5,119 research outputs found
Maximal lactate steady state in swimming tethered
This study investigated whether aerobic capacity (AC) in tethered swimming corresponds to maximal lactate steady state (MLSS) and its correlation with 30 min (V30) and 400m (V400) free swimming velocity. Twenty-five swimmers were submitted to an incremental tethered swimming test (ITS) with each stage lasting 3 minutes, initial load 20N, with 10N increments and a 30s interval to collect blood samples and lactatemia ([La-]). The abrupt increase in [La-] against force (F) corresponded to AC (ACBI). The points obtained for [La-] against force (N) were adjusted with an exponential curve model to determine AC corresponding to 3.5mmol.l-1 (AC3.5) and 4.0mmol.l-1 (AC4.0). Later swimmers performed maximum exercise for 30 minutes (V30) and 400m (V400) in free swimming. After one week, nine swimmers performed three random 30 minute tethered swimming exercises with 90%, 100%, and 110% intensity ACBI MLSS. Comparisons between ACs (AC3.5, AC4.0, and ACBI) were made by the one-way Anova test. Pearson correlation was used for possible correlations between ACs and between ACs and V30 and V400 (p0.91) and V400 (r\u3e0.63). We can conclude that ACBI corresponds to MLSS and both individually determined. AC and from the fixed lactate concentrations (3.5 and 4mM) can be used to predict mean 30 minute and 400m free swimming velocity
Overcoming inertia : drivers of the outsourcing process
Almost all managers have directly or indirectly been involved in the practice of outsourcing in recent years. But as they know, outsourcing is not straightforward. Outsourcing inertia, when companies are slow to adapt to changing circumstances that accommodate higher outsourcing levels, may undermine a firm’s performance. This article investigates the presence of outsourcing inertia and the factors that help managers overcome it. Using statistical evidence, we show that positive performance effects related to outsourcing can accumulate when circumstances change. This is then followed by rapid increases in outsourcing levels (i.e. outsourcing processes). We investigate what gives rise to these outsourcing processes through follow-up interviews with sourcing executives, which suggest five drivers behind outsourcing processes: managerial initiative (using outside experience); hierarchy (foreign headquarters); imitation (of competitors and of similar firms); outsider advice (from external institutions); knowledge sources (using external information). These five drivers all offer scope for managerial action. We tie them to academic literatures and suggest ways of investigating their presence and impact on the outsourcing process. Overall, we conclude that while economizing factors play a key role in explaining how much firms outsource, it is socializing factors that tend to drive outsourcing processes
Leafing patterns and drivers across seasonally dry tropical communities
Investigating the timing of key phenological events across environments with variable seasonality is crucial to understand the drivers of ecosystem dynamics. Leaf production in the tropics is mainly constrained by water and light availability. Identifying the factors regulating leaf phenology patterns allows efficiently forecasting of climate change impacts. We conducted a novel phenological monitoring study across four Neotropical vegetation sites using leaf phenology time series obtained from digital repeated photographs (phenocameras). Seasonality differed among sites, from very seasonally dry climate in the caatinga dry scrubland with an eight-month long dry season to the less restrictive Cerrado vegetation with a six-month dry season. To unravel the main drivers of leaf phenology and understand how they influence seasonal dynamics (represented by the green color channel (Gcc) vegetation index), we applied Generalized Additive Mixed Models (GAMMs) to estimate the growing seasons, using water deficit and day length as covariates. Our results indicated that plant-water relationships are more important in the caatinga, while light (measured as day-length) was more relevant in explaining leafing patterns in Cerrado communities. Leafing behaviors and predictor-response relationships (distinct smooth functions) were more variable at the less seasonal Cerrado sites, suggesting that different life-forms (grasses, herbs, shrubs, and trees) are capable of overcoming drought through specific phenological strategies and associated functional traits, such as deep root systems in trees
Effect of solvent-dependent viscoelastic properties of chitosan membranes on the permeation of 2-phenylethanol
The viscoelastic behaviour of chitosan was followed by dynamic mechanical analysis (DMA) while the
sample was immersed in gradient compositions of water/ethanol mixtures. The swelling equilibrium
of chitosan membranes, both crosslinked with genipin or not, increased linearly with the water content.
Increasing the water content, it was simultaneously observed a peak in the loss factor (around 25 vol.%)
and a reduction of the storage modulus, which was attributed to the a-relaxation of chitosan. This was
the first time that the glass transition dynamics in a polymer was monitored in immersion conditions
where the composition of the plasticizer in the bath is changed in a controlled way. The water content
at which tan d presented a maximum increased with both increasing frequency and increasing crosslinking
density. The permeability decreased steadily with the ethanol content, reaching very low values
around the glass transition. Therefore we hypothesize that conformational mobility of the polymeric
chains may play an important role in the diffusion properties of molecules trough polymeric matrices.This work was partially supported by the Portuguese Foundation for Science and Technology (FCT), through funds from the POCTI and/or FEDER programmes and through the scholarship SFRH/BPD/34545/2007 granted to Ricardo M.P. da Silva. This work was carried out under the scope of the European NoE EXPERTISSUES (NMP3-CT-2004-500283) and also partially supported by the EU funded projects HIPPOCRATES (STREP - NMP3-CT-2003-505758) and PROTEUS (INTERREG III A - SP1.P151/03). The technical assistance of Ana Pinheiro in the execution of the DMA experiments is also acknowledged
Chemical and Sensorial Characterization of Tropical Syrah Wines Produced at Different Altitudes in Northeast of Brazil
Over the years, viticulture has expanded to new regions outside the temperate zones, such as Northeast Brazil, India, Thailand, Myanmar, Vietnam, Bangladesh and Venezuela, characterized by the production of tropical wines. It is important for the productive sector to comprehend the effects of grapevine interaction with the characteristics of each new region on wines composition. In this study, the composition of wines of Syrah from two regions with different altitudes in Northeast Brazil were analyzed by different methodologies to characterize chemical compounds as sugar, acids, minerals, phenolics (anthocyanins, flavonols, stilbenes and condensed tannins) and the sensory profile. The wines of the Bahia region (1100 m of altitude) obtained high concentrations for chemical parameters related to color, monomeric anthocyanins, stilbenes and monomeric and oligomeric tannins. Wines of the low altitude region, Pernambuco (350 m of altitude) were characterized by higher concentrations of flavonols (kaempferol, isorhamnetin, quercetin and rutin) and polymerized tannins. The chemical composition of wines from the two studied regions was influenced by altitude. A trend towards higher concentrations in most for phenolic compounds analyzed was observed in wines from the higher altitude region during the two years of study. Regarding the sensory profile, fruity, floral, herbaceous and empyreumatic attributes aromatic obtained highest scores in wines of the 350 m altitude region, the other attributes were dependent on the year of harvest
A relevância da industria 4.0 para desenvolvimento do polo industrial brasileiro frente aos desafios: The relevance of industry 4.0 for the development of the brazilian industrial hub facing the challenges
A indústria 4.0 é o termo que convencionou a chamar a quarta revolução industrial e o conjunto de tecnologias disponíveis que permite a integração do mundo físico com o digital e traz uma série de desafios e transformações à economia, modificando a configuração das profissões atualmente no mercado. O objetivo geral do trabalho é analisar a Indústria 4.0 e os principais impactos no Polo Industrial Brasileiro. Essa pesquisa corresponderá a uma revisão de literatura, serão utilizadas as seguintes bases de dados: Scielo (Scientific Electronic Library Online), Portal de Periódicos CAPES, Repositório de Universidades Públicas e Google scholar. O total de artigos científicos consultados para a realização dos objetivos propostos na presente pesquisa, à revisão foram realizados com 202 artigos, descartados 162 artigos, e utilizados 40 artigos publicados a partir do ano 2012 ao ano de 2022. No que diz respeito à indústria 4.0 no Brasil, ela pode abrir novos mercados, aproveitar a inovação e aumentar a produtividade, especialmente nas economias em desenvolvimento. Nesse sentido, os governos apoiam a inovação e os ganhos adotando programas de incentivo, melhorando a infraestrutura e políticas que desafiam a difícil distribuição dos benefícios digitais. Assim, diante do exposto, as empresas que conseguirem se beneficiar dessa situação certamente alcançarão um novo patamar de produtividade e competitividade. É importante destacar que o setor enfrentará desafios científicos, tecnológicos, econômicos, sociais e políticos ao adotar o novo modelo. Ao final conclui-se que todo o conceito de Indústria 4.0 é inovador e através da implementação de estratégias e aplicação de princípios, embora árdua, é possível adaptar esta nova concepção e com isso melhorar todas as indústrias
Plasma-induced polymerization as a tool for surface functionalization of polymer scaffolds for bone tissue engineering: an in vitro study
A commonly applied strategy in the field of tissue engineering (TE) is the use of temporary three-dimensional
scaffolds for supporting and guiding tissue formation in various in vitro strategies and in vivo
regeneration approaches. The interactions of these scaffolds with highly sensitive bioentities such as living
cells and tissues primarily occur through the material surface. Hence, surface chemistry and topological
features have principal roles in coordinating biological events at the molecular, cellular and tissue
levels on timescales ranging from seconds to weeks. However, tailoring the surface properties of scaffolds
with a complex shape and architecture remains a challenge in materials science. Commonly applied wet
chemical treatments often involve the use of toxic solvents whose oddments in the construct could be
fatal in the subsequent application. Aiming to shorten the culture time in vitro (i.e. prior the implantation
of the construct), in this work we propose a modification of previously described bone TE scaffolds made
from a blend of starch with polycaprolactone (SPCL). The modification method involves surface grafting
of sulfonic or phosphonic groups via plasma-induced polymerization of vinyl sulfonic and vinyl phosphonic
acid, respectively. We demonstrate herein that the presence of these anionic functional groups
can modulate cell adhesion mediated through the adsorbed proteins (from the culture medium). Under
the conditions studied, both vitronectin adsorption and osteoblast proliferation and viability increased in
the order SPCL!sulfonic-grafted SPCL < phosphonic-grafted SPCL. The results revealed that plasmainduced
polymerization is an excellent alternative route, when compared to the commonly used wet
chemical treatments, for the surface functionalization of biodevices with complex shape and porosity.The authors acknowledge funding from EU Marie Curie Actions, Alea Jacta Est (MEST-CT-2004-008104) and the Portuguese Foundation for Science and Technology (FCT) (SFRH/BPD/34545/2007). This work was carried out under the scope of the European NoE EXPERTISSUES (NMP3-CT-2004-500283). The authors also acknowledge Dr. M.I. Santos and C. Serra for their assistance on the CLSM and XPS experiments
Mathematical model of brain tumour with glia-neuron interactions and chemotherapy treatment
Acknowledgements This study was possible by partial financial support from the following Brazilian government agencies: Fundação Araucária, EPSRC-EP/I032606/1 and CNPq, CAPES and Science Without Borders Program Process nos. 17656125, 99999.010583/2013-00 and 245377/2012-3.Peer reviewedPreprin
Surface phosphorylation of chitosan significantly improves osteoblast cell viability, attachment and proliferation
Chitosan biocompatibility is often associated with the structural similarities with glycosaminoglycans
(GAGs). Although all of the GAGs are built from repeating disaccharide units and some of them
contain N-glucosamine (the main hexosamine in the chitosan backbone), all of them also contain
negatively charged functional groups. These charged units are believed to have a crucial role for the
formation of proteoglycans and hence for key biochemical processes/signaling related to cell
functionality and survival. Lack of these groups in chitosan structure could be the reason for the
previously observed poor cell adhesion to this material. Herein, we report that plasma induced grafting
of negatively charged phosphonic groups can induce remarkably distinguishable cell response and
significantly improve the adhesion, proliferation and viability of osteoblast cells. The proposed plasma
induced polymerization is a very simple and versatile method and can be easily adapted to other
materials and different negatively charged units.The authors acknowledge funding from EU Marie Curie Actions, Alea Jacta Est (MEST-CT-2004-008104) and Portuguese Foundation for Science and Technology (FCT)(SFRH/BPD/34545/2007). This work was carried out under the scope of the European NoE EXPERTISSUES (NMP3-CT-2004-500283)
- …