Pump-probe technique for excited state absorption and stimulated emission measurements in rare earth ion doped solid materials

Rare earth ion doped solid state materials are the most important active media of near-infrared and visible lasers and other photonic devices. In these ions, the occurrence of Excited State Absorptions (ESA), from long lived electronic levels, is commonplace. Since ESA can deeply affect the efficiencies of the rare earth emissions, evaluation of these transitions cross sections is of greatest importance in predicting the potential applications of a given material. In this paper a detailed description of the pump-probe technique for ESA measurements is presented, with a review of several examples of applications in Nd3+, Tm3+ and Er3+ doped materials

Projection spectrograph as a tool for light polarization classrooms demonstrations

This article describes the use of a projection spectrograph based on an overhead projector for use in classroom demonstrations on light polarization and optical activity. A simple adaptation on a previously developed apparatus allows illustrating several aspects of optical activity, such as circular and linear birefringence, including their wavelength dependence. Specifically, we use the projection spectrograph to demonstrate the optical activity of an aqueous solution of sugar (circular birefringence), of a quartz plate and of an overhead projector transparence film (linear birefringence). A historical survey about the optical activity discovery and the main principles involved is also presented

Thanatophoric dysplasia: case report of an autopsy complemented by postmortem computed tomographic study

Thanatophoric dysplasia (TD) is one of the most common lethal skeletal dysplasias, which was first designated as thanatophoric dwarfism and described in 1967. The authors report a case of a Caucasian girl with TD, born to a 31-year-old woman without comorbidities. The newborn presented respiratory distress immediately after delivery, progressing to death in less than 2 hours. An autopsy was carried out after postmortem tomographic examination. The autopsy findings depicted extensive malformations of the skeletal system and the brain. The aim of this report is to discuss the pathogenesis and correlate the morphologic features of TD that were disclosed at the tomography and the autopsy

Use of the linear light sensor ILX554 in optical spectroscopy

This technical note describes the construction of a low-cost optical detector. This device is composed by a high-sensitive linear light sensor (model ILX554) and a microcontroller. The performance of the detector was demonstrated by the detection of emission and Raman spectra of the several atomic systems and the results reproduce those found in the literature

Sonographic determination of liver size in healthy newborns, infants and children under 7 years of age

OBJETIVO: Determinar o tamanho do fígado de crianças normais, entre 0 e 7 anos de idade, por ultrassonografia, correlacionando os valores obtidos com: idade, sexo, estatura, peso corporal e índice de massa corpórea. MATERIAIS E MÉTODOS: Foram examinadas 584 crianças saudáveis, subdivididas em 11 grupos etários, sendo medidos o diâmetro crânio-caudal do lobo esquerdo, na linha médio-esternal, e o diâmetro crânio-caudal da superfície posterior do lobo direito, na linha hemiclavicular. Na análise estatística foram aplicados: a) coeficiente de correlação de Pearson (estudo de correlação); b) teste t de Student não-pareado (comparação das medidas entre os sexos); c) modelos de regressão não linear (nomogramas). RESULTADOS: O tamanho hepático apresentou aumento progressivo, do nascimento aos 7 anos de idade, proporcionalmente menor que o crescimento corporal, correlacionado com idade, estatura e peso corporal (r > 0,70), não havendo correlação com índice de massa corpórea (r < 0,11). Não se observou diferença consistente das medidas hepáticas em relação ao sexo. CONCLUSÃO: Valores do tamanho do fígado de crianças normais (entre 0 e 7 anos) foram determinados mediante aplicação de técnica padronizada, verificando-se forte correlação com a idade e indicadores antropométricos. Nomogramas demonstram as variações normais do tamanho hepático na população estudada, com crescimento diferenciado para cada lobo.OBJECTIVE: The present study was aimed at sonographically determining the liver size in healthy newborns, infants and children under 7 years of age, correlating results with age, sex, height, body weight and body mass index. MATERIALS AND METHODS: A total of 584 healthy children subdivided into 11 age groups were evaluated with measurements of the left lobe craniocaudal diameter at the midsternal line, and the craniocaudal diameter of the right lobe posterior surface at the midclavicular line. The following tests were utilized for statistical analysis: a) Pearson's correlation coefficient (correlation study); b) non-paired Student's t-test (comparison of measures between sexes); c) nonlinear regression models (nomograms). RESULTS: The liver size presented a progressive growth from the birth up to the age of 7, proportionally lower than the body growth, in correlation with age, height and body weight (r > 0.70). Correlation with the body mass index was not observed (r < 0.11). There was no significant difference in liver size between male and female individuals. CONCLUSION: Liver size was sonographically determined in healthy children under the age of 7 by means of a standardized method, demonstrating a strong correlation with age and anthropometric indicators. Nomograms demonstrate the typical variations of the liver size in the population evaluated with a different growth pattern for each hepatic lobe

Continuous Learning of the Structure of Bayesian Networks: A Mapping Study

Bayesian networks can be built based on knowledge, data, or both. Independent of the source of information used to build the model, inaccuracies might occur or the application domain might change. Therefore, there is a need to continuously improve the model during its usage. As new data are collected, algorithms to continuously incorporate the updated knowledge can play an essential role in this process. In regard to the continuous learning of the Bayesian network’s structure, the current solutions are based on its structural refinement or adaptation. Recent researchers aim to reduce complexity and memory usage, allowing to solve complex and large-scale practical problems. This study aims to identify and evaluate solutions for the continuous learning of the Bayesian network’s structures, as well as to outline related future research directions. Our attention remains on the structures because the accurate parameters are completely useless if the structure is not representative

Erbium and ytterbium codoped titanoniobophosphate glasses for ion-exchange-based planar waveguides

This work presents the optical properties of erbium-doped\ud and erbium/ytterbium codoped Na2O–Al2O3–TiO2–Nb2O5–\ud P2O5 glass systems and also the characterization of planar waveguides\ud obtained by typical thermally assisted Ag12Na1 ionexchange\ud process. The glass systems allow the preparation of\ud single mode and multimode planar waveguides presenting a\ud strong and relatively broad emission at 1536 nm. The emission\ud signal in the infrared region is intensified for silver-containing\ud samples when compared with free-silver samples. The emission\ud signal intensification may be attributed to a nonplasmonic energy\ud transfer from silver species to Er31 ions as no bands related to\ud surface plasmon resonance (SPR) of silver nanoparticles were\ud observed.CNPqFAPESPMC

Natural history of 39 patients with Achondroplasia

OBJECTIVES: To characterize the natural history of 39 achondroplastic patients diagnosed by clinical, radiological and molecular assessments. METHODS: Observational and retrospective study of 39 patients who were attended at a public tertiary level hospital between 1995 and 2016. RESULTS: Diagnosis was made prenatally in 11 patients, at birth in 9 patients and within the first year of life in 13 patients. The most prevalent clinical findings were short stature, high forehead, trident hands, genu varum and macrocephaly. The most prevalent radiographic findings were rhizomelic shortening of the long bones and narrowing of the interpediculate distance of the caudal spine. There was motor developmental delay in 18 patients and speech delay in 16 patients. The most common clinical intercurrences were middle ear dysfunction, sleep apnea, limb pain and obesity from 2 to 9 years of age. One patient was large for the gestational age but did not develop obesity. One patient developed hydrocephalus at 10 years old. The current age of the patients varies from 15 months to 36 years. The molecular study performed by Sanger sequencing of the common heterozygous mutation 1138G4A in FGFR3 was positive in all patients. Four cases were inherited, and 35 were sporadic (paternal age from 19 to 66 years). CONCLUSIONS: The diagnoses were made early based on clinical and radiographic findings. All cases were confirmed molecularly. Despite presenting a benign course, it is necessary to establish a systematic protocol for the surveillance of these patients due to the common clinical intercurrences