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IntroductionEarly reports showed that Omicron (BA.1) SARS-CoV-2 could be less severe. However, the magnitude of risk reduction of hospitalization and mortality of Omicron (BA.1) infections compared with Delta (B.1.617.2) is not yet clear. This study compares the risk of severe disease among patients infected with the Omicron (BA.1) variant with patients infected with Delta (B.1.617.2) variant in Portugal.MethodsWe conducted a cohort study in individuals diagnosed with SARS-CoV-2 infection between 1stand 29thDecember 2021. Cases were individuals with a positive PCR test notified to the national surveillance system. SARS-CoV-2 variants were classified first by whole genomic sequencing (WGS) and, if this information was unavailable, by detecting the S gene target failure. We considered a hospitalization for all the patients admitted within the 14 days after the SARS-CoV-2 infection; after that period, they were censored.The comparison of the risk of hospitalization between Omicron (BA.1) and Delta (B.1.617.2) VOC was estimated using a Cox proportional hazards model. The mean length of stay was compared using linear regression, and the risk of death between Omicron and Delta patients was estimated with a penalized logistic regression. All models were adjusted for sex, age, previous infection, and vaccination status.ResultsWe included 15 978 participants aged 16 or more years old, 9 397 infected by Delta (B.1.617.2) and 6 581 infected with Omicron (BA.1). Within the Delta (B.1.617.2) group, 148 (1.6%) were hospitalized, and 16 (0.2%) were with the Omicron (BA.1). A total of 26 deaths were reported, all in participants with Delta (B.1.617.2) infection. Adjusted HR for hospitalization for the Omicron (BA.1) variant compared with Delta (B.1.617.2) was 0.25 (95%CI 0.15 to 0.43). The length of stay in hospital for Omicron (BA.1) patients was significantly shorter than for Delta (confounding-adjusted difference -4.0 days (95%CI -7.2 to -0.8). The odds of death were 0.14 (95% CI 0.0011 to 1.12), representing a reduction in the risk of death of 86% when infected with Omicron (BA.1) compared with Delta (B.1.617.2).ConclusionOmicron (BA.1) was associated with a 75% risk reduction of hospitalization compared with Delta (B.1.617.2) and reduced length of hospital stay.

A rapid (3 hours) and reliable multiplex PCR was developed for detecting simultaneously known plasmid-mediated fos genes conferring acquired resistance to fosfomycin. Our technique was tested on a collection of Escherichia coli isolates previously identified as bearing the fosA-, fosC- and fosL-like genes, showing a sensitivity and a specificity of 100%.

Brucellosis is an important zoonosis that is emerging in some regions of the world, gaining increased relevance with the inclusion of the causing agent Brucella spp. in the class B bioterrorism group. Until now, multi-locus VNTR Analysis (MLVA) based on 16 loci has been considered as the gold standard for Brucella typing. However, this methodology is laborious, and, with the rampant release of Brucella genomes, the transition from the traditional MLVA to whole genome sequencing (WGS)-based typing is on course. Nevertheless, in order to avoid a disruptive transition with the loss of massive genetic data obtained throughout the last decade and considering that the transition timings will vary considerably among different countries, it is important to determine WGS-based MLVA alleles of the nowadays sequenced genomes. On this regard, we aimed to evaluate the performance of a Python script that had been previously developed for the rapid in silico extraction of the MLVA alleles, by comparing it to the PCR-based MLVA procedure over 83 strains from different Brucella species. The WGS-based MLVA approach detected 95.3% of all possible 1,328 hits (83 strains×16 loci) and showed an agreement rate with the PCR-based MLVA procedure of 96.4% for MLVA-16. According to our dataset, we suggest the use of a minimal depth of coverage of ~50x and a maximum number of ~200 contigs as guiding “boundaries” for the future application of the script. In conclusion, the evaluated script seems to be a very useful and robust tool for the in silico determination of MLVA profiles of Brucella strains, allowing retrospective and prospective molecular epidemiological studies, which are important for maintaining an active epidemiological surveillance of brucellosis.

This article concerns the investigation of an optimal control framework based on the Maximum Principle of Pontryagin for the motion planning of Autonomous Underwater Vehicles (AUVs) that take into account not only its own controlled dynamics (unicycle) through its actuators, but also the motion effects of the water column flow fields, notably, the point vortices which might either be naturally present or intentionally generated in order to achieve the desired motion features. We do not enter into issues related to the AUV mechanical design, but assume that this can such that the shape of the (movable or not) vehicle surfaces, are such that the water column flow field energy can be used with advantage to the required motion. In this context, we simply assume that the vehicle is a point mass unicycle such that the effect of the water column vortices can be controlled to contribute to the desired AUVs longitudinal and rotational velocities. The control action usually considered in the literature is extended by including the generation of vortices whose location and circulation are chosen at discrete points in time so the their effect on the AUV motion drives it between two given in an efficient way. Necessary conditions of optimality are derived in the context of multi-processes framework.

This article concerns the formalization of a control framework for the fish-like motion control in a fluid due to a vector field generated by point vortices so that the overall power consumption required to travel between the departure and the arrival points is minimized. The control action is synthesized by specifying the time, location and circulation of at least one vortex and the extent to which this vortex, together one or more other vortices will propel the mobile platform considered as a point particle. Given the complexity of the general problem, we consider two simplifying assumptions: (i) only two vortices are active at each time interval, and (ii) the motion takes place in R2. Necessary conditions of optimality in the form of a Maximum Principle of Pontryagin are stated, and the features ensuring that they constitute a solid basis for the synthesis of the optimal control strategy are discussed.

We present the problem of minimum time control of a particle advected in Couette and Poiseuille flows and solve it by using the Pontryagin maximum principle. This study is a first step of an effort aiming at the development of a mathematical framework for the control and optimization of dynamic control systems whose state variable is driven by interacting ODEs and PDEs which can be applied in the control of underwater gliders and mechanical fishes.

The objective of this work is to develop a mathematical framework for the modeling, control and optimization of dynamic control systems whose state variable is driven by interacting ODE’s (ordinary differential equations) and solutions of PDE’s (partial differential equations). The ultimate goal is to provide a sound basis for the design and control of new advanced engineering systems arising in many important classes of applications, some of which may encompass, for example, underwater gliders and mechanical fishes. For now, the research effort has been focused in gaining insight by applying necessary conditions of optimality for shear flow driven dynamic control systems which can be easily reduced to problems with ODE dynamics. In this article we present and discuss the problem of minimum time control of a particle advected in a Couette and Poiseuille flows, and solve it by using the maximum principle.

A verificação da segurança aos sismos de estruturas portuárias assume grande relevância no contexto nacional pela conjugação de dois factores: a perigosidade sísmica moderada da faixa costeira e a importância sócio-económica que este tipo de infraestruturas representa para o País. Nesta tese realiza-se uma breve apresentação das várias soluções estruturais correntes em obras portuárias, particularizando-se o comportamento sísmico observado de estruturas de gravidade com infraestrutura em caixotão, para sismos ocorridos nas últimas duas décadas. A apresentação da Metodologia por Avaliação de Desempenho aplicada às estruturas portuárias de gravidade, como forma de verificar a segurança aos sismos, pretende concretizar a aplicação do método no controlo dos danos para a uma determinada acção sísmica e, consequentemente, da minimização dos custos associados à reparação e à inoperacionalidade do porto.