tuning optical properties of opal photonic crystals by structural defects engineering

We report on the preparation and optical characterization of three dimensional colloidal photonic crystal (PhC) containing an engineered planar defect embedding photoactive push-pull dyes. Free standing polystyrene films having thickness between 0.6 and 3 microns doped with different dipolar chromophores were prepared. These films were sandwiched between two artificial opals creating a PhC structure with planar defect. The system was characterized by reflectance at normal incidence angle (R), variable angle transmittance (T), and photoluminescence spectroscopy (PL). Clear evidence of defect states were observed in T and R spectra, which allow the light to propagate for selected frequencies within the pseudogap (stop band)

Malformazione arterovenosa della mandibola. Caso clinico e revisione della letteratura

Le malformazioni arterovenose (MAV) del distretto cervico-facciale sono patologie rare e potenzialmente letali a causa delle imponenti emorragie che possono determinare. Il trattamento dipende dall'età del paziente, dalla sede, dall'estensione e dalla tipologia della malformazione. La terapia endovascolare è efficace nella maggior parte dei casi che presentano un'estensione limitata. In casi selezionati, e sempre in associazione con l'embolizzazione, si può ricorrere alla chirurgia. Nel presente articolo riportiamo il caso di una giovane donna affetta da un'estesa MAV dell'emimandibola e della regione sottomandibolare sinistra. Viene inoltre effettuata una revisione della letteratura prodotta su questo argomento con particolare attenzione alla strategia di trattamento

Robot Perception of Static and Dynamic Objects with an Autonomous Floor Scrubber

This paper presents the perception system of a new professional cleaning robot for large public places. The proposed system is based on multiple sensors including 3D and 2D lidar, two RGB-D cameras and a stereo camera. The two lidars together with an RGB-D camera are used for dynamic object (human) detection and tracking, while the second RGB-D and stereo camera are used for detection of static objects (dirt and ground objects). A learning and reasoning module for spatial-temporal representation of the environment based on the perception pipeline is also introduced. Furthermore, a new dataset collected with the robot in several public places, including a supermarket, a warehouse and an airport, is released.Baseline results on this dataset for further research and comparison are provided. The proposed system has been fully implemented into the Robot Operating System (ROS) with high modularity, also publicly available to the community

Intraspecific variation in sensitivity to habitat fragmentation is influenced by forest cover and distance to the range edge

The relative effects of habitat loss and fragmentation on biodiversity have been a topic of discussion for decades. While it is acknowledged that habitat amount can mediate the effects of habitat fragmentation, it is unclear what other factors may drive inter- and intraspecific variation in fragmentation effects and their implications for conservation. We tested whether the effects of forest fragmentation on 362 bird species' occurrence in the Atlantic Forest of Brazil are mediated by distance to geographic range edge and habitat amount, and whether these effects explain intraspecific variation across populations. Using a single binomial linear mixed effects model, we found that fragmentation had mostly negative effects on occurrence probability up to 1080 km from the species' range edge, independent of habitat amount. We also show that above this distance, fragmentation has predominantly positive effects, more accentuated in deforested landscapes. We demonstrate that fragmentation effects can be both positive and negative, indicating that different populations of the same species can respond differently depending on distance to range edge and local forest cover. Our results help clarify one of the drivers of contradictory results found in the fragmentation literature and highlight the importance of preventing habitat fragmentation for the conservation of endangered populations. Conservation initiatives should focus on minimising fragmentation closer to range edges of target species and in regions where species range edges overlap

Do borrão às aguadas: os engenheiros militares e a representação da Capitania de São Paulo

A análise do papel dos engenheiros militares perpassa as discussões sobre regiões específicas, mesmo quando eles, aparentemente, estão ausentes delas. Sua presença ou ausência sempre foi sinônimo de interesse e de projeto colonizador mais ou menos dirigido. Este ensaio tem como objeto de estudo a cartografia dos engenheiros militares atuantes na Capitania de São Paulo, território comumente visto como economicamente periférico e mais autônomo face aos desígnios da Coroa portuguesa. Com foco no corpus cartográfico de alguns profissionais que aqui atuaram, trata indiretamente da multifacetada atuação desses engenheiros, bem como do processo de feitura das cartas geográficas, corográficas e topográficas, do borrão às aguadas. Investigar a cartografia de alguns desses profissionais permite não apenas explorar a riqueza de suas biografias, como, também, acompanhar o processo de produção técnica dos mapas e os desígnios políticos envolvidos no devassamento e representação das terras descobertas no Novo Mundo.Analyzing the role of military engineers means venturing into discussions about specific regions, even those from which they are apparently absent. Their presence or absence has always been synonymous with interest and a more or less directed colonization project. This essay examines the maps produced by the military engineers working in the Captaincy of São Paulo, a territory often looked upon as one of little economic import and a rather autonomous area in light of the plans of the Portuguese Crown. By focusing on the cartographic corpus bequeathed by certain professionals serving in this region, we deal indirectly with the multifaceted role of these engineers as well as with the process of making geographic, chorographic and topographic charts - all the way from the sketch to watercolored maps. Perusing the charts constructed by some of these professionals enabled us not only to delve into the rich details of their biographies but also to observe the technical mapmaking process and to unravel the political designs behind the exploration and representation of the lands discovered in the New World

A three-dimensional view of structural changes caused by deactivation of fluid catalytic cracking catalysts

Since its commercial introduction three-quarters of a century ago, fluid catalytic cracking has been one of the most important conversion processes in the petroleum industry. In this process, porous composites composed of zeolite and clay crack the heavy fractions in crude oil into transportation fuel and petrochemical feedstocks. Yet, over time the catalytic activity of these composite particles decreases. Here, we report on ptychographic tomography, diffraction, and fluorescence tomography, as well as electron microscopy measurements, which elucidate the structural changes that lead to catalyst deactivation. In combination, these measurements reveal zeolite amorphization and distinct structural changes on the particle exterior as the driving forces behind catalyst deactivation. Amorphization of zeolites, in particular, close to the particle exterior, results in a reduction of catalytic capacity. A concretion of the outermost particle layer into a dense amorphous silica–alumina shell further reduces the mass transport to the active sites within the composite

High spatial resolution analysis of ferromanganese concretions by LA-ICP-MS†

A procedure was developed for the determination of element distributions in cross-sections of ferromanganese concretions using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The effects of carrier flow rates, rf forward power, ablation energy, ablation spot size, repetition rate and number of shots per point on analyte intensity were studied. It is shown that different carrier gas flow rates are required in order to obtain maximum sensitivities for different groups of elements, thus complicating the optimisation of ICP parameters. On the contrary, LA parameters have very similar effects on almost all elements studied, thus providing a common optimum parameter set for the entire mass range. However, for selected LA parameters, the use of compromise conditions was necessary in order to compensate for relatively slow data acquisition by ICP-MS and maintain high spatial resolution without sacrificing the multielemental capabilities of the technique. Possible variations in ablation efficiency were corrected for mathematically using the sum of Fe and Mn intensities. Quantification by external calibration against matrix-matched standards was successfully used for more than 50 elements. These standards, in the form of pressed pellets (no binder), were prepared in-house using ferromanganese concentrates from a deep-sea nodule reference material as well as from shallow-marine concretions varying in size and having different proportions of three major phases: aluminosilicates, Fe- and Mn-oxyhydroxides. Element concentrations in each standard were determined by means of conventional solution nebulisation ICP-MS following acid digestion. Examples of selected inter-element correlations in distribution patterns along the cross-section of a concretion are given