A Telecom O-Band Emitter in Diamond

Color centers in diamond are promising platforms for quantum technologies. Most color centers in diamond discovered thus far emit in the visible or near-infrared wavelength range, which are incompatible with long-distance fiber communication and unfavorable for imaging in biological tissues. Here, we report the experimental observation of a new color center that emits in the telecom O-band, which we observe in silicon-doped bulk single crystal diamonds and microdiamonds. Combining absorption and photoluminescence measurements, we identify a zero-phonon line at 1221 nm and phonon replicas separated by 42 meV. Using transient absorption spectroscopy, we measure an excited state lifetime of around 270 ps and observe a long-lived baseline that may arise from intersystem crossing to another spin manifold

Objetivos operacionais e eficiência da aprendizagem Operational objectives and effectiveness of learning

Foi verificado em que medida a aprendizagem pode ser significativamente influenciada pela informação aos estudantes antes do ensino, sobre o que é esperado deles como resultado do ensino. Os sujeitos que participaram deste estudo eram alunos de 4 classes de 5ª série do 1º Grau. Dos 140 sujeitos, 69 de duas classes constituiram o grupo experimental (GE) e 71 de duas outras classes constituiram o grupo de controle (GC). Os sujeitos do GE receberam objetivos operacionais redigidos claramente enquanto que os do GC não receberam nenhuma informação sobre objetivos. Foram comparados os GE e GC como um todo, os GE e GC de nível socio-econômico alto e baixo, os GE e GC com notas altas e baixas, levando em conta, de um lado, mudanças em conhecimentos, atitudes e práticas e, de outro, mudanças apenas em conhecimentos. Embora os GE apresentaram consistentemente maior aprendizagem do que os GC, os resultados não foram conclusivos. Quando se comparou os diferentes grupos, observou-se que diferenças significativas na aprendizagem ocorreram em alguns, mas distribuídas ao acaso.<br>The purpose of this study is to provide data on whether student achievement can be influenced significantly by providing students, before instruction, information on what is expected of them as an outcome of instruction. The Ss were selected from four fifth-grade classes of the elementary course. Of the 140 Ss, 69 from two classes were assigned to experimental group (EG) and 71 from two other classes were assigned to the control group (CG). The Ss of EG received precisely stated behavioral objectives while SS of CG didn't receive any information about objectives whatsoever. EG and CG as a whole, high and low socio-economic EG and CG, high and low grades EG and CG were compared taking into account changes in knowledge, attitudes and practices on the one hand, and changes only in knowledge on the other hand. Although EGs consistently showed grater achievement than CGs, the results were not conclusive. Significant differences in achievement were observed at random when different groups were considered

Olive oil waste treatment: A comparative and critical presentation of methods, advantages & disadvantages

Since olive oil industries were considered responsible for a great amount of pollution there has been a strong need for optimization of olive oil waste treatment systems. The currently employed systems are numerous and fall in the following large categories; bioremediation (ex-situ, in-situ), thermal processes (incineration, pyrolysis, gasification), evaporation, membrane processes, electrolysis, ozonation, digestion, coagulation/flocculation/precipitation, and distillation. Both advantages and disadvantages in conjunction with respective methodology and explicit flow diagrams were presented per waste treatment method. Furthermore, most recent studies were reported and more than twenty-five figures showing mainly the effectiveness of the current waste treatment methods versus time or temperature were displayed. The comparative presentation of the various olive oil waste treatment methodologies showed that though bioremediation stands for the most enviromentally friendly technique, its required longer treatment time in conjuction with its weakness to deal with elemental contaminants makes imperative the employment of a second alternative technique which could either be a membrane process (low energy cost, reliability, reduced capital cost) or a coagulation/flocculation method because of its low cost and high effectiveness. Biogas production appears to be another promising and energy effective waste treatment method. On the other hand, methods like distillation and ozonation (high cost) and electrolysis (experimental level) are unlikely to dominate this field unless their high cost is substantially reduced in the nearfuture