933 resultados para stressful life events
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Offspring size can have pervasive effects throughout an organism's life history. Mothers can make either a few large or many small offspring, and the balance between these extremes is determined by the relationship between offspring size and performance. This relationship in turn is thought to be determined by the offspring's environment. Recently, it has become clear that events in one life-history stage can strongly affect performance in another. Given these strong carryover effects, we asked whether events in the larval phase can change the relationship between offspring size and performance in the adult phase. We manipulated the length of the larval period in the bryozoan Bugula neritina and then examined the relationship between offspring size and various parameters of adult performance under field conditions. We found that despite the adult stage being outplanted into identical conditions, different offspring sizes were predicted to be optimal, depending on the experience of those adults as larvae. This work highlights the fact that the strong phenotypic links between life-history stages may result in optimal offspring size being highly unpredictable for organisms with complex life cycles.
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Animals and plants in temperate regions must adapt their life cycle to pronounced seasonal variation. The research effort that has gone into studying these cyclical life history events, or phenological traits, has increased greatly in recent decades. As phenological traits are often correlated to temperature, they are relevant to study in terms of understanding the effect of short term environmental variation as well as long term climate change. Because of this, changes in phenology are the most obvious and among the most commonly reported responses to climate change. Moreover, phenological traits are important for fitness as they determine the biotic and abiotic environment an individual encounters. Fine-tuning of phenology allows for synchronisation at a local scale to mates, food resources and appropriate weather conditions. On a between-population scale, variation in phenology may reflect regional variation in climate. Such differences can not only give insights to life cycle adaptation, but also to how populations may respond to environmental change through time. This applies both on an ecological scale through phenotypic plasticity as well as an evolutionary scale through genetic adaptation. In this thesis I have used statistical and experimental methods to investigate both the larger geographical patterns as well as mechanisms of fine-tuning of phenology of several butterfly species. The main focus, however, is on the orange tip butterfly, Anthocharis cardamines, in Sweden and the United Kingdom. I show a contrasting effect of spring temperature and winter condition on spring phenology for three out of the five studied butterfly species. For A. cardamines there are population differences in traits responding to these environmental factors between and within Sweden and the UK that suggest adaptation to local environmental conditions. All populations show a strong negative plastic relationship between spring temperature and spring phenology, while the opposite is true for winter cold duration. Spring phenology is shifted earlier with increasing cold duration. The environmental variables show correlations, for example, during a warm year a short winter delays phenology while a warm spring speeds phenology up. Correlations between the environmental variables also occur through space, as the locations that have long winters also have cold springs. The combined effects of these two environmental variables cause a complex geographical pattern of phenology across the UK and Sweden. When predicting phenology with future climate change or interpreting larger geographical patterns one must therefore have a good enough understanding of how the phenology is controlled and take the relevant environmental factors in to account. In terms of the effect of phenological change, it should be discussed with regards to change in life cycle timing among interacting species. For example, the phenology of the host plants is important for A. cardamines fitness, and it is also the main determining factor for oviposition. In summary, this thesis shows that the broad geographical pattern of phenology of the butterflies is formed by counteracting environmental variables, but that there also are significant population differences that enable fine-tuning of phenology according to the seasonal progression and variation at the local scale.
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This article takes a broader theoretical perspective of the retail life cycle by incorporating threshold periods at important inflection points in the international growth process. Specifically, it considers one threshold interval between an early phase of disjointed international expansion and a more focused, accelerated international growth programme. It concludes that executives need to consider a set of threshold periods during the development and growth of international store operations, understand why these events occur, and consider in what ways to respond to them to overcome and cross the threshold. Salient lessons are extracted from Wal-Mart's experiences during the threshold period for other international managers. © 2005 Elsevier Ltd. All rights reserved.
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Adopting an institutional approach from organization studies, this paper explores the role of key actors on “purposeful governance for sustainability” (Smith, Voss et al. 2010: 444) through the case of smart metering in the UK. Institutions are enduring patterns in social life, reflected in identities, routines, rules, shared meanings and social relations, which enable, and constrain, the beliefs and behaviours of individual and collective actors within a field (Thornton and Ocasio 2008). Large-scale external initiatives designed to drive regime-level change prompt ‘institutional entrepreneurs’ to perform ‘institutional work’ – “purposive action aimed at creating, maintaining and disrupting institutions” (Lawrence and Suddaby, 2006). Organization scholars are giving increasing attention to ‘field-configuring events’ (FCEs) which provide social spaces for diverse organizational actors to come together to collectively shape socio-technical pathways (Lampel and Meyer 2008). Our starting point for this exploratory study is that FCEs can offer important insights to the dynamics, politics and governance of sustainability transitions. Methodologically, FCEs allow us to observe and “link field evolution at the macro-level with individual action at the micro-level” (Lampel and Meyer, 2008: 1025). We examine the work of actors during a series of smart metering industry forums over a three-year period (industry presentations [n= 77] and panel discussions [n= 16]). The findings reveal new insights about how institutional change unfolds, alongside technological transitions, in ways that are partial and aligned with the interests of powerful incumbents whose voices are frequently heard at FCEs. The paper offers three contributions. First, the study responds to calls for more research examining FCEs and the role they play in transforming institutional fields. Second, the emergent findings extend research on institutional work by advancing our understanding of a specific site of institutional work, namely a face-to-face inter-organizational arena. Finally, in line with the research agenda for innovation studies and sustainability transitions elaborated by Smith et al (2010), the paper illustrates how actors in a social system respond to, translate, and enact interventions designed to promote industrial transformation, ultimately shaping the sustainability transition pathway.
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Social media has become an effective channel for communicating both trends and public opinion on current events. However the automatic topic classification of social media content pose various challenges. Topic classification is a common technique used for automatically capturing themes that emerge from social media streams. However, such techniques are sensitive to the evolution of topics when new event-dependent vocabularies start to emerge (e.g., Crimea becoming relevant to War Conflict during the Ukraine crisis in 2014). Therefore, traditional supervised classification methods which rely on labelled data could rapidly become outdated. In this paper we propose a novel transfer learning approach to address the classification task of new data when the only available labelled data belong to a previous epoch. This approach relies on the incorporation of knowledge from DBpedia graphs. Our findings show promising results in understanding how features age, and how semantic features can support the evolution of topic classifiers.
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OBJECTIVES: To understand older adults' experiences of moving into extra care housing which offers enrichment activities alongside social and healthcare support. DESIGN: A longitudinal study was conducted which adopted a phenomenological approach to data generation and analysis. METHODS: Semi-structured interviews were conducted in the first 18 months of living in extra care housing. Interpretative phenomenological analysis was used because its commitment to idiography enabled an in-depth analysis of the subjective lived experience of moving into extra care housing. Themes generated inductively were examined against an existential-phenomenological theory of well-being. RESULTS: Learning to live in an extra care community showed negotiating new relationships was not straightforward; maintaining friendships outside the community became more difficult as capacity declined. In springboard for opportunity/confinement, living in extra care provided new opportunities for social engagement and a restored sense of self. Over time horizons began to shrink as incapacities grew. Seeking care illustrated reticence to seek care, due to embarrassment and a sense of duty to one's partner. Becoming aged presented an ontological challenge. Nevertheless, some showed a readiness for death, a sense of homecoming. CONCLUSIONS: An authentic later life was possible but residents required emotional and social support to live through the transition and challenges of becoming aged. Enhancement activities boosted residents' quality of life but the range of activities could be extended to cater better for quieter, smaller scale events within the community; volunteer activity facilitators could be used here. Peer mentoring may help build new relationships and opportunities for interactive stimulation. Acknowledging the importance of feeling-empathic imagination-in caregiving may help staff and residents relate better to each other, thus helping individuals to become ontologically secure and live well to the end.
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The purpose of this research was to explore the effects of a reform that took place in an elementary school during 2000/2001 as a result of a failure rating on the Florida Comprehensive Assessment Test on the structure and the personnel of the organization. ^ The exploration took place over a period of 10 months starting in August 2000 until June 2001. It focused on the effect of the failure rating on the: (a) structure and operation of the school; (b) morale, beliefs, behaviors, and daily lives of teachers and the principal; and (c) the effect of the reform effort on the leadership style of the principal, whether she became a transactional or a transformative leader. ^ The researcher assumed the role of a participant observer. Data sources were her personal recollections of major events that took place during the year of the reform, interviews, observations, and school documents. The sample included 15 teachers present during the time of the reform. Ten taught second through fifth grade. The remaining five participants were the music teacher, the counselor, and the writing, reading and technology specialists. Together they represented the instructional team or represented special education areas. ^ The findings indicated that the reform effort had an effect on the structure and the operation of the school. The changes included reorganization of the physical set up, changes in curriculum and instruction, changes in the means of communication among the staff, and the addition of new staff members including an official agent of change. The reform had a greater effect on the daily lives of teachers and their morale than on their beliefs and behaviors. Teachers reported that during the effort their daily lives were stressful and their morale very low due to the enormous expectations that they had to meet. On the other hand, the reform effort had a positive effect on the daily life, morale, beliefs, and behaviors of the principal. It energized her. She spoke positively about the change. She functioned as an effective, positive, resilient transactional leader who did what was necessary in order to enable the teachers to cope with the complex situation. ^
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This flyer promotes the event " Huber Matos: His Life and Legacy (A Panel Discussion)".
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This flyer promotes the event "The Urban Insurrection against Batista: The Life and Times of José Antonio Echeverria, A Symposium".
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This flyer promotes the event "The Life and Work of Severo Sarduy: A Conversation with Mercedes Sarduy and Catalina Quesada".
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The purpose of this research was to explore the effects of a reform that took place in an elementary school during 2000/2001 as a result of a failure rating on the Florida Comprehensive Assessment Test on the structure and the personnel of the organization. The exploration took place over a period of 10 months starting in August 2000 until June 2001. It focused on the effect of the failure rating on the: (a) structure and operation of the school; (b) morale, beliefs, behaviors, and daily lives of teachers and the principal; and (c) the effect of the reform effort on the leadership style of the principal, whether she became a transactional or a transformative leader. The researcher assumed the role of a participant observer. Data sources were her personal recollections of major events that took place during the year of the reform, interviews, observations, and school documents. The sample included 15 teachers present during the time of the reform. Ten taught second through fifth grade. The remaining five participants were the music teacher, the counselor, and the writing, reading and technology specialists. Together they represented the instructional team or represented special education areas. The findings indicated that the reform effort had an effect on the structure and the operation of the school. The changes included reorganization of the physical set up, changes in curriculum and instruction, changes in the means of communication among the staff, and the addition of new staff members including an official agent of change. The reform had a greater effect on the daily lives of teachers and their morale than on their beliefs and behaviors. Teachers reported that during the effort their daily lives were stressful and their morale very low due to the enormous expectations that they had to meet. On the other hand, the reform effort had a positive effect on the daily life, morale, beliefs, and behaviors of the principal. It energized her. She spoke positively about the change. She functioned as an effective, positive, resilient transactional leader who did what was necessary in order to enable the teachers to cope with the complex situation.
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Social attitudes, attitudes toward financial risk and attitudes toward deferred gratification are thought to influence many important economic decisions over the life-course. In economic theory, these attitudes are key components in diverse models of behavior, including collective action, saving and investment decisions and occupational choice. The relevance of these attitudes have been confirmed empirically. Yet, the factors that influence them are not well understood. This research evaluates how these attitudes are affected by large disruptive events, namely, a natural disaster and a civil conflict, and also by an individual-specific life event, namely, having children.
By implementing rigorous empirical strategies drawing on rich longitudinal datasets, this research project advances our understanding of how life experiences shape these attitudes. Moreover, compelling evidence is provided that the observed changes in attitudes are likely to reflect changes in preferences given that they are not driven just by changes in financial circumstances. Therefore the findings of this research project also contribute to the discussion of whether preferences are really fixed, a usual assumption in economics.
In the first chapter, I study how altruistic and trusting attitudes are affected by exposure to the 2004 Indian Ocean tsunami as long as ten years after the disaster occurred. Establishing a causal relationship between natural disasters and attitudes presents several challenges as endogenous exposure and sample selection can confound the analysis. I take on these challenges by exploiting plausibly exogenous variation in exposure to the tsunami and by relying on a longitudinal dataset representative of the pre-tsunami population in two districts of Aceh, Indonesia. The sample is drawn from the Study of the Tsunami Aftermath and Recovery (STAR), a survey with data collected both before and after the disaster and especially designed to identify the impact of the tsunami. The altruistic and trusting attitudes of the respondents are measured by their behavior in the dictator and trust games. I find that witnessing closely the damage caused by the tsunami but without suffering severe economic damage oneself increases altruistic and trusting behavior, particularly towards individuals from tsunami affected communities. Having suffered severe economic damage has no impact on altruistic behavior but may have increased trusting behavior. These effects do not seem to be caused by the consequences of the tsunami on people’s financial situation. Instead they are consistent with how experiences of loss and solidarity may have shaped social attitudes by affecting empathy and perceptions of who is deserving of aid and trust.
In the second chapter, co-authored with Ryan Brown, Duncan Thomas and Andrea Velasquez, we investigate how attitudes toward financial risk are affected by elevated levels of insecurity and uncertainty brought on by the Mexican Drug War. To conduct our analysis, we pair the Mexican Family Life Survey (MxFLS), a rich longitudinal dataset ideally suited for our purposes, with a dataset on homicide rates at the month and municipality-level. The homicide rates capture well the overall crime environment created by the drug war. The MxFLS elicits risk attitudes by asking respondents to choose between hypothetical gambles with different payoffs. Our strategy to identify a causal effect has two key components. First, we implement an individual fixed effects strategy which allows us to control for all time-invariant heterogeneity. The remaining time variant heterogeneity is unlikely to be correlated with changes in the local crime environment given the well-documented political origins of the Mexican Drug War. We also show supporting evidence in this regard. The second component of our identification strategy is to use an intent-to-treat approach to shield our estimates from endogenous migration. Our findings indicate that exposure to greater local-area violent crime results in increased risk aversion. This effect is not driven by changes in financial circumstances, but may be explained instead by heightened fear of victimization. Nonetheless, we find that having greater economic resources mitigate the impact. This may be due to individuals with greater economic resources being able to avoid crime by affording better transportation or security at work.
The third chapter, co-authored with Duncan Thomas, evaluates whether attitudes toward deferred gratification change after having children. For this study we also exploit the MxFLS, which elicits attitudes toward deferred gratification (commonly known as time discounting) by asking individuals to choose between hypothetical payments at different points in time. We implement a difference-in-difference estimator to control for all time-invariant heterogeneity and show that our results are robust to the inclusion of time varying characteristics likely correlated with child birth. We find that becoming a mother increases time discounting especially in the first two years after childbirth and in particular for those women without a spouse at home. Having additional children does not have an effect and the effect for men seems to go in the opposite direction. These heterogeneous effects suggest that child rearing may affect time discounting due to generated stress or not fully anticipated spending needs.
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The focus on how one is behaving, feeling, and thinking, provides a powerful source of self-knowledge. How is this self-knowledge utilized in the dynamic reconstruction of autobiographical memories? How, in turn, might autobiographical memories support identity and the self-system? I address these questions through a critical review of the literature on autobiographical memory and the self-system, with a special focus on the self-concept, self-knowledge, and identity. I then outline the methods and results of a prospective longitudinal study examining the effects of an identity change on memory for events related to that identity. Participant-rated memory characteristics, computer-generated ratings of narrative content and structure, and neutral-observer ratings of coherence were examined for changes over time related to an identity-change, as well as for their ability to predict an identity-change. The conclusions from this study are threefold: (1) when the rated centrality of an event decreases, the reported instances of retrieval, as well as the phenomenology associated with retrieval and the number of words used to describe the memory, also decrease; (2) memory accuracy (here, estimating past behaviors) was not influenced by an identity change; and (3) remembering is not unidirectional – characteristics of identity-relevant memories and the life story predict and may help support persistence with an identity (here, an academic trajectory).
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Death of an infant is acutely stressful for parents and professionals. Little is known about junior nurses' experiences providing end-of-life care in Neonatal units (NNU). This study aimed to better understand junior nurses' experiences providing end-of-life care in NNU. Neonatal nurses (n = 12) with less than 3 years experience participated in a focus group. Nominal Group Technique (NGT) was used to build consensus around the challenges faced, alongside suggested developments in improving future care provision. Primary analysis involved successive rounds of ranking and decision-making whilst secondary analysis involved thematic analysis. All issues, whether environmental, professional or social appeared driven by an awareness on the part of nurses, that there was no ‘second chance’ which created a huge pressure to ‘get if right’ for the infants and families. Regarding future care 2 areas of improvement identified were ‘Education and Training’ and Support. This paper unpacks these findings making recommendations for practice.
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Background: Pain management is a cornerstone of palliative care. The clinical issues encountered by physicians when managing pain in patients dying with advanced dementia, and how these may impact on prescribing and treatment, are unknown. Aim: To explore physicians’ experiences of pain management for patients nearing the end of life, the impact of these on prescribing and treatment approaches, and the methods employed to overcome these challenges. Design: Qualitative, semi-structured interview study exploring: barriers to and facilitators of pain management, prescribing and treatment decisions, and training needs. Thematic analysis was used to elicit key themes. Settings/Participants: Twenty-three physicians, responsible for treating patients with advanced dementia approaching the end of life, were recruited from primary care (n=9), psychiatry (n=7) and hospice care (n=7). Results: Six themes emerged: diagnosing pain, complex prescribing and treatment approaches, side-effects and adverse events, route of administration, importance of sharing knowledge and training needs. Knowledge exchange was often practised through liaison with physicians from other specialties. Cross-specialty mentoring, and the creation of knowledge networks were believed to improve pain management in this patient population. Conclusions: Pain management in end-stage dementia is complex, requiring cross-population of knowledge between palliative care specialists and non-specialists, in addition to collateral information provided by other health professionals and patients’ families. Regular, cost- and time-effective mentoring and ongoing professional development are perceived to be essential in empowering physicians to meet clinical challenges in this area.