Effect of high CO2 and ocean acidification on photosynthesis and response to oxidative stress in seagrasses

Climate change scenarios comprise significant modifications of the marine realm, notably ocean acidification and temperature increase, both direct consequences of the rising atmospheric CO2 concentration. These changes are likely to impact marine organisms and ecosystems, namely the valuable seagrass-dominated coastal habitats. The main objective of this thesis was to evaluate the photosynthetic and antioxidant responses of seagrasses to climate change, considering CO2, temperature and light as key drivers of these processes. The methodologies used to determine global antioxidant capacity and antioxidant enzymatic activity in seagrasses were optimized for the species Cymodocea nodosa and Posidonia oceanica, revealing identical defence mechanisms to those found in terrestrial plants. The detailed analysis and identification of photosynthetic pigments in Halophila ovalis, H.stipulacea, Zostera noltii, Z marina, Z. capricorni, Cymodocea nodosa and Posidonia oceanica, sampled across different climatic zones and depths, also revealed a similarity with terrestrial plants, both in carotenoid composition and in the pigment-based photoprotection mechanisms. Cymodocea nodosa plants from Ria Formosa were submitted to the combined effect of potentially stressful light and temperature ranges and showed considerable physiological tolerance, due to the combination of changes in the antioxidant system, activation of the VAZ cycle and accumulation of leaf soluble sugars, thus preventing the onset of oxidative stress. Cymodocea nodosa plants living in a naturally acidified environment near submarine volcanic vents in Vulcano Island (Italy) showed to be under oxidative stress despite the enhancement of the antioxidant capacity, phenolics concentration and carotenoids. Posidonia oceanica leaves loaded with epiphytes showed a significant increase in oxidative stress, despite the increase of antioxidant responses and the allocation of energetic resources to these protection mechanisms. Globally, the results show that seagrasses are physiologically able to deal with potentially stressful conditions from different origins, being plastic enough to avoid stress in many situations and to actively promote ulterior defence and repair mechanisms when under effective oxidative stress.

Stress e adaptação no processo de luto materno : um estudo exploratório

Tese de mestrado, Psicologia (Secção de Psicologia Clínica e da Saúde, Núcleo de Psicologia Clínica Sistémica), Universidade de Lisboa, Faculdade de Psicologia, 2014

Avaliação de fatores determinantes e da taxa de incidência da condição DFD (Dark, Firm, Dry) na carne de bovinos abatidos no matadouro da ilha Terceira

Dissertação de Mestrado, Engenharia Zootécnica, 13 de Junho de 2014, Universidade dos Açores.

An investigation into the physical and psychological stress factors that elementary teachers experience : recommendations to boards and personal calming strategies /

The prlmaiy objective of this study was to Identify and describe the physical and psychological stress factors that elementary school teachers experience and how teachers cope with stress. A secondary objective was to offer boards and teachers potential coping strategies counteracting stress and the effects of stress. The sample consisted of 120 elementaiy teachers from southern Ontario. Ten elementaiy schools were randomly chosen. The Teacher Stress Inventory questionnaire (Flmian, 1989) was used. Data were analyzed using a variety of statistics. Test norms and interpretations were performed based on standard results obtained from the author of the questionnaire (Flmian, 1988). Overall, the results indicated that work-related stressors were the main factor for teacher stress. This Included such factors as caseload/class is too big, too much administrative paperwork, and having little time to prepare lessons. Implications for further research and practical suggestions for further reseairch are discussed. Also a variety of recommendations to boards and for individual use are discussed. Some recommendations are having counselling available for teachers, workshops on how to handle stress, and learning how to breathe and using calm visualization.

An investigation of adolescent constructs of stress and academic achievement /

The present study was a phenomenological investigation of adolescent constructs of stress and academic achievement. The study utilised a modified version of George Kelly's Repertory Grid Technique to provide direct insight into adolescent stress and academic achievement. The premise of the study was that only students who exhibited extreme cases of stress and academic achievement levels would be examined. The investigation identified and examined the adolescents who exhibited these extremes and explored the underlying constructs that defined these differences. It was expected that if adolescents were able to identify the stressors in their lives, how these stressors affect their lives, and how these stressors affect their academic performance, then suggestions could be made to help students to better cope with stress and to improve their academic achievement level. Further, based on the results of the study, the pedagogical implications for classroom research are provided. Phenomenological inquiries, using modified, and less complex versions of the repertory grid, can be conducted pre-, mid-, and postacademic terms, to determine and to monitor the stressors and the academic performance of the students in a classroom. Specific assessments for individual students will help teachers to better exercise their knowledge and understanding of the realm of teaching and learning strategies (e.g., Gardiner's Multiple Intelligences) that exist.

Linking of stress offset score (SOS), work satisfaction, and organizational commitment to intentions to quit

The purpose of this study was to identify the impact of stressors and offsetting satistiers, measured in this study with Stress Offset Score (SOS), on intentions to quit and examine the mediating and moderating effects of three facets of work satisfaction (job satisfaction, pay satisfaction, and satisfaction with supervisor) and two facets of organizational commitment (affective and nonnative commitment) on this relationship. The sample was composed of 2990 employees from 21 public and private organizations. The interaction of each type of work satisfaction and organizational commitment, with SOS, was tested using Ordinary Least Squares (OLS) procedures. Intentions to quit was the dependent variable. The research questions were determine: (1) Does SOS predict intentions to quit? (2) Does work satisfaction mediate the predictive relationship of SOS on intentions to quit? (3) Does organizational commitment mediate the predictive relationship of SOS on intent to quit? (4) Does work satisfaction moderate the predictive relationship of SOS on intentions to quit? and (5) Does organizational commitment moderate the predictive relationship of SOS on intentions to quit? The results indicated that SOS was negatively correlated with intentions to quit. Each of the types of work satisfaction and organizational commitment variables showed a partial mediated relationship with SOS and each relationship was highly significant, while normative commitment explained more of the relationship then other mediators. The study also tested for interactions but no statistical significant relationships where established between any of the interaction terms (e.g., SOSxJob Satisfaction and SOSxAffcctive Commitment) and intentions to quit.

An exploration of gifted and highly able adolescents' experiences with stress and coping /

This narrative case study explored gifted and highly able adolescents' experiences with stress and coping. Nine students, ages 13-18, at 2 independent schools in southern Ontario, participated. They completed the Adolescent Coping Scale (Frydenberg & Lewis, 1993), and I generated individualized graphs of coping strategies. Participants talked about experiences they perceived as stressful in their academic, personal, social, and familial settings during a 60-90 minute one-on-one audiotaped interview. During the interview, each participant made observations about their own coping strategies profile. The interview was analyzed to identify stressor and coping themes. Participants completed a writing or art task to record perceptions of stress and coping. The 3 data sources were used to craft 9 individual story portraits, from which 5 main stressor themes emerged: issues of time; relationships, emotions, and communication; ethical, moral, and spiritual issues; global issues; and silences, or stressors not talked about in depth. Coping themes were: seeking relaxing activities; having positive attitudes and making wise choices; maintaining relationships with peers and family; understanding the role of faith and moral beliefs; having a supportive environment; knowing your own personality type; being aware of negative coping strategies; and keeping busy and avoiding stressfiil issues. The narratives are important because they present teenagers talking about their socioemotional worlds. The present findings provide empirical groundwork for curriculum development in affective education and highlight the importance of socioemotional development for future research in the area of giftedness and adolescence.

A constructivist grounded theory of firefighter perceptions of stress, coping and the relationship to health

This qualitative research was a constructivist grounded theory designed to develop an understanding of how firefighters perceive and cope with stressful situations and the impact this has on their perceptions of health. This study was framed in a social ecological perspective with the community of firefighting providing the environment within which to explore stress and coping. Of particular concern here are the stressors associated with firefighting. Prior research with firefighters has often been epidemiological and statistical in nature, focusing on measures of cardiovascular disease, cancer, and depression (Baker & Williams, 2001 ; Brown et al., 2002; Murphy et al.,1999; Regehr et al., 2002; Regehr et al., 2003). Qualitative research examining the perception of stress among firefighters that includes personal stories allows firefighters the opportunity to describe what it is like to be met with physically and mentally challenging situations on a daily basis. Twelve in-depth, semi-structured, face-to-face interviews with a brief questionnaire were conducted with firefighters from a Southern Ontario Fire Department. Four main themes emerged describing the persona of the firefighter, the stressors of firefighters, coping strategies of firefighters, and firefighters' perceptions of health. Stressors include requirements of the job, traumatic calls, tensions with co-workers, the struggle between the family at home and the family at work, political stressors with the City, and the inner struggle. Avoidance coping, approach coping, and gaining perspective emerged as the three coping styles of firefighters. Health was defined as including physical, mental, social and spiritual aspects. A model of the findings is provided that depicts the cyclical nature of the stress-coping-health relationship among firefighters.

Disambiguating the Effects of Social Instability Stress in Adolescence on Learning and Memory Tasks that Involve the Medial Prefrontal Cortex and Hippocampus

Exposure to chronic stress can alter the structure and function of brain regions involved in learning and memory, and these effects are typically long-lasting if the stress occurs during sensitive periods of development. Until recently, adolescence has received relatively little attention as a sensitive period of development, despite marked changes in behaviour, heightened reactivity to stressors, and cognitive and neural maturation. Therefore, the purpose of the present study was to investigate the long-term effects of chronic stress in adolescence on two spatial learning and memory tasks (Morris water maze and Spatial Object Location test) and on a working memory task (Delayed Alternation task). Male rats were randomly assigned to chronic social instability stress (SS; daily 1 hour isolation and subsequent change of cage partner between postnatal days 30 and 45) or to a no-stress control group (CTL). During acquisition learning in the Morris water maze task, SS rats demonstrated impaired long-term memory for the location of the hidden escape platform compared to CTL rats, although the impairment was only seen after the first day of training. Similarly, SS rats had impaired long-term memory in the Spatial Object Location test after a long delay (240 minutes), but not after shorter delays (15 or 60 minutes) compared to CTL rats. On the Delayed Alternation task, which assessed working memory across delays ranging from 5 to 90 seconds, no group differences were observed. These results are partially in line with previous research that revealed adult impairment on spatial learning and memory tasks after exposure to chronic social instability stress in adolescence. The observed deficits, however, appear to be limited to long-term memory as no group differences were observed during brief periods of retention.

Exploring Academic (Di)stress and Help-Seeking in Faculty of Education Students

This is a study of education students’ conceptions of and experiences with academic stress and help-seeking. The study explored teacher education and Master of Education students’ academic stress by examining causes of academic stress and how these stressors affect students’ academic and university experiences. Stress-related help-seeking was also a focus of this study, and was explored using inquiries regarding where participants sought stress-related support. Additionally, exploring students’ use of the Internet for stress-related information or support was a goal of this study. These research goals were pursued using a qualitative methodology that applied grounded theory design. Consequently, data were used to develop a theory that would contribute to existing literature. Specifically, participant descriptions related to causes of and responses to academic stress aligned with Maslow’s (1954) theory of human motivation and Alderfer’s (1969) E. R. G. theory, and led to theoretical contributions that took a hierarchy of student needs and motivation into consideration.

L’effet du stress sur la douleur aiguë et chronique

Objectif : Cette thèse a pour objectif de mieux comprendre l’effet du stress sur la douleur aiguë et chronique. Devis expérimental : 16 patients souffrant de douleur chronique lombalgique et 18 sujets contrôles ont participé à une étude d’imagerie par résonance magnétique (IRM) et ont collecté des échantillons de salive afin de quantifier les niveaux d’hormone de stress (i.e. cortisol) la journée de l’étude (réponse réactive) et durant les sept jours consécutifs suivants (réponse basale). Étude 1 : Une première étude a examiné le lien entre les niveaux de cortisol basal, le volume de l’hippocampe et l’activité cérébrale évoquée par la douleur thermique chez des patients souffrant de douleur chronique et les sujets contrôles. Les résultats révèlent que les patients souffrant de douleur chronique avaient des niveaux de cortisol plus élevés que ceux des sujets contrôles. Chez ces patients, un niveau élevé de cortisol était associé à un plus petit volume de l'hippocampe et à davantage d’activation dans le gyrus parahippocampique antérieure (une région impliquée dans l'anxiété anticipatoire et l'apprentissage associatif). De plus, une analyse de médiation a montré que le niveau de cortisol basal et la force de la réponse parahippocampique explique statistiquement l’association négative entre le volume de l'hippocampe et l'intensité de la douleur chronique. Ces résultats suggèrent que l’activité endocrinienne plus élevée chez les patients ayant un plus petit hippocampe modifie le fonctionnement du complexe hippocampique et contribue à l’intensité de la douleur chronique. Étude 2 : La deuxième étude a évalué la contribution de la réponse de stress réactif aux différences interindividuelles dans la perception de la douleur aiguë chez des patients souffrant de douleur chronique et chez des sujets normaux. Les deux groupes ont montré des augmentations significatives du niveau de cortisol en réponse à des stimulations nocives administrées dans un contexte d’IRM suggérant ainsi que la réactivité de l’axe hypothalamo-hypophyso-surrénalien est préservée chez les patients lombalgiques. De plus, les individus présentant une réponse hormonale de stress plus forte ont rapporté moins de douleur et ont montré une réduction de l'activation cérébrale dans le noyau accumbens, dans le cortex cingulaire antérieur (CCA), le cortex somatosensoriel primaire, et l'insula postérieure. Des analyses de médiation ont indiqué que la douleur liée à l'activité du CCA explique statistiquement la relation entre la réponse de stress et le désagrément de la douleur rapportée par les participants. Enfin, des analyses complémentaires ont révélé que le stress réduit la connectivité fonctionnelle entre le CCA et le tronc cérébral pendant la douleur aiguë. Ces résultats indiquent que le stress réactif module la douleur et contribue à la variabilité interindividuelle de l'activité cérébrale et la réponse affective à la douleur. Discussion : Conjointement, ces études suggèrent dans un premier temps que la douleur chronique peut être exacerbée par une réponse physiologique inadéquate de l'organisme exposé à un stress récurrent, et en un second temps, que le CCA contribuerait à l'analgésie induite par le stress. Sur le plan conceptuel, ces études renforcent le point de vue prédominant suggérant que la douleur chronique induit des changements dans les systèmes cérébraux régissant les fonctions motivationnelles et affective de la douleur.

La stabilité des réponses physiologiques face au stress psychologique telle qu’étudiée sur une période de trois ans

Le stress augmente le risque de développer des maladies cardiovasculaires (CV) ainsi que de mourir de ces maladies. Selon certaines hypothèses, ce phénomène se produirait par le biais de réponses répétés de réactivité physiologique élevée ou de récupération physiologique prolongée, suite à un épisode de stress. La stabilité à long terme des réponses physiologiques face au stress a reçu peu d’attention. Objectifs: (1) Évaluer la stabilité temporelle de la réactivité et de la récupération physiologique suite au stress, à travers l’évaluation des systèmes cardiovasculaires et nerveux autonome, et ce sur un intervalle de 3 ans. (2) Déterminer si le sexe et l'âge agissent comme des variables modératrices. Méthodologie: Un total de 134 hommes et femmes en santé ont été recrutés au sein de la communauté et ont pris part à 2 séances en laboratoire. Quatre tâches, d’une durée de 5 minutes chacune et composée d’un élément de stress interpersonnel différent, ont été administrées. Chaque tâche était suivie d’une période de récupération de 5 min. Des mesures de la fréquence cardiaque (FC), de la pression artérielle (PA) et de la variabilité de la fréquence cardiaque (VFC : HF, LF et VLF) ont été obtenues. Des corrélations de Spearman et des régressions linéaires ont été effectuées. Résultats: Des corrélations test-retest significatives ont été obtenues pour toutes les mesures physiologiques, sauf pour la PA diastolique et la VLF, lors de la période de récupération. Aucune différence significative quant à la stabilité des réponses face au stress en fonction du sexe ou de l’âge des participants, n’a été trouvée. Conclusion: Les réponses physiologiques face au stress représentent des caractéristiques individuelles stables sur trois ans, peu affectées par le sexe et l’âge.

Le rôle de la méthylation de l’ADN dans les fonctions cérébrales fronto-limbiques et la réactivité au stress quotidien

La sérotonine (5-HT) joue un rôle crucial dans l'étiologie des troubles mentaux comme la dépression majeure, les troubles de comportement et les troubles anxieux. Des études ont montré que des altérations précoces du système 5-HT peuvent potentiellement influencer le développement du cerveau et le fonctionnement du système fronto-limbique, engendrant des conséquences pour la régulation émotionnelle. Il existe aussi des évidences que le stress précoce peut affecter la méthylation de l'ADN résultant d'une altération de l'expression génique. Toutefois, le lien entre la méthylation de l'ADN et la réactivité comportementale à des facteurs de stress de la vie quotidienne est inconnu. La méthylation du gène transporteur 5-HT (SLC6A4) est d'un intérêt particulier, étant donné le rôle de SLC6A4 dans le développement du cerveau, les troubles mentaux et la régulation du stress. L'objectif de cette thèse est d'étudier l'association entre (1) les niveaux périphériques de méthylation de l'ADN dans le gène SLC6A4 et les réponses neurales aux stimuli émotionnels dans les circuits fronto-limbiques du cerveau, ainsi qu’entre (2) la méthylation périphérique de SLC6A4 et la réactivité comportementale au stress de la vie quotidienne. Nous explorons également l'association entre les réponses neuronales fronto-limbique à des stimuli émotionnels et la réactivité comportementale au stress de la vie quotidienne (3). À cette fin, vingt-deux personnes (11 femmes) d’âge moyen de 34,0 ans (SD : 1,5) avec différents niveaux de méthylation au gène SLC6A4 ont été recrutés à partir de deux études longitudinales. Les participants ont subi une analyse IRMf qui comprenait une tâche de traitement émotionnel. Un questionnaire en ligne sur la réactivité au stress quotidien de la vie a été réalisé pendant 5 jours consécutifs. Des analyses corrélationnelles et de régression ont été effectuées pour examiner les associations entre les variables primaires. Les résultats préliminaires de cette étude ont montré que la méthylation de l'ADN est associée à la désactivation significative du gyrus précentral et gyrus fusiforme respectivement face à des stimuli de peur et de tristesse. Aucune association significative n'a été observée entre les niveaux de méthylation et l'activation de l'amygdale. En outre, les scores obtenus aux variables de stress de la vie quotidienne tels que la détresse chronique ont été associées à la désactivation du précuneus et du cortex cingulaire postérieur face à la tristesse. Ces résultats suggèrent l'implication potentielle des processus épigénétiques dans l'activation cérébrale spécifique et la sensibilité au stress de la vie courante.

Autobiographical Memory for Stressful Events, Traumatic Memory and Posttraumatic Stress Disorder: A Systematic Review

Stressors and traumatic events may contribute to the development of many psychopathologies, PTSD among them. People with this disorder can present significant cognitive impairments and losses in memory, particularly autobiographical memory (AM).This paper aims to present a systematic review of literature considering changes on autobiographical memory in people exposed to potentially traumatic stressors. Therefore, we performed a computerized search in databases PsycINFO, PubMed, Web of Science and Pilots in March 2012.A total of 29 articles were selected and grouped into three categories: studies comparing Trauma X PTSD, studies comparing PTSD X Trauma X Control and comparison studies according to post-traumatic symptoms. Results demonstrate that people with PTSD presents alterations in a larger number of AM components compared to the cases in which PTSD did not developed. In the same way, subjects never exposed to trauma did not demonstrate significant alterations on  AM when compared to the other groups. The results of this study allowed concluding that changes of some components of the AM are primarily associated with PTSD, but it was not possible to clarify whether such changes are related to the timely development of the disorder, or if they are also observed in traumatic memories even in the absence of disorder.

La familia del paciente en Unidad de Cuidado Intensivo (UCI)

Introducción: Ingresar a la UCI no es una experiencia exclusiva del paciente; implica e involucra directamente a la familia, en aspectos generadores de estrés, estrategias de afrontamiento, temores, actitudes y expectativas, la participación de la familia en el cuidado y el rol del psicólogo. Objetivo: Revisar de los antecedentes teóricos y empíricos sobre la experiencia de la familia en UCI. Metodología: Se revisaron 62 artículos indexados en bases de datos. Resultados: la UCI es algo desconocido tanto para el paciente como para la familia, por esto este entorno acentúa la aparición de síntomas ansiosos, depresivos y en algunos casos estrés post traumático. La muerte es uno de los principales temores que debe enfrentar la familia. Con el propósito de ajustarse a las demandas de la UCI, los familiares exhiben estrategias de afrontamiento enfocadas principalmente en la comunicación, el soporte espiritual y religioso y la toma de decisiones. El cuidado centrado en la familia permite una mejor comunicación, relación con el paciente y personal médico. El papel del psicólogo es poco explorado en el espacio de la UCI, pero este puede promover estrategias de prevención y de rehabilitación en el paciente y su grupo familiar. Discusión: es importante tener en cuenta que la muerte en UCI es una posibilidad, algunos síntomas como ansiedad, depresión pueden aparecer y mantenerse en el tiempo, centrar el cuidado en la familia permite tomar las decisiones basados en el diagnóstico y pronóstico y promueve expectativas realistas. Conclusiones: temores, expectativas, actitudes, estrategias de afrontamiento, factores generadores de estrés permiten explicar y comprender la experiencia de la familia del paciente en UCI.