Biblioteca Digital do IPB
Publications Repository of the Polytechnic Institute of Bragança
Recent Submissions
Agreement Between a Wristwatch and a Free Optical Sensor with a Chest Strap in Measuring HR Variations During Front Crawl Swimming
Publication . Bartolomeu, Raúl Filipe; Silva, Vasco; Pereira, Ana; Morais, Gonçalo; Sokołowski, Kamil; Strzała, Marek; Morais, J. E.; Teixeira, José Eduardo
Wearables with optical sensors for heart rate (HR) measurement are widely available in the market. However, their accuracy in water is still underexplored. The aim of the present study was to test the agreement of two different devices for HR monitoring with a chest strap while swimming at different intensities. Twenty male and ten female subjects (mean 19.6 ± 0.7 years old, 173.3 ± 5.4 cm, and 67.1 ± 6.6 kg) performed an intermittent progressive protocol of 3 × 30 s tethered front crawl swimming followed by a 1 min rest period. A chest strap, a wristwatch, and a multi-site optical sensor placed at the temple were used simultaneously. A strong association, an excellent intra-class correlation, and a low mean bias were denoted (R2 = 0.85, ICC = 0.94, b = −1) between HRchest vs. HRtemple. Both indicators increased throughout the test, denoting an increase in accuracy from light to vigorous exercise intensity. HRchest and HRwatch showed a moderate association for the whole test (R2 = 0.23) but a weak association, a poor consistency, and a high mean bias stepwise (0.01 ≤ R2 ≤ 0.06, 0.03 ≤ ICC ≤ 0.42, −48.1 ≤ b≤ −16.1). During swimming, the HR values from the temple showed a better agreement with the chest strap than those from the wristwatch. The temple reading accuracy might be enhanced by using the device during the dryland warm-up routine
Performance of single and built-up I-shaped cold formed steel stud under double sided walls fire exposure
Publication . Hassoune, Mohammed; Kada, Abdelhak; Menadi, Belkacem; Lamri, Belkacem; Yessad, Ouissam; Piloto, Paulo A.G.; Jiang, Liming
Light-gauge Steel Frame (LSF) walls are expanded nowadays due to several advantages, especially to achieve
economy, sustainability and improved structural performance. The latter has stimulated designers to adopt Cold
Formed Steel (CFS) members as primary components of LSF walls. However, the high thermal conductivity and
slenderness of CFS sections make them vulnerable to mechanical degradation during fire. While numerous
studies have investigated the performance of CFS stud walls under one-sided fire exposure, the investigation on
double-sided fire exposure remains limited, especially for built-up studs. This study investigates the performance
of CFS stud walls under compression loading, subjected to one-sided and double-sided fire exposure. Numerical
models were developed using ANSYS APDL, considering geometric imperfections, material nonlinearities and
contact element effect. The developed models were validated against previous experimental and numerical re-
sults. Various parameters were analysed through parametric study, including steel thickness and grades, web
stiffeners and I-shaped stud configurations. The results demonstrate the significant impact of the double-sided
fire exposure on CFS walls performance, reducing the fire resistance by 41 % and 50 % for CFS thicknesses of
1.15 mm and 1.5 mm, respectively, compared to one-sided fire exposure. Steel grade and I-shaped configurations
were found to significantly enhance the load-bearing capacity and fire resistance of CFS walls. The maximum
temperatures predicted for each load ratio were used to calculate the load ratio as per EN1993–1–2. New for-
mulas, based on load ratio were proposed to predict the maximum temperature at failure for CFS walls subjected
to one-sided and double-sided fire exposure. The findings will improve fire structural design codes of CFS walls,
by ensuring accurate predictions of limiting temperatures and fire resistance and providing engineers with
substantial data for LSF structures.
Stock market effects of CrowdStrike IT outage on largest listed hotel companies
Publication . Albuquerque, Bruno; Cró, Susana; Moutinho, Nuno; Martins, António Miguel
This study analyses the short-term market effect of CrowdStrike IT outage in the 100 largest worldwide listed hotel companies. Using an event study methodology, the paper analyses how hotel companies are penalized by the market to the biggest IT disruption in history. Our results evidence a statistically significant negative reaction around the event date. This result is explained by the adverse impact caused by IT failures in the hotel’s business operations (reservation, payment, technical systems) and supply chain processes, which result in financial losses. We also observe a highest negative stock market reaction for hotel companies located in Western countries and for hotels with a low cyber risk rating. Finally, this study identifies hotel-specific characteristics that drive value during an IT outage. The research evidence that larger and more profitable hotel companies, with lower leverage and higher cyber risk ratings are more resilient to the adverse effects of IT outages.
Assessment of heart rate variability and infrared thermography in response to exercise-induced muscle damage
Publication . Marques, Wanessa Karoline Brito; Santana, Paulo Vitor Albuquerque; Oliveira, Vinícius Fernandes Ferreira de; Pussieldi, Guilherme de Azambuja; Leite, Luciano Bernardes; Forte, Pedro; Assis, Miller Gomes; Pimenta, Eduardo Mendonça; Mostarda, Cristiano Teixeira; Costa, Herikson Araújo; Dibai-Filho, Almir Vieira; Oliveira Junior, Mario Norberto Sevilio; Cabido, Christian Emmanuel Torres; Veneroso, Christiano Eduardo
The aim of this study is to investigate the behavior of autonomic nervous activation and infrared thermography
(IR) after an eccentric exercise protocol. The sample consisted of ten physically active men (22.5 ± 3.3 years) who had not practiced plyometric training
in the 6 months prior to the study. After a period of familiarization and assessment of body composition, the participants
underwent a plyometric jumping protocol, including jumps over a 50 cm obstacle and jumps from a 50 cm box, after a
5-min warm-up on the treadmill. Subsequently, the following assessments were performed: assessments included measures
of rating perceived fatigue (RPF), delayed-onset muscle soreness (DOMS), IRT and heart rate variability (HRV) performed
at 24, 48 and 72 h after exercise. The RPF results showed a significant increase from baseline at 24 h, 48 h, and 72 h after the muscle damage protocol.
For DOMS, significant increases were observed at 24 h, 48 h, and 72 h compared to baseline, with values notably higher at
24 h and 48 h than at 72 h. Thermographic assessments of the posterior thigh region showed a higher concentration of pixels
in the warm zone at 48 h and 72 h compared to baseline, as well as at 48 h and 72 h compared to 24 h. Regarding HRV, the
LF/HF ratio and %LF were elevated at 24 h and 48 h compared to baseline and 72 h, while %HF decreased at 24 h and 48 h
relative to baseline. The exercise-induced stress increased warm-zone pixels and elevated sympathetic activity (LF/HF ratio and %LF)
up to 48 h post-exercise. This was followed by a shift to increased parasympathetic modulation (higher %HF), indicating
recovery. These findings underscore the utility of IRT and HRV in monitoring recovery and optimizing training.
Incense honey (Pittosporum undulatum) in the Azores: Botanical authentication by using real-time PCR approach
Publication . Lopes, Ana; Moura, Monica B.M.V.; Grazina, Liliana; Costa, Joana; Amaral, Joana S.; Pinto, Maria Alice; Mafra, Isabel
Honey is a widely consumed food and much appreciated for its nutritional, organoleptic, and health properties. The honey produced in the Azores archipelago can be categorised as incense honey or multifloral honey. Incense honey classification should account with >30% from Pittosporum undulatum pollen grains and it is generally perceived as a unique and high-quality product and, consequently, susceptible to be adulterated through incorrect labelling or admixing with low-cost and low-quality honeys. Therefore, assessing the authenticity of such highly appreciated honey is a key issue for its valorisation. In this work, a real-time PCR method targeting the ITS region was proposed for the first time to detect
P. undulatum species. To that end, the DNA extracted from the leaves of P. undulatum from other endemic species (e.g. Eucaliptus spp., Acacia spp., Trifolium spp., Castanea sativa Mill., Hydrangea macrophylla, Rhododendro indicum, Hedychium gardnerianum, Pericallis malvifolia) of the Azores and mainland Portugal was used to test the cross-reactivity of the
ITS primers by qualitative PCR, revealing full specificity for P. undulatum. Posteriorly, a realtime PCR approach was proposed, exhibiting high analytical performance (PCR efficiency= 97.4 ± 6.4%, R͖= 0.991 ± 0.003) and a limit of quantification of 0.01 pg of incense DNA. The method was successfully applied to the 22 honey samples, from which incense was detected in all 9 monofloral incense honeys and in 5 out of 10 multifloral samples from the Azores. Generally, the quantitative results for incense DNA were in good agreement with the melissopalynological data, showing that all samples, except two, were according to their labelled statements. Herein, a new, simple, cost-effective and reliable molecular approach was proposed to authenticate and valorise the Azores honey.