On the changes in the physical properties of the ionized region around the Weigelt structures in Eta Carinae over the 5.54-yr spectroscopic cycle

We present HST/STIS observations and analysis of two prominent nebular structures around the central source of Eta Carinae, the knots C and D. The former is brighter than the latter for emission lines from intermediate or high ionization potential ions. The brightness of lines from intermediate and high ionization potential ions significantly decreases at phases around periastron. We do not see conspicuous changes in the brightness of lines from low ionization potential (<13.6 eV) that the total extinction towards the Weigelt structures is that the total extinction towards the Weigelt structures is AsubV =2/0. that the total extinction towards the Weigelt structures is AV = 2.0. Weigelt C and D are characterized by an electron density of that the total extinction towards the Weigelt structures is AV = 2.0. Weigelt C and D are characterized by an electron density of 10exp6.9 cm-3 that does not significantly change throughout the orbital cycle. The electron temperature varies from 5500 K (around periastron) to 7200 K (around apastron). The relative changes in the brightness of He I lines are well reproduced by the variations in the electron temperature alone. We found that, at phases around periastron, the electron temperature seems to be higher for Weigelt C than that of D. The Weigelt structures are located close to the Homunculus equatorial plane, at a distance of about 1240 AU from the central source. From the analysis of proper motion and age, the Weigelt complex can be associated with the equatorial structure called the Butterfly Nebula surrounding the central binary system.Comment: 19 pages, 18 figure

Magnetically controlled exciton transfer in hybrid quantum dot-quantum well nanostructures

A magnetophotoluminescence study of the carrier transfer with hybrid InAs/GaAs quantum dot(QD)-InGaAs quantum well (QW) structures is carried out where we observe an unsual dependence of the photoluminescence (PL) on the GaAs barrier thickness at strong magnetic field and excitation density. For the case of a thin barrier the QW PL intensity is observed to increase at the expense of a decrease in the QD PL intensity. This is attributed to changes in the interplane carrier dynamics in the QW and the wetting layer (WL) resulting from increasing the magnetic field along with changes in the coupling between QD excited states and exciton states in the QW and the WL

A multispectral view of the periodic events in eta Carinae

A full description of the 5.5-yr low excitation events in Eta Carinae is presented. We show that they are not as simple and brief as previously thought, but a combination of two components. The first, the 'slow variation' component, is revealed by slow changes in the ionization level of circumstellar matter across the whole cycle and is caused by gradual changes in the wind-wind collision shock-cone orientation, angular opening and gaseous content. The second, the 'collapse' component, is restricted to around the minimum, and is due to a temporary global collapse of the wind-wind collision shock. High energy photons (E > 16 eV) from the companion star are strongly shielded, leaving the Weigelt objects at low ionization state for >6 months. High energy phenomena are sensitive only to the 'collapse', low energy only to the 'slow variation' and intermediate energies to both components. Simple eclipses and mechanisms effective only near periastron (e.g., shell ejection or accretion onto the secondary star) cannot account for the whole 5.5-yr cycle. We find anti-correlated changes in the intensity and the radial velocity of P Cygni absorption profiles in FeII 6455 and HeI 7065 lines, indicating that the former is associated to the primary and the latter to the secondary star. We present a set of light curves representative of the whole spectrum, useful for monitoring the next event (2009 January 11).Comment: 16 pages, 7 EPS figures, accepted for publication on MNRA

Relating air Pollution and Respiratory Diseases Occurrences

Com o apoio RAADRI.In this article we study the impact of air pollution on children's health in Portugal. In particular, we focus our attention on the city of Barreiro. We use the general linear methods (GLM), taking advantage of all the ease of handling and analyzing data in order to relate air quality and health. We relate levels of air pollution and incidence of entries from children with symptoms of respiratory problems in the pediatric urgency service at the hospital of Barreiro. It was not easy to obtain clear and unambiguous relations in particle dispersion, air quality and health. A set of models are estimated by GLM and validated using adequate tests and residual analysis. At the end of this process, we combine the best models. The work is still going on

Aharonov-Bohm interference in quantum ring exciton: effects of built-in electric fields

We report a comprehensive discussion of quantum interference effects due to the finite structure of excitons in quantum rings and their first experimental corroboration observed in the optical recombinations. Anomalous features that appear in the experiments are analyzed according to theoretical models that describe the modulation of the interference pattern by temperature and built-in electric fields.Comment: 6 pages, 7 figure

A 3D Primary Vessel Reconstruction Framework with Serial Microscopy Images

Three dimensional microscopy images present significant potential to enhance biomedical studies. This paper presents an automated method for quantitative analysis of 3D primary vessel structures with histology whole slide images. With registered microscopy images, we identify primary vessels with an improved variational level set framework at each 2D slide. We propose a Vessel Directed Fitting Energy (VDFE) to provide prior information on vessel wall probability in an energy minimization paradigm. We find the optimal vessel cross-section associations along the image sequence with a two-stage procedure. Vessel mappings are first found between each pair of adjacent slides with a similarity function for four association cases. These bi-slide vessel components are further linked by Bayesian Maximum A Posteriori (MAP) estimation where the posterior probability is modeled as a Markov chain. The efficacy of the proposed method is demonstrated with 54 whole slide microscopy images of sequential sections from a human liver

Liver whole slide image analysis for 3D vessel reconstruction

The emergence of digital pathology has enabled numerous quantitative analyses of histopathology structures. However, most pathology image analyses are limited to two-dimensional datasets, resulting in substantial information loss and incomplete interpretation. To address this, we have developed a complete framework for three-dimensional whole slide image analysis and demonstrated its efficacy on 3D vessel structure analysis with liver tissue sections. The proposed workflow includes components on image registration, vessel segmentation, vessel cross-section association, object interpolation, and volumetric rendering. For 3D vessel reconstruction, a cost function is formulated based on shape descriptors, spatial similarity and trajectory smoothness by taking into account four vessel association scenarios. An efficient entropy-based Relaxed Integer Programming (eRIP) method is proposed to identify the optimal inter-frame vessel associations. The reconstructed 3D vessels are both quantitatively and qualitatively validated. Evaluation results demonstrate high efficiency and accuracy of the proposed method, suggesting its promise to support further 3D vessel analysis with whole slide images

A framework for 3D vessel analysis using whole slide images of liver tissue sections

Three-dimensional (3D) high resolution microscopic images have high potential for improving the understanding of both normal and disease processes where structural changes or spatial relationship of disease features are significant. In this paper, we develop a complete framework applicable to 3D pathology analytical imaging, with an application to whole slide images of sequential liver slices for 3D vessel structure analysis. The analysis workflow consists of image registration, segmentation, vessel cross-section association, interpolation, and volumetric rendering. To identify biologically-meaningful correspondence across adjacent slides, we formulate a similarity function for four association cases. The optimal solution is then obtained by constrained Integer Programming. We quantitatively and qualitatively compare our vessel reconstruction results with human annotations. Validation results indicate a satisfactory concordance as measured both by region-based and distance-based metrics. These results demonstrate a promising 3D vessel analysis framework for whole slide images of liver tissue sections

Long-term effect of intravitreal triamcinolone in the nonproliferative stage of type II idiopathic parafoveal telangiectasia

PURPOSE: To report the visual outcomes and ocular complications of intravitreal triamcinolone acetonide (IVTA) in the treatment of the nonproliferative stage of type II idiopathic parafoveal telangiectasia (IPT). METHODS: Retrospective, multicenter, uncontrolled interventional case series of 19 eyes of 14 consecutive patients with the nonproliferative stage of IPT that had undergone at least one intravitreal injection of 4 mg of triamcinolone acetonide. Demographic, medical, and ocular data were obtained through chart review. The main outcome measures included best-corrected visual acuity at several timepoints of follow up and ocular complications. RESULTS: At baseline the mean logMAR visual acuity was 0.83 ± 0.41 (Snellen 20/135, range 0.3-2). After an average follow-up of 21.2 months (range 6-44 months), the mean logMAR visual acuity remained essentially unchanged from baseline. At 3 months, the logMAR visual acuity was 0.86 ± 0.44 (Snellen 20/145, P = 0.8378), at 6 months 0.86 ± 0.42 (Snellen 20/145, P = 0.8149), at 12 months 0.87 ± 0.46 (Snellen 20/148, P > 0.9999), at 18 months 0.84 ± 0.35 (Snellen 20/138, P = 0.8385), and at the last follow-up 0.82 ± 0.44 (Snellen 20/132, P = 0.9301). Seven eyes were reinjected once. Ten of 19 eyes (53%) developed cataract (3 eyes underwent phacoemulsification and intraocular lens implantation) and 7 of 19 eyes (37%) had an elevated intraocular pressure, none of which required surgical treatment. CONCLUSION: IVTA does not seem to improve visual acuity in most eyes with the nonproliferative stage of IPT. © The Ophthalmic Communications Society, Inc

Acaricidal activity of palm oil on Aceria guerreronis (Acari:Eriophyidae) and a nontarget predator.

The coconut mite,Aceria guerreronisKeifer (Acari: Eriophyidae), is a severe andubiquitous pest of coconut plantations worldwide. Vegetable oils contain fatty acids that areactive against a variety of agricultural pests; however, little is known about their efficiency incontrollingA. guerreronisas well as their adverse effects on its natural enemies. Here, weassessed the chemical profile of palm oil as well as its toxicity and repellence to bothA.guerreronisandTyphlodromus ornatusDenmark and Muma (Acari: Phytoseiidae), a naturalenemy of the pest. Oleic, palmitic, and linoleic acids accounted for over 85% of palm oil fattyacid composition. Also, palm oil was approximately 4-fold more toxic to the coconut mite thanto its predator. Furthermore, the lethal concentration percentage (LC)50and LC99of palm oilindicated greater activity against the coconut mite than to its predator. Therefore, by exhibitinghigher toxicity and repellence to the coconut mite, with substantial selectivity to the predatorT.ornatus, palm oil is a promising tool to be integrated in the control ofA. guerreronisin coconutplantations