948 research outputs found
Construção de uma bomba peristáltica e de um sistema de detecção utilizando um hardware de código fonte aberto “arduino” para análise em fluxo
This work describes the development of a peristaltic pump and a photometric detector, using “Arduino” and alternative and low-cost materials for flow analysis system. The analytical calibration curve of the acid-red-283 using the proposed system presents 0.9984 and 3.9% as the coefficients of determination and variation, and 1.1 and 3.8 mg L-1 as limits of detection and quantification, respectively. Three prepared samples of the acid-red-283 (25, 30 and 35 mg L-1) showed recovery between 99 to 104%. For construction of the peristaltic pump and the photometer using Light Emitting Diodes (LED), light-dependent resistor (LDR) were spent less than 10% of the cost was spent on a commercial system employing a peristaltic pump and a spectrophotometer. Furthermore, the peristaltic pump and the photometer developed in this work allow the implementation of practical disciplines, such as molecular absorption spectrophotometry and flow analysis system in undergraduate courses, making these instruments more accessible, especially for the chemistry students
State-dependent complexity of the local field potential in the primary visual cortex
The local field potential (LFP) is as a measure of the combined activity of
neurons within a region of brain tissue. While biophysical modeling schemes for
LFP in cortical circuits are well established, there is a paramount lack of
understanding regarding the LFP properties along the states assumed in cortical
circuits over long periods. Here we use a symbolic information approach to
determine the statistical complexity based on Jensen disequilibrium measure and
Shannon entropy of LFP data recorded from the primary visual cortex (V1) of
urethane-anesthetized rats and freely moving mice. Using these information
quantifiers, we find consistent relations between LFP recordings and measures
of cortical states at the neuronal level. More specifically, we show that LFP's
statistical complexity is sensitive to cortical state (characterized by spiking
variability), as well as to cortical layer. In addition, we apply these
quantifiers to characterize behavioral states of freely moving mice, where we
find indirect relations between such states and spiking variability
Morphological analysis and description of the ovaries of female silky sharks, Carcharhinus falciformis (Müller & Henle, 1839)
This work aims to study the female reproductive tract of silky sharks, Carcharhinus falciformis, captured in the South and
Equatorial Atlantic Ocean. Samples were collected between January 2008 and March 2010 through oceanic commercial vessels
that targeted tuna and swordfish, with a total of 17 females collected. The methodologies followed for analyzing the ovaries
of those females included both macroscopic and histological analysis. Macroscopically, it was possible to determine that the
ovaries on these sharks is suspended by mesenteries in the anterior section of the body cavity, heavily irrigated by blood
vessels, and contains a wide range of oocytes. Ovaries were found in three distinct maturational stages: Stage I (Immature),
Stage II (Maturing) and Stage III (Mature). Immature ovaries were small, with widths ranging from 1.0 to 3.1 cm, and had a
gelatinous or granulose internal structure; maturing ovaries were slightly larger, ranging in width between 5.2 and 6.0 cm;
mature ovaries ranged in width between 6.5 and 7.8 cm, and had a more rounded shape and the presence of large and well
developed oocytes. Under microscopic examination, it was observed that the ovaries were covered with simple epithelial
tissue during the early development stages and a simple cubic epithelium in the final stages of maturation. During the initial
maturation stages the epigonal organ was not differentiated from the ovary. In mature specimens, the ovary showed a simple
cubic epithelium and just below this epithelium there was a layer of dense connective tissue and muscle with the presence of
vitellogenic oocytes and fat cells. A thin yolk membrane enclosing the oocytes was also evident. Finally, it was possible to
distinguish a zona pellucida, separating the oocytes from the follicle wall and a basal lamina between the granular layers and
the teak layer.info:eu-repo/semantics/publishedVersio
Promover a fluência em leitura: um estudo com alunos do 2º ano de escolaridade
Neste artigo são analisados os resultados de um Programa de Promoção da
Fluência em Leitura (PPFL), implementado junto de 74 alunos do 2º ano
de escolaridade de um Agrupamento Escolar do norte de Portugal. O PPFL
é constituído por 22 sequências didáticas, elaboradas a partir de 22 textos
(9 narrativos, 4 informativos e 9 poemas). Cada sequência foi operacionalizada
em sessões de 10 a 15 minutos, durante 22 semanas, em ciclos
de cinco dias (quinta-feira a quarta-feira). Em cada semana foi trabalhado
apenas uma sequência didáctica (i.e. um texto). Foi utilizado um design
quase experimental, com grupo experimental e grupo de controlo e com pré
e pós-teste. Os sujeitos foram avaliados através de um teste de fluência de
leitura – o Teste de Fluência em Leitura (TFL) –, considerando as variáveis
velocidade e precisão. Os resultados evidenciam diferenças significativas
a favor do grupo experimental, que superou as diferenças iniciais que se
registavam no pré-teste. A análise qualitativa do impacto do PPFL aponta
para um incremento na motivação para ler, no envolvimento da família e
para a mudança de práticas por parte dos professores envolvidos.CIEC - Centro de Investigação em Estudos da Criança, IE, UMinho (UI 317 da FCT), PortugalFundos Nacionais através da FCT (Fundação para a Ciência e a Tecnologia) e cofinanciado pelo Fundo Europeu de Desenvolvimento Regional (FEDER) através do COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) no âmbito do CIEC (Centro de Investigação em Estudos da Criança, da Universidade do Minho) com a referência POCI-01-0145-FEDER-00756
Forage cactus associated with different fiber sources for lactating Sindhi cows: intake, digestibility and microbial protein production
Forage cactus associated with different fiber sources for lactating Sindhi cows: production and composition of milk and ingestive behavior
The genomes of two key bumblebee species with primitive eusocial organization
Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation
Valor nutritivo de pastagens de capim-elefante manejadas sob sistema convencional e agroecológico.
O capim-elefante é utilizado, na sua grande maioria, em sistemas convencionais de produção animal. O objetivo deste trabalho foi comparar o valor nutritivo do capimelefante em sistemas de manejo agroecológico e convencional, quanto a proteína bruta (PB), fibra em detergente neutro (FDN) e digestibilidade in vitro da matéria seca (DIVMS). Foram usados quatro piquetes, com 0,12ha cada um. No sistema convencional, o capim-elefante foi estabelecido singularmente. No sistema agroecológico, o plantio foi feito em linhas afastadas de 3m. Nas entrelinhas, estabeleceu-se a aveia e o azevém no período hibernal, enquanto que no período estival permitiu-se o desenvolvimento de espécies espontâneas. A adubação foi feita com fertilizantes orgânicos (150kg ha-1 de N). No sistema agroecológico, foram conduzidos sete pastejos, de 24/04/2004 a 05/05/2005. Na pastagem convencional, usouse a mesma quantidade de N (uréia), sendo conduzidos quatro ciclos de pastejo, de 06/10/2004 a 05/05/2005. Para ambos os sistemas foram utilizadas vacas da raça Holandês, recebendo complementação alimentar de 3,5kg dia-1 de concentrado com 20% de proteína bruta, constituindo-se nos animais experimentais. Nas avaliações, considerou-se a massa de forragem inicial com base na matéria seca (MS), os componentes botânicos da pastagem e estruturais do capimelefante. As análises de qualidade foram feitas em amostras de pastejo simulado. O delineamento experimental foi o inteiramente casualizado com dois tratamentos, convencional e agroecológico, duas repetições (piquetes) e em parcelas incompletas subdivididas no tempo (pastejos). Houve interação (P<0,05) entre tratamentos e pastejos em todas as variáveis. Na pastagem agroecológica, o modelo que melhor se ajustou foi o cúbico para todas as variáveis, em função do tempo de pastejo. Na pastagem convencional, a PB e a DIVMS ajustaram-se melhor ao modelo linear, com taxa positiva de crescimento, sendo observado comportamento inverso para FDN, com o decorrer dos pastejos. Tanto na pastagem convencional quanto na agroecológica encontraram-se associações negativas entre lâmina foliar do capim-elefante com PB e DIVMS e positiva com FDN. Ambos os sistemas apresentaram teores qualitativos elevados das pastagens, considerando-se a adubação, o manejo e o tempo de utilização
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