239 research outputs found
Estudos sobre pastas de ânforas de fornos do Vale do Tejo e do Vale do Sado : análises macro e microscópicas
Jornadas realizadas em Conimbriga de 13-14 de Outubro de 198
Cerâmicas da necrópole da Idade do Bronze de Alfarrobeira (Silves) : análises macro e microscópicas
Neste trabalho estudam-se três fragmentos de recipientes cerâmicos, recolhidos no interior de duas cistas da necrópole, do Bronze do Sudoeste, de Alfarrobeira (Silves). Os trabalhos efectuados sobre tais fragmentos constaram: da observação macroscópica, na superfície de fractura; da observação em lâmina delgada, ao microscópio petrográfico.
São, até ao presente, escassos os trabalhos realizados, no nosso país, sobre análises de pastas cerâmicas recorrendo ao microscópio petrográfico. Parece-nos, no entanto, que se trata de método particularmente aplicável ao estudo das cerâmicas pré-históricas. Estas, com efeito, ao contrário das cerâmicas mais recentes, em geral de pastas mais finas e depuradas, encerram grande quantidade de elementos não plásticos, frequentemente de mineralogia variada. Estão, pois, reunidas as condições para que, através do estudo petrográfico, se possam constituir agrupamentos de pastas, de acordo com a respectiva mineralogia para, numa fase ulterior, tendo presente as características petrográficas dos afloramentos geológicos da região mais ou menos adjacente, se possam definir prováveis zonas de abastecimento da respectiva matéria-prima ou outras informações a que o estudo comparado dos diferentes tipos de pastas devam conduzir.
Foi tendo em consideração tais preocupações que se decidiu pela realização do presente trabalho
Airborne PM Impact on Health, Overview of Variables, and Key Factors to Decision Making in Air Quality
This chapter intends to contribute to the understanding of the multiple aspects related to particulate matter (PM) in an air urban environment, in particular, regarding its impact on human health. A general overview of variables and key factors is presented to identify, relate, and understand the diverse and multidisciplinary variables that contribute to PM concentration in urban environments associated with health impacts. This relation is difficult to quantify, given the numerous variables that are interlinked due to the multidisciplinary aspects involved. Our aim is to identify the main multidisciplinary aspects, namely, meteorology, urban geometry, buildings, roads and footpaths, road traffic, industries, air concentration measurements, and health. The main strategic aspects for decision making related to airborne PM impact on health are also discussed
Assessment of four portuguese wheat landrace diversity to cope with global warming
Original ResearchWheat is a dietary staple consumed worldwide strongly responsible for proteins
and carbohydrate population intake. However, wheat production and quality will
scarcely fulfill forward demands, which are compounded by high-temperature (HT)
events as heatwaves, increasingly common in Portugal. Thus, landraces assume
crucial importance as potential reservoirs of useful traits for wheat breeding and
may be pre-adapted to extreme environmental conditions. This work evaluates four
Portuguese landrace yield and grain composition through attenuated total reflection
Fourier transform infrared (ATR-FTIR) spectroscopy, particularly protein content, and
their responses to HT treatment mimicking a heatwave. Landraces showed distinct yield
traits, especially plant height and first spike grain number, and a similar pattern in FTIR
spectra, although revealing differences in grain components’ proportions. Comparison
between spectra band intensity indicates that Ardito has the highest protein-related
peaks, contrary to Magueija, which appears to be the landrace with higher lipid content.
In plants submitted to 1 week of HT treatment 10 days after anthesis, the first spike grain
size and weight were markedly reduced in all landraces. Additionally, it was observed
that a general increase in grain protein content in the four landraces, being the increment
observed in Ardito and Grécia, is statistically significant. The comparative assessment
of control and HT average FTIR spectra denoted also the occurrence of alterations
in grain polysaccharide composition. An integrated assessment of the evaluations
performed revealed that Ardito and Magueija landraces presented diverse yield-related
characteristics and distinct responses to cope with HT. In fact, the former landrace
revealed considerable grain yield diminution along with an increase in grain protein
proportion after HT, while the latter showed a significant increase in spikes and grain
number, with grain quality detriment. These results reinforce the relevance of scrutinizing
old genotype diversity seeking for useful characteristics, particularly considering HT
impact on grain production and qualityinfo:eu-repo/semantics/publishedVersio
A comparison of presmoothing methods in the estimation of transition probabilities
One major goal in clinical applications of multi-state models is the estimation of transition probabilities. In a recent paper, landmark estimators were proposed to estimate these quantities, and their superiority with respect to the competing estimators has been proved in situations in which the Markov condition is violated.
The idea behind their estimator is to use a procedure based on (differences between) Kaplan-Meier estimators derived from a subset of the data consisting of all subjects observed to be in the given state at the given time. Because of this, the computation of their estimator is performed in small sample sizes providing large standard errors in some circumstances. A valid approach is to consider a modification of the landmark estimator based on presmoothing. In this two presmoothing methods are compared. Simulation results indicate that both methods may be much more efficient than the unsmoothed estimator. Real data illustration is included.Portuguese Funds through FCT - “Fundação para a Ciência e
a Tecnologia
Methods for checking the markov condition in multi-state survival data
The inference in multi-state models is traditionally performed under a Markov assumption. This assumption claims that given the present state, the future evolution of the process is independent of the states previously visited and the transition times among them. Usually, this assumption is checked including covariates depending on the history. However, since the landmark methods of the transition probabilities proposed by de Uña-Alvarez and Meira-Machado (2015), and by Putter and Spitoni (2018) are free of the Markov assumption, they can also be used to introduce such tests (at least in the scope of the progressive multi-state models) by measuring their discrepancy to Markovian estimators. In this paper, we introduce two local tests for the Markov assumption and compare them with the usual approach based on local future-past association through
simulations. An application to a clinical trial on colon cancer is included.This research was financed by Portuguese Funds
through FCT - “Fundaçãao para a Ciência e a Tecnologia”, within the research grants PTDC/MAT-STA/28248/2017 and PD/BD/142887/201
Estimation of the transition probabilities condition on repeated measures in multi-state models
The topic of joint modeling of longitudinal and survival data has received remarkable attention in recent years. In cancer studies for example, these models can be used to assess the impact that a longitudinal marker has on the time to death or relapse. Analyzes of such studies, in which individuals may experience several events, can be successfully performed by multi-state models. The goal of this work is to introduce feasible estimation methods for the transition probabilities conditionally on covariates observed with repeated measures
through the use of the landmark methodology and the adaptation of existing methods for joint modeling of longitudinal and survival data. Results of the simulation studies con rm the superiority of the proposed estimator when compared to methods that do not take in consideration the effect of the covariate on the estimated transition probabilities or do not assume all the existence of repeated measures (Breslow estimator)
Partial replication in the database state machine
This paper investigates the use of partial replication in the Database State Machine approach introduced ear- lier for fully replicated databases. It builds on the or- der and atomicity properties of group communication primitives to achieve strong consistency and proposes two new abstractions: Resilient Atomic Commit and Fast Atomic Broadcast. Even with atomic broadcast, partial replication re- quires a termination protocol such as atomic commit to ensure transaction atomicity. With Resilient Atomic Commit our termination protocol allows the commit of a transaction despite the failure of some of the par- ticipants. Preliminary performance studies suggest that the additional cost of supporting partial replica- tion can be mitigated through the use of Fast Atomic Broadcast
Overweight, central obesity and abdominal obesity in middle-age adults in an inland region of Northeast Portuguese: a pilot study
The prevalence of central and abdominal obesity has been increasing over last decades in developed
countries. As well, the high prevalence of obesity in Portugal has already been documented, however it
is need to better understand the prevalence in each region of the country. Thus, the aim of this study was to evaluate the prevalence of the overweight, central obesity and abdominal obesity in middle-age in an inland
region of Northeast Portuguese.
Methods: A descriptive and cross-sectional community sample was collected from two Portuguese primary
health care centres between January 2019 and December 2020. A total of 673 individuals aged 40–65 years
were included for analysis, among which 400 women (53.34 ± 7.33 years) and 273 men (53.01 ± 7.20 years).
Prevalence of overweight, central obesity and abdominal obesity were analysed across sexes using body mass
index and waist circumference. Categorical variables were expressed by counts and proportions with a 95%
confidence interval (CI). Chi-squared test or fisher exact test were applied whenever appropriate. To compare
continuous variables independent sample t-test or Mann-Whitney U test were used. Statistical significance
was set at p < 0.05.
Results: The prevalence of overweight, central obesity and abdominal obesity in this cross-sectorial sample
were 41.01%, 30.61% and 67.20%, respectively. Significant differences among men and women were found
for abdominal obesity (p < 0.001). Women presented a higher prevalence of abdominal obesity (67.5%). Men
have higher prevalence of overweight (48.72%) and central obesity (31.14%) than women (35.75% and 30.25%,
respectively). However, differences were not statistically significant between sexes for overweight and central
obesity (p ≥ 0.05).
Conclusion: A higher prevalence of overweight, central obesity and abdominal obesity was reported for middle-
age adults in this inland region of Northeast Portuguese. Our data suggest a higher prevalence of all three
clinical conditions, comparing previous Portuguese epidemiological studies. Current report provides the study
pilot for a more detailed epidemiological research. Also, preliminary findings emphasise the importance of
implementing physical activity programmes and promoting healthy lifestyles to tackling this growing public
health problem.Project “GreenHealth – Digital strategies in biological assets to improve well-being and promote green health” (Norte-01-0145-FEDER-000042), supported by North Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF).info:eu-repo/semantics/publishedVersio
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