1% are favoured. SAGE allows us to connect the photometric variability to the stellar contamination of transmission spectra, enhancing our ability to jointly interpret transmission spectra obtained at different epochs.
Summary
Objective To determine the comparability between cause of death (COD) by a single physician coder and a two‐physician panel, using verbal autopsy.
Methods The study was conducted between ...May 2007 and June 2008. Within a week of a perinatal death in 38 rural remote communities in Guatemala, the Democratic Republic of Congo, Zambia and Pakistan, VA questionnaires were completed. Two independent physicians, unaware of the others decisions, assigned an underlying COD, in accordance with the causes listed in the chapter headings of the International classification diseases and related health problems, 10th revision (ICD‐10). Cohen’s kappa statistic was used to assess level of agreement between physician coders.
Results There were 9461 births during the study period; 252 deaths met study enrolment criteria and underwent verbal autopsy. Physicians assigned the same COD for 75% of stillbirths (SB) (K = 0.69; 95% confidence interval: 0.61–0.78) and 82% early neonatal deaths (END) (K = 0.75; 95% confidence interval: 0.65–0.84). The patterns and proportion of SBs and ENDs determined by the physician coders were very similar compared to causes individually assigned by each physician. Similarly, rank order of the top five causes of SB and END was identical for each physician.
Conclusion This study raises important questions about the utility of a system of multiple coders that is currently widely accepted and speculates that a single physician coder may be an effective and economical alternative to VA programmes that use traditional two‐physician panels to assign COD.
Objectif: Déterminer la comparabilité entre la cause de la mort codée par un seul médecin et celle codée par un comité de deux médecins, utilisant l’autopsie verbale (AV).
Méthodes: L’étude a été menée entre mai 2007 et juin 2008. Endéans la semaine d’un décès périnatal dans 38 collectivités rurales éloignées au Guatemala, en République Démocratique du Congo, en Zambie et au Pakistan, des questionnaires AV ont été remplis. Deux médecins indépendants, ignorant les décisions de l’un et l’autre, ont attribué une cause sous‐jacente du décès, conformément aux causes listées dans les entêtes de chapitre de ‘La Classification Internationale des maladies et problèmes de santé connexes, 10e révision (ICD‐10). La statistique Kappa de Cohen a été utilisée pour évaluer le degré de concordance entre les médecins codeurs.
Résultats: Il y a eu 9461 naissances au cours de la période d’étude; 252 décès répondaient aux critères d’inclusion dans l’étude et ont subi une AV. Les médecins ont attribué le même code pour 75% des mort‐nés (K = 0,69; intervalle de confiance 95% IC95%: 0,61 à 0,78) et pour 82% des décès néonataux précoces (K = 0,75; IC95%: 0,65 à 0,84). Les profils et la proportion des mort‐nés et des décès néonataux précoces déterminés par les deux codeurs médecins étaient très similaires comparés aux causes attribuées individuellement par chacun d’eux. De la même façon, l’ordre de classement des 5 principales causes de mort‐nés et de décès néonataux précoces était identique pour chaque médecin.
Conclusion: Cette étude soulève des questions importantes quant à l’utilité d’un système à plusieurs codeurs qui est actuellement largement acceptée, et spécule qu’un seul codeur médecin pourrait être une alternative efficace et économique pour les programmes d’AV par rapport à l’utilisation traditionnelle de comitéà deux médecins pour attribuer un code de décès.
Objetivo: Determinar el nivel de concordancia entre la causa de muerte determinada mediante autopsia verbal (AV) por un único médico y por un panel de dos médicos.
Métodos: El estudio fue conducido entre Mayo 2007 y Junio 2008. Dentro de la semana siguiente a una muerte perinatal, se completaron cuestionarios de AV en 38 comunidades rurales remotas de Guatemala, la República Democrática del Congo, Zambia y Paquistán. Dos médicos independientes, que desconocían las decisiones de los demás, asignaron la causa de muerte subyacente, de acuerdo con las causas listadas en los títulos de los capítulos de la Clasificación internacional de enfermedades y problemas relacionados con la salud, décima edición (CIE‐10). Se utilizó la Kappa de Cohen para evaluar el nivel de concordancia entre los diferentes médicos codificadores.
Resultados: Se produjeron 9461 nacimientos durante el periodo de estudio; hubo 252 muertes que cumplían los criterios de inclusión y a las que se les realizó una autopsia verbal. Los médicos asignaron la misma causa de muerte (CDM) en un 75% de las muertes de mortinatos (K = 0.69; intervalo de confianza (IC) 95%: 0.61–0.78) y en 82% de las muertes neonatales tempranas (K = 0.75; IC 95%: 0.65–0.84). Los patrones y proporción de mortinatos y muertes neonatales tempranas determinadas por los médicos realizando la codificación eran muy similares al compararlas con las causas asignadas de forma individual por cada médico. De forma similar, el orden de rango de las primeras 5 causas de mortinato y muertes neonatales tempranas eran idénticas para cada uno de los médicos.
Conclusión: Este estudio plantea preguntas importantes sobre la utilidad de un sistema de múltiples codificadores que actualmente es ampliamente aceptado, y especula que un único médico codificando podría ser efectivo y una alternativa económica a los programas de AV que utilizan el panel tradicional de dos médicos asignando la CDM.
Attosecond time delays in C 60 valence photoemissions at the giant plasmon Barillot, T; Magrakvelidze, M; Loriot, V ...
29th International Conference on Photonic, Electronic, and Atomic Collisions (ICPEAC),Toledo, Spain,2015-07-22 - 2015-07-28,
01/2015, Letnik:
635, Številka:
11
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
We perform time-dependent local density functional calculations of the time delay in C60 HOMO and HOMO-1 photoionization at giant plasmon energies. A semiclassical model is used to develop further ...insights.
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•• Electron-impact ionization of pyrazine.•• Dynamics of the scattering process.•• The role of molecular structure in ionization.
We report an experimental and theoretical ...investigation into the dynamics of electron-impact ionization of the unresolved outermost molecular orbitals (6ag + 1b1g) of pyrazine (C4N2H4). Experimental triple differential cross sections (TDCS) are compared with cross sections calculated within a molecular 3-body distorted wave (M3DW) framework. The M3DW theory was able to reproduce the qualitative scattering behaviour in the binary region, but failed to describe the absolute intensity of the TDCS and the recoil scattering behaviour. Momentum profiles were used to identify possible sources where the M3DW may mask the quantum character of the ionized orbitals in describing the ionization dynamics.
Synopsis Due to the bulk electron capture from the molecular shell of fullerenes by incoming positron projectiles and a dephasing effect across the shell width, the positronium formation signal ...yields diffraction fringes in the target recoil momentum space. Our results show the variance in the separation and shape of the fringe pattern as a function of the fullerene size from C60 to larger C240.
If a vesicle is a better model of a membrane in the context of the hydrophobic effect, then from the charge distribution point of view, a catanionic micelle is a closer model to a biomembrane. We ...have prepared and characterized two different types of catanionic micelles of sodium dodecyl sulfate (SDS) and cetyl N,N,N-trimethylammonium bromide (CTAB) having different surface charge ratios using optical spectroscopy and transmission electron microscopy. The average size of both types of mixed micelles was found to be much larger than that of micelles containing uniformly charged headgroups. Catanionic micelles containing higher concentrations of positively charged headgroups (CTAB) are larger in size, less compact, and more polar compared to the micelles containing higher concentrations of negatively charged headgroups (SDS). We have used these catanionic micelles as membrane mimetic systems to understand the interaction of piroxicam, a nonsteroidal anti-inflammatory drug (NSAID) of the oxicam group, with biomembranes. In continuation of our work on membrane mimetic systems, we have used spectral properties of the drug itself to understand the effect of the presence of mixed charges on the micellar surface in guiding the interaction of catanionic micelles with piroxicam. Our earlier studies of the interaction of piroxicam with micelles having uniform surface charges have shown that the charge on the micellar surface not only dictates which prototropic form of the drug will be incorporated in the micelles but also induces a switch-over between different prototropic forms of piroxicam. The equilibrium of this switch-over is extremely sensitive to the environment. In this study, we demonstrate how even small changes in the electrostatic forces obtained by doping the uniformly charged surface of the micelles with oppositely charged headgroups (as in catanionic micelles) are capable of fine-tuning this equilibrium. This implies that the surface charge of biomembranes, which are quite diverse in vivo, might play a significant role in selecting a particular form of the drug to be presented to its targets.
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