511 research outputs found
Web evaluator for students: a case example
Getting the attention of students has always been a hard task for most teachers. In this context the use of new technologies can be taken into consideration for giving the teacher new means to incentive his students.
The tool described in this article gives importance to the opinion of the students for their own evaluation. Thanks to it a group of students from the University of Minho was able to post questions to their colleagues and to evaluate their peer’s works on the discipline of Power Electronics Complement
Genotype determines Arbutus unedo L. physiological and metabolomic responses to drought and recovery
Strawberry tree (Arbutus unedo) is a small resilient species with a circum-Mediterranean distribution, high ecological relevance in southern European forests and with several economical applications. As most orchards are usually installed on marginal lands where plants usually face severe drought, selecting plants that can better cope with water restriction is critical, and a better understanding of the tolerance mechanisms is required. Strawberry tree plants under drought follow a typical isohydric strategy, by limiting transpiration through stomata closure. However, the contribution of genotype and its bio-geographic origin on plant performance needs clarification, as well as the involvement of a specific metabolic reactions associated with the mechanical response. To test this hypothesis, several eco-physiological and biochemical parameters were assessed on different genotypes, and the metabolic profiles studied, including important stress-related phytohormones, on plants under different water regimes (plants watered to 70% and 18% field capacity) and a recovery assay. A contrasting drought tolerance was found in plants from different genotypes, associated with physiological and metabolic responses. Metabolomics revealed more than 500 metabolic features were differentially accumulated, including abscisic and salicylic acids, for the genotype with better performance under drought (A4). This genotype also recovered faster when the imposed stress was interrupted, thus indicating the relevance of metabolic adaptation under water deficit conditions. By correlating carbon assimilation with identified metabolites, some proved to be satisfactory predictors of plant performance under drought and might be used for marker assisted breeding. Therefore, our study proves the importance of genotype as a major selection criterion of resistant plants to drought and provides empirical knowledge of the metabolic response involved. We also hypothesized the involvement of phenolics on response mechanisms under drought, which is worth to be explored to shed light on the metabolic pathways involved in plant response to water stress
Nutrient Content with Different Fertilizer Management and Influence on Yield and Fruit Quality in Apple cv. Gala
Assessing a plant’s nutritional status and fertilizer rates and types that can optimize fruit
quality and yield are critical in intensive apple orchards. The aim of this work was to identify
correlations between nutrients in the different organs that allow the early diagnosis of the nutritional
status and to assess the impact on the optimal nutrient content in apple leaves, as well as in the
yield and quality of chemical and organic fertilization. Five orchards of ‘Gala’ were fertilized with
different levels of NPK over a period of four years. Macro and micronutrients of buds, flowers, 45 and
90–110 days after full bloom (DAFB) leaves and 60 DAFB and 15 days before harvest (DBH) fruits were
determined. Boron was the only element for which strong correlations, 0.7 < r < 0.9, were observed
between all organ pairs. The fertilization treatments did not affect the nutrient concentrations in
the leaves of 90–110 DAFB other than P, Ca and Mg and did not affect the macronutrients in the
fruit. In one of the five orchards, the yield increased by 26% with double fertilization compared to
standard fertilization and, for the other four orchards, the impact depended on the year. Fruit size
was more related to crop load than to fertilization and TSS and firmness were not affected by the type
or amount of fertilizers. Replacing part of the chemical fertilizer with organic materials did not affect
productivity or fruit qualityinfo:eu-repo/semantics/publishedVersio
Classificação Geotécnica do maciço rochoso da Pedreira do Monte das Flores – Évora (Portugal)
No âmbito da atualização do processo de homologação da Pedreira do Monte das Flores - Évora, como fornecedora de balastro ferroviário, procedeu-se à classificação geotécnica do maciço rochoso existente no local. Esta exploração possui 96,90 ha de área arrendada estando 70,70 ha concessionados à exploração.
Geologicamente, a área estudada pertence à Zona de Ossa-Morena (Maciço de Évora), enquanto parte integrante do Maciço Ibérico que constitui o setor mais ocidental e contínuo da Cadeia Orogénica Varisca na Europa. Também os eventos tectonotérmicos alpinos se fizeram sentir neste maciço de forma atenuada, permitindo a preservação da história geológica mesozóica [Moita, 2008]. A unidade geológica onde se insere a exploração é constituída por litótipos ígneos e metamórficos de idade precâmbrica e paleozóica [Andrade et al., 1976], denotando-se um domínio das formações de rochas eruptivas. Na área estudada ocorre um afloramento de quartzodiorito e granodiorito de grão médio, não porfiróide, onde os minerais mais representativos da rocha são o feldspato potássico, a plagioclase e o quartzo, sem evidenciarem qualquer orientação à vista desarmada [Moita, 2008].
Neste estudo fez-se a descrição geotécnica da qualidade do maciço rochoso que ocorre na Pedreira do Monte das Flores. Por se tratar de um sistema de classificação generalista e correntemente utilizado na avaliação do comportamento geomecânico dos maciços rochosos, utilizou-se a Descrição Geotécnica Básica (“Basic Geotechnical Description”- BGD), proposta pela Sociedade Internacional de Mecânica das Rochas [ISRM, 1981]. O principal objetivo da aplicação desta classificação foi o de efetuar um zonamento geotécnico do maciço rochoso, quer do local atualmente em exploração, quer da área contígua para onde se prevê o alargamento da corta da exploração, com base no reconhecimento geológico e, na amostragem efetuada em locais selecionados para posterior realização de ensaios laboratoriais de caracterização mecânica. Este reconhecimento geológico de superfície permitiu identificar o tipo de rocha presente, determinar as características estruturais e caracterizar a alteração do maciço rochoso, assim como, definir as diferentes famílias de fraturas presentes e quantificar o espaçamento entre as descontinuidades nestas famílias.
Com o objetivo de determinar as características mecânicas, tais como, a resistência à compressão uniaxial e o ângulo de atrito das fraturas, foi realizada uma campanha de ensaios laboratoriais e de campo, nomeadamente, o ensaio de resistência à compressão uniaxial, complementado pelo ensaio de carga pontual, de modo a determinar o valor daquela resistência. Realizou-se também o ensaio com o martelo de Schmidt dado ser um ensaio simples e rápido na caracterização de materiais [Pinho, 2003], que permite estimar o valor da
resistência à compressão uniaxial dos planos das descontinuidades do maciço rochoso (JCS), nos diferentes locais de amostragem. O parâmetro JCS, o coeficiente de rugosidade da descontinuidade (JRC) e a tensão efectiva normal (’n ), foram necessários para obter o ângulo de atrito das diaclases (Øpico), de acordo com o método proposto pela Sociedade Internacional de Mecânica das Rochas [ISRM, 1978].
O estudo realizado permitiu concluir que o maciço apresenta boa qualidade, em regra, homogénea relativamente às suas características geológicas e geotécnicas. No entanto, distinguem-se duas zonas, ZG1 e ZG2, com base em pequenas diferenças nos valores da resistência à compressão uniaxial da rocha e do ângulo de atrito das fraturas
α-Selective glycosylation affords mucin-related GalNAc amino acids and diketopiperazines active on Trypanosoma cruzi
AbstractThis work addresses the synthesis and biological evaluation of glycosyl diketopiperazines (DKPs) cyclo[Asp-(αGalNAc)Ser] 3 and cyclo[Asp-(αGalNAc)Thr] 4 for the development of novel anti-trypanosomal agents and Trypanosoma cruzi trans-sialidase (TcTS) inhibitors. The target compounds were synthetized by coupling reactions between glycosyl amino acids αGalNAc-Ser 7 or αGalNAc-Thr 8 and the amino acid (O-tBu)-Asp 17, followed by one-pot deprotection-cyclisation reaction in the presence of 20% piperidine in DMF. The protected glycosyl amino acid intermediates 7 and 8 were, in turn, obtained by α-selective, HgBr2-catalysed glycosylation reactions of Fmoc-Ser/Thr benzyl esters 12/14 with αGalN3Cl 11, being, subsequently, fully deprotected for comparative biological assays. The DKPs 3 and 4 showed relevant anti-trypanosomal effects (IC50 282–124μM), whereas glycosyl amino acids 1 and 2 showed better TcTS inhibition (57–79%) than the corresponding DKPs (13–25%)
Hamstring muscles volume of elite football athletes assessed using magnetic resonance imaging
N/
Harvest of endangered marine invertebrates in a priority area for conservation in Brazil
The harvesting of marine organisms for aquarium and ornamental art crafts is a very common and widespread activity, threatening a number of coral reef species. The goal of this manuscript is to report the intensive harvesting of two marine invertebrate species, the starfish Oreaster reticulatus and the gorgonian Phyllogorgia dilatata, in reef environments of a national priority area for the creation of a Marine Protected Area (MPA) in the Espírito Santo State, central coast of Brazil. These species were present on the 2003 Brazilian Red List of Endangered species as threatened of extinction, but P. dilatata was removed from the most recent 2014 Brazilian Red List, while O. reticulatus is currently considered vulnerable. Neither species have been assessed by IUCN. The harvest of these invertebrates was registered in 17% of the 51 days of monitoring (ten expeditions between March 2005 and February 2006), with catches of up to 24 starfishes and 1000 gorgonians in a single day. Starfishes used to be sold to local traders for US 0.15. This starfish is already in decline on a regional scale, and the actual harvesting rate of the gorgonian could lead to the extinction of the local population in about 17 years of exploitation. Due to the ecological importance of these two endangered species, their harvest threatens the entire local rocky reef ecosystem. Further ecological and fisheries studies on these species should be conducted, and the definition and creation of the MPA could help to manage all the unsustainable activities conducted and expected in the region
Theoretical analysis of the interaction of CO, CO2, and NH3 with ZnO
This paper presents a study of the interaction of small molecules with ZnO surfaces by means of theoretical methods. The AM1 semi-empirical method was used for optimizing the geometric parameters of adsorbed molecules. The optimized AM1 structures were used in the calculations of the ab initio RHF method with the 3-21G* basis set. The interaction of CO, CO2 and NH3 molecules were studied with (ZnO)22 and (ZnO)60 cluster models. We have analyzed the interaction energy, SCF orbital energies, Mulliken charges and the density of states (DOS)
Ornithodoros brasiliensis Aragão (Acari: Argasidae): description of the larva, redescription of male and female, and neotype designation
Ornithodoros brasiliensis is an endemic tick from Brazil and is very aggressive to humans, resulting in pain, fever and intense inflammatory response. After more than 50 years without report, this species was recently found in rural areas of São Francisco de Paula municipality, State of Rio Grande do Sul, southern Brazil, from where it was originally described. Herein, we describe the larva and redescribe the adults of O. brasiliensis based on scanning electron microscopy. Since the type was lost we designate the neotype specimen under the number IBSP 10409. In addition, the relationship between O. brasiliensis and other species from the Neotropical region that share the morphological characteristics of Ornithodoros with dorsal humps on tarsi, and also live under the soil and feed on hosts other than bats, are discussed. Molecular analysis inferred from a portion of the 16S rRNA mitochondrial gene is also provided and it placed O. brasiliensis in a cluster supported by a maximal bootstrap value (100%) with Ornithodoros parkeri, Ornithodoros rostratus, and Ornithodoros turicata.Fil: Barros Battesti, Darci M.. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: Onofrio, Valeria C.. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: Nieri Bastos, Fernanda A.. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; BrasilFil: Soares, João Fábio. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; BrasilFil: Marcili, Arlei. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; BrasilFil: Famadas, Kátia M.. Universidad Federal Rural de Rio de Janeiro; BrasilFil: Faccini, Joao Luiz H.. Universidad Federal Rural de Rio de Janeiro; BrasilFil: Ramirez, Diego G.. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; BrasilFil: Doyle, Rovaina L.. Instituto de Pesquisas Veterinárias Desidério Finamor; BrasilFil: Martins, João Ricardo. Instituto de Pesquisas Veterinárias Desidério Finamor; BrasilFil: Junior, José R.. Universidade Federal do Rio Grande do Sul; BrasilFil: Guglielmone, Alberto Alejandro. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Labruna, Marcelo B.. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; Brasi
- …