Showing papers by "INESC-ID published in 2022"

A novel <i>Chaphamaparvovirus</i> is the etiological agent of hepatitis outbreaks in pheasants ( <i>Phasianus colchicus)</i> characterized by high mortality

Abstract: In the present study, we report the occurrence of several outbreaks of hepatitis in flocks of young pheasants in France, between 2017 and 2021. The disease was characterized by prostration, apathy and a median cumulative mortality of 12%, with the birds presenting multifocal to coalescing necrotizing hepatitis on necropsy. Severe extensive areas of degeneration and necrosis were observed in the liver, with degenerative hepatocytes presenting large amphophilic to acidophilic intranuclear inclusion bodies. Transmission electron microscopy examination of liver samples showed the presence of parvovirus-like virions of 21-24 nm, a finding already reported decades ago. Further investigations by Next Generation Sequencing and PCR revealed the complete genome of a novel species of parvovirus, here designated Phasianus chaphamaparvovirus 1 (PhChPV-1), that belongs to the new genus Chaphamaparvovirus in the Hamaparvovirinae subfamily. In situ hybridization and real-time PCR confirmed the etiology of the outbreaks, demonstrating the viral genome in the lesions. The findings establish the etiology of a pathology first described in pheasants 50 years ago and pave the way for a targeted protection strategy.

LINES: muLtImodal traNsportation rEsilience analySis

Abstract: This study aims to contribute to more sustainable mobility solutions by proposing robust and actionable methods to assess the resilience of a multimodal transport system. Resilience is seen in a dynamic lean setting, looking at aspects in the network topology and user’s flow and demand throughout a parameterizable period. We hypothesize that this network’s appropriate multi-layered and traffic-sensitive modeling can promote the integrated analysis of different transport modes and support an improved resilience analysis. We operationalize the lean resilience conceptual construct with the proposed muLtImodal traNsportation rEsilience aSsessment (LINES) methodological process. Using the city of Lisbon as a study case, we illustrate the relevance of the proposed methodology to detect actionable vulnerabilities in the bus–tram–subway network.

Comprehending Algorithmic Design

Abstract: Algorithmic Design (AD) allows for the creation of form through algorithms. Its inherent flexibility encourages the exploration of a wider design space, the automation of design tasks and design optimization, considerably reducing project costs and environmental impact. Nevertheless, current AD uses representation methods that radically differ from those used in architectural practice, creating a mismatch that is further exacerbated by the inadequacy of current programming environments. This creates a barrier to the adoption of AD, demotivating architects from its use. We propose to address this problem by coupling AD with adequate representation methods for designing complex architectural projects. To this end, we explore three essential concepts: storytelling, interactive evaluation, and reactivity. These concepts can be both complementary and mutually exclusive, which means compromises must be made to accommodate them all. We outline a strategy for their integration with the AD workflow, highlighting the advantages and disadvantages of each one, and pinpointing their intersection. Finally, we evaluate the proposed strategy using computational notebooks as programming environments.

Covariant formulation of relativistic mechanics

Abstract: Accretion disks surrounding compact objects, and other environmental factors, deviate satellites from geodetic motion. Unfortunately, setting up the equations of motion for such relativistic trajectories is not as simple as in Newtonian mechanics. The principle of general (or Lorentz) covariance and the mass-shell constraint make it difficult to parametrize physically adequate 4-forces. Here, we propose a solution to this old problem. We apply our framework to several conservative and dissipative forces. In particular, we propose covariant formulations for Hooke's law and the constant force, and compute the drag due to gravitational and hard-sphere collisions in dust, gas and radiation media. We recover and covariantly extend known forces such as Epstein drag, Chandrasekhar's dynamical friction and Poynting-Robertson drag. Variable-mass effects are also considered, namely Hoyle-Lyttleton accretion and the variable-mass rocket. We conclude with two applications: 1. The free-falling spring. We find that Hooke's law corrects the deviation equation by an effective Anti-de Sitter tidal force; 2. Black hole infall with drag. We numerically compute some trajectories on a Schwarzschild background supporting a dust-like accretion disk.

A survey of the extraction and applications of causal relations

Abstract: Abstract Causationin written natural language can express a strong relationship between events and facts. Causation in the written form can be referred to as a causal relation where a cause event entails the occurrence of an effect event. A cause and effect relationship is stronger than a correlation between events, and therefore aggregated causal relations extracted from large corpora can be used in numerous applications such as question-answering and summarisation to produce superior results than traditional approaches. Techniques like logical consequence allow causal relations to be used in niche practical applications such as event prediction which is useful for diverse domains such as security and finance. Until recently, the use of causal relations was a relatively unpopular technique because the causal relation extraction techniques were problematic, and the relations returned were incomplete, error prone or simplistic. The recent adoption of language models and improved relation extractors for natural language such as Transformer-XL (Dai et al . (2019). Transformer-xl: Attentive language models beyond a fixed-length context . arXiv preprint arXiv:1901.02860 ) has seen a surge of research interest in the possibilities of using causal relations in practical applications. Until now, there has not been an extensive survey of the practical applications of causal relations; therefore, this survey is intended precisely to demonstrate the potential of causal relations. It is a comprehensive survey of the work on the extraction of causal relations and their applications, while also discussing the nature of causation and its representation in text.

Editorial note

Abstract: We propose a generic framework to describe modifications on 3D objects (surfaces and volumes) based on a query and replace mechanism. These modifications are described in terms of rewriting rules: a set of patterns is provided, each one defining a possible replacement. The patterns are expressed using 3D combinatorial maps, ensuring the global topological validity of the transformed mesh. At the core of the framework, we use topological signatures to efficiently query and match patterns on the input. Our formalism can generically describe many different transformations like subdivision, smoothing, topological correction, or remeshing. Its interest is twofold. It provides an easy implementation for such operations, especially when many cases arise: we provide an example with over 300 cases. It is also able to detect corner cases that were not provided and are required to ensure the topological correctness of the output.