Lorentz-violating nonminimal coupling contributions in mesonic hydrogen atoms and generation of photon higher-order derivative terms

We have studied the contributions of Lorentz-violating CPT-odd and CPT-even nonminimal couplings to the energy spectrum of the mesonic hydrogen and the higher-order radiative corrections to the effective action of the photon sector of a Lorentz-violating version of the scalar electrodynamics. By considering the complex scalar field describes charged mesons (pion or kaon), the non-relativistic limit of the model allows to attain upper-bounds by analyzing its contribution to the mesonic hydrogen energy. By using the experimental data for the $1S$ strong correction shift and the pure QED transitions $4P \rightarrow 3P$, the best upper-bound for the CPT-odd coupling is $<10^{-12}\text{eV}^{-1}$ and for the CPT-even one is $<10^{-16}\text{eV}^{-2}$. Besides, the CPT-odd radiative correction to the photon action is a dimension-5 operator which looks like a higher-order Carroll-Field-Jackiw term. The CPT-even radiative contribution to the photon effective action is a dimension-6 operator which would be a higher-order derivative version of the minimal CPT-even term of the standard model extension

Betões correntes em situação de incêndio

Na área da engenharia civil, o comportamento ao fogo de estruturas de betão armado é de primordial importância no contexto da segurança estrutural, dada a probabilidade elevada de ocorrerem colapsos locais ou globais, com impactos consideráveis ao nível de perdas humanas e de prejuízos económicos. Esta temática é de tal forma importante, que desde os anos 40 que se tem vindo a estudar a influência das altas temperaturas no desempenho mecânico e térmico do betão Neste artigo é feita uma recensão sobre as diferentes propriedades mecânicas, nomeadamente, resistência à compressão, à tração, à flexão e módulo de elasticidade, os parâmetros de que dependem e a relação entre os mesmos

Experimental methods on the determination of the mechanical properties of concrete at high temperatures

Até ao momento não existem ainda procedimentos padrão para ensaios a altas temperaturas no betão, pelo que têm sido realizados ensaios a temperaturas elevadas adaptados de ensaios à temperatura ambiente. Os ensaios têm-se dividido entre ensaios a altas temperaturas e residuais após aquecimento e arrefecimento. O primeiro procedimento é mais adequado para a determinação das propriedades mecânicas do betão durante um incêndio enquanto o segundo procedimento é usado para determinar a resistência residual do betão após incêndio. Nesta comunicação apresentam-se os resultados de ensaios realizados por diferentes autores para a determinação das propriedades mecânicas residuais do betão após aquecimento e arrefecimento. Os resultados apresentados dizem respeito a resistências residuais à compressão, tração e flexão e módulo de elasticidade. Os métodos de ensaio aplicados são devidamente descritos e os resultados obtidos são objeto de análises comparativas.ABSTRACT: So far there are no standard procedures for testing concrete at high temperatures which have been conducted according to the ones at ambient temperature. The tests have been divided between tests at high temperatures and residual after heating and cooling. The first procedure is appropriate for determining the mechanical properties of concrete during fire while the second is used to determine the residual mechanical properties of concrete after fire. In this paper are presented the results of tests carried out by different authors for assessing the residual mechanical properties of concrete after heating and cooling. The results presented are respecting to residual compressive, tensile and flexural strength and elasticity modulus. The test methods are described and results obtained are compared

A Multiple Criteria Framework to Evaluate Bank Branch Potential Attractiveness

Remarkable progress has occurred over the years in the performance evaluation of bank branches. Even though financial measures are usually considered the most important in assessing branch viability, we posit that insufficient attention has been given to other factors that affect the branches’ potential profitability and attractiveness. Based on the integrated used of cognitive maps and MCDA techniques, we propose a framework that adds value to the way that potential attractiveness criteria to assess bank branches are selected and to the way that the trade-offs between those criteria are obtained. This framework is the result of a process involving several directors from the five largest banks operating in Portugal, and follows a constructivist approach. Our findings suggest that the use of cognitive maps systematically identifies previously omitted criteria that may assess potential attractiveness. The use of MCDA techniques may clarify and add transparency to the way trade-offs are dealt with. Advantages and disadvantages of the proposed framework are also discussed.

Enhancing STEM Learning with ChatGPT and Bing Chat as Objects to Think With: A Case Study

This study investigates the potential of ChatGPT and Bing Chat, advanced conversational AIs, as "objects-to-think-with," resources that foster reflective and critical thinking, and concept comprehension in enhancing STEM education, using a constructionist theoretical framework. A single-case study methodology was used to analyse extensive interaction logs between students and both AI systems in simulated STEM learning experiences. The results highlight the ability of ChatGPT and Bing Chat to help learners develop reflective and critical thinking, creativity, problem-solving skills, and concept comprehension. However, integrating AIs with collaborative learning and other educational activities is crucial, as is addressing potential limitations like concerns about AI information accuracy and reliability of the AIs' information and diminished human interaction. The study concludes that ChatGPT and Bing Chat as objects-to-think-with offer promising avenues to revolutionise STEM education through a constructionist lens, fostering engagement in inclusive and accessible learning environments

On the Estimation of Hospital Beds Occupancy After Hip Surgery

For hospitals, the variability on demand (number of daily urgent admissions) and the variability in the Length of Stay (LoS) (bed occupancy) may affect the quality of service provided to patients and the effectiveness of the overall service. This paper studies the LoS of 238 patients who performed hip surgery in the orthopedic service of a Portuguese hospital in 2014. It uses variables available in electronic databases, such as Age, Gender, ASA classification; Surgical Apgar Score, Type of hip surgery; Weekday of the surgery; Starting hour of the surgery and Duration of surgery to predict LoS and provides a model that correctly indicate if a patient stays more than 7 days in 72.1% of the cases.- This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT - Fundacao para a Ciencia e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio