Observation of the dielectric-waveguide mode of light propagation in p-n junctions

Theoretical considerations of the propagation of electromagnetic energy near a p-n junction (1) show that the “sandwich” formed by having a depletion layer bounded by the p and n regions can act as a dielectric waveguide. (1,2

Adipocytes and macrophages secretomes coregulate catecholamine-synthesizing enzymes

Obesity associates with macrophage accumulation in adipose tissue where these infiltrating cells interact with adipocytes and contribute to the systemic chronic metabolic inflammation present in immunometabolic diseases. Tyrosine hydroxylase (TH) and phenylethanolamine N-methyltransferase (PNMT) are two of the main enzymes of catecholamines (CA) synthesis. Adipocytes and macrophages produce, secrete and respond to CA, but the regulation of their synthesis in the interplay between immune and metabolic systems remains unknown. A model of indirect cell coculture with conditioned medium (CM) from RAW 264.7 macrophages with or without LPS-activation and 3T3-L1 adipocytes and preadipocytes was established to study the effect of cellular secretomes on the expression of the above enzymes. During the adipocyte differentiation process, we found a decrease of TH and PNMT expression. The secretome from LPS-activated macrophages downregulated TH and PNMT expression in preadipocytes, but not in mature adipocytes. Mature adipocytes CM induced a decrease of PNMT levels in RAW 264.7 macrophages. Pre and mature adipocytes showed a similar pattern of TH, PNMT and peroxisome proliferator-activated receptor gamma expression after exposure to pro and anti-inflammatory cytokines. We evidenced macrophages and adipocytes coregulate the expression of CA synthesis enzymes through secretome, with non-inflammatory signaling networks possibly being involved. Mediators released by macrophages seem to equally affect CA production by adipocytes, while adipocytes secretome preferentially affect AD production by macrophages. CA synthesis seems to be more determinant in early stages of adipogenic differentiation. Our results suggest that CA are key signaling molecules in the regulation of immune-metabolic crosstalk within the adipose tissue.This study was supported by national funds through Foundation for Science and Technology (FCT) (PIDDAC) (EXPL/IVC-PEC/1302/2013), FCT (Ref UID/BIM/04293/2013), PhD grant from FCT (SFRH/BD/88622/2012) and co-funded by FEDER, COMPETE – POFC programs referenced FCOMP-01-0124-FEDER-041872, NORTE-01-0145-FEDER-000012

Questions in Science textbooks: development and validation of a checklist

Questões são enunciadas que requerem uma resposta refletida e que desempenham diversas funções educativas, incluindo o despoletar novas aprendizagens. Neste caso, o seu uso enquadra-se na Aprendizagem Baseada na Resolução de Problemas (ABRP, do inglês, Problem-Based Learning, PBL), que coloca o aluno no centro dos processos de ensino e aprendizagem, atribuindo-lhe um papel ativo na aprendizagem de novo conhecimento. Atendendo à influência que os manuais exercem nas práticas de ensino, a questão que se coloca é a de saber em que medida as questões incluídas nos manuais escolares de Ciências podem fomentar um ensino orientado para a ABRP. Neste texto, descrever-se-á o processo de construção e validação de uma grelha de análise de questões incluídas em manuais escolares de Ciências com essa finalidade, apresentando-se não só essa grelha, mas também, a título ilustrativo, uma aplicação da mesma a um tópico de Ciências, 8º ano, abordado nas duas disciplinas desta área.Questions require a thoughtful answer and can play diverse educational roles, such as stimulating the learning of new knowledge, as is the case in Problem-Based Learning (PBL) contexts. In this context, the student is placed at the center of the teaching and learning processes and plays an active role in the learning of new knowledge. Bearing in mind the influence that textbooks exert on teaching practices, it is worthwhile questioning to which extent questions included in school science textbooks promote a PBL oriented teaching approach. This paper describes the development and validation of a checklist for analyzing the questions included in science textbooks. After introducing the checklist, an example of its application to a science unit assigned to two junior high school science courses (8th grade) is given, approaching the two disciplines in the area

Using multiple related ontologies in a fuzzy information retrieval model.

With the Semantic Web progress many independently developed distinct domain ontologies have to be shared and reused by a variety of applications. The use of ontologies in information retrieval applications allows the retrieval of semantically related documents to an initial users´ query. This work presents a fuzzy information retrieval model for improving the document retrieval process considering a knowledge base composed of multiple domain ontologies that are fuzzy related. Each ontology can be represented independently as well as their relationships. This knowledge organization is used in a novel method to expand the user initial query and to index the documents in the collection. Experimental results show that the proposed model presents better overall performance when compared with another fuzzy-based approach for information retrieval.SBIA 2008

Ecologia microbiana do solo.

Fatores abióticos que afetam os microrganismos; Temperatura do solo; pH do solo; Fontes de energia e substratos orgânicos; Nutrientes minerais; Práticas de manejo e cultivo dos solos; Interação entre microrganismos; Interações microbianas de importância para a produção agrícola.bitstream/item/35904/1/Doc164.pd

100 Years of BCG Immunization: Past, Present, and Future

The 100th anniversary of the introduction of Bacille–Calmette–Guérin (BCG) as a tuberculosis (TB) vaccine is an occasion warranting further investigation of the early attempts which culminated in the introduction of BCG as a TB vaccine, as well as of subsequent recognition of failures, new findings that broaden its applications, outstanding questions, and approaches towards the development of novel vaccine candidates [...