51,820 research outputs found

    A high-precision liDAR-based method for surveying and classifying coastal notches

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    Formation of notches is an important process in the erosion of seaside cliffs. Monitoring of coastal notch erosion rate and processes has become a prime research focus for many coastal geomorphologists. Observation of notch erosion rate considers a number of characteristics, including cliff collapse risk, distinction of historical sea levels, and recognition of ongoing erosional mechanisms. This study presents new approaches for surveying and classifying marine notches based on a high-precision light detection and ranging (LiDAR)-based experiment performed on a small region of a coastal cliff in southern Portugal. A terrestrial LiDAR scanner was used to measure geometrical parameters and surface roughness of selected notches, enabling their classification according to shape and origin. The implemented methodology proved to be a highly effective tool for providing an unbiased analysis of marine morphodynamic processes acting on the seaside cliffs. In the analyzed population of voids carved into Miocene calcarenites in a coastal cliff section, two types of notch morphology were distinguished, namely U-shaped and V-shaped. The method presented here provides valuable data for landscape evaluation, sea-level changes, and any other types of analyses that rely on the accurate interpretation of cliff morphological features.National Science Centre [UMO-2015/17/D/ST10/02191

    Detection of Airborne Allegen Phl p5 and its Correlation with Poaceae Pollen Counts in Evora, South Portugal

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    Introduction: Airborne pollen of grasses (Poaceae family) is the main aeroallergen in many european countries, namely in Portugal. Their pollen can be found in the air all over the year but higher concentrations are reached in springtime (Mars to June). Exposure to its allergens is deduced from pollen counts of environmental air samples. The aim of this study is to analyse the relationship between these pollen counts and the concentration of allergen Phl p5, through a new sampling technology, developed under an European LIFE/Environment program. Methods: Airborne pollen were monitored with a Hirst-type sampler (Burkard 7-day pollen trap). Simultaneously, daily air samples were collected with a high volumetric cyclone-type sampler (Coriolis ® d by Bertin Technologies, France) and Phl p5 concentration was measured from liquid samples through a “sandwich” ELISA with a kit from Indoor Biotecnologies®. Both samplers were placed side by side on a meteorological platform at the town center of Evora, 17 m above ground level and 320 m above sea level. ELISA analysis were performed on samples collected between the 2th of Mars and 12 th of June 2007, which includes the main pollen season for grasses and Phleum pratense. Results: Pollen counts from both samplers were not correlated, with absolute values higher in Burkard sampler. Phl p5 concentration in air samples followed the same features of cyclone-type sampler but it was quantified even when pollen counts were low or null, particularly in the beginning of pollen season. Several peaks of allergen were detected at the end of March and on the 1st - 2nd of April. Conclusions: Coriolis ® d cyclone sampler allowed the quantification of Poaceae either by pollen counts and by an ELISA assay but further analysis on the efficiency of sampling and its relationship with biophysical parameters are needed. These results suggest that pollen counts may not reflect exposure to Poaceae pollen. Immuno-sampling could provide a better understanding of exposure to airborne pollen allergens, namely out of the pollen season

    Probabilistic sampling of finite renewal processes

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    Consider a finite renewal process in the sense that interrenewal times are positive i.i.d. variables and the total number of renewals is a random variable, independent of interrenewal times. A finite point process can be obtained by probabilistic sampling of the finite renewal process, where each renewal is sampled with a fixed probability and independently of other renewals. The problem addressed in this work concerns statistical inference of the original distributions of the total number of renewals and interrenewal times from a sample of i.i.d. finite point processes obtained by sampling finite renewal processes. This problem is motivated by traffic measurements in the Internet in order to characterize flows of packets (which can be seen as finite renewal processes) and where the use of packet sampling is becoming prevalent due to increasing link speeds and limited storage and processing capacities.Comment: Published in at http://dx.doi.org/10.3150/10-BEJ321 the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

    Teaching and play. Early childhood teachers perspectives

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    Poster apresentado na 27ª Conferencia da EECERA, realizada em Bolonha, Itália, a 30 de Agosto de 2017.The purpose of the present on-going study is to investigate early childhood teachers’ perspectives about the use of play for promoting learning and development. This research is a result of a study, made within a community of practice for research and curriculum development, involving teachers, cooperating teachers and students of a Portuguese School of Education. The common interest is the focus on Imagination and Play in Education. The Portuguese curriculum guidelines for early childhood Education sustains that play should be valued for learning and development (OCEPE, 2016). Nevertheless many students observations of early childhood contexts relate that teaching is mainly centred in activities for the all group of children, teacher directed, so perhaps the role of play has been misunderstood. The early childhood teacher's pedagogical role in play has been re-thought in the light of new theoretical understandings of play (Rogers & Evans, 2008, Fleer, 2010, Bruce, 2011). The study includes early childhood teachers in different stages of professional development. A survey through on-line questionnaire was made to 100 participants. Personal anonymity was central to gain reliable information. Discussion will focus on these issues: - early childhood teachers’ conceptions about play, - relation between play and learning, - role of play in planning and curriculum development, - evidence of child learning through play in evaluation. Results will be discussed in the community of practice and impact on curriculum development for those involved should be expected.N/
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