1,603 research outputs found
Associação da competência motora com a atividade física: estudo longitudinal em crianças
Analisar longitudinalmente a influência da proficiência em habilidades motoras e dos níveis de coordenação motora nos níveis de atividade física (AF) das crianças. Métodos: Estudo longitudinal que decorreu entre o ano de 2009 e 2012, com uma amostra de 98 crianças (6 a 8 anos de idade no início do estudo), que realizaram avaliações anuais da AF (pedómetro), da coordenação motora (KTK) e de habilidades motoras fundamentais (TGM D-2). Para a análise dos dados recorreu-se à modelação hierárquica, com o intuito de determinar os preditores da AF, através do sucessivo ajustamento de cinco modelos. Resultados: O nível de AF das crianças diminuiu significativamente ao longo do tempo em ambos os sexos. No início do
estudo as raparigas tinham um nível de AF significativamente inferior ao dos rapazes. A magnitude das diferenças no nível de AF entre rapazes e rapa rigas não se alterou significativamente ao longo das observações. Os níveis de coordenação motora e a proficiência das habilidades de controlo de objetos não foram preditores da AF, enquanto que a proficiência das habilidades de locomoção foi o único preditor significativo da AF. Conclusões: As habilidades motoras de locomoção foram um preditor significativo da AF das crianças
Using cost of quality to select alternative suppliers and determine incoming inspection in dynamic contexts
Process quality planning should establish the incoming quality inspection plan to achieve the
desired quality level with minimum Cost of Quality (CoQ). Additionally, the selection of
alternative suppliers must be defined, and, in a dynamic context, the best solution may vary.
The purpose of this study is to, through a simulation approach, minimize the total CoQ of two
related decisions: i) supplier selection and ii) incoming quality inspection selection. We will
determine the CoQ of alternative suppliers and determine the CoQ of alternative incoming
inspections that are associated with such decisions. The inputs to the model are components
costs, inspection costs, proportion of defectives from incoming lots, Type I and Type II
inspection errors, alternative control methods, and the cost of delivering defective
components to the manufacturing system. The uncertainty of some inputs is modelled through
probability distributions and the dynamic context is modelled through different scenarios. The
results from simulations estimate the total CoQ of each alternative decision. This model allows
to determine the CoQ of the alternative scenarios and to define a best supplier and incoming
quality inspection plan. A numerical example based on a manufacturing process demonstrates
the applicability of this model and the results indicate that the optimal solution may vary
when the model parameters are updated.(undefined
Patrones de diversidad de Araneae en un gradiente de prácticas de cultivo en olivares: vinculados entre patrones del paisaje, prácticas de gestión e interacciones entre especies
Trabalho apresentado em XIX Jornadas del Grupo Ibérico de Aracnología, 4-6 outubro 2019, Priego, Espanha.N/
Functional responses of three guilds of spiders: Comparing single- and multiprey approaches
Spiders are successful natural enemies of pests occurring throughout the different
strata of an agroecosystem. The study of their functional responses can provide
information related to the potential effectiveness of different species and guilds on
reducing a pest population. However, multiple prey availability may change the functional
response of a predator. In this study, the functional responses of three species
of spiders in single-prey and multiple-prey experiments were modelled. The spider
species Haplodrassus rufipes, Araniella cucurbitina and Synema globosum were chosen
as being representatives of ground runners, orb-weavers and ambushers, respectively.
Three prey species were selected: a target prey, the Mediterranean fruit fly
Ceratitis capitata and two alternate prey species, the flour moth Ephestia kuehniella
and the house cricket Acheta domesticus. When the selected target prey C. capitata
was supplied in the single-prey experiments, the most and the least efficient spider
species were H. rufipes and S. globosum, respectively. However, opposite results were
obtained when alternative preys were supplied. Also, A. cucurbitina significantly changed
its functional response with the presence of alternative prey species. Considering
the prey preference during the multiple-prey experiments, A. domesticus, used as representative
of a heavy, long-sized and highly motile prey, was avoided whereas
C. capitata, the target pest used as representative of light, small-sized and moderately
motile prey was preferred by the three species of spiders. Ephestia kuehniella, used as
representative of light, medium-sized and low motile prey was occasionally consumed.
Each guild could include efficient predators against pests according to its
hunting strategies and the ecological exploited niches. Orb-weavers could be efficient
predators against flying pests; ambushers such as S. globosum could contribute
to the reduction of the populations of flower-visiting pests, whereas active ground
hunters may also play an important role preying on pests that develop a part or all of
its life cycle in the ground. However, further research on feeding behaviour such as
prey switching is needed for a better understanding of the effectiveness of spiders as
natural enemies.This work was funded by Portuguese Foundation for Science and
Technology (FCT) through the project EXCL/AGR-PRO/0591/2012
“Olive crop protection in sustainable production under global climatic
changes: linking ecological infrastructures to ecosystem functions”
and by the project ReNATURE – Valorization of the Natural Endogenous
Resources of the Centro Region” funded by Centro 2020
(Centro-01-0145-FEDER-000007). Jacinto Benhadi-Marín is grateful
to the Portuguese Foundation of Science and Technology for financial
support through the Ph.D. grant SFRH/BD/97248/2013. This manuscript
is part of Jacinto Benhadi-Marín's Ph.D. thesis.info:eu-repo/semantics/publishedVersio
Distribution of the spider community in the olive grove agroecosystem (Portugal): potential bioindicators
Spiders are successful natural enemies in different crops. Research on the role of
spiders as natural enemies within agroecosystems needs to address the distribution
of their communities across different spatial scales, as well as the dominant species.
We studied the spatial distribution of the community of spiders of the olive agroecosystem
in Northeastern Portugal and investigated potential species that could be used as
bioindicators of agricultural management in the olive grove.
We found nine functional groups (ambushers, foliage runner hunters, ground hunters,
orb-web builders, sheet web builders, sensing web-builders, space web builders, stalkers
and wandering sheet/tangle weavers) encompassing a community that changed
significantly across the horizontal and vertical gradient.
We propose Thanatus vulgaris Simon, 1870 as potential bioindicator for the ground
of the olive grove central area and Ozyptila pauxilla (Simon, 1870) for the ground of
the olive grove peripheral area.
Adjacent shrubland areas could play an important role in biological control of pests,
allowing the exchange of species and individuals with the olive crop. The role of agrobiont
species as indicators of agricultural managements deserves further investigation
towards the enhancement of the effectiveness of spiders within low-impact crop management in arable landscapes.Thisworkwas funded byCentro 2020 (Centro-01-0145-FEDER-
000007) through the project ‘ReNATURE – Valorization of the
Natural Endogenous Resources of the Centro Region’. The
authors are indebted to all of the farmers who allowed access
to their olive groves. Jacinto Benhadi-Marín is grateful to the
Portuguese Foundation of Science and Technology (FCT) for
financial support through the PhD grant SFRH/BD/97248/2013.
This manuscript is part of Jacinto Benhadi-Marín’s PhD thesis.
The authors declare that they have no conflicts of interest.info:eu-repo/semantics/publishedVersio
Topological field theories in n-dimensional spacetimes and Cartan's equations
Action principles of the BF type for diffeomorphism invariant topological
field theories living in n-dimensional spacetime manifolds are presented. Their
construction is inspired by Cuesta and Montesinos' recent paper where Cartan's
first and second structure equations together with first and second Bianchi
identities are treated as the equations of motion for a field theory. In
opposition to that paper, the current approach involves also auxiliary fields
and holds for arbitrary n-dimensional spacetimes. Dirac's canonical analysis
for the actions is detailedly carried out in the generic case and it is shown
that these action principles define topological field theories, as mentioned.
The current formalism is a generic framework to construct geometric theories
with local degrees of freedom by introducing additional constraints on the
various fields involved that destroy the topological character of the original
theory. The latter idea is implemented in two-dimensional spacetimes where
gravity coupled to matter fields is constructed out, which has indeed local
excitations.Comment: LaTeX file, no figure
Chemical characterization of “Alcaparras” stoned table olives from Northeast Portugal
Commercial stoned table olives named "alcaparras" from Trás-os-Montes (Portugal) were chemically characterized. During three consecutive years (2004-2006) 30 samples (10 per year) were examined for their nutritional value (moisture, crude protein, total fat, ash, carbohydrates, and energy), with a detailed report of the fatty acids and tocopherols composition. Water was the major constituent (72.5 ± 5.5%), followed by fat (14.6 ± 5.1%). The average amount of protein and ash were 1.1% and 3.4%, respectively, reporting unusual ash values for table olives, related to the technological process. One hundred grams of fresh stoned table olives presented an average energetic value of 156 kcal, lower than most table olives. The lipids are rich in oleic acid (average of 77.7 ± 2.0%), followed by palmitic acid and linoleic acid. Samples showed an average of total tocopherols of 1.2 mg/100 g of fresh weight, being α-tocopherol the most abundant. Table olives are important sources of MUFA, as olive oil, recognized as a preventive factor in diseases in which free radicals are implicated, complemented by the amounts of vitamin E, with both antioxidant and vitamin action.The authors are grateful to INTERREG III A Program, Project PIREFI for financial support of
this work.info:eu-repo/semantics/publishedVersio
Digital Learning Is an Educational Format towards Sustainable Education
The year 2020, due to the pandemic, was a milestone in the history of digital technology in
the education sector, allowing a sustainable education although the world was facing a pandemic
crisis without precedents. Therefore, in a few days occur a transformation from traditional classroom
teaching to online teaching and consequently forced to use digital learning. Nevertheless, more
researches are needed to know how was this experience and if there is the intention to maintain the
online format. The main goal of this article is to study how digital learning can be an educational
format focused on sustainable education. This paper presents a systematic literature review on
digital learning through PRISMA methodology, based on a literature search and field research aimed
to analyze the significant predictors related to the digital learning experience on the likelihood of
choosing to “keep” the online format in the next academic year. An online survey was conducted
with 173 university students. The results obtained showed that the significant predictors were
factor 1-”Characteristics of online classes; factor 2-”Support from the School and Professors; factor
3-”Online classes vs. face-to-face classes” and gender. The probability of choosing to keep online
classes increases exponentially with the characteristics of online classes, with Support from school
and teachers; Online classes vs. Face-to-face classes, and keeping factors 1, 2, and 3 constant the
probability if a man chooses the online format compared to a woman is higher. This online format thus
acquires central importance in the contemporary sustainability debate. The kind of life, education,
and society we will have in the future will depend on the quality, depth, and extent of the learning
processes we can create and exercise individually and socially. Education, and educators in particular,
who concentrate on the tasks of designing and implementing social teaching and learning models,
have a unique responsibility in this process. Although the reduced sample size the present work can
provide strategic information for university staff, contributing to designing and implementation a
sustainable education.info:eu-repo/semantics/publishedVersio
The C677T polymorphism in MTHFR is not associated with migraine in Portugal
Migraine is a debilitating disorder affecting a large proportion of the population. The effect of methylenetetrahydrofolate reductase (GeneID: 4524) polymorphisms in migraine etiology and development has been a theme of great interest. Several populations were evaluated with contradictory results. In this case-control study, we investigated the effect of the C677T polymorphism in MTHFR, as a genetic risk factor for migraine, in the Portuguese population. We observed that, overall, there was no significant difference in the frequencies of MTHFR C677T genotypes or of the T-allele among the Portuguese migraineurs when compared to controls. There was also no association of migraine with aura with MTHFR genotypes or with the T-allele, in contrast with previous studies. Regarding the risk of the T-allele homozygote carriers, there was an equal probability to develop migraine with aura over migraine without aura in our patients. Thus, we conclude that the C677T MTHFR polymorphism, responsible for a reduction of the MTHFR activity in folate metabolism, is not a major genetic susceptibility factor for migraine in the Portuguese population.Fundação para a Ciência e Tecnologia (POCTI-034390/99/FCT) and A.F. (SFRH/BD/
1288/2000), M.-J.C. (POCTI-034390-PR332009-BTI),
M.S. (SFRH/BD/9111/2002), C.L. (SFRH/BD/17761/
2004
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