363 research outputs found
Anxiety, cognitive appraisal and burnout in sport: a study with young athletes
Este estudo analisa a importância dos processos de avaliação cognitiva na experiência de ansiedade e de burnout bem como a importância da avaliação cognitiva e da ansiedade na predição do burnout. Participaram nesta investigação 711 atletas (89 do sexo feminino e 622 do sexo masculino), com idades compreendidas entre os 12 e os 19 anos (M = 14.77; DP = 1.86). Os participantes responderam a um protocolo de avaliação composto por três instrumentos, além de um questionário demográfico: Escala de Ansiedade no Desporto-2; Escala de Avaliação Cognitiva e Questionário de Burnout para Atletas. Os resultados demonstraram que a avaliação cognitiva primária desempenha um papel fundamental na experiência de ansiedade e de burnout, dado que a perceção de ameaça correspondeu a maiores nÃveis de ansiedade e burnout e a perceção de desafio correspondeu a menores nÃveis nestas variáveis. Além disso, verificou-se que as dimensões da avaliação cognitiva primária, em conjunto com as dimensões da ansiedade, foram variáveis preditoras do burnout. Em suma, os resultados evidenciaram a importância da avaliação cognitiva no estudo dos estados emocionais dos atletas, sugerindo a continuação de investigações futuras neste domÃnio.This study analyzed the importance of cognitive appraisal in the experience of anxiety and burnout as well
as the importance of cognitive appraisal and anxiety in the prediction of burnout. The study included 711
athletes (89 females and 622 males), with ages between 12 and 19 years old (M = 14.77; DP = 1.86). The
participants answered an assessment protocol that included the Sport Anxiety Scale-2; the Cognitive
Appraisal Scale and the Athlete Burnout Questionnaire, besides a demographic questionnaire. The results
showed that primary cognitive appraisal influence the experience of anxiety and burnout, because athletes
with higher levels of threat perception assumed more anxiety and burnout, and athletes with higher levels
of challenge perception assumed lower levels of anxiety and burnout. The results also showed that the
dimensions of primary cognitive appraisal and anxiety predicted the experience of athletes’ burnout. In
sum, this study highlights the importance of cognitive appraisal in the study of athletes’ emotional states,
suggesting the continuation of future research on this topic.Este estudo foi realizado no Centro de Investigação em Psicologia (UID/PSI/01662/2013), Universidade do Minho, e foi financeiramente suportado pela Fundação para a Ciência e Tecnologia e pelo Ministérios da Ciência, Tecnologia e Ensino Superior, através de fundos nacionais, e co-financiado pelo FEDER, através do COMPETE2020, no âmbito do acordo Portugal 2020 (POCI-01-0145-FEDER-007653)
Leadership efficacy in youth football: athletes and coaches’ perspective
According to the Leadership Efficacy Model, leadership efficacy depends on leaders’ tendency to make linear relationships between leadership philosophy, practice, and criteria (i.e., congruence of leadership cycles). Moreover, efficacy increases if coaches make these linear relationships by using the optimal leadership profile and by considering the antecedent factors of leadership (characteristics of the leader, team members, and organizational conditions; i.e., favorability of conditions for leadership). This study compared the perceptions of athletes and their coaches regarding leadership cycles, and tested the moderator role of optimal leadership profile and leadership favorability in the relationship between leadership cycles and leadership efficacy. This study included 92 football athletes (ages less than 17 and 19 years) and respective coaches (n = 5). The evaluation protocol included measures of leadership cycles, leadership styles, leadership favorability, and sport performance perception. Athletes and coaches agreed on coaches’ need to increase their practice and criteria, but athletes also considered that coaches should better clarify their philosophy. Regression analyses confirmed that leadership congruency predicts higher perceptions of team performance in athletes. Moreover, optimal leadership profile and higher leadership favorability were associated with higher team and individual performance. However, these two factors did not moderate the relationship between leadership congruency and efficacy.info:eu-repo/semantics/acceptedVersio
Cognitive appraisal as a mediator in the relationship between stress and burnout
The relation between job stressors and burnout is well established in the literature. However, the mechanisms behind this relationship are still not clear. Thus, this study has the main goal of analysing the mediating role of cognitive appraisal on the relation between occupational stress and burnout. To test this relation, structural equation modelling was used in a sample of teachers (N=333) working at a public university in the north of Portugal. The participants answered a protocol with measures that included the level of stress on academic staff, cognitive appraisal of their work activity, and a burnout inventory for educators. The results indicated distinct sources of stress on their work activity and a relation between stress, cognitive appraisal, and burnout. Most importantly, the results confirmed that primary and secondary cognitive appraisals partially mediated the relationship between occupational stress and burnout at work, making these variables a promising underlying mechanism for explaining adaptation at work
Feed Supplementation with a Commercially Available Probiotic Solution Does Not Alter the Composition of the Microbiome in the Biofilters of Recirculating Aquaculture Systems
Three-Dimensional CFD modelling and analysis of the thermal entrainment in open refrigerated display cabinets
This study presents a three-dimensional Computational Fluid Dynamics (CFD) simulation of the air flow pattern and the temperature distribution in a refrigerated display cabinet. The thermal entrainment is evaluated by the variations of the mass flow rate and thermal power along and across the air curtain considering the numerical predictions of abovementioned properties. The evaluation on the ambient air velocity for the three-dimensional (3D) effects in the pattern of this type of turbulent air flow is obtained. Additionally, it is verified that the longitudinal air flow oscillations and the length extremity effects have a considerable influence in the overall
thermal performance of the equipment. The non uniform distribution of the air temperature and velocity throughout the re-circulated air curtain determine the temperature differences in the linear display space and inside the food products, affecting the refrigeration power of display cabinets. The numerical predictions have been validated by comparison with experimental tests performed in accordance with the climatic class n.º 3 of EN 441 Standard (Tamb = 25 ºC,φamb = 60%; vamb = 0,2 m s-1). These tests were conducted using the point measuring technique for the air temperature, air relative humidity and air velocity throughout the air curtain, the
display area of conservation of food products and nearby the inlets/outlets of the air mass flow.info:eu-repo/semantics/publishedVersio
Experimental analysis of the thermal entrainment three dimensional effects in re-circulated air curtains
The application of air curtains devices to HVAC&R systems have been developed in order to improve the thermal and mass separation between two contiguous spaces with differentiated air behaviours. The refrigeration equipments installed inside commercial spaces and open to the surroundings suffer alterations of their thermal behaviours and energy efficiency due to variations in magnitude and orientation of the air velocity. The location of the air conditioning system discharge grilles, the mass flows rates originated by pressure differences due to openings to the external environment and the air flow perturbation due to the circulation of the consumers nearby the opening of the display cases, among others, affect the re-circulated air curtain
behaviour and the overall performance of the equipment.This study presents the experimental results obtained from tests carried out for the climatic class n.º 3 of EN 441 (Tamb = 25 ºC, φamb = 60%; vamb = 0,2 m/s) and the analysis of the threedimensional effects observed in the thermal interaction through the air curtains installed in open vertical refrigerated display cases.
The obtained results are related to the air temperature, air relative humidity and air velocity measurements fields throughout the air curtain. From the analysis of the obtained results some comparable effects in the fields of the same properties for the display space of the exposition and conservation of food products and nearby the inlets/outlets of the air mass flow, can be sorted out.
The evaluation of the ambient air velocity three-dimensional effects in the pattern of this type of turbulent air flow is obtained. Additionally, it is verified that the longitudinal airflow fluctuations and the length extremity effects of the display case have a considerable influence in the overall thermal performance of the equipment.
The non-uniform distribution of the air temperature, relative humidity and velocity throughout the air curtain determines temperature differences in the linear dimension display space and inside the food products, affecting the correct behaviour of the display cases. Besides that, this study helps to show some of the fragilities of the numerical models bi-dimensional formulation.info:eu-repo/semantics/publishedVersio
Work–family conflicts, cognitive appraisal, and burnout: testing the mediation effect with structural equation modelling
Work-family conflict constitutes an important source of occupational stress predicting teachers’ burnout, and cognitive variables have shown to be core structures in explaining human adaptation to stress. Nevertheless, the role of cognitive appraisal needs to be fully analysed to comprehend how it can mediate the relationship between stress and burnout. In order to understand the potential mediation of cognitive appraisal in the relationship between stress and burnout, we adopted conceptual models of stress that highlighted the value of cognitive appraisal on positive and negative reactions to work demands. Also, we analysed the potential moderation of sex and age in the relationship between work-family conflict, cognitive appraisal, and burnout due inconsistent findings on how these personal variables can interfere on these relations. In this study, we used Structural Equation Modelling (SEM) to test the mediating of cognitive appraisal in the relationship between work-family conflicts and burnout. A survey with measures of work-family conflicts, cognitive appraisal, and burnout was administered to the participants consisting of 438 Portuguese teachers from kindergarten through high school, aged between 28 and 67 years (M = 46.85; SD = 7.88), 304 of whom were females (69.41%). The results confirmed that cognitive appraisal partially mediated the relationship between work-family conflict and burnout. The mediation effect of cognitive appraisal on the relationship between work-family conflict and burnout was invariant regardless of teachers’ sex or age. In sum, cognitive appraisal should be considered in order to understand teachers’ adaptation to work.This study was conducted at the Psychology Research Centre (PSI/01662), School of Psychology, University of Minho, and supported by the Portuguese Foundation for Science and Technology and the Portuguese Ministry of Science, Technology and Higher Education (UID/PSI/01662/2019), through the national funds (PIDDAC).
The authors have no conflicts of interest to report
Incorporation of solid lipid nanoparticles into stirred yogurt: effects in physicochemical and rheological properties during shelf-life
The aim of this work was to develop a yogurt fortified with curcumin. Curcumin is a lipophilic compound with a wide range of biological activities; however, it presents low water solubility and low bioavailability, and therefore it was the first to be encapsulated in solid lipid nanoparticles (SLNs). Then the influence of the incorporation of curcumin-loaded SLNs on the physicochemical (i.e., pH, titratable acidity, syneresis and color) and rheological properties of yogurt during its shelf-life (30 days at 4 °C) was evaluated. SLN incorporation into yogurt did not affect pH and titratable acidity compared to the control (i.e., plain yogurt) during shelf-life, even though the yogurt with SLNs presented lower values of pH (4.25 and 4.34) and acidity (0.74% lactic acid and 0.84% lactic acid) than the control in the end, respectively. Furthermore, the yogurt with SLNs presented slightly higher values of syneresis than the control during the shelf-life; however, it did not present visual differences in whey separation. Relative to the color, the incorporation of SLNs into the yogurt imparted a strong yellow color to the sample but did not affect color stability during shelf-life. Both samples showed flow curves with yield stress and shear-thinning behavior during shelf-life, and, regarding the viscoelastic behavior, both showed a typical weak viscoelastic gel with an elastic structure. Overall, curcumin-loaded SLNs incorporation did not affect the physicochemical and rheological stability of yogurt during shelf-life, showing a promising application for the development of new functional foods.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and by LABBELS Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems, LA/P/0029/2020.info:eu-repo/semantics/publishedVersio
Control of zootechnology leads to improved Cuttlefish (Sepia officinalis, L.) reproduction performance up to pre-industrial levels
Cephalopods are gaining momentum as an alternate group for aquaculture species diversification, not only because they are a good food source (highly appreciated in some worldwide markets) but they also have the potential to quickly reach a market size. However, there are some bottlenecks impeding the transition of culture technology from the laboratory to industry. One is related to control over reproduction in captivity. The objective of the present experiment was to verify the effects of tanks with different bottom areas/volumes on the reproduction performance of S. officinalis breeding stocks, when sex ratios were controlled a priori; and the food cost associated with such performance when individuals are fed a natural frozen diet. One hundred and ninety two juvenile cuttlefish were used to compare three different round-shaped tanks: one type with 3000L volume and two types with 9000L volume (with differences in bottom areas and water column). Individuals had their sex and maturity stage determined to establish a sexual ratio of 2 female:1 male per tank and assure that cuttlefish were still immature. Biological data was collected during both growth and reproduction stages and until the death of all females in each tank. The experiment lasted nearly 300 days. Temperature differences between tank types were registered during both stages. The optimizing of rearing conditions has allowed for higher growth and a higher amount of cuttlefish available for breeding purposes. A total of 123,751 eggs (in 85 batches) was obtained during this experiment, which is a number that may meet a small scale cuttlefish commercial hatchery facility requirements. The present conditions contributed to a better and predictable reproduction performance in specific 9000L tanks, with values reaching pre-industrial numbers (approximate to 24,000 eggs/tank). Moreover, both the amount of eggs per batch and the overall quality of eggs has increased. Three of these 9000L tanks have an overall consumption of approximate to 38.64 Kg tank(-1), which translates in an investment in feed of approximate to 193 (sic) tank(-1), 8.40 (sic) per cuttlefish and an overall daily tank expense of 1.76 (sic) d(-1).info:eu-repo/semantics/publishedVersio
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