1,986 research outputs found
A datação pelo radiocarbono de elementos de rodas romanas de Madeira para elevação de água nas Minas de Rio Tinto
Fragmentos de madeira dos raios das rodas utilizadas
no sistema de drenagem das minas romanas
de Rio Tinto e que se encontram depositados no
Museu Mineiro de Rio Tinto foram datados pelo
radiocarbono. Todos os fragmentos datados foram
identificados como de madeira de sobreiro (Quercus
suber) e as datas obtidas foram consideradas
como terminii post quem para o fabrico e utilização
das referidas rodas. Assim, estas serão atribuíveis
aos Sécs. I a III d. C.Wood remains from spokes of Roman water
wheels discovered in the Rio Tinto mines
(Southern Spain) and currently deposited at the
Mines Museum of Rio Tinto were radiocarbon
dated. Five samples identified as wood from corkoak
(Quercus suber) were processed providing
post quem dates for the manufacture and use of
the wheels. In this way, these Roman wheels must
be ascribed to a period between the first and the
third century A.D
Influence of the storage conditions on the quality of bee pollen
Bee pollen is a healthful food product with a good nutritional profile and therapeutic properties. However, the
storage conditions may affect its composition and characteristics. This study aimed to evaluate the effect of the
storage conditions on chemical composition of different monofloral bee pollen samples, namely acidity (pH),
water activity, total acidity and the content of fibre, ash, reducing sugars, protein, lipids, total phenols and total
flavonoids. Nine bee pollen samples were harvested in three places in the Northeast of Portugal and divided into
two aliquots: one was frozen at −20°C, while the other was dried at 42°C, until reaching moisture of 6–8%. Even
though differences in the botanical origin are a significant factor explaining the variation between samples, the
storage method was also found to be a highly significant factor for several parameters: reducing sugars, lipids,
total phenols and total flavonoids. Higher counts were obtained on the frozen bee pollen samples regarding aerobic
mesophiles and moulds and yeasts. Even so, for all samples and conservation methods, the values were below those
given by the standards.
Our study suggests that it is better to consume bee pollen frozen at −20°C in comparison to that dried in an electric oven.Centro de Estudos Florestais is a research unit
funded by Fundação para a Ciência e Tecnologia, (UID/
AGR/00239/2019).info:eu-repo/semantics/publishedVersio
Development of a metric of aquatic invertebrates for volunteers (MAIV): a simple and friendly biotic metric to assess ecological quality of streams
Citizen science activities, involving local people in volunteer-supported and sustainable
monitoring programs, are common. In this context, the objective of the present work was to develop a
simple Metric of Aquatic Invertebrates for Volunteers (MAIV), including a user-friendly tool that can
be easily accessed by volunteers, and to evaluate the e ciency of a volunteer monitoring program
following an audit procedure. To obtain MAIV values, macroinvertebrate communities were reduced
to 18 surrogate taxa, which represented an acceptable compromise between simplicity, e ciency, and
reproducibility of the data, compared to the regular Water Framework Directive monitoring. When
compared to results obtained with the National Classification System of Portugal, MAIV accurately
detected moderate, poor, and bad ecological status. Thus, MAIV can be used by volunteers as a
complement to the o cial monitoring program, as well as a prospective early warning tool for
local problems related to ecological quality. Volunteers were students supervised by their teachers.
Results obtained by volunteers were compared to results obtained by experts on macroinvertebrate
identification to measure the e ciency of the procedure, by counting gains and losses on sorting,
and identification. Characteristics of groups of volunteers (age and school level) did not influence
significantly the e ciency of the procedure, and generally results of volunteers and experts matched.info:eu-repo/semantics/publishedVersio
Use of Frequency Distribution Functions to Establish Safe Conditions in Relation to the Foodborne Pathogen Bacillus cereus
Minimal processing implementation greatly depends on a detailed knowledge of the effects of preservation factors and their combinations on the spoilage and foodborne pathogenic microorganisms. The effectiveness of mild preservation conditions will become increasingly dependent on a more stochastic approach linking microbial physiological factors with product preservation factors. In this study, the validity of frequency distributions to efficiently describe the inactivation and growth of Bacillus cereus in the presence of natural antimicrobials (essential oils) has been studied. For this purpose, vegetative cells were exposed to 0.6 mM of thymol or cymene, obtaining survival curves that were best described by the distribution of Weibull, since a tailing effect was observed. B. cereus was also exposed in a growth medium to a low concentration (0.1 mM) of both antimicrobials, separately or combined, and the lag times obtained were fitted to a normal distribution, which allowed a description of dispersion of the start of growth. This allowed a more efficient evaluation of the experimental data to establish safe processing conditions according to accurate parameters and their implementation in risk assessment
Enzyme inhibitory potential of Ligustrum lucidum Aiton berries
Ligustrum lucidum Aiton and its berries have been used in Chinese traditional medicine
for around two thousand years. In the present study, L. lucidium berries harvested in two regions
of Portugal were studied. Haemolytic activity and inhibition of oxidative haemolysis as well as the
enzyme inhibitory activities ( -amylase enzyme and acetylcholinesterase) were assessed. Results
suggest that the different biological activities varied according to the region where samples were
collected. Results demonstrated that the sample obtained from region R1 was the most efficient
extract for all parameters evaluated, presenting the lowest values of IC50, 10.67 0.46 g/mL for the
inhibition of erythrocyte oxidative haemolysis, 58.28 3.77 g/mL for the -amylase enzyme and
67.67 _+ 2.10 ug/mL for the acetylcholinesterase inhibition. L. Lucidum berries may be an interesting
source of compounds for use in the development of the therapeutic armamentarium for diseases
where enzymatic disruption is believed to play a roleinfo:eu-repo/semantics/publishedVersio
Special Bioactivities of Phenolics from Acacia dealbata L. with Potential for Dementia, Diabetes and Antimicrobial Treatments
Some diseases still need better therapeutic approaches, including the prevention of development.
Natural resources are investigated with this purpose; among them, we decided to use an
invasive plant as a main strategy. This will help in two ways: screening new compounds in flowers
prevents the plant from causing widespread damage by controlling the dissemination and also obtains
crude material for further applications. In the present study, flower extracts from Acacia dealbata
Link harvested in Portugal were studied during three stages of flowering. Phenolic compounds were
evaluated using HPLC/DAD and the total phenolics as the total flavonoids content was determined.
The bioactivities screened were antioxidant potential, inhibitory activities of some enzymes (acetylcholinesterase,
lipase and -glucosidase) and, to complete the screening, the inhibition of microbial
growth was determined against Gram-negative and Gram-positive bacteria, as well as for yeasts. The
data obtained suggested that the hydroethanolic extracts gave good results for all these biological
activities and varied according to the maturation status of the flowers, with the early stage being
the most active, which can be related to the chalcones content. This new approach will lead to the
possible control of the invasive plant and also future perspective research for therapeutic purposesinfo:eu-repo/semantics/publishedVersio
Resource partitioning and niche segregation in a steppe bird assemblage
Niche theory predicts that coexisting species will partition resources to limit the effects of interspecific competition. We examined microhabitat partitioning in six sets of steppe birds associated to agroecosystems in central Spain (female and male Great Bustards Otis tarda, female and male Little Bustards Tetrax tetrax, Red-legged Partridges Alectoris rufa and Eurasian Stone-curlews Burhinus oedicnemus) to estimate realized niche breadth, overlap and segregation. Principal Components Analysis on data from used and random microhabitat locations produced two axes we retained for analysis related with two key factors: cover-visibility and food availability. Non-parametric kernel density functions were calculated for each of the PCA axes and species (or sexes), and niche overlap estimated as the area shared between species’ density functions. Null models were run to evaluate overlap significance. In analyses of microhabitat selection by the six sets of birds, 13 out of 15 pairs had significant resource partitioning and niche segregation, except for the pairs partridge and female Great Bustard and the two sexes of Great Bustard. Eurasian Stone-curlew showed wider trophic niche breadth, although segregated from the other species, probably because of its higher invertebrate requirements. Great and Little Bustards segregated in both niche axes, selecting microhabitat according to their body size. Accessibility to food resources and shelter seems to be similar for partridges and female Great Bustards, overlapping in their selection, which may indicate the existence of segregation in other niche factors (e.g., feeding habits). Great Bustard males showed niche overlap with females. Little Bustard males showed feeding microhabitat selection patterns similar to those of females, although they preferred more open microhabitats to meet their sexual display requirements. The entire assemblage had significantly less overlap than expected by chance, suggesting that differential microhabitat selection and realized niche partitioning may explain coexistence in steppe bird communities. Our results suggest that the maintenance of different microhabitat structure should be a priority in the management of agricultural environments
Nanopartículas metálicas funcionalizadas con el neuropéptido VIP y procedimiento de preparación
Nanopartículas metálicas funcionalizadas con el neuropéptido
VIP y procedimiento de preparación.
Constituye el objeto de la presente invención nanopartículas
metálicas funcionalizadas con el neuropéptido VIP,
así como el procedimiento de preparación de dichas nanopartículas.
Las nanopartículas objeto de la presente invención presentan
uniones selectivas de nanopartículas a péptidos en dos orientaciones posibles, grupo NH2 o grupo COOH.
En esta última orientación, los péptidos si son reconocidos por los receptores de membranas celulares, lo que proporciona una herramienta que permite discernir efectos
dependientes e independientes de receptor.
El péptido empleado ha sido el VIP, mediante el cual se obtiene un amplio espectro de funciones biológicas, incluida inmunomodulación, actuando predominantemente
como un potente anti-inflamatorio y un agente inhibidor de la respuesta del Th1 en el sistema inmunitario y emergiendo
como un importante factor terapéutico para el tratamiento de enfermedades con componentes inflamatorias y autoinmunes.Universidad Pablo de Olavide, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas (España), Fundación Reina Mercedes para la Investigación SanitariaA1 Solicitud de patentes con informe sobre el estado de la técnic
- …