2,241 research outputs found
Coincident and Leading Indicators for the Euro Area: A Frequency Band Approach
In the context of a common monetary policy, tracking euro area economic developments becomes essential. The aim of this paper is to build monthly coincident and leading composite indicators for the euro area business cycle. However, instead of looking at the overall comovement between the variables as it is standard in the literature, we show how one can resort to both time and frequency domain analysis to achieve additional insight about their relationship. We find that, in general, the lead/lag properties of economic indicators depend on the cycles periodicity. Following a frequency band approach, we take advantage of this in the construction of the coincident and leading composite indicators. The resulting indicators are analysed and a comparison with other composite indicators proposed in the literature is made.
International comovement of stock market returns: a wavelet analysis
The assessment of the comovement among international stock markets is of key interest, for example, for the international portfolio diversification literature. In this paper, we re-examine such comovement by resorting to a novel approach, wavelet analysis. Wavelet analysis allows one to measure the comovement in the time-frequency space. In this way, one can characterize how international stock returns relate in the time and frequency domains simultaneously, which allows one to provide a richer analysis of the comovement. We focus on Germany, Japan, UK and US and the analysis is done at both the aggregate and sectoral levels.
Effect of cooking on arsenic concentration in rice
This study assessed the effect of rinsing and boiling on total content of As (tAs) and of its inorganic and organic forms in different types of rice (polished and brown) from Spain and Ecuador. Rice was subjected to five different treatments. The results showed that the treatment consisting of three grain rinsing cycles followed by boiling in excess water showed a significant decrease in tAs content compared with raw rice. Regarding As species, it is worth noting that the different treatments significantly reduced the content of the most toxic forms of As. The estimated lifetime health risks indicate that pre-rinsing alone can reduce the risk by 50%, while combining it with discarding excess water can reduce the risk by 83%; therefore, the latter would be the preferable method.Universidad de las Fuerzas Armadas-ESPE through Project 2015- PIC-017, Xunta de Galicia-ConsellerĂa de EducaciĂłn, Universidades e FormaciĂłn Profesional, Plan Galego IDT, Consolidation of competitive research groups (ref. ED31C2018/12), and Cross-Research in Environmental Technologies (CRETUS, AGRUP2015/02, ref. 2018-PG100). XLOP is grateful for the financial support from the Proyecto PROMETEO (SENESCYT Ecuador).info:eu-repo/semantics/publishedVersio
Hypothetical answers to continuous queries over data streams
Continuous queries over data streams may suffer from blocking operations
and/or unbound wait, which may delay answers until some relevant input arrives
through the data stream. These delays may turn answers, when they arrive,
obsolete to users who sometimes have to make decisions with no help whatsoever.
Therefore, it can be useful to provide hypothetical answers - "given the
current information, it is possible that X will become true at time t" -
instead of no information at all.
In this paper we present a semantics for queries and corresponding answers
that covers such hypothetical answers, together with an online algorithm for
updating the set of facts that are consistent with the currently available
information
Ărvores de Risco
Ărvores de Risco
Para além da sua beleza e formas graciosas, a årvore
em meio urbano desempenha uma série de funçÔes
benéficas. Deve haver uma preocupação em assegurar
a vitalidade e a segurança das årvores em meio urbano,
sobretudo nas ĂĄreas de domĂnio pĂșblico mas tambĂ©m
nas ĂĄreas de uso privado. Neste sentido Ă© importante
o reconhecimento das denominadas âĂĄrvores de riscoâ.
Uma ĂĄrvore Ă© considerada de risco se possui uma
estrutura debilitada aliada ao facto de poder vir a atingir
pessoas ou bens em caso de queda total ou parcial
(Dujesiefken et al. 2005; Smiley et al. 2007)
Organochlorine Compounds in Beached Plastics and Marine Organisms
Here we compare bioaccumulation factors in marine organisms to partition ratios in marine debris for dichlorodiphenyltrichloroethane and polychlorinated biphenyls. Both organochlorines are synthetic persistent organic pollutants emitted into the environment since the beginning of the last century in approximately equal amounts. Their vast use and dispersion have resulted in approximately similar median concentrations of the two organochlorines in some pelagic organisms, namely in the liver and muscle tissue of fish. Molluscs, on the other hand, show higher median uptake of PCBs (median = 2.34 ng/g) than of DDTs (median = 1.70 ng/g), probably reflecting more localized conditions. We found that the bioaccumulation factors can be several orders of magnitude higher than the partition ratios. For instance, the median concentrations of organochlorines in the different matrices of fish, birds, and mammals are between one to four orders of magnitude higher than those found in marine debris, when lipid-normalized; or up to two orders of magnitude when measured as wet-weight. But, in molluscs, bioaccumulation/partition equals unity, which agrees with previous studies using passive samplers. Future research should focus on reducing sources of uncertainty by 1) homogenization of chemical procedures; 2) better assessment of chemical partition equilibrium between water and polymers in environmental conditions; 3) use of (multi)polymer passive samplers better aimed at mimicking uptake of specific living tissues.info:eu-repo/semantics/publishedVersio
Forecasting Euro Area Aggregates with Bayesian VAR and VECM Models
This paper focuses on Bayesian Vector Auto-Regressive (BVAR) models for the euro area. A modified hyperparameterization scheme based on the Minnesota prior that takes into account the economic nature of the variables in the model is used. The merits of incorporating long-run relationships are also discussed. Alternative methods to estimate eventual cointegrating relations in the variables are considered, and the problem of choice of appropriate prior distributions for BVAR with Error Correction Mechanism (BECM) models is addressed. Results show that using a flat prior on factor loadings can seriously endanger the forecasting performance of BECM models. Overall, the BVAR model in levels outperforms all other models across variables and forecasting horizons. This is in contrast with other empirical studies where some gains could be obtained when incorporating long-run relationships in the model.
Automatic extraction of quotes and topics from news feeds
The explosive growth in information production poses increasing challenges to consumers, confronted with problems often described as information overow. We present verbatim, a software system that can be used as a personal information butler to help structure and lter information. We address a small part of the information landscape, namely quotes extraction from portuguese news. This problem includes several challenges, specically in the areas of information extraction and topic distillation. We present a full description of the problems and our adopted approach. verbatim is available online at http://irlab.fe.up.pt/p/verbatim
The Montado agroforestry system microclimatic specificity in the context of global change
The effects of oak trees on microclimatic
parameters in Quercus rotundifolia Lam. woodland in the
Alentejo, Southern Portugal, are reported. Results show that
oak tree create a marked differentiation in the grass matrix,
between open and undercanopy areas. Compared to open
areas, it presents lower soil moisture beneath the oak canopy,
lower soil temperatures and lower photosynthetically active
radiation (PAR). Soil temperatures outside trees canopy
were generally higher than undercanopy areas, reaching
twice its values during the winter. The decrease of soil water
content is more rapid in areas outside the trees canopy
action, but the replenishment starts early and is faster in
those areas. PAR intercepted by tree canopy is greater than
60%, and affects dramatically herbaceous production.
Different climatic conditions due to the presence of the tree,
associated with greater variability in chemistry environment
undercanopy, if combined with the IPCC forecasts for
Mediterranean region, pose new challenges in the
management of the montado areas
Phenotypical and molecular characterization of portuguese usher syndrome patients
Trabalho final de mestrado integrado em Medicina (Oftalmologia), apresentado Ă Faculdade de Medicina da Universidade de Coimbra.Introduction: Usher syndrome (USH) is a recessive inherited disease characterized by
sensorineural hearing loss (HL), visual loss due to retinitis pigmentosa (RP) and, in some
cases, vestibular dysfunction. This syndrome is the most common cause that affects those two
major senses, vision and hearing and encompasses three clinical sub-types (USH1, USH2 and
USH3) as well as some additional atypical forms.
Usher type II is the most common clinical form, in all published series; since the USH2A gene
is the most commonly mutated gene, our aim is to characterize from a molecular and
phenotypical standpoint, a cohort of 48 portuguese Usher patients, determine if they carry
mutations in USH2A gene and establish potential genotype-phenotype correlations.
Methods: Forty eight affected individuals were characterized from a molecular standpoint,
and those carrying USH2A underwent complete phenotypical ophthalmological examination
including, fundus photography, fundus autofluorescence (FAF), full-field ERG, multifocal
electrophysiology (MF ERG), and ENT assessment.
Results: Disease-causing mutations in the USH2A gene were identified in 15 patients, of ten
independent families. Consanguinity could be documented in 40% of families. Fourteen
different USH2A mutations were detected (6 missense, 14 nonsense, 1 small rearrangement, 2
large gene rearrangements and 6 splice-site mutations), eight patients were homozygous and
7, either compound heterozygous or heterozygous. Mutations in the DFNB31 gene (USH2D)
were also identified in heterozygosity in two siblings. Five novel mutations were identified:
three intragenic deletions encompassing several exons c. 7121_9258del, USH2A exon 3-exon34 del, USH2A exon 39 â exon 47 del, a nonsense mutation, c.7932G>A, and a deep
intronic homozygous mutation c.4988-19T>G, all of them showing potential to interfere with
protein function.
Concerning to ophthalmological phenotype, nyctalopia was consistently the presenting
complaint in 100% of patients. Best Corrected Visual Acuity (BCVA) varied from 0.1 and
0.8, at the last evaluation. Fundus appearance was compatible with RP in all probands varying
from isolated peripheral bone spicules, patchy retinal pigment epithelium (RPE) areas of
atrophy, thin vessels and normal discs (20%), to pale discs, near confluent peripheral bone
spicules, extensive atrophic RPE changes and thin vessels (47%) to typical RP with preserved
macula (33%). The full field ERG disclosed, in the majority, an unrecordable response (87%)
and two probands had a severely attenuated, yet recordable, response (13%). Multifocal ERG
analysis showed decreased central peak (100% cohort cases lower than 100microV), and
occasional drift of the peak of maximal response to an extrafoveal hexagone. FAF revealed
that 77% presented a typical ring of hyperautofluorescence while the remainder disclosed
patchy hypoautofluorescence. Conclusion: We characterized from both clinical and genetic standpoints, the first series of
Portuguese patients with type II Usher syndrome. Molecular characterization is essencial to
improve early diagnosis of USH and better understand the molecular pathomechanism so that
is possible to develop treatment strategies to stop or revert the degenerative process of the
retina, in a near future.Introdução: A sĂndroma de Usher Ă© uma condição com transmissĂŁo autossĂłmica recessiva
caracterizada por surdez neurossensorial, perda de visĂŁo por Retinopatia Pigmentar e, em
alguns casos, disfunção vestibular. Esta sĂndroma Ă© a causa mais comum da afeção destes dois
sentidos, visĂŁo e audição, englobando trĂȘs sub-tipos clĂnicos (USH1, USH2 e USH3) bem
como formas atĂpicas adicionais.
USH2 Ă© o sub-tipo clinico mais comum, em todas as series publicadas; sendo USH2A o gene
mais comummente mutado, o nosso objectivo Ă© caracterizar de um ponto de vista molecular e
fenotĂpico 48 portugueses com SĂndrome de Usher, determinar se sĂŁo portadores de mutaçÔes
no gene USH2A e estabelecer potenciais correlaçÔes genótipo-fenótipo.
MĂ©todos: Quarenta e oito indivĂduos com a sĂndroma da Usher foram caracterizados do
ponto de vista molecular, submetendo-se os portadores de USH2A a um exame oftalmolĂłgico
fenotĂpico completo, fundoscopia, auto-fluorescĂȘncia da retina, eletrorretinograma full field,
eletrorretinograma multifocal e avaliação otorrinolaringológica.
Resultados: MutaçÔes patológicas no gene USH2A foram identificadas em 15 pacientes, de
10 famĂlias nĂŁo-relacionadas. Em 40% das famĂlias foi possĂvel documentar consanguinidade.
Detetaram-se 14 mutaçÔes diferentes no gene USH2A (6 missense, 14 nonsense, 1 pequeno
rearranjo, 2 grandes rearranjos e 6 mutaçÔes de splicing; em 8 doentes as alteraçÔes genéticas
eram homozigĂłticas e em 7, heterozigĂłticas compostas ou em heterozigotia. Foram
igualmente identificadas mutaçÔes no gene DFNB31 em heterozigotia, em 2 irmãos.
Foram identificadas cinco novas mutaçÔes: trĂȘs delecçÔes intragĂ©nicas envolvendo vĂĄrios
exĂ”es c. 7121_9258del, USH2A exon 3- exon 34 del, USH2A exon 39 â exon 47 del, uma mutação nonsense c.7932G>A, e uma mutação homozigĂłtica deep intronic c.4988-19T>G,
todas mostrando potencial interferĂȘncia com a função proteica.
No que diz respeito ao fenĂłtipo oftalmolĂłgico, a nictalopia foi, de forma consistente, o sinal
de apresentação em 100% dos doentes. A melhor acuidade visual corrigida variou entre 0.1 a
0.8, na Ășltima avaliação. Os aspetos fundoscĂłpicos eram compatĂveis com Retinopatia
Pigmentar em todos os doentes, variando de espĂculas Ăłsseas perifĂ©ricas isoladas, ĂĄreas
dispersas de atrofia do epitélio pigmentar da retina, vasos de calibre reduzido e disco óptico
normal (20%), disco pĂĄlido, espĂculas Ăłsseas confluentes perifĂ©ricas, atrofia de ĂĄreas extensas
do epitélio pigmentar da retina e redução importante do calibre vascular (47%) a um padrão
tĂpico de RP com preservação da mĂĄcula (33%). No ERG, a maioria dos doentes apresentou
uma resposta indetetĂĄvel (87%), com somente 2 doentes a revelar uma resposta
profundamente atenuada mas detetåvel (13%). O MfERG evidenciou uma redução da
amplitude do pico central (100% dos casos inferior a 100microV), e ocasionais picos de
resposta maxima detetados fora do hexagono extra-foveal. A auto-fluorescĂȘncia mostrou em
77% dos casos o tĂpico anel de hiperautofluorescĂȘncia macular enquanto nos restantes se
observou um padrĂŁo mosqueado de hipoautofluorescĂȘncia.
ConclusĂŁo: CaracterizĂĄmos do ponto de vista clĂnico e genĂ©tico, a primeira sĂ©rie de doentes
portugueses com SĂndroma de Usher tipo 2. A caracterização molecular Ă© essencial para
aprimorar o diagnĂłstico precoce desta sĂndroma e melhor conhecer os mecanismos
patogĂ©nicos de forma a permitir o desenvolvimento de estratĂ©gias terapĂȘuticas para frenar ou
reverter este processo degenerativo da retina, num futuro prĂłximo
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