National case study: Portugal

info:eu-repo/semantics/publishedVersio

Regularity of maximal functions on Hardy–Sobolev spaces

We prove that maximal operators of convolution type associated to smooth kernels are bounded in the homogeneous Hardy–Sobolev spaces H1,p(Rd) when p > d/(d + 1). This range of exponents is sharp. As a by-product of the proof, we obtain similar results for the local Hardy–Sobolev spaces h1,p(Rd) in the same range of exponents

Deep Learning Multidimensional Projections

Dimensionality reduction methods, also known as projections, are frequently used for exploring multidimensional data in machine learning, data science, and information visualization. Among these, t-SNE and its variants have become very popular for their ability to visually separate distinct data clusters. However, such methods are computationally expensive for large datasets, suffer from stability problems, and cannot directly handle out-of-sample data. We propose a learning approach to construct such projections. We train a deep neural network based on a collection of samples from a given data universe, and their corresponding projections, and next use the network to infer projections of data from the same, or similar, universes. Our approach generates projections with similar characteristics as the learned ones, is computationally two to three orders of magnitude faster than SNE-class methods, has no complex-to-set user parameters, handles out-of-sample data in a stable manner, and can be used to learn any projection technique. We demonstrate our proposal on several real-world high dimensional datasets from machine learning

Do environmental, social and governance practices affect portfolio returns? Evidence from the US stock market from 2002 to 2020

Purpose: This paper aims to investigate whether environmental, social and governance (ESG) practices influence stock returns in the US stock market, looking at the period from 2002 to 2020. Design/methodology/approach: The authors quasi-replicate two reference articles that found that socially responsible funds used to underperform, but that this underperformance tendency has disappeared in more recent periods. Findings: Using US data, the authors show that independent of the ESG database used, portfolios of neutral stocks present consistently higher systematic risk (beta) than ESG portfolios, although this difference decreases over time. This may be due to the significant increase in demand for ESG portfolios in the past decade, and their consequent price inflation and increase in volatility. However, concerning risk-adjusted returns and contrary to the authors’ reference literature, the results are highly dependent on the rating provider used, and neither support underperformance nor indicate a tendency over time. These inconsistent results suggest that the “ESG label” is not a determinant of portfolio performance. Research limitations/implications: If ESG ratings are a legitim benchmark for sustainability, then the costs of going sustainable in stock portfolios might be marginal for fund managers. Originality/value: Two different ESG-rating agencies, Morgan Stanley Capital International (MSCI) and Thomson Reuters, are used to identify sustainable stocks. Different from the literature, the authors selected stocks for their portfolios stochastically following a uniform probability distribution, thus avoiding fund manager bias

Giardia sp. and Cryptosporidium sp. in Iberian Wolf

ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗA subsample consisting of fifty fecal samples from wild Iberian Wolf (Canis lupus signatus), from the northwest of Spain were collected in the field. The samples were analyzed for cysts of Giardia sp. and oocysts of Cryptosporidium sp. using a direct immunofluorescence antibody test (IFA). Giardia sp. and Cryptosporidium sp. were found in 20.0 % of the samples examined. Simple infections were more frequent (90.0 %) with seven (14.0 %) positive for Giardia sp. and two (4.0 %) positive for Cryptosporidium sp. To the authors’ knowledge, this is the first report of occurrence of Cryptosporidium sp. in Iberian Wolf

Variation in allele frequencies at the bg112 locus reveals unequal inheritance of nuclei in a dikaryotic isolate of the fungus Rhizophagus irregularis.

The genetic state of the arbuscular mycorrhizal fungus species Rhizophagus irregularis differs among isolates, including both homokaryotic and dikaryotic isolates. Via the production of multi-nucleate axexual spores, siblings of dikaryotic isolates may inherit unequal frequencies of nucleotypes. Using bg112, a microsatellite marker, previous studies revealed that lines deriving from single spores of the dikaryotic R. irregularis isolate C3 differed in their proportions of different alleles. A genomic study of single nuclei of R. irregularis, however, suggested that this marker was a multi-copy locus and that therefore it was inappropriate to study the inheritance of nuclei in dikaryotic isolates. In this study, we first analysed whole genome data of several R. irregularis isolates and demonstrated that bg112 is indeed a single copy locus in these genomes. Thus, the bg112 locus is a suitable marker to study the relative frequency of nucleotypes in R. irregularis. Second, by using amplicon sequencing, we confirmed the existence of one allele of bg112 in two homokaryotic isolates (DAOM197198 and C2) and two alleles in the dikaryotic isolate (C3). Finally, we found that the relative proportions of two bg112 alleles differed significantly among dikaryotic single-spore lines derived from isolate C3, indicating that genetically different nucleotypes are inherited unequally in this dikaryotic R. irregularis isolate

Neuroanatomy of the crocodylomorph Portugalosuchus azenhae from the late cretaceous of Portugal

We present the first detailed braincase anatomical description and neuroanatomical study of Portugalosuchus azenhae, from the Cenomanian (Late Cretaceous) of Portugal. This eusuchian crocodylomorph was originally described as a putative Crocodylia and one of the oldest representatives of this clade; however, its phylogenetic position remains controversial. Based on new data obtained from high resolution Computed Tomography images (by micro-CT scan), this study aims to improve the original description of this taxon and also update the scarce neuroanatomical knowledge of Eusuchia and Crocodylia from this time interval, a key period to understand the origin and evolution of these clades. The resulting three-dimensional models from the CT data allowed a detailed description of its well-preserved neurocranium and internal cavities. Therefore, it was possible to reconstruct the cavities of the olfactory region, nasopharyngeal ducts, brain, nerves, carotid arteries, blood vessels, paratympanic sinus system and inner ear, which allowed to estimate some neurosensorial capabilities. By comparison with other crocodylomorphs, these analyses showed that Portugalosuchus, back in the Cenomanian, already displayed an olfactive acuity, sight, hearing and cognitive skills within the range of that observed in other basal eusuchians and crocodylians, including extant species. In addition, and in order to test its disputed phylogenetic position, these new anatomical data, which helped to correct and complete some of the original observations, were included in one of the most recent morphology-based phylogenies. The position of Portugalosuchus differs slightly from the original publication since it is now located as a "thoracosaurid" within Gavialoidea, but still as a crocodylian. Despite all this, to better contrast these results, additional phylogenetic analyses including this new morphological character coding together with DNA data should be performed