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Sample records for adaptive coping mechanisms

  1. Combat health care providers and resiliency: adaptive coping mechanisms during and after deployment.

    PubMed

    Gibbons, Susanne W; Shafer, Michaela; Aramanda, Larry; Hickling, Edward J; Benedek, David M

    2014-05-01

    The purpose of this investigation was to understand the varied health care provider responses to traumas by identifying perceptions of control and self-efficacy, appraisal styles, and postevent coping strategies in active duty military nurses and physicians deployed to combat/terrorist regions. Twenty purposively sampled military health care providers completed a descriptive questionnaire, the Posttraumatic Stress Disorder Checklist, the General Self-Efficacy Scale, and a recorded semistructured interview that was later transcribed and content analyzed. Cognitive-behavioral determinants of healthy response to trauma were used to frame this descriptive interpretive study and to assist with developing a model for healthy adaptation in trauma-exposed health care providers. Participants felt they had the greatest control over their health care provider role in theater, and most expressed a belief that a sense of control and a sense of purpose were important to their coping. All used some form of social support to cope and many found calming activities that allowed for self-reflection to be helpful. Results from this analysis can be used to inform interventions and promote postevent coping behaviors that increase social support, strengthen important bonds, and enhance involvement in activities that elicit positive emotions. Health care providers experienced positive outcomes despite considerable traumatic exposure by using coping strategies that map closely to several principles of psychological first aid. This suggests a need to train all medical personnel in these concepts as they appear helpful in mitigating responses to the stress of combat-related exposures. PMID:23855421

  2. Coping with the Forced Swim Stressor: Towards Understanding an Adaptive Mechanism.

    PubMed

    de Kloet, E R; Molendijk, M L

    2016-01-01

    In the forced swim test (FST) rodents progressively show increased episodes of immobility if immersed in a beaker with water from where escape is not possible. In this test, a compound qualifies as a potential antidepressant if it prevents or delays the transition to this passive (energy conserving) behavioural style. In the past decade however the switch from active to passive "coping" was used increasingly to describe the phenotype of an animal that has been exposed to a stressful history and/or genetic modification. A PubMed analysis revealed that in a rapidly increasing number of papers (currently more than 2,000) stress-related immobility in the FST is labeled as a depression-like phenotype. In this contribution we will examine the different phases of information processing during coping with the forced swim stressor. For this purpose we focus on the action of corticosterone that is mediated by the closely related mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) in the limbic brain. The evidence available suggests a model in which we propose that the limbic MR-mediated response selection operates in complementary fashion with dopaminergic accumbens/prefrontal executive functions to regulate the transition between active and passive coping styles. Upon rescue from the beaker the preferred, mostly passive, coping style is stored in the memory via a GR-dependent action in the hippocampal dentate gyrus. It is concluded that the rodent's behavioural response to a forced swim stressor does not reflect depression. Rather the forced swim experience provides a unique paradigm to investigate the mechanistic underpinning of stress coping and adaptation. PMID:27034848

  3. Coping with the Forced Swim Stressor: Towards Understanding an Adaptive Mechanism

    PubMed Central

    de Kloet, E. R.; Molendijk, M. L.

    2016-01-01

    In the forced swim test (FST) rodents progressively show increased episodes of immobility if immersed in a beaker with water from where escape is not possible. In this test, a compound qualifies as a potential antidepressant if it prevents or delays the transition to this passive (energy conserving) behavioural style. In the past decade however the switch from active to passive “coping” was used increasingly to describe the phenotype of an animal that has been exposed to a stressful history and/or genetic modification. A PubMed analysis revealed that in a rapidly increasing number of papers (currently more than 2,000) stress-related immobility in the FST is labeled as a depression-like phenotype. In this contribution we will examine the different phases of information processing during coping with the forced swim stressor. For this purpose we focus on the action of corticosterone that is mediated by the closely related mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) in the limbic brain. The evidence available suggests a model in which we propose that the limbic MR-mediated response selection operates in complementary fashion with dopaminergic accumbens/prefrontal executive functions to regulate the transition between active and passive coping styles. Upon rescue from the beaker the preferred, mostly passive, coping style is stored in the memory via a GR-dependent action in the hippocampal dentate gyrus. It is concluded that the rodent's behavioural response to a forced swim stressor does not reflect depression. Rather the forced swim experience provides a unique paradigm to investigate the mechanistic underpinning of stress coping and adaptation. PMID:27034848

  4. Prochlorococcus and Synechococcus have Evolved Different Adaptive Mechanisms to Cope with Light and UV Stress

    PubMed Central

    Mella-Flores, Daniella; Six, Christophe; Ratin, Morgane; Partensky, Frédéric; Boutte, Christophe; Le Corguillé, Gildas; Marie, Dominique; Blot, Nicolas; Gourvil, Priscillia; Kolowrat, Christian; Garczarek, Laurence

    2012-01-01

    Prochlorococcus and Synechococcus, which numerically dominate vast oceanic areas, are the two most abundant oxygenic phototrophs on Earth. Although they require solar energy for photosynthesis, excess light and associated high UV radiations can induce high levels of oxidative stress that may have deleterious effects on their growth and productivity. Here, we compared the photophysiologies of the model strains Prochlorococcus marinus PCC 9511 and Synechococcus sp. WH7803 grown under a bell-shaped light/dark cycle of high visible light supplemented or not with UV. Prochlorococcus exhibited a higher sensitivity to photoinactivation than Synechococcus under both conditions, as shown by a larger drop of photosystem II (PSII) quantum yield at noon and different diel patterns of the D1 protein pool. In the presence of UV, the PSII repair rate was significantly depressed at noon in Prochlorococcus compared to Synechococcus. Additionally, Prochlorococcus was more sensitive than Synechococcus to oxidative stress, as shown by the different degrees of PSII photoinactivation after addition of hydrogen peroxide. A transcriptional analysis also revealed dramatic discrepancies between the two organisms in the diel expression patterns of several genes involved notably in the biosynthesis and/or repair of photosystems, light-harvesting complexes, CO2 fixation as well as protection mechanisms against light, UV, and oxidative stress, which likely translate profound differences in their light-controlled regulation. Altogether our results suggest that while Synechococcus has developed efficient ways to cope with light and UV stress, Prochlorococcus cells seemingly survive stressful hours of the day by launching a minimal set of protection mechanisms and by temporarily bringing down several key metabolic processes. This study provides unprecedented insights into understanding the distinct depth distributions and dynamics of these two picocyanobacteria in the field. PMID:23024637

  5. Surviving the crisis: Adaptive wisdom, coping mechanisms and local responses to avian influenza threats in Haining, China.

    PubMed

    Zhang, Letian; Pan, Tianshu

    2008-04-01

    Based on ethnographic research conducted in the summer of 2006, this paper examines local responses to the imminent threat of avian flu in Haining County of Zhejiang Province. During our field investigation, we conducted interviews with officials from local medical institutions (including the hospitals, the animal husbandry and veterinary station, and health clinics), to bureaus of public health and agro-economy. We also visited chicken farms, restaurants and farming households. We address the following factors that commonly structured the perceptions and actions of different social actors in the area of study: The changing mode of information-sharing and communication practices in the local communities; the official drive to professionalize the emergency response management system in the county; and the coping mechanisms that helped the villagers and town residents to weather the storm of avian flu. Our field research suggests that collective survival consciousness was translated into a spirit of voluntarism during the crisis. One important practical lesson we have learned from this study is that the adaptive wisdom embedded in local memories demonstrated its operational worth as a resourceful knowledge base for ordinary farmers to deal with food shortage, famine, plague and future pandemics. PMID:27268990

  6. Coping and adaptation process during puerperium

    PubMed Central

    Muñoz de Rodríguez, Lucy; Ruiz de Cárdenas, Carmen Helena

    2012-01-01

    Introduction: The puerperium is a stage that produces changes and adaptations in women, couples and family. Effective coping, during this stage, depends on the relationship between the demands of stressful or difficult situations and the recourses that the puerperal individual has. Roy (2004), in her Middle Range Theory about the Coping and Adaptation Processing, defines Coping as the ''behavioral and cognitive efforts that a person makes to meet the environment demands''. For the puerperal individual, the correct coping is necessary to maintain her physical and mental well being, especially against situations that can be stressful like breastfeeding and return to work. According to Lazarus and Folkman (1986), a resource for coping is to have someone who receives emotional support, informative and / or tangible. Objective: To review the issue of women coping and adaptation during the puerperium stage and the strategies that enhance this adaptation. Methods: search and selection of database articles: Cochrane, Medline, Ovid, ProQuest, Scielo, and Blackwell Synergy. Other sources: unpublished documents by Roy, published books on Roy´s Model, Websites from of international health organizations. Results: the need to recognize the puerperium as a stage that requires comprehensive care is evident, where nurses must be protagonist with the care offered to women and their families, considering the specific demands of this situation and recourses that promote effective coping and the family, education and health services. PMID:24893059

  7. Eating Disorders as Coping Mechanisms

    ERIC Educational Resources Information Center

    Wagener, Amy M.; Much, Kari

    2010-01-01

    This article focuses on the complex nature of eating disorders, specifically highlighting their use as coping mechanisms for underlying emotional and psychological concerns. Case examples of college counseling center clients are discussed in order to illustrate common ways in which eating disorders are utilized by clients with varying…

  8. Assessing the Process of Marital Adaptation: The Marital Coping Inventory.

    ERIC Educational Resources Information Center

    Zborowski, Lydia L.; Berman, William H.

    Studies on coping with life events identify marriage as a distinct situational stressor, in which a wide range of coping strategies specific to the marital relationship are employed. This study examined the process of martial adaptation, identified as a style of coping, in 116 married volunteers. Subjects completed a demographic questionnaire, the…

  9. Involuntary coping mechanisms: a psychodynamic perspective

    PubMed Central

    Vaillant, George E.

    2011-01-01

    Coping responses to stress can be divided into three broad categories. The first coping category involves voluntarily mobilizing social supports. The second category involves voluntary coping strategies like rehearsing responses to danger. The third coping category, like fever and leukocytosis, is involuntary. It entails deploying unconscious homeostatic mechanisms that reduce the disorganizing effects of sudden stress, DSM-5 offers a tentative hierarchy of defenses, from psychotic to immature to mature. The 70-year prospective Study of Development at Harvard provides a clinical validation of this hierarchy Maturity of coping predicted psychosocial adjustment to aging 25 years later, and was associated with not developing symptoms of post-traumatic stress disorder after very severe WWII combat. PMID:22034454

  10. Coping Mechanisms of Part-Time Students

    ERIC Educational Resources Information Center

    Yum, Jessie C. K.; Kember, David; Siaw, Irene

    2005-01-01

    A characteristic shared by the majority of adult students is that they are undertaking part-time study. For these adult learners one of the major difficulties is how to find time for their study. This paper reports the coping mechanisms that part-time adult students adopt to meet the additional demands that study puts on their existing commitments…

  11. [Coping strategies in adaptation of higher education students].

    PubMed

    das Neves Mira Freitas, Helena Cristina

    2007-01-01

    The adjustment to higher education can be understood as a multidimensional process, which requires by the student a development of adaptive skills to a new and dynamic context in itself. To meet these challenges students have to develop effective coping strategies, enabling them to be adapted to the context. The school has a key role in the help it can give to these young people, in order to adapt effectively. PMID:18372532

  12. Is academic buoyancy anything more than adaptive coping?

    PubMed

    Putwain, David W; Connors, Liz; Symes, Wendy; Douglas-Osborn, Erica

    2012-05-01

    Academic buoyancy refers to a positive, constructive, and adaptive response to the types of challenges and setbacks experienced in a typical and everyday academic setting. In this project we examined whether academic buoyancy explained any additional variance in test anxiety over and above that explained by coping. Two hundred and ninety-eight students in their final two years of compulsory schooling completed self-report measures of academic buoyancy, coping, and test anxiety. Results suggested that buoyancy was inversely related to test anxiety and unrelated to coping. With the exception of test-irrelevant thoughts, test anxiety was positively related to avoidance coping and social support. Test-irrelevant thoughts were inversely related to task focus, unrelated to social support, and positively related to avoidance. A hierarchical regression analysis showed that academic buoyancy explained a significant additional proportion of variance in test anxiety when the variance for coping had already been accounted for. These findings suggest that academic buoyancy can be considered as a distinct construct from that of adaptive coping. PMID:21644112

  13. Coping Strategies and Adaptation of Mothers of Children with Handicapping Conditions.

    ERIC Educational Resources Information Center

    Hooshyar, Nahid T.

    Mothers' coping mechanisms and adaptations to having a handicapped child were analyzed through extensive structured interviews with mothers of eight preschool-aged Down syndrome children and a language impaired child. Three illustrative case studies are presented, and general conclusions are drawn. Mothers of Down syndrome children go through the…

  14. Coping styles and behavioural flexibility: towards underlying mechanisms

    PubMed Central

    Coppens, Caroline M.; de Boer, Sietse F.; Koolhaas, Jaap M.

    2010-01-01

    A coping style (also termed behavioural syndrome or personality) is defined as a correlated set of individual behavioural and physiological characteristics that is consistent over time and across situations. This relatively stable trait is a fundamental and adaptively significant phenomenon in the biology of a broad range of species, i.e. it confers differential fitness consequences under divergent environmental conditions. Behavioural flexibility appears to be an important underlying attribute or feature of the coping style that might explain consistency across situations. Proactive coping is characterized by low flexibility expressed as rather rigid, routine-like behavioural tendencies and reduced impulse control (behavioural inhibition) in operant conditioning paradigms. This article summarizes some of the evidence that individual differentiation in behavioural flexibility emerges as a function of underlying variability in the activation of a brain circuitry that includes the prefrontal cortex and its key neurochemical signalling pathways (e.g. dopaminergic and serotonergic input). We argue that the multidimensional nature of animal personality and the terminology used for the various dimensions should reflect the differential pattern of activation of the underlying neuronal network and the behavioural control function of its components. Accordingly, unravelling the molecular mechanisms that give rise to individual differences in the coping style will be an important topic in biobehavioural neurosciences, ecology and evolutionary biology. PMID:21078654

  15. Age Differences in the Use of Coping Mechanisms.

    ERIC Educational Resources Information Center

    McCrae, Robert R.

    1982-01-01

    Reports two cross-sectional studies assessing the influence of age on the use of 28 coping mechanisms. Results showed older people coped similiarly to younger people, and where they employed different mechanisms it was because of different types of stress. Middle-aged and older people used less hostile and escapist reactions. (Author/RC)

  16. Coping Mechanisms of Unemployed African Men with Dependents.

    ERIC Educational Resources Information Center

    van der Merwe, Pauline; Greeff, Abraham P.

    2003-01-01

    Evaluates the efficiency of the coping mechanisms of 82 unemployed African men with dependents. Results revealed significant relationships between perceived stress and stressful life events, as well as between perceived stress and four groups of coping mechanisms, the strongest relationships being reported for stressful life events, psychological…

  17. Interactions between Adaptive Coping and Drinking to Cope in Predicting Naturalistic Drinking and Drinking Following a Lab-Based Psychosocial Stressor

    PubMed Central

    Merrill, Jennifer E.; Thomas, Suzanne E.

    2012-01-01

    Using alcohol to cope (i.e., coping motivation) and general coping style both are theorized and demonstrated empirically to lead to problematic drinking. In the present study, we sought to examine whether these factors interact to predict alcohol use, both retrospectively reported and in the lab following a stressor task. Social drinkers (N=50, 50% women) received the Trier Social Stress Test (TSST), and then consumed beer under the guise of a taste-test. A Timeline Followback interview to assess past month alcohol use, the Drinking Motives Questionnaire (DMQ), and the COPE (to assess adaptive coping) were administered prior to the laboratory challenge. Multiple regression models were used to examine DMQ coping motives, adaptive coping, and their interaction as predictors of milliliters (mls) of beer consumed in a clinical laboratory setting. The association between coping motives and mls beer was positive at both high and low levels of adaptive coping, but at low levels of adaptive coping, this association was stronger. In contrast, there was no interaction between adaptive coping and coping motives in predicting quantity and frequency of drinking in the prior month. Findings suggest that stronger coping motives for drinking predict greater alcohol consumption following a stress provocation to a greater extent when an individual is lacking in adaptive coping strategies. As both general coping skills and coping motives for alcohol use are responsive to intervention, study of the conditions under which they exert unique and interactive effects is important. PMID:23254217

  18. Internet Addiction and Psychosocial Maladjustment: Avoidant Coping and Coping Inflexibility as Psychological Mechanisms.

    PubMed

    Cheng, Cecilia; Sun, Peizhen; Mak, Kwok-Kei

    2015-09-01

    This 6 month prospective study systematically tested some multivariate models that advanced the understanding of the psychological mechanisms underlying Internet addiction and psychosocial maladjustment. On the basis of previous theories, avoidant coping and coping inflexibility were proposed as underlying mechanisms. Participants were 271 Chinese undergraduates (75% women, Mage=20.49) who took part in both phases of this study. Structural equation modeling was performed to obtain the best fit models for both the cross-sectional and the prospective data. The cross-sectional model testing revealed statistically significant mediating effects for both avoidant coping (β=0.149 [95% CI 0.071-0.226], p=0.002) and coping flexibility (β=0.048 [95% CI 0.013-0.081], p=0.032). The prospective model testing further showed that avoidant coping mediated the relationship between Internet addiction and Time 2 psychosocial maladjustment (β=0.141 [95% CI 0.065-0.216], p=0.005), as well as that between coping flexibility and Time 2 psychosocial maladjustment (β=-0.096 [95% CI -0.161 to -0.031], p=0.015). This study was the first to establish theory-driven models, which unveiled an inflexible, avoidant coping style as psychological mechanisms that explained the link between Internet addiction and psychosocial maladjustment. PMID:26348815

  19. Adaptive Capacity in Tanzanian Maasailand: Changing strategies to cope with drought in fragmented landscapes

    PubMed Central

    Riosmena, Fernando

    2014-01-01

    This study examines the ways in which the adaptive capacity of households to climatic events varies within communities and is mediated by institutional and landscape changes. We present qualitative and quantitative data from two Maasai communities differentially exposed to the devastating drought of 2009 in Northern Tanzania. We show how rangeland fragmentation combined with the decoupling of institutions and landscapes are affecting pastoralists ability to cope with drought. Our data highlight that mobility remains a key coping mechanism for pastoralists to avoid cattle loss during a drought. However, mobility is now happening in new ways that require not only large amounts of money but new forms of knowledge and connections outside of customary reciprocity networks. Those least affected by the drought, in terms of cattle lost, were those with large herds who were able to sell some of their cattle and to pay for private access to pastures outside of Maasai areas. Drawing on an entitlements framework, we argue that the new coping mechanisms are not available to all, could be making some households more vulnerable to climate change, and reduce the adaptive capacity of the overall system as reciprocity networks and customary institutions are weakened. As such, we posit that adaptive capacity to climate change is uneven within and across communities, is scale-dependent, and is intimately tied to institutional and landscape changes. PMID:25400331

  20. Adaptive Capacity in Tanzanian Maasailand: Changing strategies to cope with drought in fragmented landscapes.

    PubMed

    Goldman, Mara J; Riosmena, Fernando

    2013-06-01

    This study examines the ways in which the adaptive capacity of households to climatic events varies within communities and is mediated by institutional and landscape changes. We present qualitative and quantitative data from two Maasai communities differentially exposed to the devastating drought of 2009 in Northern Tanzania. We show how rangeland fragmentation combined with the decoupling of institutions and landscapes are affecting pastoralists ability to cope with drought. Our data highlight that mobility remains a key coping mechanism for pastoralists to avoid cattle loss during a drought. However, mobility is now happening in new ways that require not only large amounts of money but new forms of knowledge and connections outside of customary reciprocity networks. Those least affected by the drought, in terms of cattle lost, were those with large herds who were able to sell some of their cattle and to pay for private access to pastures outside of Maasai areas. Drawing on an entitlements framework, we argue that the new coping mechanisms are not available to all, could be making some households more vulnerable to climate change, and reduce the adaptive capacity of the overall system as reciprocity networks and customary institutions are weakened. As such, we posit that adaptive capacity to climate change is uneven within and across communities, is scale-dependent, and is intimately tied to institutional and landscape changes. PMID:25400331

  1. Perceived Control and Adaptive Coping: Programs for Adolescent Students Who Have Learning Disabilities

    ERIC Educational Resources Information Center

    Firth, Nola; Frydenberg, Erica; Greaves, Daryl

    2008-01-01

    This study explored the effect of a coping program and a teacher feedback intervention on perceived control and adaptive coping for 98 adolescent students who had specific learning disabilities. The coping program was modified to build personal control and to address the needs of students who have specific learning disabilities. The teacher…

  2. Mechanisms of intestinal adaptation.

    PubMed

    Rubin, Deborah C; Levin, Marc S

    2016-04-01

    Following loss of functional small bowel surface area due to surgical resection for therapy of Crohn's disease, ischemia, trauma or other disorders, the remnant gut undergoes a morphometric and functional compensatory adaptive response which has been best characterized in preclinical models. Increased crypt cell proliferation results in increased villus height, crypt depth and villus hyperplasia, accompanied by increased nutrient, fluid and electrolyte absorption. Clinical observations suggest that functional adaptation occurs in humans. In the immediate postoperative period, patients with substantial small bowel resection have massive fluid and electrolyte loss with reduced nutrient absorption. For many patients, the adaptive response permits partial or complete weaning from parenteral nutrition (PN), within two years following resection. However, others have life-long PN dependence. An understanding of the molecular mechanisms that regulate the gut adaptive response is critical for developing novel therapies for short bowel syndrome. Herein we present a summary of key studies that seek to elucidate the mechanisms that regulate post-resection adaptation, focusing on stem and crypt cell proliferation, epithelial differentiation, apoptosis, enterocyte function and the role of growth factors and the enteric nervous system. PMID:27086888

  3. Vulnerability, Sensitivity, and Coping/Adaptive Capacity Worldwide

    SciTech Connect

    Malone, Elizabeth L.; Brenkert, Antoinette L.

    2009-10-01

    Research and analyses have repeatedly shown that impacts of climate change will be unevenly distributed and will affect various societies in various ways. The severity of impacts will depend in part on ability to cope in the short term and adapt in the longer term. However, it has been difficult to find a comparative basis on which to assess differential impacts of climate change. This chapter describes the Vulnerability-Resilience Indicator Model that uses 18 proxy indicators, grouped into 8 elements, to assess on a quantitative basis the comparative potential vulnerability and resilience of countries to climate change. The model integrates socioeconomic and environmental information such as land use, crop production, water availability, per capita GDP, inequality, and health status. Comparative results for 160 countries are presented and analyzed.

  4. Development of Maladaptive Coping: A Functional Adaptation to Chronic, Uncontrollable Stress

    PubMed Central

    Wadsworth, Martha E.

    2015-01-01

    Health disparities are rooted in childhood and stem from adverse early environments that damage physiologic stress-response systems. Developmental psychobiological models of the effects of chronic stress account for both the negative effects of a stress-response system calibrated to a dangerous and unpredictable environment from a health perspective, and the positive effects of such an adaptively calibrated stress response from a functional perspective. Our research suggests that contexts that produce functionally adapted physiologic responses to stress also encourage a functionally adapted coping response—coping that can result in maladjustment in physical and mental health, but enables children to grow and develop within those contexts. In this article, I highlight the value of reframing maladaptive coping as functional adaptation to understand more completely the development of children’s coping in different contexts, and the value of such a conceptual shift for coping-based theory, research, and intervention. PMID:26019717

  5. Change in Coping and Defense Mechanisms across Adulthood: Longitudinal Findings in a European-American Sample

    PubMed Central

    Diehl, Manfred; Chui, Helena; Hay, Elizabeth L.; Lumley, Mark A.; Grühn, Daniel; Labouvie-Vief, Gisela

    2014-01-01

    This study examined longitudinal changes in coping and defense mechanisms in an age- and gender-stratified sample of 392 European-American adults. Nonlinear age-related changes were found for the coping mechanisms of sublimation and suppression and the defense mechanisms of intellectualization, doubt, displacement, and regression. The change trajectories for sublimation and suppression showed that their use increased from adolescence to late middle age and early old age, and remained mostly stable into late old age. The change trajectory for intellectualization showed that the use of this defense mechanism increased from adolescence to middle age, remained stable until late midlife, and started to decline thereafter. The defense mechanisms of doubt, displacement, and regression showed decreases from adolescence until early old age, with increases occurring again after the age of 65. Linear age-related decreases were found for the coping mechanism of ego regression and the defense mechanisms of isolation and rationalization. Gender and socioeconomic status were associated with the mean levels of several coping and defense mechanisms, but did not moderate age-related changes. Increases in ego level were associated with increased use of the defense mechanism intellectualization and decreased use of the defense mechanisms of doubt and displacement. Overall, these findings in a European-American sample suggest that most individuals showed development in the direction of more adaptive and less maladaptive coping and defense strategies from adolescence until late middle age or early old age. However, in late old age this development was reversed, presenting potential challenges to the adaptive capacity of older adults. PMID:23834293

  6. Coping with Relationship Stressors: The Impact of Different Working Models of Attachment and Links to Adaptation

    ERIC Educational Resources Information Center

    Seiffge-Krenke, Inge

    2006-01-01

    The study explores the role of working models of attachment in the process of coping with relationship stressors with a focus on long-term adaptation. In a 7-year longitudinal study of 112 participants, stress and coping were assessed during adolescence and emerging adulthood. In addition, working models of attachment were assessed by employing…

  7. Women's Eating Problems: An Analysis of a Coping Mechanism.

    ERIC Educational Resources Information Center

    Hooker, Dawn; Convisser, Ellen

    1983-01-01

    Discusses clinical observations of women (N=100) with eating problems, focusing on emotional issues as well as how these women use food as a coping mechanism. Reported that therapy helped these women shed anxiety and fear about food and to see eating as something they consciously choose to do. (LLL)

  8. Mapping Nondominant Voices into Understanding Stress-Coping Mechanisms

    ERIC Educational Resources Information Center

    Iwasaki, Yoshitaka; Bartlett, Judith; MacKay, Kelly; Mactavish, Jennifer; Ristock, Janice

    2008-01-01

    This study reports key findings from a research project, which examined the stress and coping mechanisms of several nondominant groups of individuals. The groups were based in Winnipeg, Manitoba, Canada and included (a) Aboriginal individuals with diabetes, (b) individuals with disabilities, and (c) gays and lesbians. Our analyses of personal…

  9. EFL Foreign Teacher Stress in Korea: Causes and Coping Mechanisms

    ERIC Educational Resources Information Center

    Brundage, Gregory C.

    2007-01-01

    Survey study of 53 foreign EFL teachers in Jeonju City, South Korea looks at causes of teacher stress and coping mechanisms between the years of 2004 and 2006. Results show foreign EFL teachers report moderate levels of stress and attribute stresses in roughly equal measures to student misbehavior and school director/administrative sources. Survey…

  10. Stress Coping Mechanisms in Elderly Adults: An Initial Study of Recreational and Other Coping Behaviors in Nursing Home Patients

    ERIC Educational Resources Information Center

    Hunter, I. Roy; Gillen, Mark C.

    2009-01-01

    Residents (N = 32) of 3 skilled nursing homes participated in a study designed to document the nature of the stressors they experienced and the coping mechanisms they used. Medical issues were the most common stressors. The most common coping responses were prayer, reading, watching television, listening to music, and talking to friends and…

  11. Family Adaptation and Coping among Siblings of Cancer Patients, Their Brothers and Sisters, and Nonclinical Controls.

    ERIC Educational Resources Information Center

    Madan-Swain, Avi; And Others

    1993-01-01

    Examined coping and family adaptation in siblings (n=32) of cancer patients, their ill brothers and sisters (n=19), and control group of nonclinical children (n=10) with healthy siblings. Gender and age of sibling, birth order, and number of siblings were examined. Found better adaptation in larger families and decreased family involvement among…

  12. Compulsive Eating: The Emotional Link of Its Use as a Coping Mechanism for Resident Freshman Female College Students.

    ERIC Educational Resources Information Center

    Beylerian, Nvair Kadian

    An 18-year old's freshman year in college is not only a test of his or her intellect, but also a test in social skills, adaptability to new living situations, and other conditions. This study examined the link of emotions to compulsive eating and its use as a coping mechanism for female college students. It explores the stresses of the transition…

  13. Coping Mechanisms Used by Rural Principals. SSTA Research Centre Report #95-13.

    ERIC Educational Resources Information Center

    SSTA Research in Brief, 1995

    1995-01-01

    A survey examined the use of coping mechanisms by rural Saskatchewan principals and principals' perceptions of the effectiveness of coping mechanisms used. A modified form of the Ways of Coping questionnaire was mailed to 110 rural principals throughout Saskatchewan (Canada); 48 usable responses were returned. The questionnaire focused on eight…

  14. At a Foreign University: An International Study of Adaptation and Coping.

    ERIC Educational Resources Information Center

    Klineberg, Otto; Hull, Frank W., IV

    An international study of adaptation and coping of students, faculty, and administrators involved with foreign student exchange is examined using data obtained in 11 countries--Brazil, Canada, the Federal Republic of Germany, France, Hong Kong, India, Iran, Japan, Kenya, the United Kingdom, and the United States. The following are included:…

  15. Bibliography of Selected Literature in the 1970s Related to Crises, Family Stress, Coping and Adaptation.

    ERIC Educational Resources Information Center

    Chesser, Barbara

    This bibliography of literature from the 1970s related to crises, family stress, coping, and adaptation contains references of particular interest to professionals in the areas of counseling, education, and family social, psychological and health services. The bibliography is divided into 26 categories; references are classified according to major…

  16. The Sense of Self-Continuity as a Resource in Adaptive Coping with Job Loss

    ERIC Educational Resources Information Center

    Sadeh, Noa; Karniol, Rachel

    2012-01-01

    This study examined the relation between the sense of self-continuity, defined as the ability to perceive oneself as extending temporally backwards into the past and forwards into the future, and the adaptiveness of strategies of coping with job loss. We created a web site that was linked to several Israeli web sites dealing with unemployment in…

  17. Pain in Breast Cancer Treatment: Aggravating Factors and Coping Mechanisms

    PubMed Central

    Guerreiro Godoy, Maria de Fatima; Pereira de Godoy, Livia Maria; Barufi, Stelamarys; de Godoy, José Maria Pereira

    2014-01-01

    The objective of this study was to evaluate pain in women with breast cancer-related lymphedema and the characteristics of aggravating factors and coping mechanisms. The study was conducted in the Clinica Godoy, São Jose do Rio Preto, with a group of 46 women who had undergone surgery for the treatment of breast cancer. The following variables were evaluated: type and length of surgery; number of radiotherapy and chemotherapy sessions; continued feeling of the removed breast (phantom limb), infection, intensity of pain, and factors that improve and worsen the pain. The percentage of events was used for statistical analysis. About half the participants (52.1%) performed modified radical surgery, with 91.3% removing only one breast; 82.6% of the participants did not perform breast reconstruction surgery. Insignificant pain was reported by 32.60% of the women and 67.3% said they suffered pain; it was mild in 28.8% of the cases (scale 1–5), moderate in 34.8% (scale 6–9), and severe in 4.3%. The main mechanisms used to cope with pain were painkillers in 41.30% of participants, rest in 21.73%, religious ceremonies in 17.39%, and chatting with friends in 8.69%. In conclusion, many mastectomized patients with lymphedema complain of pain, but pain is often underrecognized and undertreated. PMID:25349741

  18. Adaptation.

    PubMed

    Broom, Donald M

    2006-01-01

    The term adaptation is used in biology in three different ways. It may refer to changes which occur at the cell and organ level, or at the individual level, or at the level of gene action and evolutionary processes. Adaptation by cells, especially nerve cells helps in: communication within the body, the distinguishing of stimuli, the avoidance of overload and the conservation of energy. The time course and complexity of these mechanisms varies. Adaptive characters of organisms, including adaptive behaviours, increase fitness so this adaptation is evolutionary. The major part of this paper concerns adaptation by individuals and its relationships to welfare. In complex animals, feed forward control is widely used. Individuals predict problems and adapt by acting before the environmental effect is substantial. Much of adaptation involves brain control and animals have a set of needs, located in the brain and acting largely via motivational mechanisms, to regulate life. Needs may be for resources but are also for actions and stimuli which are part of the mechanism which has evolved to obtain the resources. Hence pigs do not just need food but need to be able to carry out actions like rooting in earth or manipulating materials which are part of foraging behaviour. The welfare of an individual is its state as regards its attempts to cope with its environment. This state includes various adaptive mechanisms including feelings and those which cope with disease. The part of welfare which is concerned with coping with pathology is health. Disease, which implies some significant effect of pathology, always results in poor welfare. Welfare varies over a range from very good, when adaptation is effective and there are feelings of pleasure or contentment, to very poor. A key point concerning the concept of individual adaptation in relation to welfare is that welfare may be good or poor while adaptation is occurring. Some adaptation is very easy and energetically cheap and

  19. Change in Coping and Defense Mechanisms across Adulthood: Longitudinal Findings in a European American Sample

    ERIC Educational Resources Information Center

    Diehl, Manfred; Chui, Helena; Hay, Elizabeth L.; Lumley, Mark A.; Grühn, Daniel; Labouvie-Vief, Gisela

    2014-01-01

    This study examined longitudinal changes in coping and defense mechanisms in an age- and gender-stratified sample of 392 European American adults. Nonlinear age-related changes were found for the coping mechanisms of sublimation and suppression and the defense mechanisms of intellectualization, doubt, displacement, and regression. The change…

  20. Cultural adaptation of the Brief COPE for persons living with HIV/AIDS in southern India.

    PubMed

    Mohanraj, Rani; Jeyaseelan, Visalakshi; Kumar, Shuba; Mani, Thenmozhi; Rao, Deepa; Murray, Katherine R; Manhart, Lisa E

    2015-02-01

    Physical and psychological stressors of HIV infection demand adequate coping responses from persons living with HIV/AIDS (PLHA) and coping strategies may vary by cultural context. The Brief COPE is a well validated scale that has been used extensively to assess coping with cancer, depression, and HIV infection in other settings, but never in India. In this study we translated and validated the 28 item Brief COPE among 299 PLHA in South India, assessing reliability, validity, and cultural appropriateness. Although the original scale demonstrated acceptable internal consistency (alpha = 0.70) and good convergent validity with depression, the test-retest reliability was marginal (test-retest = 0.6) and the original factor structure demonstrated poor fit in a confirmatory factor analysis (CFA). An exploratory factor analysis yielded a 16 item scale with five factors (active planning, social support, avoidant emotions, substance use, religion). A second CFA demonstrated good model fit and acceptable reliability (alpha = 0.61) of the adapted scale. PMID:25096895

  1. Cultural adaptation of the Brief COPE for Persons Living with HIV/AIDS in Southern India

    PubMed Central

    Mohanraj, Rani; Jeyaseelan, Visalakshi; Kumar, Shuba; Mani, Thenmozhi; Rao, Deepa; Murray, Katherine R.; Manhart, Lisa E.

    2014-01-01

    Physical and psychological stressors of HIV infection demand adequate coping responses from persons living with HIV/AIDS (PLHA) and coping strategies may vary by cultural context. The Brief COPE is a well validated scale that has been used extensively to assess coping with cancer, depression, and HIV infection in other settings, but never in India. In this study we translated and validated the 28 item Brief COPE among 299 PLHA in South India, assessing reliability, validity, and cultural appropriateness. Although the original scale demonstrated acceptable internal consistency (alpha=0.70) and good convergent validity with depression, the test-retest reliability was marginal (test-retest=0.6) and the original factor structure demonstrated poor fit in a confirmatory factor analysis (CFA). An exploratory factor analysis (EFA) yielded a 16 item scale with 5 factors (active planning, social support, avoidant emotions, substance use, religion). A second CFA demonstrated good model fit and acceptable reliability (alpha=0.61) of the adapted scale. PMID:25096895

  2. Multi-type Childhood Abuse, Strategies of Coping, and Psychological Adaptations in Young Adults

    PubMed Central

    Sesar, Kristina; Šimić, Nataša; Barišić, Marijana

    2010-01-01

    Aim To retrospectively analyze the rate of multi-type abuse in childhood and the effects of childhood abuse and type of coping strategies on the psychological adaptation of young adults in a sample form the student population of the University of Mostar. Methods The study was conducted on a convenience sample of 233 students from the University of Mostar (196 female and 37 male), with a median age of 20 (interquartile range, 2). Exposure to abuse was determined using the Child Maltreatment Scales for Adults, which assesses emotional, physical, and sexual abuse, neglect, and witnessing family violence. Psychological adaptation was explored by the Trauma Symptom Checklist, which assesses anxiety/depression, sexual problems, trauma symptoms, and somatic symptoms. Strategies of coping with stress were explored by the Coping Inventory for Stressful Situations. Results Multi-type abuse in childhood was experienced by 172 participants (74%) and all types of abuse by 11 (5%) participants. Emotional and physical maltreatment were the most frequent types of abuse and mostly occurred together with other types of abuse. Significant association was found between all types of abuse (r = 0.436-0.778, P < 0.050). Exposure to sexual abuse in childhood and coping strategies were significant predictors of anxiety/depression (R2 = 0.3553), traumatic symptoms (R2 = 0.2299), somatic symptoms (R2 = 0.2173), and sexual problems (R2 = 0.1550, P < 0.001). Conclusion Exposure to multi-type abuse in childhood is a traumatic experience with long-term negative effects. Problem-oriented coping strategies ensure a better psychosocial adaptation than emotion-oriented strategies. PMID:20960590

  3. How Students Cope with Part-Time Study: An Analysis of Coping Mechanisms through an On-Line Forum

    ERIC Educational Resources Information Center

    Kember, David; Ying, Chan Kwok; Wan, Chan Shun; Yung, Chan Siu; Wai, Chan Tze; Mui, Chang Yuk; Wing, Cheung Kwong; Heung, Lau Kwai; Sam, Lee Lai; Chi, Lee Wai; Wanze, Li Wing Sze; Chuen, Tam Kam; Anne, Tang Oi Yin; Chu, Tse Lin; Jason, Tse Wai

    2005-01-01

    This study provides a qualitative test and illustration of a model of how students cope with the demands of part-time study. The model shows that students who are successful in finding the time to complete the requirements of part-time courses do so by adopting three mechanisms; sacrifice, support and the negotiation of arrangements. All three…

  4. Coping, acculturation, and psychological adaptation among migrants: a theoretical and empirical review and synthesis of the literature

    PubMed Central

    Kuo, Ben C.H.

    2014-01-01

    Given the continuous, dynamic demographic changes internationally due to intensive worldwide migration and globalization, the need to more fully understand how migrants adapt and cope with acculturation experiences in their new host cultural environment is imperative and timely. However, a comprehensive review of what we currently know about the relationship between coping behavior and acculturation experience for individuals undergoing cultural changes has not yet been undertaken. Hence, the current article aims to compile, review, and examine cumulative cross-cultural psychological research that sheds light on the relationships among coping, acculturation, and psychological and mental health outcomes for migrants. To this end, this present article reviews prevailing literature pertaining to: (a) the stress and coping conceptual perspective of acculturation; (b) four theoretical models of coping, acculturation and cultural adaptation; (c) differential coping pattern among diverse acculturating migrant groups; and (d) the relationship between coping variabilities and acculturation levels among migrants. In terms of theoretical understanding, this review points to the relative strengths and limitations associated with each of the four theoretical models on coping-acculturation-adaptation. These theories and the empirical studies reviewed in this article further highlight the central role of coping behaviors/strategies in the acculturation process and outcome for migrants and ethnic populations, both conceptually and functionally. Moreover, the review shows that across studies culturally preferred coping patterns exist among acculturating migrants and migrant groups and vary with migrants' acculturation levels. Implications and limitations of the existing literature for coping, acculturation, and psychological adaptation research are discussed and recommendations for future research are put forth. PMID:25750766

  5. Coping Mechanisms for Crop Plants in Drought-prone Environments

    PubMed Central

    Neumann, Peter M.

    2008-01-01

    Background Drought is a major limitation to plant productivity. Various options are available for increasing water availability and sustaining growth of crop plants in drought-prone environments. Scope After a general introduction to the problems of water availability, this review focuses on a critical evaluation of recent progress in unravelling mechanisms for modifying plant growth responses to drought. Conclusions Investigations of key regulatory mechanisms integrating plant growth responses to water deficits at the whole-organism, cellular and genomic levels continue to provide novel and exiting research findings. For example, recent reports contradict the widespread conception that root-derived abscisic acid is necessarily involved in signalling for stomatal and shoot-growth responses to soil water deficits. The findings bring into question the theoretical basis for alternate-side root-irrigation techniques. Similarly, recent reports indicate that increased ABA production or increased aquaporin expression did not lead to improved drought resistance. Other reports have concerned key genes and proteins involved in regulation of flowering (FT), vegetative growth (DELLA), leaf senescence (IPT) and desiccation tolerance (LEA). Introgression of such genes, with suitable promoters, can greatly impact on whole-plant responses to drought. Further developments could facilitate the introduction by breeders of new crop varieties with growth physiologies tailored to improved field performance under drought. Parallel efforts to encourage the introduction of supplementary irrigation with water made available by improved conservation measures and by sea- or brackish-water desalination, will probably provide comprehensive solutions to coping with drought-prone environments. PMID:18252764

  6. Evolution of adaptation mechanisms: Adaptation energy, stress, and oscillating death.

    PubMed

    Gorban, Alexander N; Tyukina, Tatiana A; Smirnova, Elena V; Pokidysheva, Lyudmila I

    2016-09-21

    In 1938, Selye proposed the notion of adaptation energy and published 'Experimental evidence supporting the conception of adaptation energy.' Adaptation of an animal to different factors appears as the spending of one resource. Adaptation energy is a hypothetical extensive quantity spent for adaptation. This term causes much debate when one takes it literally, as a physical quantity, i.e. a sort of energy. The controversial points of view impede the systematic use of the notion of adaptation energy despite experimental evidence. Nevertheless, the response to many harmful factors often has general non-specific form and we suggest that the mechanisms of physiological adaptation admit a very general and nonspecific description. We aim to demonstrate that Selye׳s adaptation energy is the cornerstone of the top-down approach to modelling of non-specific adaptation processes. We analyze Selye׳s axioms of adaptation energy together with Goldstone׳s modifications and propose a series of models for interpretation of these axioms. Adaptation energy is considered as an internal coordinate on the 'dominant path' in the model of adaptation. The phenomena of 'oscillating death' and 'oscillating remission' are predicted on the base of the dynamical models of adaptation. Natural selection plays a key role in the evolution of mechanisms of physiological adaptation. We use the fitness optimization approach to study of the distribution of resources for neutralization of harmful factors, during adaptation to a multifactor environment, and analyze the optimal strategies for different systems of factors. PMID:26801872

  7. A comparison of the marginal adaptation of cathode-arc vapor-deposited titanium and cast base metal copings

    PubMed Central

    Wu, JC; Lai, LC; Sheets, CG; Earthman, J; Newcomb, R

    2011-01-01

    Statement of problem A new fabrication process has been developed where a titanium coping, which has a gold colored titanium nitride outer layer can be reliably fused to porcelain, but the marginal adaptation characteristics are still undetermined. Purpose The primary purpose of this study is to compare the rate of Clinically Acceptable Marginal Adaptation (CAMA-defined as a marginal gap mean ≤60 μm) of cathode-arc vapor-deposited titanium with the CAMA rate for the cast base metal copings. In addition, the study will evaluate the marginal gap scores themselves to assess their mean difference between the two study groups. Finally, the study will present two analyses of group differences in variability to support the contention that the titanium copings perform more consistently than their base metal counterparts. Material and methods Thirty-seven cathode-arc vapor-deposited titanium copings and 40 cast base metal copings were evaluated by computer-based image analysis using an optical microscope. The conventional lost wax technique was used to fabricate the 40 cast base metal copings that were 0.3 mm thick. The titanium copings were 0.3 mm thick and were formed by a collection of atomic titanium vapor onto a refractory die duplicate in a high vacuum chamber. Fifty vertical marginal gap measurements were collected from each of the 77 copings and the mean of these measurements was computed to form a gap score for each coping. Next, the gap score was compared to the 60 μm criterion to classify each coping as to whether it did or did not achieve Clinically Acceptable Marginal Adaption (CAMA). A comparison of the CAMA rates for each type of coping was used to address the primary purpose of this study. In addition, the gap scores themselves were used to test the (one-sided) hypothesis that the mean of the titanium gap scores is smaller than the mean of the base metal gap scores. Finally, the assertion that the titanium copings provide more consistency in their

  8. Molecular mechanisms of temperature adaptation

    PubMed Central

    Bagriantsev, Sviatoslav N; Gracheva, Elena O

    2015-01-01

    Thermal perception is a fundamental physiological process pertaining to the vast majority of organisms. In vertebrates, environmental temperature is detected by the primary afferents of the somatosensory neurons in the skin, which express a ‘choir’ of ion channels tuned to detect particular temperatures. Nearly two decades of research have revealed a number of receptor ion channels that mediate the perception of several temperature ranges, but most still remain molecularly orphaned. Yet even within this well-researched realm, most of our knowledge largely pertains to two closely related species of rodents, mice and rats. While these are standard biomedical research models, mice and rats provide a limited perspective to elucidate the general principles that drive somatosensory evolution. In recent years, significant advances have been made in understanding the molecular mechanism of temperature adaptation in evolutionarily distant vertebrates and in organisms with acute thermal sensitivity. These studies have revealed the remarkable versatility of the somatosensory system and highlighted adaptations at the molecular level, which often include changes in biophysical properties of ion channels from the transient receptor potential family. Exploiting non-standard animal models has the potential to provide unexpected insights into general principles of thermosensation and thermoregulation, unachievable using the rodent model alone. PMID:25433072

  9. Molecular mechanisms of temperature adaptation.

    PubMed

    Bagriantsev, Sviatoslav N; Gracheva, Elena O

    2015-08-15

    Thermal perception is a fundamental physiological process pertaining to the vast majority of organisms. In vertebrates, environmental temperature is detected by the primary afferents of the somatosensory neurons in the skin, which express a 'choir' of ion channels tuned to detect particular temperatures. Nearly two decades of research have revealed a number of receptor ion channels that mediate the perception of several temperature ranges, but most still remain molecularly orphaned. Yet even within this well-researched realm, most of our knowledge largely pertains to two closely related species of rodents, mice and rats. While these are standard biomedical research models, mice and rats provide a limited perspective to elucidate the general principles that drive somatosensory evolution. In recent years, significant advances have been made in understanding the molecular mechanism of temperature adaptation in evolutionarily distant vertebrates and in organisms with acute thermal sensitivity. These studies have revealed the remarkable versatility of the somatosensory system and highlighted adaptations at the molecular level, which often include changes in biophysical properties of ion channels from the transient receptor potential family. Exploiting non-standard animal models has the potential to provide unexpected insights into general principles of thermosensation and thermoregulation, unachievable using the rodent model alone. PMID:25433072

  10. The adaptive problems of female teenage refugees and their behavioral adjustment methods for coping

    PubMed Central

    Mhaidat, Fatin

    2016-01-01

    This study aimed at identifying the levels of adaptive problems among teenage female refugees in the government schools and explored the behavioral methods that were used to cope with the problems. The sample was composed of 220 Syrian female students (seventh to first secondary grades) enrolled at government schools within the Zarqa Directorate and who came to Jordan due to the war conditions in their home country. The study used the scale of adaptive problems that consists of four dimensions (depression, anger and hostility, low self-esteem, and feeling insecure) and a questionnaire of the behavioral adjustment methods for dealing with the problem of asylum. The results indicated that the Syrian teenage female refugees suffer a moderate degree of adaptation problems, and the positive adjustment methods they have used are more than the negatives. PMID:27175098

  11. Coping Mechanisms, Stressful Events and Suicidal Behavior among Youth Admitted to Juvenile Justice and Child Welfare Services

    ERIC Educational Resources Information Center

    Chagnon, Francois

    2007-01-01

    This study examines the relationship between coping mechanisms and suicide attempts among 84 adolescents in the Quebec youth residential services. A new measure based on in-depth interviews is used to identify coping mechanisms. The suicidal youths used fewer adequate coping mechanisms than nonsuicidal youths when faced with comparable stressful…

  12. Adaptive ability to cope with atypical or novel situations involving tool use: an fMRI approach.

    PubMed

    Wakusawa, Keisuke; Sugiura, Motoaki; Sassa, Yuko; Jeong, Hyeonjeong; Yomogida, Yukihito; Horie, Kaoru; Sato, Shigeru; Yokoyama, Hiroyuki; Kure, Shigeo; Takei, Noriyoshi; Mori, Norio; Kawashima, Ryuta

    2015-01-01

    We investigated the neural mechanisms underlying the ability to cope in atypical or novel situations using tools. We hypothesized that two cognitive components support this ability: adaptive coordination (for adapting to situational demands) and cognitive inhibition (for inhibiting the incongruent actions afforded by tools). We had subjects choose novel tools for a given task or choose among familiar tools in an atypical situation, during which we examined cortical activation in their brains using functional magnetic resonance imaging. Neural activation during adaptive coordination was observed in the left lateral orbitofrontal cortex, inferior frontal gyrus and sulcus, middle and medial frontal gyrus, intraparietal sulcus, precentral sulcus, inferior temporal gyrus, supramarginal gyrus, the bilateral insula, anterior cingulate cortex, and the right callosal sulcus. Activation indicating cognitive inhibition was observed in the right middle and inferior frontal gyrus. These findings demonstrate that the left parietal region shapes basic action, whereas the right frontal region inhibits stereotypical action. The left frontal regions are thought to be linked to the processing of ambiguous actions and play key roles in coordinating actions, whereas other regions are involved in processing situational contexts. Our results may be important for understanding the neural systems underlying adaptability to daily social situations. PMID:24709370

  13. Adaptive Coping under Conditions of Extreme Stress: Multilevel Influences on the Determinants of Resilience in Maltreated Children

    ERIC Educational Resources Information Center

    Cicchetti, Dante; Rogosch, Fred A.

    2009-01-01

    The study of resilience in maltreated children reveals the possibility of coping processes and resources on multiple levels of analysis as children strive to adapt under conditions of severe stress. In a maltreating context, aspects of self-organization, including self-esteem, self-reliance, emotion regulation, and adaptable yet reserved…

  14. First-Year Students' Psychological and Behavior Adaptation to College: The Role of Coping Strategies and Social Support

    ERIC Educational Resources Information Center

    Wang, Aiping; Chen, Lang; Zhao, Bo; Xu, Yan

    2006-01-01

    This study investigates 311 first-year students' psychological and behavior adaptation to college and the mediate role of coping strategies and social support. The investigates reveal that: (1) first-year students who are from countryside, live in poor families, speak in dialects or major in science and engineering have poorer adaptation to…

  15. Coping with infertility: Comparison of coping mechanisms and psychological immune competence in fertile and infertile couples.

    PubMed

    Nagy, Erika; Nagy, Beáta Erika

    2016-08-01

    This study compared coping strategies and psychological immunity of parents with a child conceived with assisted reproductive technology (n = 84) and parents with a naturally conceived child (n = 84) in a Hungarian fertility-age population. Results showed that in vitro fertilization parents are able to control their emotions in a better way than comparison couples. They interpret trials as challenges and consider themselves more worthy than the members of the control group. Our research confirms that consideration and management of psychological factors in treating infertility have an important preventive role to play. PMID:25616427

  16. Effect of anatomic, semi-anatomic and non-anatomic occlusal surface tooth preparations on the adaptation of zirconia copings

    PubMed Central

    Asiri, Waleed; Hefne, Mohammed Jameel

    2014-01-01

    PURPOSE To compare the accuracy of marginal and internal adaptation of zirconia (Zr) copings fabricated on anatomic (A), semi-anatomic (SA) and non-anatomic (NA) occlusal surface preparations. MATERIALS AND METHODS 45 extracted bicuspid teeth were prepared for receiving zirconia crowns, with different occlusal preparation designs A=15, SA=15 & NA=15. The Zr copings were fabricated by using CAD4DENT, CAD/CAM. The copings were adjusted, cemented and were cross sectioned centrally from buccal cusp tip to lingual cusp tip into mesial and distal halves. The copings were examined under electron microscope at ×200 magnification and the measurements were recorded at 9 predetermined areas in micrometers. RESULTS Overall mean gap values for the three groups was found to be 155.93±33.98 µm with Anatomical Occlusal preparation design having the least gap value of 139.23±30.85 µm showing the best adaptation among the groups. Post Hoc Tukey's test showed a statistically significant difference (P=.007) between the means of gap for A & NA preparation designs. Measurements recorded at 9 predetermined points showed variations for the three groups. CONCLUSION Anatomical occlusal preparation designs resulted in better marginal and internal adaptation of Zr copings. There is a considerable variation between the measured marginal and internal gap values for the Zr copings fabricated by the (CAD4DENT-CAD/CAM). This variation may be associated with the lack of standardization of the preparation of teeth, computerized designing of the coping for each tooth, cement used, uniform pressure application during the cementation of the copings, sectioning of the copings and the microscopic measurements. PMID:25551003

  17. Monocular and binocular mechanisms mediating flicker adaptation.

    PubMed

    Zhuang, Xiaohua; Shevell, Steven K

    2015-12-01

    Flicker adaptation reduces subsequent temporal contrast sensitivity. Recent studies show that this adaptation likely results from neural changes in the magnocellular visual pathway, but whether this adaptation occurs at a monocular or a binocular level, or both, is unclear. Here, two experiments address this question. The first experiment exploits the observation that flicker adaptation is stronger at higher than lower temporal frequencies. Observers' two eyes adapted to 3Hz flicker with an incremental pulse at 1/4 duty cycle, either in-phase or out-of-phase in the two eyes. At the binocular level, the flicker rate was 6Hz in the out-of-phase condition if the two eyes' pulse trains sum. Similar sensitivity reduction was found in both phase conditions, as expected for independent monocular adapting mechanisms. The second experiment tested for interocular transfer of adaptation between eyes. Results showed that (1) flicker adaptation was strongest with adapting and test fields in only the same eye, (2) adaptation can be partially transferred interocularly with adaptation in only the opposite eye, and (3) adaptation was weakened when both eyes were adapted simultaneously at different contrasts, compared to test-eye adaptation alone. Taken together, the findings are consistent with mechanisms of flicker adaptation at both the monocular and binocular level. PMID:26505684

  18. Drought Adaptation Mechanisms Should Guide Experimental Design.

    PubMed

    Gilbert, Matthew E; Medina, Viviana

    2016-08-01

    The mechanism, or hypothesis, of how a plant might be adapted to drought should strongly influence experimental design. For instance, an experiment testing for water conservation should be distinct from a damage-tolerance evaluation. We define here four new, general mechanisms for plant adaptation to drought such that experiments can be more easily designed based upon the definitions. A series of experimental methods are suggested together with appropriate physiological measurements related to the drought adaptation mechanisms. The suggestion is made that the experimental manipulation should match the rate, length, and severity of soil water deficit (SWD) necessary to test the hypothesized type of drought adaptation mechanism. PMID:27090148

  19. Relationship between the Employment of Coping Mechanisms and a Sense of Belonging for Part-Time Students

    ERIC Educational Resources Information Center

    Kember, David; Leung, Doris Y. P.

    2004-01-01

    This study examined the way part-time students cope with fitting in study on top of other demands on their time. To measure the deployment of coping mechanisms, an instrument was developed based on previous qualitative work. The earlier work had identified three coping mechanisms--sacrifice, support, and negotiation of arrangements--operating in…

  20. Mixed-gender groups: coping strategies and factors of psychological adaptation in a polar environment.

    PubMed

    Rosnet, Elisabeth; Jurion, Sylvie; Cazes, Geneviève; Bachelard, Claude

    2004-07-01

    The polar environment is often seen as a good analog for long-term space missions in terms of isolation and confinement. This paper focuses on the psychological adaptation of both the men and women in mixed-gender groups in the French polar station Dumont d'Urville. The first 49 expeditions to this station were composed of men only in groups of 25-30. In 2000, two women were included in the first mixed-gender wintering group, followed by five women in 2001. This study on coping strategies and psychological adaptation was included in an end-of-mission debriefing performed by a psychologist. Data were collected using a few quantitative tools and a semi-structured interview, and focused on adaptation to wintering, coping strategies, and information on interpersonal relationships. Including women in a wintering group seems to have had positive effects on the general climate of the group by reducing men's rude behavior, but it also seems to be an important stressor for both men and women when the females' average age is close to the males' because seduction behaviors appear and rivalry, frustration, and sexual harassment frequently result. The use of problem-oriented strategies helps women to adapt. There are strong arguments indicating that living in an isolated and confined environment magnifies the usual difficulties that arise in mixed-gender relationships. Difficulties may be magnified in space since the group size is smaller and the confinement more extreme. This implies the need for rigorous select-in criteria for both men and women, especially for relational criteria, and for group training after selection. PMID:15267070

  1. Positive coping styles and perigenual ACC volume: two related mechanisms for conferring resilience?

    PubMed

    Holz, Nathalie E; Boecker, Regina; Jennen-Steinmetz, Christine; Buchmann, Arlette F; Blomeyer, Dorothea; Baumeister, Sarah; Plichta, Michael M; Esser, Günter; Schmidt, Martin; Meyer-Lindenberg, Andreas; Banaschewski, Tobias; Brandeis, Daniel; Laucht, Manfred

    2016-05-01

    Stress exposure has been linked to increased rates of depression and anxiety in adults, particularly in females, and has been associated with maladaptive changes in the anterior cingulate cortex (ACC), which is an important brain structure involved in internalizing disorders. Coping styles are important mediators of the stress reaction by establishing homeostasis, and may thus confer resilience to stress-related psychopathology. Anatomical scans were acquired in 181 healthy participants at age 25 years. Positive coping styles were determined using a self-report questionnaire (German Stress Coping Questionnaire, SVF78) at age 22 years. Adult anxiety and depression symptoms were assessed at ages 22, 23 and 25 years with the Young Adult Self-Report. Information on previous internalizing diagnoses was obtained by diagnostic interview (2-19 years). Positive coping styles were associated with increased ACC volume. ACC volume and positive coping styles predicted anxiety and depression in a sex-dependent manner with increased positive coping and ACC volume being related to lower levels of psychopathology in females, but not in males. These results remained significant when controlled for previous internalizing diagnoses. These findings indicate that positive coping styles and ACC volume are two linked mechanisms, which may serve as protective factors against internalizing disorders. PMID:26743466

  2. Social Support, Conflict, Major Life Stressors, and Adaptive Coping Strategies in Latino Middle School Students: An Integrative Model

    ERIC Educational Resources Information Center

    Crean, Hugh F.

    2004-01-01

    Structural equation modeling techniques were used to test a conceptual framework for improved understanding of the relationships involved in adolescent risk and protective factors. Specifically, the model examined the direct and indirect associations, via adaptive coping strategies, that acute life stressors and contextual support and conflict…

  3. Mental Health, Substance Use, and Adaptive Coping among Social Work Students in the Aftermath of Hurricanes Katrina and Rita

    ERIC Educational Resources Information Center

    Lemieux, Catherine M.; Plummer, Carol A.; Richardson, Roslyn; Simon, Cassandra E.; Ai, Amy L.

    2010-01-01

    The current study examined mental health symptomology, substance use, and adaptive coping among 416 social work students following Hurricanes Katrina and Rita. Among participants, 47% scored at or above the clinical level for depression, with 6% of students showing clinical PTSD-like symptoms, and 16.9% reporting substance use. Two thirds (66.9%)…

  4. Water management to cope with and adapt to climate variability and change.

    NASA Astrophysics Data System (ADS)

    Hamdy, A.; Trisorio-Liuzzi, G.

    2009-04-01

    In many parts of the world, variability in climatic conditions is already resulting in major impacts. These impacts are wide ranging and the link to water management problems is obvious and profound. The know-how and the available information undoubtedly indicate that climate change will lead to an intensification of the global hydrological cycle and can have major impacts on regional water resources, affecting both ground and surface water supply for sectorial water uses and, in particular, the irrigation field imposing notable negative effects on food security and poverty alleviation programs in most arid and semi-arid developing countries. At the United Nations Millennium Summit, in September 2000, world leaders adopted the Millennium Development Declaration. From this declaration, the IWRM was recognised as the key concept the water sector should be using for water related development and measures and, hence, for achieving the water related MDG's. However, the potential impacts of climate change and increasing climate variability are not sufficiently addressed in the IWRM plans. Indeed, only a very limited IWRM national plans have been prepared, coping with climate variability and changes. This is mainly due to the lack of operational instruments to deal with climate change and climate variability issues. This is particularly true in developing countries where the financial, human and ecological impacts are potentially greatest and where water resources may be already highly stressed, but the capacity to cope and adapt is weakest. Climate change has now brought realities including mainly rising temperatures and increasing frequency of floods and droughts that present new challenges to be addressed by the IWRM practice. There are already several regional and international initiatives underway that focus on various aspects of water resources management those to be linked with climate changes and vulnerability issues. This is the way where the water resources

  5. Building adaptive capacity to cope with increasing vulnerability due to climatic change in Africa A new approach

    NASA Astrophysics Data System (ADS)

    Twomlow, Steve; Mugabe, Francis T.; Mwale, Moses; Delve, Robert; Nanja, Durton; Carberry, Peter; Howden, Mark

    The world community faces many risks from climate change, with most scenarios indicating higher temperatures and more erratic rainfall in Africa. Predictions for southern Africa suggest a general decrease in total seasonal rainfall, accompanied by more frequent in-season dry spells that will significantly impact crop and livestock production, and hence economic growth in the region. The hardest hit will be the rural poor in the drier areas, where crop failure due to drought is already common and chronic food emergencies afflict the region in most years. Lessons can be learnt on how the rural poor currently cope with the vagaries of climate and these can be used to help them adapt their current production systems to the future threats of further climate change. But this assumes the institutions that work towards the economic empowerment of the rural poor have the requisite skills to understand their current coping strategies and how adaptation can be facilitated. A new initiative led by Midlands State University and the Zambian Meteorological Office proposes that improving the ability of institutions that train the ‘Future Change Agents’, who will subsequently support smallholder communities in adapting their agricultural practices to current climate variability, is the first step in building adaptive capacity to cope with future climate change. The capacity of African scientists, regional organizations and decision-makers in dealing with the issues of climate change and adaptation will be enhanced on a continuing basis, and the impacts of their agricultural development programs improved.

  6. [Probability mechanism of species adaptation].

    PubMed

    Kachevskiĭ, N V; Pavlovich, O N; Kachevskiĭ, D N

    2002-01-01

    A variant of mathematical description of the structure of a population was proposed. A possible mechanism of selection with respect to population structure was shown by a mathematical method. The dependence of the population heterogeneity on environmental factors and the relationship between heterogeneity and selection were considered. It is recommended to realize the conception of threshold values in each experiment of "dose-test-effect" type. PMID:12500581

  7. Stresses, coping mechanisms and job satisfaction in general practitioner registrars.

    PubMed Central

    Chambers, R; Wall, D; Campbell, I

    1996-01-01

    BACKGROUND: There is concern about the morale of general practitioner registrars. There may be stress-provoking factors that could be avoided or minimized. AIMS: The aims of the study were to assess the sources of stress and job satisfaction of general practitioner registrars, to compare registrars' job satisfaction with that of established principals using a recently published survey and to identify registrars' usual responses to stress. METHOD: A postal questionnaire survey was sent to all 143 general practitioner registrars in the West Midlands Region. The main measures were: self-rating scales of stresses associated with work and training; the Warr, Cook and Wall job satisfaction scale; and self-reported responses to stress. RESULTS: A total of 118 (83%) general practitioner registrars responded. The most potent sources of stress were family-job conflict, working for the Membership of the Royal College of General Practitioners, patients' unrealistic expectations and disruption of social life. Registrars practised good coping responses to stress. Registrars in this study had significantly greater job satisfaction than general practitioner principals in a 1993 survey for three out of 10 items measured (responsibility given, hours of work and the job as a whole) and significantly worse scores for three items (recognition for good work, rate of pay and variety of work). CONCLUSIONS: Registrars have additional stresses to those of established principals because they need to study for examinations, learn new tasks in general practice and carry out their service commitments at a stage in life when many are newly married or have a young family. Training in stress management for general practitioner registrars is recommended. PMID:8983252

  8. Dealing with environmental challenges: mechanisms of adaptation in Trypanosoma cruzi

    PubMed Central

    Jimenez, Veronica

    2014-01-01

    Protozoan parasites have a significant impact upon global health, infecting millions of people around the world. With limited therapeutic options and no vaccines available, research efforts are focused upon unraveling cellular mechanisms essential for parasite survival. During its life cycle, Trypanosoma cruzi, the causal agent of Chagas disease, is exposed to multiple external conditions and different hosts. Environmental cues are linked to the differentiation process allowing the parasite to complete its life cycle. Successful transmission depends on the ability of the cells to trigger adaptive responses and cope with stressors while regulating proliferation and transition to different life stages. This review focuses upon different aspects of the stress response in T. cruzi, proposing new hypotheses regarding cross-talk and cross-tolerance with respect to environmental changes and discussing open questions and future directions. PMID:24508488

  9. Spirituality: A Coping Mechanism in the Lives of Adults with Congenital Disabilities

    ERIC Educational Resources Information Center

    Specht, Jacqueline A.; King, Gillian A.; Willoughby, Colleen; Brown, Elizabeth G.; Smith, Linda

    2005-01-01

    The purpose of this study was to gain insight into the perspective of individuals with congenital disabilities about spirituality as a coping mechanism during crucial times in their lives, Qualitative analysis of interviews assessing turning points in the lives of 15 adults (6 women and 9 men; M = 37 years) with spina bifida, cerebral palsy, or…

  10. Mechanisms Linking Violence Exposure to Health Risk Behavior in Adolescence: Motivation to Cope and Sensation Seeking

    ERIC Educational Resources Information Center

    Brady, Sonya S.; Donenberg, Geri R.

    2006-01-01

    Objective: This study examined two potential mechanisms linking violence exposure and health risk behavior among adolescents in psychiatric care: sensation seeking and coping with stress through escape behavior. Method: Male (59%) and female adolescents (N = 251), ages 12 to 19 years, from diverse ethnic backgrounds (61% African American, 19%…

  11. Families of Adolescents and Adults with Autism Spectrum Disorders in Taiwan: The Role of Social Support and Coping in Family Adaptation and Maternal Well-Being

    ERIC Educational Resources Information Center

    Lin, Ling-Yi; Orsmond, Gael I.; Coster, Wendy J.; Cohn, Ellen S.

    2011-01-01

    In this study we examined differences in social support and coping between mothers of adolescents and adults with an autism spectrum disorder (ASD) in Taiwan and the United States and to investigate the effects of social support and coping strategies on family adaptation and maternal well-being. Participants were 76 Taiwanese mothers who had at…

  12. Financial Adaptation among College Students: Helping Students Cope with Financial Strain

    ERIC Educational Resources Information Center

    Serido, Joyce; Shim, Soyeon; Xiao, Jing Jian; Tang, Chuanyi; Card, Noel A.

    2014-01-01

    This study examines the impact of the recent financial crisis on co-occurring patterns of change in financial strain and financial coping behaviors of college students (N = 748) using two-timed, longitudinal data collected prior to the 2008 financial crisis and again one year later. Using a stress and coping framework, we found that different…

  13. Coping Repertoires of Families Adapting to Prolonged War-Induced Separations

    ERIC Educational Resources Information Center

    McCubbin, Hamilton I.; And Others

    1976-01-01

    Coping with husband absence, an enigma of family life in the military, stimulated questions as to how wives endure hardships engendered by war-induced separations. The investigators studied the adjustment of 47 families of servicemen missing in action. Findings are explained in terms of psychological and sociological theories of coping. (Author)

  14. Mechanism of high temperature adaptation in maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High temperature (HT) stress severely limits plant productivity and causes extensive economic loss to US agriculture. Understanding HT adaptation mechanisms in crop plants is crucial to the success of developing HT tolerant varieties to alleviate the negative impact of HT stress on plant growth and...

  15. Evaluation of marginal fit and internal adaptation of zirconia copings fabricated by two CAD - CAM systems: An in vitro study

    PubMed Central

    Rajan, Balaji N; Jayaraman, Srinivasan; Kandhasamy, Baburajan; Rajakumaran, Ilangkumaran

    2015-01-01

    Statement of Problem: Three main factors which determine the success of an All-ceramic restoration are esthetic value, resistance to fracture and third being the marginal fit. Marginal fit and internal adaptation are crucial factors in increasing the longevity of the restoration. Newer and economical CAD CAM systems have been introduced claiming better marginal fit and adaptation of All ceramic crowns. CAD CAM systems involves scanning of the die or the tooth preparation and milling of the restoration, which may have variations among the systems available. Aim of the Study: Our study intended to check the marginal fit and internal adaptation of commonly used CAD CAM systems namely CERAMILL and CEREC -In Lab MC XL. Materials and Methods: Two groups of typodont teeth (n = 10) were prepared using a standardized protocol to receive All ceramic copings. 10 samples of Group A were used for fabrication of copings using CERAMILL system and 10 samples of Group B were used for fabrication of copings using CEREC -In Lab MC XL system. They were then luted with glass ionomer cement under mild finger pressure. Samples were embedded in resin and sliced longitudinally. They were then viewed under stereomicroscope and readings were measured along 15 points using ImageScope software. The P value was set at 0.05 at 95% confidence interval with 80% power. The data were checked for normality and unpaired t-test was used to evaluate the results of the two groups. Results: The overall internal adaptation was 61.5 ± 5.2 μm for CERAMILL and 56.9 ± 5.7 μm for CEREC -In Lab MC XL (P < 0.05). The marginal fit for CERAMILL was 83 μm and for CEREC -In Lab MC XL was 68 μm (P < 0.05). Conclusion: The marginal adaptation of CEREC -In Lab MC XL (68 μm) was found to be superior to CERAMILL (83 μm) (P < 0.05). Both the CEREC -In Lab MC XL and CERAMILL copings demonstrated internal adaptation and marginal fit within acceptable discrepancy range. When corroborating both the internal adaptation

  16. Ionizing Radiation: how fungi cope, adapt, and exploit with the help of melanin

    PubMed Central

    Dadachova, Ekaterina; Casadevall, Arturo

    2008-01-01

    SUMMARY OF RECENT ADVANCES Life on Earth has always existed in the flux of ionizing radiation. However, fungi seem to interact with the ionizing radiation differently from other Earth’s inhabitants. Recent data show that melanized fungal species like those from Chernobyl’s reactor respond to ionizing radiation with enhanced growth. Fungi colonize space stations and adapt morphologically to extreme conditions. Radiation exposure causes upregulation of many key genes, and an inducible microhomology-mediated recombination pathway could be a potential mechanism of adaptive evolution in eukaryotes. The discovery of melanized organisms in high radiation environments, the space stations, Antarctic mountains, and in the reactor cooling water combined with phenomenon of ‘radiotropism’ raises the tantalizing possibility that melanins have functions analogous to other energy harvesting pigments such as chlorophylls. PMID:18848901

  17. Statistical mechanics of Hamiltonian adaptive resolution simulations.

    PubMed

    Español, P; Delgado-Buscalioni, R; Everaers, R; Potestio, R; Donadio, D; Kremer, K

    2015-02-14

    The Adaptive Resolution Scheme (AdResS) is a hybrid scheme that allows to treat a molecular system with different levels of resolution depending on the location of the molecules. The construction of a Hamiltonian based on the this idea (H-AdResS) allows one to formulate the usual tools of ensembles and statistical mechanics. We present a number of exact and approximate results that provide a statistical mechanics foundation for this simulation method. We also present simulation results that illustrate the theory. PMID:25681895

  18. Peer Victimization: The Role of Emotions in Adaptive and Maladaptive Coping

    ERIC Educational Resources Information Center

    Kochenderfer-Ladd, Becky

    2004-01-01

    Mediator models were examined in which children's emotional reactions to peer aggression were hypothesized to mediate their selection of coping strategies and subsequent peer victimization and internalizing problems. Self-report data were collected from 145 ethnically diverse kindergarten through fifth grade children (66 females and 79 males) who…

  19. Coping behaviour as an adaptation to stress: post-disturbance preening in colonial seabirds.

    PubMed

    Henson, Shandelle M; Weldon, Lynelle M; Hayward, James L; Greene, Daniel J; Megna, Libby C; Serem, Maureen C

    2012-01-01

    In humans, coping behaviour is an action taken to soothe oneself during or after a stressful or threatening situation. Some human behaviours with physiological functions also serve as coping behaviours, for example, comfort sucking in infants and comfort eating in adults. In birds, the behaviour of preening, which has important physiological functions, has been postulated to soothe individuals after stressful situations. We combine two existing modelling approaches - logistic regression and Darwinian dynamics - to explore theoretically how a behaviour with crucial physiological function might evolve into a coping behaviour. We apply the method to preening in colonial seabirds to investigate whether and how preening might be co-opted as a coping behaviour in the presence of predators. We conduct an in-depth study of the environmental correlates of preening in a large gull colony in Washington, USA, and we perform an independent field test for comfort preening by computing the change in frequency of preening in gulls that were alerted to a predator, but did not flee. PMID:22873521

  20. Mechanisms of Adaptation to Nitrosative Stress in Bacillus subtilis▿ †

    PubMed Central

    Rogstam, Annika; Larsson, Jonas T.; Kjelgaard, Peter; von Wachenfeldt, Claes

    2007-01-01

    Bacteria use a number of mechanisms for coping with the toxic effects exerted by nitric oxide (NO) and its derivatives. Here we show that the flavohemoglobin encoded by the hmp gene has a vital role in an adaptive response to protect the soil bacterium Bacillus subtilis from nitrosative stress. We further show that nitrosative stress induced by the nitrosonium cation donor sodium nitroprusside (SNP) leads to deactivation of the transcriptional repressor NsrR, resulting in derepression of hmp. Nitrosative stress induces the sigma B-controlled general stress regulon. However, a sigB null mutant did not show increased sensitivity to SNP, suggesting that the sigma B-dependent stress proteins are involved in a nonspecific protection against stress whereas the Hmp flavohemoglobin plays a central role in detoxification. Mutations in the yjbIH operon, which encodes a truncated hemoglobin (YjbI) and a predicted 34-kDa cytosolic protein of unknown function (YjbH), rendered B. subtilis hypersensitive to SNP, suggesting roles in nitrosative stress management. PMID:17293416

  1. Mechanisms of Sensorimotor Adaptation to Centrifugation

    NASA Technical Reports Server (NTRS)

    Paloski, W. H.; Wood, S. J.; Kaufman, G. D.

    1999-01-01

    We postulate that centripetal acceleration induced by centrifugation can be used as an inflight sensorimotor countermeasure to retain and/or promote appropriate crewmember responses to sustained changes in gravito-inertial force conditions. Active voluntary motion is required to promote vestibular system conditioning, and both visual and graviceptor sensory feedback are critical for evaluating internal representations of spatial orientation. The goal of our investigation is to use centrifugation to develop an analog to the conflicting visual/gravito-inertial force environment experienced during space flight, and to use voluntary head movements during centrifugation to study mechanisms of adaptation to altered gravity environments. We address the following two hypotheses: (1) Discordant canal-otolith feedback during head movements in a hypergravity tilted environment will cause a reorganization of the spatial processing required for multisensory integration and motor control, resulting in decreased postural stability upon return to normal gravity environment. (2) Adaptation to this "gravito-inertial tilt distortion" will result in a negative after-effect, and readaptation will be expressed by return of postural stability to baseline conditions. During the third year of our grant we concentrated on examining changes in balance control following 90-180 min of centrifugation at 1.4 9. We also began a control study in which we exposed subjects to 90 min of sustained roll tilt in a static (non-rotating) chair. This allowed us to examine adaptation to roll tilt without the hypergravity induced by centrifugation. To these ends, we addressed the question: Is gravity an internal calibration reference for postural control? The remainder of this report is limited to presenting preliminary findings from this study.

  2. Mechanisms of temperature adaptation in poikilotherms.

    PubMed

    Guschina, Irina A; Harwood, John L

    2006-10-01

    For good function, membrane lipids have to be arranged appropriately and be in the correct physical state. In poikilotherms, exposure to cold stress or heat shock can alter membrane properties such that, unless they are corrected quickly, damage and, possibly, death can result. Low temperature stress is countered by modifying membrane lipids such that their average transition temperature is lowered. There are various ways in which this can be achieved but an increase in fatty acid unsaturation is the most common. For heat shock, various changes in lipids have been noted and some defensive strategies involving heat shock proteins noted. In this short review, we will describe recent results where adaptive lipid changes, as a result of temperature stress, have been found. Mechanisms for bringing about such alterations are discussed, together with the contrasting data for different organisms. PMID:16824520

  3. Adaptive mechanically controlled lubrication mechanism found in articular joints.

    PubMed

    Greene, George W; Banquy, Xavier; Lee, Dong Woog; Lowrey, Daniel D; Yu, Jing; Israelachvili, Jacob N

    2011-03-29

    Articular cartilage is a highly efficacious water-based tribological system that is optimized to provide low friction and wear protection at both low and high loads (pressures) and sliding velocities that must last over a lifetime. Although many different lubrication mechanisms have been proposed, it is becoming increasingly apparent that the tribological performance of cartilage cannot be attributed to a single mechanism acting alone but on the synergistic action of multiple "modes" of lubrication that are adapted to provide optimum lubrication as the normal loads, shear stresses, and rates change. Hyaluronic acid (HA) is abundant in cartilage and synovial fluid and widely thought to play a principal role in joint lubrication although this role remains unclear. HA is also known to complex readily with the glycoprotein lubricin (LUB) to form a cross-linked network that has also been shown to be critical to the wear prevention mechanism of joints. Friction experiments on porcine cartilage using the surface forces apparatus, and enzymatic digestion, reveal an "adaptive" role for an HA-LUB complex whereby, under compression, nominally free HA diffusing out of the cartilage becomes mechanically, i.e., physically, trapped at the interface by the increasingly constricted collagen pore network. The mechanically trapped HA-LUB complex now acts as an effective (chemically bound) "boundary lubricant"--reducing the friction force slightly but, more importantly, eliminating wear damage to the rubbing/shearing surfaces. This paper focuses on the contribution of HA in cartilage lubrication; however, the system as a whole requires both HA and LUB to function optimally under all conditions. PMID:21383143

  4. Coping Power Adapted as Universal Prevention Program: Mid Term Effects on Children's Behavioral Difficulties and Academic Grades.

    PubMed

    Muratori, Pietro; Bertacchi, Iacopo; Giuli, Consuelo; Nocentini, Annalaura; Ruglioni, Laura; Lochman, John E

    2016-08-01

    Aggressive behaviors in schools have the potential to cause serious harm to students' emotional and social well-being and to limit their ability to achieve their full academic potential. Prevention programs developed to reduce children's aggressive behaviors in school settings can provide interventions at a universal or targeted level. The main aim of our randomized control study was to examine the efficacy of Coping Power, adapted as a universal prevention program, in reducing children's behavioral problems and improving school grades. Nine classes participated (184 students, mean age 91 months) from two elementary state schools in Tuscany, Italy. Study findings showed a significant reduction in behavioral problems and an improvement in school grades for the intervention classes relative to the control classes. This study suggests the Coping Power program can be delivered in school settings at both universal and targeted prevention levels, and that in this multi-tiered prevention model, teachers, educators and school psychologists can learn a set of intervention skills which can be delivered with flexibility, thus reducing some of the complexity and costs of schools using multiple interventions. PMID:27129573

  5. HIV Stigma and Physical Health Symptoms: Do Social Support, Adaptive Coping, and/or Identity Centrality Act as Resilience Resources?

    PubMed Central

    Lang, Shawn M.; Lippitt, Margaret; Jin, Harry; Chaudoir, Stephenie R.

    2015-01-01

    Despite efforts to eliminate it at the societal level, HIV stigma persists and continues to threaten the health of people living with HIV (PLWH). We tested whether social support, adaptive coping, and/or HIV identity centrality act as resilience resources by buffering people from the negative impact of enacted and/or anticipated stigma on stress and ultimately HIV symptoms. Ninety-three PLWH completed a survey, and data analyses tested for evidence of mediation and moderation. Results demonstrated that instrumental social support, perceived community support, and HIV identity centrality buffered participants from the association between anticipated stigma and HIV symptoms. That is, anticipated stigma was associated with HIV symptoms via stress only at low levels of these resources. No resources buffered participants from the impact of enacted stigma. Identifying and enhancing resilience resources among PLWH is critical for protecting PLWH from the harmful effects of stigma. PMID:24715226

  6. Adaptive and maladaptive mechanisms of cellular priming.

    PubMed Central

    Meldrum, D R; Cleveland, J C; Moore, E E; Partrick, D A; Banerjee, A; Harken, A H

    1997-01-01

    OBJECTIVE: The mechanisms of cellular priming resulting in both adaptive and maladaptive responses to subsequent injury and strategies for manipulating this priming to constructive therapeutic advantage are explored. BACKGROUND DATA: A cell is prepared or educated by an initial insult (priming stimulus). Investigations in both laboratory animals and humans indicate that cells, organs, and perhaps even whole patients respond differently to a proximal second insult ("second hit") by virtue of this prior environmental history. The opportunity to achieve the primed state appears to be conserved across almost all cell types. The initial stimulus transmits a message to the cellular machinery that influences the cell's response to a subsequent challenge. This response may result in an exaggerated inflammatory response in the case of the neutrophil (an often maladaptive process) or an improved tolerance to injury by the myocyte (adaptive response). Our global hypothesis is that cellular priming is a conserved, receptor-dependent process that invokes common intracellular targets across multiple cell types. We further postulate that these targets create a language based on the transient phosphorylation and dephosphorylation of intracellular enzymes that is therapeutically accessible. CONCLUSIONS: Priming is a conserved, receptor-dependent process transduced by means of intracellular targets across multiple cell types. The potential therapeutic strategies outlined involve the receptor-mediated manipulation of cellular events. These events are transmitted through an intracellular language that instructs the cell regarding its behavior in response to subsequent stimulation. Understanding these intracellular events represents a realistic goal of priming and preconditioning biology and will likely lead to clinical control of the primed state. PMID:9389392

  7. Neurobiological mechanisms of adaptative plasticity. A possible contribution to cybernetic studies.

    PubMed

    Giaquinto, S

    1990-10-01

    Cybernetics can take advantages of future development in the field of Plasticity. The adaptative abilities of the nervous tissue, which is capable to modify its own functional organization and cope with pathological events, are triggered by communication within a network carrying memorized variations in the functional activity of the system induced by external inputs. Plasticity is served by anatomical modifications, as well as by neurophysiological processes. Regeneration, reactive synaptogenesis, functional reorganization, redundancy, equipotentiality are discussed. Some of these mechanisms are still unclear in the human and probably far-fetched. Personal EEG contribution argues against redundancy and equipotentiality. PMID:2082721

  8. Reproducible increases in blood pressure during intermittent noise exposure: underlying haemodynamic mechanisms specific to passive coping.

    PubMed

    Sawada, Y

    1993-01-01

    The purpose of the present study was to investigate the reproducibility of the increases in blood pressure found in our recent study on exposure to intermittent noise, to confirm the haemodynamic mechanism raising blood pressure (via an increase in peripheral vascular resistance expected to be specific to passive coping), and to assess baroreceptor cardiac reflex sensitivity in connection with the blood pressure elevation. A group of 16 young normotensive men participated in the experiment and underwent a 10-min intermittent exposure to pink noise at 100 dB (sound pressure level). The subjects also underwent three other stresses: a 1-min cold pressor test, a 3-min isometric handgrip and 3-min of mental arithmetic. The results indicated that blood pressure was elevated reproducibly for most of the noise exposure periods and that peripheral vascular resistance increased simultaneously, as expected. Baroreflex sensitivity was not suppressed. The results, as a whole, were in agreement with our recent findings for exposure to a similar type of noise and thus the reproducibility was corroborated. The mechanism raising blood pressure was similar in the cold pressor test. Conversely, during the isometric handgrip and mental arithmetic, blood pressure elevations were attributable mainly to increases in cardiac output. The implications of the opposing haemodynamic mechanisms raising blood pressure among the four stressful tasks have been discussed in relation to active versus passive coping required for each task. Differences in the magnitude of suppression observed in baroreflex sensitivity among the tasks have also been discussed in the context of defence reactions. PMID:8299606

  9. Methadone maintenance treatment versus methadone maintenance treatment plus auricular acupuncture: impacts on patient satisfaction and coping mechanism.

    PubMed

    Lua, Pei Lin; Talib, Nor Samira; Ismail, Zabidah

    2013-12-01

    This study intended to (1) describe the baseline patient satisfaction level and preferred coping strategies and (2) assess patient satisfaction and coping mechanisms pre- and postintervention. Patients on methadone maintenance treatment (MMT) in Terengganu, Malaysia, were randomized into either MMT or MMT plus auricular acupuncture (MMT + AA) groups. All received the standard MMT, while participants on MMT + AA underwent concurrent AA session thrice weekly for 2 months (each session = 30 minutes). Data analysis was carried out using SPSS 16.0, employing descriptive and nonparametric statistics. Participations were received from 97 eligible male patients (median age = 36.0 years; Malay = 97.9%). After screening for dropouts, only 69 patients were considered for subsequent analysis (MMT = 40; MMT + AA = 29). At preintervention, both groups did not differ significantly in the parameters investigated. During postintervention, no significant difference was detected for satisfaction level but coping-wise, substance use was significantly and frequently adopted by MMT + AA patients compared to MMT respondents (P < .05). On separate analysis, those who received MMT alone adopted active coping, venting, and self-blame significantly more frequently postintervention (P < .05). Nevertheless, no significant difference for coping styles of MMT + AA patients was exhibited over time (P >.05). The addition of AA therapy into the standard MMT treatment did not seem to influence patient satisfaction and their coping ways. PMID:23764566

  10. Effect of Roy’s Adaptation Model-Guided Education on Coping Strategies of the Veterans with Lower Extremities Amputation: A Double-Blind Randomized Controlled Clinical Trial

    PubMed Central

    Farsi, Zahra; Azarmi, Somayeh

    2016-01-01

    Background: Any defect in the extremities of the body can affect different life aspects. The purpose of this study was to investigate the effect of Roy’s adaptation model-guided education on coping strategies of the veterans with lower extremities amputation. Methods: In a double-blind randomized controlled clinical trial, 60 veterans with lower extremities amputation referring to Kowsar Orthotics and Prosthetics Center of Veterans Clinic in Tehran, Iran were recruited using convenience method and randomly assigned to intervention and control groups in 2013-2014. Lazarus and Folkman coping strategies questionnaire was used to collect the data. After completing the questionnaires in both groups, maladaptive behaviours were determined in the intervention group and an education program based on Roy’s adaptation model was implemented. After 2 months, both groups completed the questionnaires again. Data were analyzed using SPSS software. Results: Independent T-test showed that the score of the dimensions of coping strategies did not have a statistically significant difference between the intervention and control groups in the pre-intervention stage (P>0.05). This test showed a statistically significant difference between the two groups in the post-intervention stage in terms of the scores of different dimensions of coping strategies (P>0.05), except in dimensions of social support seeking and positive appraisal (P>0.05). Conclusion: The findings of this research indicated that the Roy’s adaptation model-guided education improved the majority of coping strategies in veterans with lower extremities amputation. It is recommended that further interventions based on Roy’s adaptation model should be performed to improve the coping of the veterans with lower extremities amputation. Trial Registration Number: IRCT2014081118763N1 PMID:27218110

  11. Substance Abuse, Coping Strategies, Adaptive Skills and Behavioral and Emotional Problems in Clients with Mild to Borderline Intellectual Disability Admitted to a Treatment Facility: A Pilot Study

    ERIC Educational Resources Information Center

    Didden, Robert; Embregts, Petri; van der Toorn, Mirjam; Laarhoven, Nina

    2009-01-01

    Many clients with mild to borderline intellectual disability (ID) who are admitted to a treatment facility show serious problems in alcohol and/or drugs use. In the present case file study, we explored differences in coping strategies, adaptive skills and emotional and behavioral problems between clients who showed substance abuse and clients who…

  12. Stress: perceptions, manifestations, and coping mechanisms of student registered nurse anesthetists.

    PubMed

    Chipas, Anthony; Cordrey, Dan; Floyd, David; Grubbs, Lindsey; Miller, Sarah; Tyre, Brooks

    2012-08-01

    Stress is a response to change from the norm. Stress affects all individuals to varying degrees and can be positive, such as eustress, or negative, such as distress. The purpose of this qualitative, cross-sectional study was to investigate the stressors of the typical student registered nurse anesthetist (SRNA), with the objective of identifying trends in the perceptions, manifestations, and coping mechanisms of stress. An online (SurveyMonkey) questionnaire composed of 54 study-specific questions was developed to assess stress in the SRNA population. The questionnaire was sent to members of the American Association of Nurse Anesthetists via email invitation. The study yielded a sample of 1,282 SRNA participants. Analysis revealed statistically significant relationships between self-reported stress and negative outcomes, such as increased sick days, decreased health and wellness, and depression. The study demonstrated that SRNAs perceive their stress as above average, and it remains a central concern for them. PMID:23248831

  13. Adaptive mechanically controlled lubrication mechanism found in articular joints

    PubMed Central

    Greene, George W.; Banquy, Xavier; Lee, Dong Woog; Lowrey, Daniel D.; Yu, Jing; Israelachvili, Jacob N.

    2011-01-01

    Articular cartilage is a highly efficacious water-based tribological system that is optimized to provide low friction and wear protection at both low and high loads (pressures) and sliding velocities that must last over a lifetime. Although many different lubrication mechanisms have been proposed, it is becoming increasingly apparent that the tribological performance of cartilage cannot be attributed to a single mechanism acting alone but on the synergistic action of multiple “modes” of lubrication that are adapted to provide optimum lubrication as the normal loads, shear stresses, and rates change. Hyaluronic acid (HA) is abundant in cartilage and synovial fluid and widely thought to play a principal role in joint lubrication although this role remains unclear. HA is also known to complex readily with the glycoprotein lubricin (LUB) to form a cross-linked network that has also been shown to be critical to the wear prevention mechanism of joints. Friction experiments on porcine cartilage using the surface forces apparatus, and enzymatic digestion, reveal an “adaptive” role for an HA-LUB complex whereby, under compression, nominally free HA diffusing out of the cartilage becomes mechanically, i.e., physically, trapped at the interface by the increasingly constricted collagen pore network. The mechanically trapped HA-LUB complex now acts as an effective (chemically bound) “boundary lubricant”—reducing the friction force slightly but, more importantly, eliminating wear damage to the rubbing/shearing surfaces. This paper focuses on the contribution of HA in cartilage lubrication; however, the system as a whole requires both HA and LUB to function optimally under all conditions. PMID:21383143

  14. Viewing health expenditures, payment and coping mechanisms with an equity lens in Nigeria

    PubMed Central

    2013-01-01

    Background This paper examines socio-economic and geographic differences in payment and payment coping mechanisms for health services in southeast Nigeria. It shows the extent to which the poor and rural dwellers disproportionally bear the burden of health care costs and offers policy recommendations for improvements. Methods Questionnaires were used to collect data from 3071 randomly selected households in six communities in southeast Nigeria using a four week recall. The sample was divided into quintiles (Q1-Q5) using a socio-economic status (SES) index as well as into geographic groups (rural, peri-urban and urban). Tabulations and logistic regression were used to determine the relationships between payment and payment coping mechanisms and key independent variables. Q1/Q5 and rural/urban ratios were the measures of equity. Results Most of the respondents used out-of-pocket spending (OOPS) and own money to pay for healthcare. There was statistically significant geographic differences in the use of own money to pay for health services indicating more use among rural dwellers. Logistic regression showed statistically significant geographic differences in the use of both OOPS and own money when controlling for the effects of potential cofounders. Conclusions This study shows statistically significant geographic differences in the use of OOPS and own money to pay for health services. Though the SES differences were not statistically significant, they showed high equity ratios indicating more use among poor and rural dwellers. The high expenditure incurred on drugs alone highlights the need for expediting pro-poor interventions like exemptions and waivers aimed at improving access to health care for the vulnerable poor and rural dwellers. PMID:23497246

  15. [The impact of religious coping on adaptation strategy among the sick].

    PubMed

    Debout, Christophe

    2015-10-01

    The influence of religious practice on sick people's adaptation processes has been demonstrated in many studies. It is important for the clinical reasoning implemented by caregivers to integrate this aspect in a context defined by the principle of "laïcité" as understood in France. PMID:26461216

  16. Adapting to and Coping with the Threat and Impacts of Climate Change

    ERIC Educational Resources Information Center

    Reser, Joseph P.; Swim, Janet K.

    2011-01-01

    This article addresses the nature and challenge of adaptation in the context of global climate change. The complexity of "climate change" as threat, environmental stressor, risk domain, and impacting process with dramatic environmental and human consequences requires a synthesis of perspectives and models from diverse areas of psychology to…

  17. Development of the Coping Flexibility Scale: Evidence for the Coping Flexibility Hypothesis

    ERIC Educational Resources Information Center

    Kato, Tsukasa

    2012-01-01

    "Coping flexibility" was defined as the ability to discontinue an ineffective coping strategy (i.e., evaluation coping) and produce and implement an alternative coping strategy (i.e., adaptive coping). The Coping Flexibility Scale (CFS) was developed on the basis of this definition. Five studies involving approximately 4,400 Japanese college…

  18. Coping with Spatial Heterogeneity and Temporal Variability in Resources and Risks: Adaptive Movement Behaviour by a Large Grazing Herbivore

    PubMed Central

    Martin, Jodie; Benhamou, Simon; Yoganand, K.; Owen-Smith, Norman

    2015-01-01

    Movement is a key mean for mobile species to cope with heterogeneous environments. While in herbivorous mammals large-scale migration has been widely investigated, fine-scale movement responses to local variations in resources and predation risk remain much less studied, especially in savannah environments. We developed a novel approach based on complementary movement metrics (residence time, frequency of visits and regularity of visits) to relate movement patterns of a savannah grazer, the blue wildebeest Connochaetes taurinus, to fine-scale variations in food availability, predation risk and water availability in the Kruger National Park, South Africa. Wildebeests spent more time in grazing lawns where the grass is of higher quality but shorter than in seep zones, where the grass is of lower quality but more abundant. Although the daily distances moved were longer during the wet season compared to the dry season, the daily net displacement was lower, and the residence time higher, indicating a more frequent occurrence of area-concentred searching. In contrast, during the late dry season the foraging sessions were more fragmented and wildebeests moved more frequently between foraging areas. Surprisingly, predation risk appeared to be the second factor, after water availability, influencing movement during the dry season, when resources are limiting and thus expected to influence movement more. Our approach, using complementary analyses of different movement metrics, provided an integrated view of changes in individual movement with varying environmental conditions and predation risk. It makes it possible to highlight the adaptive behavioral decisions made by wildebeest to cope with unpredictable environmental variations and provides insights for population conservation. PMID:25719494

  19. Individual and Public-Program Adaptation: Coping with Heat Waves in Five Cities in Canada

    PubMed Central

    Alberini, Anna; Gans, Will; Alhassan, Mustapha

    2011-01-01

    Heat Alert and Response Systems (HARS) are currently undergoing testing and implementation in Canada. These programs seek to reduce the adverse health effects of heat waves on human health by issuing weather forecasts and warnings, informing individuals about possible protections from excessive heat, and providing such protections to vulnerable subpopulations and individuals at risk. For these programs to be designed effectively, it is important to know how individuals perceive the heat, what their experience with heat-related illness is, how they protect themselves from excessive heat, and how they acquire information about such protections. In September 2010, we conducted a survey of households in 5 cities in Canada to study these issues. At the time of the survey, these cities had not implemented heat outreach and response systems. The study results indicate that individuals’ recollections of recent heat wave events were generally accurate. About 21% of the sample reported feeling unwell during the most recent heat spell, but these illnesses were generally minor. Only in 25 cases out of 243, these illnesses were confirmed or diagnosed by a health care professional. The rate at which our respondents reported heat-related illnesses was higher among those with cardiovascular and respiratory illnesses, was higher among younger respondents and bore no relationship with the availability of air conditioning at home. Most of the respondents indicated that they would not dismiss themselves as “not at risk” and that they would cope with excessive heat by staying in air conditioned environments and keeping well hydrated. Despite the absence of heat outreach and education programs in their city, our respondents at least a rough idea of how to take care of themselves. The presence of air conditioning and knowledge of cooling centers is location-specific, which provides opportunities for targeting HARS interventions. PMID:22408596

  20. Parallel Adaptive Multi-Mechanics Simulations using Diablo

    SciTech Connect

    Parsons, D; Solberg, J

    2004-12-03

    Coupled multi-mechanics simulations (such as thermal-stress and fluidstructure interaction problems) are of substantial interest to engineering analysts. In addition, adaptive mesh refinement techniques present an attractive alternative to current mesh generation procedures and provide quantitative error bounds that can be used for model verification. This paper discusses spatially adaptive multi-mechanics implicit simulations using the Diablo computer code. (U)

  1. Solution-adaptive finite element method in computational fracture mechanics

    NASA Technical Reports Server (NTRS)

    Min, J. B.; Bass, J. M.; Spradley, L. W.

    1993-01-01

    Some recent results obtained using solution-adaptive finite element method in linear elastic two-dimensional fracture mechanics problems are presented. The focus is on the basic issue of adaptive finite element method for validating the applications of new methodology to fracture mechanics problems by computing demonstration problems and comparing the stress intensity factors to analytical results.

  2. Do common mechanisms of adaptation mediate color discrimination and appearance? Contrast adaptation

    NASA Astrophysics Data System (ADS)

    Hillis, James M.; Brainard, David H.

    2007-08-01

    Are effects of background contrast on color appearance and sensitivity controlled by the same mechanism of adaptation? We examined the effects of background color contrast on color appearance and on color-difference sensitivity under well-matched conditions. We linked the data using Fechner's hypothesis that the rate of apparent stimulus change is proportional to sensitivity and examined a family of parametric models of adaptation. Our results show that both appearance and discrimination are consistent with the same mechanism of adaptation.

  3. Population differentiation in a Mediterranean relict shrub: the potential role of local adaptation for coping with climate change.

    PubMed

    Lázaro-Nogal, Ana; Matesanz, Silvia; Hallik, Lea; Krasnova, Alisa; Traveset, Anna; Valladares, Fernando

    2016-04-01

    Plants can respond to climate change by either migrating, adapting to the new conditions or going extinct. Relict plant species of limited distribution can be especially vulnerable as they are usually composed of small and isolated populations, which may reduce their ability to cope with rapidly changing environmental conditions. The aim of this study was to assess the vulnerability of Cneorum tricoccon L. (Cneoraceae), a Mediterranean relict shrub of limited distribution, to a future drier climate. We evaluated population differentiation in functional traits related to drought tolerance across seven representative populations of the species' range. We measured morphological and physiological traits in both the field and the greenhouse under three water availability levels. Large phenotypic differences among populations were found under field conditions. All populations responded plastically to simulated drought, but they differed in mean trait values as well as in the slope of the phenotypic response. Particularly, dry-edge populations exhibited multiple functional traits that favored drought tolerance, such as more sclerophyllous leaves, strong stomatal control but high photosynthetic rates, which increases water use efficiency (iWUE), and an enhanced ability to accumulate sugars as osmolytes. Although drought decreased RGR in all populations, this reduction was smaller for populations from the dry edge. Our results suggest that dry-edge populations of this relict species are well adapted to drought, which could potentially mitigate the species' extinction risk under drier scenarios. Dry-edge populations not only have a great conservation value but can also change expectations from current species' distribution models. PMID:26662734

  4. SAMCO: Society Adaptation for coping with Mountain risks in a global change COntext

    NASA Astrophysics Data System (ADS)

    Grandjean, Gilles; Bernardie, Severine; Malet, Jean-Philippe; Puissant, Anne; Houet, Thomas; Berger, Frederic; Fort, Monique; Pierre, Daniel

    2013-04-01

    The SAMCO project aims to develop a proactive resilience framework enhancing the overall resilience of societies on the impacts of mountain risks. The project aims to elaborate methodological tools to characterize and measure ecosystem and societal resilience from an operative perspective on three mountain representative case studies. To achieve this objective, the methodology is split in several points with (1) the definition of the potential impacts of global environmental changes (climate system, ecosystem e.g. land use, socio-economic system) on landslide hazards, (2) the analysis of these consequences in terms of vulnerability (e.g. changes in the location and characteristics of the impacted areas and level of their perturbation) and (3) the implementation of a methodology for quantitatively investigating and mapping indicators of mountain slope vulnerability exposed to several hazard types, and the development of a GIS-based demonstration platform. The strength and originality of the SAMCO project will be to combine different techniques, methodologies and models (multi-hazard assessment, risk evolution in time, vulnerability functional analysis, and governance strategies) and to gather various interdisciplinary expertises in earth sciences, environmental sciences, and social sciences. The multidisciplinary background of the members could potentially lead to the development of new concepts and emerging strategies for mountain hazard/risk adaptation. Research areas, characterized by a variety of environmental, economical and social settings, are severely affected by landslides, and have experienced significant land use modifications (reforestation, abandonment of traditional agricultural practices) and human interferences (urban expansion, ski resorts construction) over the last century.

  5. Mitigation of climate change impacts on raptors by behavioural adaptation: ecological buffering mechanisms

    NASA Astrophysics Data System (ADS)

    Wichmann, Matthias C.; Groeneveld, Jürgen; Jeltsch, Florian; Grimm, Volker

    2005-07-01

    The predicted climate change causes deep concerns on the effects of increasing temperatures and changing precipitation patterns on species viability and, in turn, on biodiversity. Models of Population Viability Analysis (PVA) provide a powerful tool to assess the risk of species extinction. However, most PVA models do not take into account the potential effects of behavioural adaptations. Organisms might adapt to new environmental situations and thereby mitigate negative effects of climate change. To demonstrate such mitigation effects, we use an existing PVA model describing a population of the tawny eagle ( Aquila rapax) in the southern Kalahari. This model does not include behavioural adaptations. We develop a new model by assuming that the birds enlarge their average territory size to compensate for lower amounts of precipitation. Here, we found the predicted increase in risk of extinction due to climate change to be much lower than in the original model. However, this "buffering" of climate change by behavioural adaptation is not very effective in coping with increasing interannual variances. We refer to further examples of ecological "buffering mechanisms" from the literature and argue that possible buffering mechanisms should be given due consideration when the effects of climate change on biodiversity are to be predicted.

  6. Mechanics and applications of pressure adaptive honeycomb

    NASA Astrophysics Data System (ADS)

    Vos, Roelof

    A novel adaptive aerostructure is presented that relies on certified aerospace materials and can therefore be applied in conventional passenger aircraft. This structure consists of a honeycomb material which' cells extend over a significant length perpendicular to the plane of the cells. Each of the cells contains an inelastic pouch (or bladder) that forms a circular tube when the cell forms a perfect hexagon. By changing the cell differential pressure (CDP) the stiffness of the honeycomb can be altered. Using an external force or the elastic force within the honeycomb material, the honeycomb can be deformed such that the cells deviate from their perfect-hexagonal shape. It can be shown that by increasing the CDP, the structure eventually returns to a perfect hexagon. By doing so, a fully embedded pneumatic actuator is created that can perform work and substitute conventional low-bandwidth flight control actuators. It is shown that two approaches can be taken to regulate the stiffness of this embedded actuator: (1) The first approach relies on the pouches having a fixed amount of air in them and stiffness is altered by a change in ambient pressure. Coupled to the ambient pressure-altitude cycle that aircraft encounter during each flight, this approach yields a true adaptive aerostructure that operates independently of pilot input and is controlled solely by the altitude the aircraft is flying at. (2) The second approach relies on a controlled constant CDP. This CDP could be supplied from one of the compressor stages of the engine as a form of bleed air. Because of the air-tight pouches there would essentially be no mass flow, meaning engine efficiency would not be significantly affected due to this application. By means of a valve system the pilot could have direct control over the pressure and, consequently, the stiffness of the structure. This allows for much higher CDPs (on the order of 1MPa) than could physically be achieved by relying on the ambient pressure

  7. Adaptive Finite-Element Computation In Fracture Mechanics

    NASA Technical Reports Server (NTRS)

    Min, J. B.; Bass, J. M.; Spradley, L. W.

    1995-01-01

    Report discusses recent progress in use of solution-adaptive finite-element computational methods to solve two-dimensional problems in linear elastic fracture mechanics. Method also shown extensible to three-dimensional problems.

  8. Managing Expectations: Results from Case Studies of US Water Utilities on Preparing for, Coping with, and Adapting to Extreme Events

    NASA Astrophysics Data System (ADS)

    Beller-Simms, N.; Metchis, K.

    2014-12-01

    Water utilities, reeling from increased impacts of successive extreme events such as floods, droughts, and derechos, are taking a more proactive role in preparing for future incursions. A recent study by Federal and water foundation investigators, reveals how six US water utilities and their regions prepared for, responded to, and coped with recent extreme weather and climate events and the lessons they are using to plan future adaptation and resilience activities. Two case studies will be highlighted. (1) Sonoma County, CA, has had alternating floods and severe droughts. In 2009, this area, home to competing water users, namely, agricultural crops, wineries, tourism, and fisheries faced a three-year drought, accompanied at the end by intense frosts. Competing uses of water threatened the grape harvest, endangered the fish industry and resulted in a series of regulations, and court cases. Five years later, new efforts by partners in the entire watershed have identified mutual opportunities for increased basin sustainability in the face of a changing climate. (2) Washington DC had a derecho in late June 2012, which curtailed water, communications, and power delivery during a record heat spell that impacted hundreds of thousands of residents and lasted over the height of the tourist-intensive July 4th holiday. Lessons from this event were applied three months later in anticipation of an approaching Superstorm Sandy. This study will help other communities in improving their resiliency in the face of future climate extremes. For example, this study revealed that (1) communities are planning with multiple types and occurrences of extreme events which are becoming more severe and frequent and are impacting communities that are expanding into more vulnerable areas and (2) decisions by one sector can not be made in a vacuum and require the scientific, sectoral and citizen communities to work towards sustainable solutions.

  9. Coping with Decline

    ERIC Educational Resources Information Center

    Boulding, Kenneth

    1977-01-01

    A quantitative decline is predicted because of the leveling off of industrial production and exhaustion of resources. Coping with these conditions requires flexibility and adaptability. Delusions of certainty zero in on catastrophe. (Author/MLF)

  10. A socio-ecological adaptive approach to contaminated mega-site management: From 'control and correct' to 'coping with change'

    NASA Astrophysics Data System (ADS)

    Schirmer, Mario; Lyon, Ken; Armstrong, James E.; Farrell, Katharine N.

    2012-01-01

    Mega-sites have a notable impact on surrounding ecological systems. At such sites there are substantial risks associated with complex socio-ecological interactions that are hard to characterize, let alone model and predict. While the urge to control and clean-up mega-sites (control and correct) is understandable, rather than setting a goal of cleaning up such sites, we suggest a more realistic response strategy is to address these massive and persistent sources of contamination by acknowledging their position as new features of the socio-ecological landscapes within which they are located. As it seems nearly impossible to clean up such sites, we argue for consideration of a 'coping with change' rather than a 'control and correct' approach. This strategy recognizes that the current management option for a mega-site, in light of its physical complexities and due to changing societal preferences, geochemical transformations, hydrogeology knowledge and remedial technology options may not remain optimal in future, and therefore needs to be continuously adapted, as community, ecology, technology and understanding change over time. This approach creates an opportunity to consider the relationship between a mega-site and its human and ecological environments in a different and more dynamic way. Our proposed approach relies on iterative adaptive management to incorporate mega-site management into the overall socio-ecological systems of the site's context. This approach effectively embeds mega-site management planning in a triple bottom line and environmental sustainability structure, rather than simply using single measures of success, such as contaminant-based guidelines. Recognizing that there is probably no best solution for managing a mega-site, we present a starting point for engaging constructively with this seemingly intractable issue. Therefore, we aim to initiate discussion about a new approach to mega-site management, in which the complexity of the problems posed

  11. Do common mechanisms of adaptation mediate color discrimination and appearance? Contrast adaptation

    PubMed Central

    Hillis, James M.; Brainard, David H.

    2009-01-01

    Are effects of background contrast on color appearance and sensitivity controlled by the same mechanism of adaptation? We examined the effects of background color contrast on color appearance and on color-difference sensitivity under well-matched conditions. We linked the data using Fechner’s hypothesis that the rate of apparent stimulus change is proportional to sensitivity and examined a family of parametric models of adaptation. Our results show that both appearance and discrimination are consistent with the same mechanism of adaptation. PMID:17621318

  12. A synaptic mechanism for retinal adaptation to luminance and contrast.

    PubMed

    Jarsky, Tim; Cembrowski, Mark; Logan, Stephen M; Kath, William L; Riecke, Hermann; Demb, Jonathan B; Singer, Joshua H

    2011-07-27

    The gain of signaling in primary sensory circuits is matched to the stimulus intensity by the process of adaptation. Retinal neural circuits adapt to visual scene statistics, including the mean (background adaptation) and the temporal variance (contrast adaptation) of the light stimulus. The intrinsic properties of retinal bipolar cells and synapses contribute to background and contrast adaptation, but it is unclear whether both forms of adaptation depend on the same cellular mechanisms. Studies of bipolar cell synapses identified synaptic mechanisms of gain control, but the relevance of these mechanisms to visual processing is uncertain because of the historical focus on fast, phasic transmission rather than the tonic transmission evoked by ambient light. Here, we studied use-dependent regulation of bipolar cell synaptic transmission evoked by small, ongoing modulations of membrane potential (V(M)) in the physiological range. We made paired whole-cell recordings from rod bipolar (RB) and AII amacrine cells in a mouse retinal slice preparation. Quasi-white noise voltage commands modulated RB V(M) and evoked EPSCs in the AII. We mimicked changes in background luminance or contrast, respectively, by depolarizing the V(M) or increasing its variance. A linear systems analysis of synaptic transmission showed that increasing either the mean or the variance of the presynaptic V(M) reduced gain. Further electrophysiological and computational analyses demonstrated that adaptation to mean potential resulted from both Ca channel inactivation and vesicle depletion, whereas adaptation to variance resulted from vesicle depletion alone. Thus, background and contrast adaptation apparently depend in part on a common synaptic mechanism. PMID:21795549

  13. Grandparents in a Parental or Near-Parental Role: Sources of Stress and Coping Mechanisms

    ERIC Educational Resources Information Center

    Lumpkin, James R.

    2008-01-01

    Although about 11% of grandparents are raising their grandchildren, a larger percentage provide a significant amount of care and serve in a near-parental role. Both parental and near-parental roles create stress. The stressors that these grandparents face and the strategies that they use to cope were investigated in this descriptive, exploratory…

  14. Microwear, mechanics and the feeding adaptations of Australopithecus africanus.

    PubMed

    Strait, David S; Weber, Gerhard W; Constantino, Paul; Lucas, Peter W; Richmond, Brian G; Spencer, Mark A; Dechow, Paul C; Ross, Callum F; Grosse, Ian R; Wright, Barth W; Wood, Bernard A; Wang, Qian; Byron, Craig; Slice, Dennis E

    2012-01-01

    Recent studies of dental microwear and craniofacial mechanics have yielded contradictory interpretations regarding the feeding ecology and adaptations of Australopithecus africanus. As part of this debate, the methods used in the mechanical studies have been criticized. In particular, it has been claimed that finite element analysis has been poorly applied to this research question. This paper responds to some of these mechanical criticisms, highlights limitations of dental microwear analysis, and identifies avenues of future research. PMID:22130183

  15. Root developmental adaptation to Fe toxicity: Mechanisms and management

    PubMed Central

    Li, Guangjie; Kronzucker, Herbert J.; Shi, Weiming

    2016-01-01

    ABSTRACT Iron (Fe) is an essential microelement but is highly toxic when in excess. To cope with Fe excess, plants have evolved complex adaptive responses that include morphological and physiological modifications. The highly dynamic adjustments in overall root system architecture (RSA) determine root plasticity and allow plants to efficiently adapt to environmental constraints. However, the effects of Fe excess on RSA are poorly understood. Recently, we showed that excess Fe treatment in Arabidopsis not only directly impairs primary root (PR) growth but also arrests lateral root (LR) formation by acting at the tip of the growing primary root. Such a change is believed to help RSA adjust and restrict excessive Fe absorption in the part of the rhizosphere subject to acute toxicity while maintaining the absorption of other nutrients in the less stressed components of the root system. We further showed that the suppression of PR growth and LR formation under excess Fe is alleviated by K+ addition, providing useful insight into the effectiveness of nutrient management to improve RSA and alleviate Fe toxicity symptoms in the field. PMID:26619064

  16. Root developmental adaptation to Fe toxicity: Mechanisms and management.

    PubMed

    Li, Guangjie; Kronzucker, Herbert J; Shi, Weiming

    2016-01-01

    Iron (Fe) is an essential microelement but is highly toxic when in excess. To cope with Fe excess, plants have evolved complex adaptive responses that include morphological and physiological modifications. The highly dynamic adjustments in overall root system architecture (RSA) determine root plasticity and allow plants to efficiently adapt to environmental constraints. However, the effects of Fe excess on RSA are poorly understood. Recently, we showed that excess Fe treatment in Arabidopsis not only directly impairs primary root (PR) growth but also arrests lateral root (LR) formation by acting at the tip of the growing primary root. Such a change is believed to help RSA adjust and restrict excessive Fe absorption in the part of the rhizosphere subject to acute toxicity while maintaining the absorption of other nutrients in the less stressed components of the root system. We further showed that the suppression of PR growth and LR formation under excess Fe is alleviated by K(+) addition, providing useful insight into the effectiveness of nutrient management to improve RSA and alleviate Fe toxicity symptoms in the field. PMID:26619064

  17. Adaptive and Nonadaptive Help Seeking with Peer Harassment: An Integrative Perspective of Coping and Self-Regulation

    ERIC Educational Resources Information Center

    Newman, Richard S.

    2008-01-01

    When harassed by peers, elementary school students often face a dilemma of whether to ask their teacher for help. Assistance may be useful, and perhaps necessary. However, there can be social costs; children generally are expected to resolve interpersonal conflicts on their own. Two theoretical perspectives (i.e., coping and self-regulation)…

  18. Adaptive Coping Reduces the Impact of Community Violence Exposure on Violent Behavior among African American and Latino Male Adolescents

    ERIC Educational Resources Information Center

    Brady, Sonya S.; Gorman-Smith, Deborah; Henry, David B.; Tolan, Patrick H.

    2008-01-01

    This study examined whether coping moderated the impact of community violence exposure (CVE) on violent behavior among 285 urban African American and Latino adolescent males assessed annually across 5 years. Composites indicating overall CVE (having knowledge of others' victimization, witnessing violence, direct victimization) and approach to…

  19. When Do Adaptive Developmental Mechanisms Yield Maladaptive Outcomes?

    ERIC Educational Resources Information Center

    Frankenhuis, Willem E.; Del Giudice, Marco

    2012-01-01

    This article discusses 3 ways in which adaptive developmental mechanisms may produce maladaptive outcomes. First, natural selection may favor risky strategies that enhance fitness on average but which have detrimental consequences for a subset of individuals. Second, mismatch may result when organisms experience environmental change during…

  20. Never the Twain shall meet? Closing the gap between coping research and clinical intervention research.

    PubMed

    Coyne, J C; Racioppo, M W

    2000-06-01

    Two distinct literatures have contributed to a tremendous growth of interest in coping. The 1st consists of descriptive studies that have used coping checklists. This literature is in crisis because of its failure to yield substantive findings concerning the role of coping in adaptation that cannot be dismissed as truisms, trivia, or the product of a confounding of stress, coping, and distress. The 2nd literature concerns interventions to improve adaptation by enhancing coping. It provides evidence of the efficacy of intervention but provides little understanding of crucial ingredients, mechanisms of change, or barriers to maintaining gains. Both literatures would benefit from cross-fertilization. Process studies of interventions designed to improve coping provide an alternative to fruitless and potentially misleading correlational studies using checklists. Such studies might also aid in understanding and refining intervention strategies. PMID:10892208

  1. Aneuploidy as a mechanism of adaptation to telomerase insufficiency.

    PubMed

    Millet, Caroline; Makovets, Svetlana

    2016-08-01

    Cells' survival is determined by their ability to adapt to constantly changing environment. Adaptation responses involve global changes in transcription, translation, and posttranslational modifications of proteins. In recent years, karyotype changes in adapting populations of single cell organisms have been reported in a number of studies. More recently, we have described aneuploidy as an adaptation mechanism used by populations of budding yeast Saccharomyces cerevisiae to survive telomerase insufficiency induced by elevated growth temperature. Genetic evidence suggests that telomerase insufficiency is caused by decreased levels of the telomerase catalytic subunit Est2. Here, we present experiments arguing that the underlying cause of this phenomenon may be within the telomerase RNA TLC1: changes in the expression of TLC1 as well as mutations in the TLC1 template region affect telomere length equilibrium and the temperature threshold for the induction of telomerase insufficiency. We discuss what lies at the root of telomerase insufficiency, how cell populations overcome it through aneuploidy and whether reversible aneuploidy could be an adaptation mechanism for a variety of environmental stresses. PMID:26758992

  2. Utilized Resources of Hope, Orientation, and Inspiration in Life of Persons with Multiple Sclerosis and Their Association with Life Satisfaction, Adaptive Coping Strategies, and Spirituality.

    PubMed

    Wirth, Anne-Gritli; Büssing, Arndt

    2016-08-01

    In a cross-sectional survey among 213 patients with multiple sclerosis, we intended to analyze their resources of hope, orientation, and inspiration in life, and how these resources are related to health-associated variables, adaptive coping strategies, and life satisfaction. Resources were categorized as Faith (10 %), Family (22 %), Other sources (16 %), and No answer (53 %). These non-respondents were predominantly neither religious nor spiritual (70 % R-S-). Although R-S- persons are a heterogeneous group with varying existential interest, they did not significantly differ from their spiritual/religious counterparts with respect to physical and mental health or life satisfaction, but for an adaptive Reappraisal strategy and Gratitude/Awe. PMID:26169606

  3. Importance of plasticity and local adaptation for coping with changing salinity in coastal areas: a test case with barnacles in the Baltic Sea

    PubMed Central

    2014-01-01

    Background Salinity plays an important role in shaping coastal marine communities. Near-future climate predictions indicate that salinity will decrease in many shallow coastal areas due to increased precipitation; however, few studies have addressed this issue. The ability of ecosystems to cope with future changes will depend on species’ capacities to acclimatise or adapt to new environmental conditions. Here, we investigated the effects of a strong salinity gradient (the Baltic Sea system – Baltic, Kattegat, Skagerrak) on plasticity and adaptations in the euryhaline barnacle Balanus improvisus. We used a common-garden approach, where multiple batches of newly settled barnacles from each of three different geographical areas along the Skagerrak-Baltic salinity gradient were exposed to corresponding native salinities (6, 15 and 30 PSU), and phenotypic traits including mortality, growth, shell strength, condition index and reproductive maturity were recorded. Results We found that B. improvisus was highly euryhaline, but had highest growth and reproductive maturity at intermediate salinities. We also found that low salinity had negative effects on other fitness-related traits including initial growth and shell strength, although mortality was also lowest in low salinity. Overall, differences between populations in most measured traits were weak, indicating little local adaptation to salinity. Nonetheless, we observed some population-specific responses – notably that populations from high salinity grew stronger shells in their native salinity compared to the other populations, possibly indicating adaptation to differences in local predation pressure. Conclusions Our study shows that B. improvisus is an example of a true brackish-water species, and that plastic responses are more likely than evolutionary tracking in coping with future changes in coastal salinity. PMID:25038588

  4. Chronic stress and brain plasticity: Mechanisms underlying adaptive and maladaptive changes and implications for stress-related CNS disorders.

    PubMed

    Radley, Jason; Morilak, David; Viau, Victor; Campeau, Serge

    2015-11-01

    Stress responses entail neuroendocrine, autonomic, and behavioral changes to promote effective coping with real or perceived threats to one's safety. While these responses are critical for the survival of the individual, adverse effects of repeated exposure to stress are widely known to have deleterious effects on health. Thus, a considerable effort in the search for treatments to stress-related CNS disorders necessitates unraveling the brain mechanisms responsible for adaptation under acute conditions and their perturbations following chronic stress exposure. This paper is based upon a symposium from the 2014 International Behavioral Neuroscience Meeting, summarizing some recent advances in understanding the effects of stress on adaptive and maladaptive responses subserved by limbic forebrain networks. An important theme highlighted in this review is that the same networks mediating neuroendocrine, autonomic, and behavioral processes during adaptive coping also comprise targets of the effects of repeated stress exposure in the development of maladaptive states. Where possible, reference is made to the similarity of neurobiological substrates and effects observed following repeated exposure to stress in laboratory animals and the clinical features of stress-related disorders in humans. PMID:26116544

  5. Quotidian resilience: exploring mechanisms that drive resilience from a perspective of everyday stress and coping.

    PubMed

    DiCorcia, Jennifer A; Tronick, Ed

    2011-06-01

    Resilience is often associated with extreme trauma or overcoming extraordinary odds. This way of thinking about resilience leaves most of the ontogenetic picture a mystery. In the following review we put forth the Everyday Stress Resilience Hypothesis where resilience is analyzed from a systems perspective and seen as a process of regulating everyday life stressors. Successful regulation accumulates into regulatory resilience which emerges during early development from successful coping with the inherent stress in typical interactions. These quotidian stressful events lead to activation of behavioral and physiologic systems. Stress that is effectively resolved in the short run and with reiteration over the long-term increases children's as well as adults' capacity to cope with more intense stressors. Infants, however, lack the regulatory capacities to take on this task by themselves. Therefore, through communicative and regulatory processes during infant-adult interactions, we demonstrate that the roots of regulatory resilience originate in infants' relationship with their caregiver and that maternal sensitivity can help or hinder the growth of resilience. PMID:21513731

  6. First adaptation of coping power program as a classroom-based prevention intervention on aggressive behaviors among elementary school children.

    PubMed

    Muratori, Pietro; Bertacchi, Iacopo; Giuli, Consuelo; Lombardi, Lavinia; Bonetti, Silvia; Nocentini, Annalaura; Manfredi, Azzurra; Polidori, Lisa; Ruglioni, Laura; Milone, Annarita; Lochman, John E

    2015-04-01

    Children with high levels of aggressive behavior create a major management problem in school settings and interfere with the learning environment of their classmates. We report results from a group-randomized trial of a program aimed at preventing aggressive behaviors. The purpose of the current study, therefore, was to determine the extent to which an indicated prevention program, Coping Power Program, is capable of reducing behavioral problems and improving pro-social behavior when delivered as a universal classroom-based prevention intervention. Nine classes (five first grade and four second grade) were randomly assigned to intervention or control conditions. Findings showed a significant reduction in overall problematic behaviors and in inattention-hyperactivity problems for the intervention classes compared to the control classes. Students who received Coping Power Program intervention also showed more pro-social behaviors at postintervention. The implications of these findings for the implementation of strategies aimed at preventing aggressive behavior in school settings are discussed. PMID:24942813

  7. Phenotypic Plasticity and Selection: Nonexclusive Mechanisms of Adaptation

    PubMed Central

    Grenier, S.; Barre, P.; Litrico, I.

    2016-01-01

    Selection and plasticity are two mechanisms that allow the adaptation of a population to a changing environment. Interaction between these nonexclusive mechanisms must be considered if we are to understand population survival. This review discusses the ways in which plasticity and selection can interact, based on a review of the literature on selection and phenotypic plasticity in the evolution of populations. The link between selection and phenotypic plasticity is analysed at the level of the individual. Plasticity can affect an individual's response to selection and so may modify the end result of genetic diversity evolution at population level. Genetic diversity increases the ability of populations or communities to adapt to new environmental conditions. Adaptive plasticity increases individual fitness. However this effect must be viewed from the perspective of the costs of plasticity, although these are not easy to estimate. It is becoming necessary to engage in new experimental research to demonstrate the combined effects of selection and plasticity for adaptation and their consequences on the evolution of genetic diversity. PMID:27313957

  8. Visual-adaptation-mechanism based underwater object extraction

    NASA Astrophysics Data System (ADS)

    Chen, Zhe; Wang, Huibin; Xu, Lizhong; Shen, Jie

    2014-03-01

    Due to the major obstacles originating from the strong light absorption and scattering in a dynamic underwater environment, underwater optical information acquisition and processing suffer from effects such as limited range, non-uniform lighting, low contrast, and diminished colors, causing it to become the bottleneck for marine scientific research and projects. After studying and generalizing the underwater biological visual mechanism, we explore its advantages in light adaption which helps animals to precisely sense the underwater scene and recognize their prey or enemies. Then, aiming to transform the significant advantage of the visual adaptation mechanism into underwater computer vision tasks, a novel knowledge-based information weighting fusion model is established for underwater object extraction. With this bionic model, the dynamical adaptability is given to the underwater object extraction task, making them more robust to the variability of the optical properties in different environments. The capability of the proposed method to adapt to the underwater optical environments is shown, and its outperformance for the object extraction is demonstrated by comparison experiments.

  9. Physiologically responsive, mechanically adaptive bio-nanocomposites for biomedical applications.

    PubMed

    Jorfi, Mehdi; Roberts, Matthew N; Foster, E Johan; Weder, Christoph

    2013-02-01

    We report mechanically adaptive bionanocomposites based on poly(vinyl alcohol) (PVOH) and cellulose nanocrystals (CNCs), whose mechanical properties change significantly upon exposure to simulated physiological conditions. These nanocomposites were made using CNCs derived from tunicates (t-CNCs) and cotton (c-CNCs) to explore how aspect ratio, surface charge density, and filler content influence the mechanical properties. Dynamic mechanical analysis data reveal a significant enhancement of the tensile storage modulus (E') upon introduction of CNCs, which scaled with the CNC type and content. For example, in the dry, glassy state at 25 °C, E' increased up to 23% (for c-CNCs) and 88% (for t-CNCs) compared to the neat polymer. Exposing the materials to simulated physiological conditions caused a drastic softening of the materials, from 9.0 GPa to 1 MPa for c-CNCs and from 13.7 GPa to 160 MPa for t-CNCs. The data show that the swelling characteristics of the nanocomposites and the extent of mechanical switching could be influenced via the amount and type of CNCs and also the processing conditions. The high stiffness in the dry state and the ability to tailor the mechanical contrast via composition and processing makes the new materials particularly useful as basis for adaptive biomedical implants. PMID:23379302

  10. In vivo deployment of mechanically adaptive nanocomposites for intracortical microelectrodes

    PubMed Central

    Harris, J P; Hess, A E; Rowan, S J; Weder, C; Zorman, C A; Tyler, D J; Capadona, J R

    2012-01-01

    We recently introduced a series of stimuli-responsive, mechanically-adaptive polymer nanocomposites. Here, we report the first application of these bio-inspired materials as substrates for intracortical microelectrodes. Our hypothesis is that the ideal electrode should be initially stiff to facilitate minimal trauma during insertion into the cortex, yet becomes mechanically compliant to match the stiffness of the brain tissue and minimize forces exerted on the tissue, attenuating inflammation. Microprobes created from mechanically reinforced nanocomposites demonstrated a significant advantage compared to model microprobes composed of neat polymer only. The nanocomposite microprobes exhibit a higher storage modulus (E’ = ~5 GPa) than the neat polymer microprobes (E’ = ~2 GPa) and could sustain higher loads (~17 mN), facilitating penetration through the pia mater and insertion into the cerebral cortex of a rat. In contrast, the neat polymer microprobes mechanically failed under lower loads (~7 mN) before they were capable of inserting into cortical tissue. Further, we demonstrated the material’s ability to morph while in the rat cortex to more closely match the mechanical properties of the cortical tissue. Nanocomposite microprobes that were implanted into the rat cortex for up to 8 weeks demonstrated increased cell density at the microelectrode-tissue interface and a lack of tissue necrosis or excessive gliosis. This body of work introduces our nanocomposite-based microprobes as adaptive substrates for intracortical microelectrodes and potentially other biomedical applications. PMID:21654037

  11. The impact of self-efficacy on stressor-strain relations: coping style as an explanatory mechanism.

    PubMed

    Jex, S M; Bliese, P D; Buzzell, S; Primeau, J

    2001-06-01

    The present study was designed to examine whether coping style influences the impact of self-efficacy on stressor-strain relations. It was hypothesized that high self-efficacy would weaken stressor-strain relations when accompanied by frequent use of active coping and infrequent use of avoidance coping. Data collected from 2,293 members of the U.S. Army revealed 3-way interactions among self-efficacy, role clarity, and active coping and among self-efficacy, work overload, and avoidance coping. As predicted, self-efficacy mitigated the effects of low role clarity on strain only when active coping was high. Also as expected, strain levels were lower for participants with high self-efficacy than for participants with lower self-efficacy when work overload was low but avoidance coping was high. Implications of these findings for occupational stress research are discussed. PMID:11419800

  12. Prevalence of PTSD Symptoms and Depression and Level of Coping among the Victims of the Kashmir Conflict

    ERIC Educational Resources Information Center

    Yaswi, Arooj; Haque, Amber

    2008-01-01

    This study examined the prevalence of posttraumatic stress disorder (PTSD) symptoms, depression, and coping mechanisms among the adult civilian population in Indian Kashmir. The Everstine Trauma Response Index-Adapted, the Beck Depression Inventory, and the Coping Resources Inventory were used to assess the three domains. Independent-sample t…

  13. Selective brain cooling in Arabian oryx (Oryx leucoryx): a physiological mechanism for coping with aridity?

    PubMed

    Hetem, Robyn S; Strauss, W Maartin; Fick, Linda G; Maloney, Shane K; Meyer, Leith C R; Fuller, Andrea; Shobrak, Mohammed; Mitchell, Duncan

    2012-11-15

    Selective brain cooling is a thermoregulatory effector proposed to conserve body water and, as such, may help artiodactyls cope with aridity. We measured brain and carotid blood temperature, using implanted data loggers, in five Arabian oryx (Oryx leucoryx) in the desert of Saudi Arabia. On average, brain temperature was 0.24±0.05°C lower than carotid blood temperature for four oryx in April. Selective brain cooling was enhanced in our Arabian oryx compared with another species from the same genus (gemsbok Oryx gazella gazella) exposed to similar ambient temperatures but less aridity. Arabian oryx displayed a lower threshold (37.8±0.1°C vs 39.8±0.4°C), a higher frequency (87±6% vs 15±15%) and a higher maximum magnitude (1.2±0.2°C vs 0.5±0.3°C) of selective brain cooling than did gemsbok. The dominant male oryx displayed less selective brain cooling than did any of the other oryx, but selective brain cooling was enhanced in this oryx as conditions became hotter and drier. Enhanced selective brain cooling in Arabian oryx supports the hypothesis that selective brain cooling would bestow survival advantages for artiodactyl species inhabiting hot hyper-arid environments. PMID:22899527

  14. Mechanism of Thermal Adaptation in the Lactate Dehydrogenases.

    PubMed

    Peng, Huo-Lei; Egawa, Tsuyoshi; Chang, Eric; Deng, Hua; Callender, Robert

    2015-12-10

    The mechanism of thermal adaptation of enzyme function at the molecular level is poorly understood but is thought to lie within the structure of the protein or its dynamics. Our previous work on pig heart lactate dehydrogenase (phLDH) has determined very high resolution structures of the active site, via isotope edited IR studies, and has characterized its dynamical nature, via laser-induced temperature jump (T-jump) relaxation spectroscopy on the Michaelis complex. These particular probes are quite powerful at getting at the interplay between structure and dynamics in adaptation. Hence, we extend these studies to the psychrophilic protein cgLDH (Champsocephalus gunnari; 0 °C) and the extreme thermophile tmLDH (Thermotoga maritima LDH; 80 °C) for comparison to the mesophile phLDH (38-39 °C). Instead of the native substrate pyruvate, we utilize oxamate as a nonreactive substrate mimic for experimental reasons. Using isotope edited IR spectroscopy, we find small differences in the substate composition that arise from the detailed bonding patterns of oxamate within the active site of the three proteins; however, we find these differences insufficient to explain the mechanism of thermal adaptation. On the other hand, T-jump studies of reduced β-nicotinamide adenine dinucleotide (NADH) emission reveal that the most important parameter affecting thermal adaptation appears to be enzyme control of the specific kinetics and dynamics of protein motions that lie along the catalytic pathway. The relaxation rate of the motions scale as cgLDH > phLDH > tmLDH in a way that faithfully matches kcat of the three isozymes. PMID:26556099

  15. AMBRA1-induced mitophagy: A new mechanism to cope with cancer?

    PubMed Central

    Strappazzon, Flavie; Cecconi, Francesco

    2015-01-01

    Dysfunctions in mitophagy, the process by which mitochondria are eliminated, are associated with cancer. We found that the proautophagic protein AMBRA1 (activating molecule in beclin 1 regulated autophagy) binds the autophagosome adapter LC3, and that this interaction is crucial for mitochondrial clearance with or without involvement of the E3-ligase PARKIN. The discovery of a novel mitophagy pathway has the potential to promote new anticancer strategies. PMID:27308437

  16. [Molecular mechanisms of tissue hypoxia and organism adaptation].

    PubMed

    Luk'ianova, L D

    2003-01-01

    The mechanism for participation of aerobic energy metabolism in formation of urgent and long-term adaptation to hypoxia is under consideration. It is stated that changes in kinetic properties of mitochondrial enzyme complexes (MEC), primarily enzymes of the respiratory chain substrate region (MEC I), in response to oxygen shortage underlie diverse stages of bioenergetic (tissue) hypoxia. It was shown that economization of energy metabolism in adaptation to hypoxia occurs due to formation of a new mitochondrial population. The mitochondria possess lesser size and decreased content of cytochromes; however, they are characterized by higher activities of enzymes and lower affinity of the enzymes to their substrates as well as high efficiency of oxidative phosphorylation. Furthermore the amount of mitochondria increases in the cell. It was demonstrated that oxygen shortage can both directly affect the bioenergetic apparatus of cell and indirectly influence it via stress activation of the neuro-humoral system. The latter triggers a non-specific cascade of functional and metabolic responses and eventually disturbs oxygen delivery to cells, which also promotes bioenergetic hypoxia. Genotypically determined differences in kinetic properties of MEC are established, which play a leading role in formation of the functional and metabolic "portrait" of resistant and non-resistant to hypoxia animals and also in development of urgent and long-term mechanisms of adaptation to hypoxia. It was shown that these mechanisms can be used not only for development of the tactics and strategy for pharmacological correction of hypoxic states, but also for optimization of non-drug methods for enhancing the non-specific resistance of the organism. PMID:12918247

  17. Application of flexure structures to active and adaptive opto-mechanical mechanisms

    NASA Astrophysics Data System (ADS)

    Zago, Lorenzo; Genequand, Pierre M.; Kjelberg, Ivar; Morschel, Joseph

    1997-03-01

    Active and adaptive structures, also commonly called 'smart' structures, combine in one integrated system various functions such as load carrying and structural function, mechanical (cinematic) functions, sensing, control and actuating. Originally developed for high accuracy opto-mechanical applications, CSEM's technology of flexure structures and flexible mechanisms is particularly suited to solve many structural and mechanical issues found in such active/adaptive mechanisms. The paper illustrates some recent flexure structures developments at CSEM and outlines the comprehensive know-how involved in this technology. This comprises in particular the elaboration of optimal design guidelines, related to the geometry, kinematics and dynamics issues (for instance, the minimization of spurious high frequency effects), the evaluation and predictability of all performance quantities relevant to the utilization of flexure structures in space (reliability, fatigue, static and dynamic modeling, etc.). material issues and manufacturing procedures.

  18. Adaptation of core mechanisms to generate cell polarity

    PubMed Central

    Nelson, W. James

    2012-01-01

    Cell polarity is defined as asymmetry in cell shape, protein distributions and cell functions. It is characteristic of single-cell organisms, including yeast and bacteria, and cells in tissues of multi-cell organisms such as epithelia in worms, flies and mammals. This diversity raises several questions: do different cell types use different mechanisms to generate polarity, how is polarity signalled, how do cells react to that signal, and how is structural polarity translated into specialized functions? Analysis of evolutionarily diverse cell types reveals that cell-surface landmarks adapt core pathways for cytoskeleton assembly and protein transport to generate cell polarity. PMID:12700771

  19. Compressive adaptive ghost imaging via sharing mechanism and fellow relationship.

    PubMed

    Huo, Yaoran; He, Hongjie; Chen, Fan

    2016-04-20

    For lower sampling rate and better imaging quality, a compressive adaptive ghost imaging is proposed by adopting the sharing mechanism and fellow relationship in the wavelet tree. The sharing mechanisms, including intrascale and interscale sharing mechanisms, and fellow relationship are excavated from the wavelet tree and utilized for sampling. The shared coefficients, which are part of the approximation subband, are localized according to the parent coefficients and sampled based on the interscale sharing mechanism and fellow relationship. The sampling rate can be reduced owing to the fact that some shared coefficients can be calculated by adopting the parent coefficients and the sampled sum of shared coefficients. According to the shared coefficients and parent coefficients, the proposed method predicts the positions of significant coefficients and samples them based on the intrascale sharing mechanism. The ghost image, reconstructed by the significant coefficients and the coarse image at the given largest scale, achieves better quality because the significant coefficients contain more detailed information. The simulations demonstrate that the proposed method improves the imaging quality at the same sampling rate and also achieves a lower sampling rate for the same imaging quality for different types of target object images in noise-free and noisy environments. PMID:27140111

  20. MECHANISMS OF STATIONARY PHASE MUTATION: A Decade of Adaptive Mutation

    PubMed Central

    Foster, P. L.

    2010-01-01

    A decade of research on adaptive mutation has revealed a plethora of mutagenic mechanisms that may be important in evolution. The DNA synthesis associated with recombination could be an important source of spontaneous mutation in cells that are not proliferating. The movement of insertion elements can be responsive to environmental conditions. Insertion elements not only activate and inactivate genes, they also provide sequence homology that allows large-scale genomic rearrangements. Some conjugative plasmids can recombine with their host’s chromosome, and may acquire chromosomal genes that could then spread through the population and even to other species. Finally, a subpopulation of transient hypermutators could be a source of multiple variant alleles, providing a mechanism for rapid evolution under adverse conditions. PMID:10690404

  1. Adaptive and injury response of bone to mechanical loading

    PubMed Central

    McBride, Sarah H; Silva, Matthew J

    2012-01-01

    Bone responds to supraphysiological mechanical loads by increasing bone formation. Depending on the applied strain magnitude (and other loading parameters) the response can be either adaptive (mostly lamellar bone) or injury (mostly woven bone). Seminal studies of Hert, Lanyon and Rubin originally established the basic 'rules' of bone mechanosensitivity. These were reinforced by subsequent studies using noninvasive rodent loading models, most notably by Turner et al. More recent works with these models have been able to explore the structural, transcriptional and molecular mechanisms which distinguish the two responses (lamellar vs woven). Wnt/Lrp signaling has emerged as a key mechanoresponsive pathway for lamellar bone. However, there is still much to study with regard to effects of ageing, osteocytes, other signaling pathways, and the molecular regulation that modulates lamellar vs woven bone formation. This review summarizes not only the historical findings but also the current data for these topics. PMID:23505338

  2. Adaptive mechanisms of Campylobacter jejuni to erythromycin treatment

    PubMed Central

    2013-01-01

    Background Macrolide is the drug of choice to treat human campylobacteriosis, but Campylobacter resistance to this antibiotic is rising. The mechanisms employed by Campylobacter jejuni to adapt to erythromycin treatment remain unknown and are examined in this study. The transcriptomic response of C. jejuni NCTC 11168 to erythromycin (Ery) treatment was determined by competitive microarray hybridizations. Representative genes identified to be differentially expressed were further characterized by constructing mutants and assessing their involvement in antimicrobial susceptibility, oxidative stress tolerance, and chicken colonization. Results Following the treatment with an inhibitory dose of Ery, 139 genes were up-regulated and 119 were down-regulated. Many genes associated with flagellar biosynthesis and motility was up-regulated, while many genes involved in tricarboxylic acid cycle, electron transport, and ribonucleotide biosynthesis were down-regulated. Exposure to a sub-inhibitory dose of Ery resulted in differential expression of much fewer genes. Interestingly, two putative drug efflux operons (cj0309c-cj0310c and cj1173-cj1174) were up-regulated. Although mutation of the two operons did not alter the susceptibility of C. jejuni to antimicrobials, it reduced Campylobacter growth under high-level oxygen. Another notable finding is the consistent up-regulation of cj1169c-cj1170c, of which cj1170c encodes a known phosphokinase, an important regulatory protein in C. jejuni. Mutation of the cj1169c-cj1170c rendered C. jejuni less tolerant to atmospheric oxygen and reduced Campylobacter colonization and transmission in chickens. Conclusions These findings indicate that Ery treatment elicits a range of changes in C. jejuni transcriptome and affects the expression of genes important for in vitro and in vivo adaptation. Up-regulation of motility and down-regulation of energy metabolism likely facilitate Campylobacter to survive during Ery treatment. These findings

  3. Automated mechanical ventilation: adapting decision making to different disease states.

    PubMed

    Lozano-Zahonero, S; Gottlieb, D; Haberthür, C; Guttmann, J; Möller, K

    2011-03-01

    The purpose of the present study is to introduce a novel methodology for adapting and upgrading decision-making strategies concerning mechanical ventilation with respect to different disease states into our fuzzy-based expert system, AUTOPILOT-BT. The special features are: (1) Extraction of clinical knowledge in analogy to the daily routine. (2) An automated process to obtain the required information and to create fuzzy sets. (3) The controller employs the derived fuzzy rules to achieve the desired ventilation status. For demonstration this study focuses exclusively on the control of arterial CO(2) partial pressure (p(a)CO(2)). Clinical knowledge from 61 anesthesiologists was acquired using a questionnaire from which different disease-specific fuzzy sets were generated to control p(a)CO(2). For both, patients with healthy lung and with acute respiratory distress syndrome (ARDS) the fuzzy sets show different shapes. The fuzzy set "normal", i.e., "target p(a)CO(2) area", ranges from 35 to 39 mmHg for healthy lungs and from 39 to 43 mmHg for ARDS lungs. With the new fuzzy sets our AUTOPILOT-BT reaches the target p(a)CO(2) within maximal three consecutive changes of ventilator settings. Thus, clinical knowledge can be extended, updated, and the resulting mechanical ventilation therapies can be individually adapted, analyzed, and evaluated. PMID:21069471

  4. A density-based adaptive quantum mechanical/molecular mechanical method.

    PubMed

    Waller, Mark P; Kumbhar, Sadhana; Yang, Jack

    2014-10-20

    We present a density-based adaptive quantum mechanical/molecular mechanical (DBA-QM/MM) method, whereby molecules can switch layers from the QM to the MM region and vice versa. The adaptive partitioning of the molecular system ensures that the layer assignment can change during the optimization procedure, that is, on the fly. The switch from a QM molecule to a MM molecule is determined if there is an absence of noncovalent interactions to any atom of the QM core region. The presence/absence of noncovalent interactions is determined by analysis of the reduced density gradient. Therefore, the location of the QM/MM boundary is based on physical arguments, and this neatly removes some empiricism inherent in previous adaptive QM/MM partitioning schemes. The DBA-QM/MM method is validated by using a water-in-water setup and an explicitly solvated L-alanyl-L-alanine dipeptide. PMID:24954803

  5. NaCl-induced physiological and biochemical adaptative mechanisms in the ornamental Myrtus communis L. plants.

    PubMed

    Acosta-Motos, José Ramón; Diaz-Vivancos, Pedro; Álvarez, Sara; Fernández-García, Nieves; Sánchez-Blanco, María Jesús; Hernández, José Antonio

    2015-07-01

    Physiological and biochemical changes in Myrtus communis L. plants after being subjected to different solutions of NaCl (44, and 88 mM) for up to 30 days (Phase I) and after recovery from the salinity period (Phase II) were studied. Myrtle plants showed salinity tolerance by displaying a series of adaptative mechanisms to cope with salt-stress, including controlled ion homeostasis, the increase in root/shoot ratio, the reduction of water potentials and stomatal conductance to limit water loss. In addition, they displayed different strategies to protect the photosynthetic machinery, including limiting toxic ion accumulation in leaves, increase in chlorophyll content, and changes in chlorophyll fluorescence parameters, leaf anatomy and increases in catalase activity. Anatomical modifications in leaves, including a decrease in spongy parenchyma and increased intercellular spaces, allow CO2 diffusion in a situation of reduced stomatal aperture. In spite of all these changes, salinity produced oxidative stress in myrtle plants as monitored by increases in oxidative stress parameter values. The post-recovery period is perceived as a new stress situation, as observed through effects on plant growth and alterations in non-photochemical quenching parameters and lipid peroxidation values. PMID:26074356

  6. Adaptation of Grapevine Flowers to Cold Involves Different Mechanisms Depending on Stress Intensity

    PubMed Central

    Sawicki, Mélodie; Jeanson, Etienne; Celiz, Vanessa; Clément, Christophe

    2012-01-01

    Grapevine flower development and fruit set are influenced by cold nights in the vineyard. To investigate the impact of cold stress on carbon metabolism in the inflorescence, we exposed the inflorescences of fruiting cuttings to chilling and freezing temperatures overnight and measured fluctuations in photosynthesis and sugar content. Whatever the temperature, after the stress treatment photosynthesis was modified in the inflorescence, but the nature of the alteration depended on the intensity of the cold stress. At 4°C, photosynthesis in the inflorescence was impaired through non-stomatal limitations, whereas at 0°C it was affected through stomatal limitations. A freezing night (−3°C) severely deregulated photosynthesis in the inflorescence, acting primarily on photosystem II. Cold nights also induced accumulation of sugars. Soluble carbohydrates increased in inflorescences exposed to −3°C, 0°C and 4°C, but starch accumulated only in inflorescences of plants treated at 0 and −3°C. These results suggest that inflorescences are able to cope with cold temperatures by adapting their carbohydrate metabolism using mechanisms that are differentially induced according to stress intensity. PMID:23071684

  7. Neural Mechanisms Behind Identification of Leptokurtic Noise and Adaptive Behavioral Response

    PubMed Central

    d'Acremont, Mathieu; Bossaerts, Peter

    2016-01-01

    Large-scale human interaction through, for example, financial markets causes ceaseless random changes in outcome variability, producing frequent and salient outliers that render the outcome distribution more peaked than the Gaussian distribution, and with longer tails. Here, we study how humans cope with this evolutionary novel leptokurtic noise, focusing on the neurobiological mechanisms that allow the brain, 1) to recognize the outliers as noise and 2) to regulate the control necessary for adaptive response. We used functional magnetic resonance imaging, while participants tracked a target whose movements were affected by leptokurtic noise. After initial overreaction and insufficient subsequent correction, participants improved performance significantly. Yet, persistently long reaction times pointed to continued need for vigilance and control. We ran a contrasting treatment where outliers reflected permanent moves of the target, as in traditional mean-shift paradigms. Importantly, outliers were equally frequent and salient. There, control was superior and reaction time was faster. We present a novel reinforcement learning model that fits observed choices better than the Bayes-optimal model. Only anterior insula discriminated between the 2 types of outliers. In both treatments, outliers initially activated an extensive bottom-up attention and belief network, followed by sustained engagement of the fronto-parietal control network. PMID:26850528

  8. Family Background, Adolescent Coping Styles, and Adjustment.

    ERIC Educational Resources Information Center

    Schludermann, Shirin; And Others

    This study explored the effects of family background variables on coping styles, and the contribution of coping styles and locus of control to the overall adjustment of older adolescents. The objectives of this study were to develop a Canadian adaptation of the Seiffge-Krenke Adolescent Coping Style Scale; to explore the influences of family and…

  9. A proposed mechanism for rapid adaptation to spectrally distorted speech.

    PubMed

    Azadpour, Mahan; Balaban, Evan

    2015-07-01

    The mechanisms underlying perceptual adaptation to severely spectrally-distorted speech were studied by training participants to comprehend spectrally-rotated speech, which is obtained by inverting the speech spectrum. Spectral-rotation produces severe distortion confined to the spectral domain while preserving temporal trajectories. During five 1-hour training sessions, pairs of participants attempted to extract spoken messages from the spectrally-rotated speech of their training partner. Data on training-induced changes in comprehension of spectrally-rotated sentences and identification/discrimination of spectrally-rotated phonemes were used to evaluate the plausibility of three different classes of underlying perceptual mechanisms: (1) phonemic remapping (the formation of new phonemic categories that specifically incorporate spectrally-rotated acoustic information); (2) experience-dependent generation of a perceptual "inverse-transform" that compensates for spectral-rotation; and (3) changes in cue weighting (the identification of sets of acoustic cues least affected by spectral-rotation, followed by a rapid shift in perceptual emphasis to favour those cues, combined with the recruitment of the same type of "perceptual filling-in" mechanisms used to disambiguate speech-in-noise). Results exclusively support the third mechanism, which is the only one predicting that learning would specifically target temporally-dynamic cues that were transmitting phonetic information most stably in spite of spectral-distortion. No support was found for phonemic remapping or for inverse-transform generation. PMID:26233005

  10. Endocrine and Cognitive Adaptations to Cope with Stress in Immature Common Marmosets (Callithrix jacchus): Sex and Age Matter

    PubMed Central

    de Sousa, Maria Bernardete Cordeiro; Galvão, Ana Cecília de Menezes; Sales, Carla Jéssica Rodrigues; de Castro, Dijenaide Chaves; Galvão-Coelho, Nicole Leite

    2015-01-01

    Phenotypic sex differences in primates are associated with body differentiation during the early stages of life, expressed in both physiological and behavioral features. Hormones seem to play a pivotal role in creating a range of responses to meet environmental and social demands, resulting in better reactions to cope with challenges to survival and reproduction. Steroid hormones actively participate in neuroplasticity and steroids from both gonads and neurons seem to be involved in behavioral modulation in primates. Indirect evidence suggests the participation of sexual steroids in dimorphism of the stress response in common marmosets. This species is an important experimental model in psychiatry, and we found a dual profile for cortisol in the transition from juvenile to subadult, with females showing higher levels. Immature males and females at 6 and 9 months of age moved alone from the family group to a new cage, over a 21-day period, expressed distinct patterns of cortisol variation with respect to range and duration of response. Additional evidence showed that at 12 months of age, males and females buffered the hypothalamic–pituitary–adrenal axis during chronic stress. Moreover, chronic stressed juvenile marmoset males showed better cognitive performance in working memory tests and motivation when compared to those submitted to short-term stress living in family groups. Thus, as cortisol profile seems to be sexually dimorphic before adulthood, age and sex are critical variables to consider in approaches that require immature marmosets in their experimental protocols. Moreover, available cognitive tests should be scrutinized to allow better investigation of cognitive traits in this species. PMID:26648876

  11. Coping among the caregivers of patients with schizophrenia

    PubMed Central

    Grover, Sandeep; Pradyumna; Chakrabarti, Subho

    2015-01-01

    Coping is understood as the process of managing external or internal demands that are considered as taxing or exceeding the resources of the person. There is no formal classification of coping strategies, and these are understood as adaptive versus maladaptive and problem focuses versus emotion-focused. Understanding the commonly used coping strategies in a particular group of subjects can provide valuable insights for designing interventions to reduce the stress. In this review, we look at the literature which is available with regards to the coping strategies used by the caregivers of patients with schizophrenia. Findings suggest that caregivers of patients with schizophrenia use mixed type of coping mechanisms to deal with the stress of caregiving. The coping strategies are shown to have association with variables such as caregiver burden, caregiving experience, expressed emotions, social support, psychological morbidity in the caregivers, quality of life of caregivers and psychopathology in patients. One of the major limitations of the literature is that there is a lot of variability in the assessment instruments used across different studies to assess coping. PMID:26257476

  12. When do adaptive developmental mechanisms yield maladaptive outcomes?

    PubMed

    Frankenhuis, Willem E; Del Giudice, Marco

    2012-05-01

    This article discusses 3 ways in which adaptive developmental mechanisms may produce maladaptive outcomes. First, natural selection may favor risky strategies that enhance fitness on average but which have detrimental consequences for a subset of individuals. Second, mismatch may result when organisms experience environmental change during ontogeny, for instance, because they move from one environment to another. Third, organisms may learn about their environment in order to develop an appropriate phenotype; when cues indicate the environmental state probabilistically, as opposed to deterministically, sampling processes may produce mismatch. For each source of maladaptation, we present a selection of the relevant empirical research and illustrate how models from evolutionary biology can be used to make predictions about maladaptation. We also discuss what data can be collected to test these models in humans. Our goal is to show that evolutionary approaches not only yield insights into adaptive outcomes but can also illuminate the conditions leading to maladaptation. This perspective provides additional nuance to the dialectic between the developmental psychopathology model and evolutionary developmental psychology. PMID:21967567

  13. Adaptive mechanical properties of topologically interlocking material systems

    NASA Astrophysics Data System (ADS)

    Khandelwal, S.; Siegmund, T.; Cipra, R. J.; Bolton, J. S.

    2015-04-01

    Topologically interlocked material systems are two-dimensional granular crystals created as ordered and adhesion-less assemblies of unit elements of the shape of platonic solids. The assembly resists transverse forces due to the interlocking geometric arrangement of the unit elements. Topologically interlocked material systems yet require an external constraint to provide resistance under the action of external load. Past work considered fixed and passive constraints only. The objective of the present study is to consider active and adaptive external constraints with the goal to achieve variable stiffness and energy absorption characteristics of the topologically interlocked material system through an active control of the in-plane constraint conditions. Experiments and corresponding model analysis are used to demonstrate control of system stiffness over a wide range, including negative stiffness, and energy absorption characteristics. The adaptive characteristics of the topologically interlocked material system are shown to solve conflicting requirements of simultaneously providing energy absorption while keeping loads controlled. Potential applications can be envisioned in smart structure enhanced response characteristics as desired in shock absorption, protective packaging and catching mechanisms.

  14. Adaptive control of vibrissae-like mechanical sensors

    NASA Astrophysics Data System (ADS)

    Behn, Carsten

    2011-05-01

    This paper is a contribution to the modeling and the adaptive control of bio-inspired sensors which have the animal vibrissae as a paradigm. Mice and rats employ a sophisticated tactile sensory system to explore their environment in addition to their visual and auditory sense. Vibrissae in the mystical pad (region around the mouth) are used both passively to sense environmental influences (wind, objects) and actively to detect surface and object structures. Inspired by this particular version of tactile sense we consider the following three stages of a sensory system: perception, transduction and processing of information. We model this system in combining two existing mechanical models and obtain an uncertain nonlinear control system. An applied adaptive controller implements the ability of the animals to employ their vibrissae actively as well as passively. Numerical simulations show that the developed nonlinear model compensates noise signals and reacts strongly to sudden perturbations while guaranteeing a pre-specified control objective (working in active or passive mode).

  15. Adaptive information interactive mechanism for multi-UAV visual navigation

    NASA Astrophysics Data System (ADS)

    Liu, Hui; Dai, Qionghai

    2012-06-01

    Multi-unmanned aerial vehicle (UAV) cooperative communication for visual navigation has recently generated significant concern. It has large amounts of visual information to be transmitted and processed among UAVs with realtime requirements. And the UAV clusters have self-organized, time-varying and high dynamic characteristics. Considering the above conditions, we propose an adaptive information interactive mechanism (AIIM) for multi-UAV visual navigation. In the mechanism, the function modules for UAV inter-communication interface are designed, the mobility-based link lifetime is established and the information interactive protocol is presented. Thus we combine the mobility of UAVs with the corresponding communication requirements to make effective information interaction for UAVs. Task-oriented distributed control is adopted to improve the collaboration flexibility in the multi-UAV visual navigation system. In order to timely obtain the necessary visual information, each UAV can cooperate with other relevant UAVs which meet some certain terms such as situation, task or environmental conditions. Simulation results are presented to show the validity of the proposed mechanism in terms of end-to-end delay and links stability.

  16. Multiple representations and mechanisms for visuomotor adaptation in young children.

    PubMed

    Tahej, Pierre-Karim; Ferrel-Chapus, Carole; Olivier, Isabelle; Ginhac, Dominique; Rolland, Jean-Pierre

    2012-12-01

    In this study, we utilized transformed spatial mappings to perturb visuomotor integration in 5-yr-old children and adults. The participants were asked to perform pointing movements under five different conditions of visuomotor rotation (from 0° to 180°), which were designed to reveal explicit vs. implicit representations as well as the mechanisms underlying the visual-motor mapping. Several tests allowed us to separately evaluate sensorimotor (i.e., the dynamic dimension of movement) and cognitive (i.e., the explicit representations of target position and the strategies used by the participants) representations of visuo-proprioceptive distortion. Our results indicate that children do not establish representations in the same manner as adults and that children exhibit multiple visuomotor representations. Sensorimotor representations were relatively precise, presumably due to the recovery of proprioceptive information and efferent copy. Furthermore, a bidirectional mechanism was used to re-map visual and motor spaces. In contrast, cognitive representations were supplied with visual information and followed a unidirectional visual-motor mapping. Therefore, it appears that sensorimotor mechanisms develop before the use of explicit strategies during development, and young children showed impaired visuomotor adaptation when confronted with large distortions. PMID:22704964

  17. Mechanisms of Cardiopulmonary Adaptation to Microgravity. Part 1

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Session TA1 includes short reports covering: (1) Indices of Baroreceptor Reflex Sensitivity: The Use in Rehabilitation Medicine and Space Cardiology; (2) +Gz and +Gx Tolerance of Healthy Persons of Non-Flying Trades at Primary Selection of the Centrifuge; (3) Effect of Dry Immersion on Calf Blood Supply During Sustained Contraction and Upright Exercise in Man; (4) Cardiovascular and Valsalva Responses during Parabolic flight; (5) An Analysis of the Cardiovascular Responses under Hyper- and Hypo-Gravity Environments using a Mathematical model; (6) Effect of Very Gradual Onset Rate +Gz Exposures on the Cardiovascular System; and (7) NASA Specialized Center of Research and Training (NSCORT) in Integrated Physiology: Mechanisms of Physiological Adaptations to Microgravity.

  18. Adaptive Broadcasting Mechanism for Bandwidth Allocation in Mobile Services

    PubMed Central

    Horng, Gwo-Jiun; Wang, Chi-Hsuan; Chou, Chih-Lun

    2014-01-01

    This paper proposes a tree-based adaptive broadcasting (TAB) algorithm for data dissemination to improve data access efficiency. The proposed TAB algorithm first constructs a broadcast tree to determine the broadcast frequency of each data and splits the broadcast tree into some broadcast wood to generate the broadcast program. In addition, this paper develops an analytical model to derive the mean access latency of the generated broadcast program. In light of the derived results, both the index channel's bandwidth and the data channel's bandwidth can be optimally allocated to maximize bandwidth utilization. This paper presents experiments to help evaluate the effectiveness of the proposed strategy. From the experimental results, it can be seen that the proposed mechanism is feasible in practice. PMID:25057509

  19. Synaptic mechanisms of adaptation and sensitization in the retina

    PubMed Central

    Nikolaev, Anton; Leung, Kin-Mei; Odermatt, Benjamin; Lagnado, Leon

    2014-01-01

    Sensory systems continually adjust the way stimuli are processed. What are the circuit mechanisms underlying this plasticity? We investigated how synapses in the retina of zebrafish adjust to changes in the temporal contrast of a visual stimulus by imaging activity in vivo. Following an increase in contrast, bipolar cell synapses with strong initial responses depressed, whereas synapses with weak initial responses facilitated. Depression and facilitation predominated in different strata of the inner retina, where bipolar cell output was anticorrelated with the activity of amacrine cell synapses providing inhibitory feedback. Pharmacological block of GABAergic feedback converted facilitating bipolar cell synapses into depressing ones. These results indicate that depression intrinsic to bipolar cell synapses causes adaptation of the ganglion cell response to contrast, whereas depression in amacrine cell synapses causes sensitization. Distinct microcircuits segregating to different layers of the retina can cause simultaneous increases or decreases in the gain of neural responses. PMID:23685718

  20. Block-adaptive quantum mechanics: an adaptive divide-and-conquer approach to interactive quantum chemistry.

    PubMed

    Bosson, Maël; Grudinin, Sergei; Redon, Stephane

    2013-03-01

    We present a novel Block-Adaptive Quantum Mechanics (BAQM) approach to interactive quantum chemistry. Although quantum chemistry models are known to be computationally demanding, we achieve interactive rates by focusing computational resources on the most active parts of the system. BAQM is based on a divide-and-conquer technique and constrains some nucleus positions and some electronic degrees of freedom on the fly to simplify the simulation. As a result, each time step may be performed significantly faster, which in turn may accelerate attraction to the neighboring local minima. By applying our approach to the nonself-consistent Atom Superposition and Electron Delocalization Molecular Orbital theory, we demonstrate interactive rates and efficient virtual prototyping for systems containing more than a thousand of atoms on a standard desktop computer. PMID:23108532

  1. Deciphering the protein translation inhibition and coping mechanism of trichothecene toxin in resistant fungi.

    PubMed

    Kumari, Indu; Ahmed, Mushtaq; Akhter, Yusuf

    2016-09-01

    In modern times for combating the deleterious soil microbes for improved sustainable agricultural practices, there is a need to have a proper understanding of the plant-microbe interactions present in the rhizospheric microbiome of the plant roots. In the present study, the interactions of trichodermin with petidyltransferase centre of ribosomal complex was studied by molecular dynamics and in silico interaction methods to demonstrate its mechanism of action and to decipher the possible reason how it may inhibit protein synthesis at the ribosomal complex. Further we have illustrated how trichodermin resistance protein (60S ribosomal protein L3) helps to overcome the deleterious effects of trichothecene compounds like trichodermin. Normal mode analysis of trichodermin resistance protein and 25S rRNA that constitutes the petidyltransferase centre showed that the W-finger region of the protein moved towards 25S rRNA. Further analysis of molecular dynamics simulation time frames showed that several intermediate states of large motions of the protein molecules towards the 25S rRNA which finally blocks the binding pocket of the trichodermin. It indicated that this protein not only changes the local environment and conformation of the petidyltransferase centre but also restrain trichodermin from binding to the 25S rRNA at the petidyltransferase centre. PMID:27495375

  2. Molecular mechanisms involved in plant adaptation to low K(+) availability.

    PubMed

    Chérel, Isabelle; Lefoulon, Cécile; Boeglin, Martin; Sentenac, Hervé

    2014-03-01

    Potassium is a major inorganic constituent of the living cell and the most abundant cation in the cytosol. It plays a role in various functions at the cell level, such as electrical neutralization of anionic charges, protein synthesis, long- and short-term control of membrane polarization, and regulation of the osmotic potential. Through the latter function, K(+) is involved at the whole-plant level in osmotically driven functions such as cell movements, regulation of stomatal aperture, or phloem transport. Thus, plant growth and development require that large amounts of K(+) are taken up from the soil and translocated to the various organs. In most ecosystems, however, soil K(+) availability is low and fluctuating, so plants have developed strategies to take up K(+) more efficiently and preserve vital functions and growth when K(+) availability is becoming limited. These strategies include increased capacity for high-affinity K(+) uptake from the soil, K(+) redistribution between the cytosolic and vacuolar pools, ensuring cytosolic homeostasis, and modification of root system development and architecture. Our knowledge about the mechanisms and signalling cascades involved in these different adaptive responses has been rapidly growing during the last decade, revealing a highly complex network of interacting processes. This review is focused on the different physiological responses induced by K(+) deprivation, their underlying molecular events, and the present knowledge and hypotheses regarding the mechanisms responsible for K(+) sensing and signalling. PMID:24293613

  3. Molecular mechanisms of Tetranychus urticae chemical adaptation in hop fields.

    PubMed

    Piraneo, Tara G; Bull, Jon; Morales, Mariany A; Lavine, Laura C; Walsh, Douglas B; Zhu, Fang

    2015-01-01

    The two-spotted spider mite, Tetranychus urticae Koch is a major pest that feeds on >1,100 plant species. Many perennial crops including hop (Humulus lupulus) are routinely plagued by T. urticae infestations. Hop is a specialty crop in Pacific Northwest states, where 99% of all U.S. hops are produced. To suppress T. urticae, growers often apply various acaricides. Unfortunately T. urticae has been documented to quickly develop resistance to these acaricides which directly cause control failures. Here, we investigated resistance ratios and distribution of multiple resistance-associated mutations in field collected T. urticae samples compared with a susceptible population. Our research revealed that a mutation in the cytochrome b gene (G126S) in 35% tested T. urticae populations and a mutation in the voltage-gated sodium channel gene (F1538I) in 66.7% populations may contribute resistance to bifenazate and bifenthrin, respectively. No mutations were detected in Glutamate-gated chloride channel subunits tested, suggesting target site insensitivity may not be important in our hop T. urticae resistance to abamectin. However, P450-mediated detoxification was observed and is a putative mechanism for abamectin resistance. Molecular mechanisms of T. urticae chemical adaptation in hopyards is imperative new information that will help growers develop effective and sustainable management strategies. PMID:26621458

  4. Molecular mechanisms of genetic adaptation to xenobiotic compounds.

    PubMed Central

    van der Meer, J R; de Vos, W M; Harayama, S; Zehnder, A J

    1992-01-01

    Microorganisms in the environment can often adapt to use xenobiotic chemicals as novel growth and energy substrates. Specialized enzyme systems and metabolic pathways for the degradation of man-made compounds such as chlorobiphenyls and chlorobenzenes have been found in microorganisms isolated from geographically separated areas of the world. The genetic characterization of an increasing number of aerobic pathways for degradation of (substituted) aromatic compounds in different bacteria has made it possible to compare the similarities in genetic organization and in sequence which exist between genes and proteins of these specialized catabolic routes and more common pathways. These data suggest that discrete modules containing clusters of genes have been combined in different ways in the various catabolic pathways. Sequence information further suggests divergence of catabolic genes coding for specialized enzymes in the degradation of xenobiotic chemicals. An important question will be to find whether these specialized enzymes evolved from more common isozymes only after the introduction of xenobiotic chemicals into the environment. Evidence is presented that a range of genetic mechanisms, such as gene transfer, mutational drift, and genetic recombination and transposition, can accelerate the evolution of catabolic pathways in bacteria. However, there is virtually no information concerning the rates at which these mechanisms are operating in bacteria living in nature and the response of such rates to the presence of potential (xenobiotic) substrates. Quantitative data on the genetic processes in the natural environment and on the effect of environmental parameters on the rate of evolution are needed. PMID:1480115

  5. Molecular mechanisms of Tetranychus urticae chemical adaptation in hop fields

    PubMed Central

    Piraneo, Tara G.; Bull, Jon; Morales, Mariany A.; Lavine, Laura C.; Walsh, Douglas B.; Zhu, Fang

    2015-01-01

    The two-spotted spider mite, Tetranychus urticae Koch is a major pest that feeds on >1,100 plant species. Many perennial crops including hop (Humulus lupulus) are routinely plagued by T. urticae infestations. Hop is a specialty crop in Pacific Northwest states, where 99% of all U.S. hops are produced. To suppress T. urticae, growers often apply various acaricides. Unfortunately T. urticae has been documented to quickly develop resistance to these acaricides which directly cause control failures. Here, we investigated resistance ratios and distribution of multiple resistance-associated mutations in field collected T. urticae samples compared with a susceptible population. Our research revealed that a mutation in the cytochrome b gene (G126S) in 35% tested T. urticae populations and a mutation in the voltage-gated sodium channel gene (F1538I) in 66.7% populations may contribute resistance to bifenazate and bifenthrin, respectively. No mutations were detected in Glutamate-gated chloride channel subunits tested, suggesting target site insensitivity may not be important in our hop T. urticae resistance to abamectin. However, P450-mediated detoxification was observed and is a putative mechanism for abamectin resistance. Molecular mechanisms of T. urticae chemical adaptation in hopyards is imperative new information that will help growers develop effective and sustainable management strategies. PMID:26621458

  6. [Coping psychologically with amputation].

    PubMed

    Schulz, M

    2009-02-01

    An amputation is a "tragic event" in someone's biography which causes a dramatic change in the outer appearance, the loss of mobility, independence and self esteem. The following article is about how people learn to cope with this difficult situation; with the practical problems of everyday life as well as their emotional problems. It is important for the amputees to go through the different stages of mourning: The first stage is the rejection of the situation. Repression and denial of the loss protects the patient from emotional overstrain. Confrontation is the next step: emotionally as well as mentally. "How could it happen?", (understanding the reasons why ...) "What will my future be like?", "How will I cope?" (ability of coping) "Why did it happen to me?" (sense) The last stage of coping with the amputation is to accept and deal with the new situation and to build up new self-confidence. A successful process of coping leads to a new identity. If a person fails to adapt to the new situation, he will develop an inferiority complex and fall into a depression. He might also try to look for culprit and blame the situation on someone else. About two thirds of all amputees don't cope with their amputation and become depressive. 15% develop symptoms of anxiety. Therefore it is important to offer help. The patients should get together in self helping groups and talk about their experiences and problems. If they need more intensive and individual help, they should have the opportunity to contact a psychologist. During the process of coping with their amputation the patients often alternate between optimistic and pessimistic moods. Sometimes they fall back into a negative and resigned state of mind. This is natural and part of the process as long as they find their own way to a positive attitude and view of life. PMID:19259934

  7. Coping styles of pregnant adolescents.

    PubMed

    Myors, K; Johnson, M; Langdon, R

    2001-01-01

    This descriptive study examined the coping styles and specific strategies used by a group of pregnant adolescents attending an adolescent family support service. Seventy-one adolescents, with a mean age of 17 years, and a mean gestation of 25 weeks, completed the Revised Jalowiec Coping Scale (JCS-R). The findings demonstrated that the optimistic coping style (emotion-focused) was the most frequently used and most effective coping style for these young women. A confrontive coping style (problem-focused) was also used and found to be effective. A combination of problem-focused and emotion-focused styles is recommended, with an increased emphasis on problem-focused approaches. The focus by the adolescents on optimistic approaches is suggestive of a lack of understanding of the challenges that motherhood will place upon them, but is consistent with their age and developmental stage. A longitudinal study of coping styles and changes in style throughout pregnancy and early motherhood is recommended. Initial assessment and monitoring of coping styles of pregnant adolescents is proposed. This assessment would be the beginning point for a teaching program that highlights increased use of adaptive coping styles (problem-focused) with decreased use of maladaptive approaches, and includes emotion-focused styles. By expanding the repertoire of coping styles and strategies available to the adolescent, the public health nurse (PHN) prepares these vulnerable mothers for the challenges ahead. PMID:11251870

  8. Co-adaptation mechanisms in plant-nematode systems.

    PubMed

    Zinovieva, S V

    2014-01-01

    The review is aimed to analyze the biochemical and immune-breaking adaptive mechanisms established in evolution of plant parasitic nematodes. Plant parasitic nematodes are obligate, biotrophic pathogens of numerous plant species. These organisms cause dramatic changes in the morphology and physiology of their hosts. The group of sedentary nematodes which are among the most damaging plant-parasitic nematodes cause the formation of special organs called nematode feeding sites in the root tissue called syncytium (cyst nematodes, CN; Heterodera and Globodera spp.) or giant cells (root-knot nematodes, RKN; Meloidogyne spp.). The most pronounced morphological adaptations of nematodes for plant parasitism include a hollow, protrusible stylet (feeding spear) connected to three esophageal gland cells that express products secreted into plant tissues through the stylet. Several gene products secreted by the nematode during parasitism have been identified. The current battery of candidate parasitism proteins secreted by nematodes to modify plant tissues for parasitism includes cell-wall-modifying enzymes, multiple regulators of host cell cycle and metabolism, proteins that can localize near the plant cell nucleus, potential suppressors of host defense, and mimics of plant molecules. Plants are usually able to recognize and react to parasites by activating various defense responses. When the response of the plant is too weak or too late, a successful infection (compatible interaction) will result. A rapid and strong defense response (e. g. due to the presence of a resistance gene) will result in the resistant (incompatible) reaction. Defense responses include the production of toxic oxygen radicals and systemic signaling compounds as well as the activation of defense genes that lead to the production of structural barriers or other toxins. PMID:25272462

  9. RNA Sequencing of Populus x canadensis Roots Identifies Key Molecular Mechanisms Underlying Physiological Adaption to Excess Zinc

    PubMed Central

    Ariani, Andrea; Di Baccio, Daniela; Romeo, Stefania; Lombardi, Lara; Andreucci, Andrea; Lux, Alexander; Horner, David Stephen; Sebastiani, Luca

    2015-01-01

    Populus x canadensis clone I-214 exhibits a general indicator phenotype in response to excess Zn, and a higher metal uptake in roots than in shoots with a reduced translocation to aerial parts under hydroponic conditions. This physiological adaptation seems mainly regulated by roots, although the molecular mechanisms that underlie these processes are still poorly understood. Here, differential expression analysis using RNA-sequencing technology was used to identify the molecular mechanisms involved in the response to excess Zn in root. In order to maximize specificity of detection of differentially expressed (DE) genes, we consider the intersection of genes identified by three distinct statistical approaches (61 up- and 19 down-regulated) and validate them by RT-qPCR, yielding an agreement of 93% between the two experimental techniques. Gene Ontology (GO) terms related to oxidation-reduction processes, transport and cellular iron ion homeostasis were enriched among DE genes, highlighting the importance of metal homeostasis in adaptation to excess Zn by P. x canadensis clone I-214. We identified the up-regulation of two Populus metal transporters (ZIP2 and NRAMP1) probably involved in metal uptake, and the down-regulation of a NAS4 gene involved in metal translocation. We identified also four Fe-homeostasis transcription factors (two bHLH38 genes, FIT and BTS) that were differentially expressed, probably for reducing Zn-induced Fe-deficiency. In particular, we suggest that the down-regulation of FIT transcription factor could be a mechanism to cope with Zn-induced Fe-deficiency in Populus. These results provide insight into the molecular mechanisms involved in adaption to excess Zn in Populus spp., but could also constitute a starting point for the identification and characterization of molecular markers or biotechnological targets for possible improvement of phytoremediation performances of poplar trees. PMID:25671786

  10. The relationship between burnout and coping in adult and young offender center correctional officers: an exploratory investigation.

    PubMed

    Gould, Drew D; Watson, Shelley L; Price, Stephanie R; Valliant, Paul M

    2013-02-01

    High levels of occupational stress and burnout are costly for correctional services and their employees. Correctional officers report high levels of burnout, absenteeism, turnover, and poor physical health. The purpose of this study was to investigate the prevalence of burnout and the coping mechanisms used to buffer the effects of burnout within correctional centers. In the current study, 208 correctional officers from adult and young offender centers completed an online survey measuring burnout and coping strategies. Results from the Maslach Burnout Inventory-Human Services Survey (MBI-HSS) and the Brief Coping Orientation to Problems Experienced (COPE) Scale indicated that even though correctional center officers mostly used adaptive coping strategies, they still reported high levels of burnout. The results of this study suggest that there are variables other than coping strategies, such as gender and length of experience, that lead to the level of burnout as observed in correctional officers. PMID:22924799

  11. Coping as a multisystem construct associated with pathways mediating HIV-relevant immune function and disease progression.

    PubMed

    Temoshok, Lydia R; Wald, Rebecca L; Synowski, Stephen; Garzino-Demo, Alfredo

    2008-06-01

    We review psychoneuroimmunological research linking coping with HIV disease progression and its indicators, as well as with viral and host factors that may mediate or contribute to HIV progression. Our perspective on coping broadly encompasses the attempts of multiple mental and biological systems to adapt to changing internal and environmental conditions and to reestablish homeostasis. Accordingly, we discuss studies within four dimensions of coping: cognitive (appraisals, expectancies, and explanatory style), emotional (the Type C coping pattern and related constructs), active-passive strategies and behavior patterns, and physiological (autonomic reactivity and recovery). Finally, we present a model that integrates key studies linking coping with HIV prognostic indicators and clinical disease progression. Based on empirical evidence, the model suggests plausible mechanisms by which coping may be connected to HIV progression/antiprogression factors and immunopathogenesis to affect HIV clinical progression. PMID:18519884

  12. Molecular mechanisms underlying phosphate sensing, signaling, and adaptation in plants.

    PubMed

    Zhang, Zhaoliang; Liao, Hong; Lucas, William J

    2014-03-01

    As an essential plant macronutrient, the low availability of phosphorus (P) in most soils imposes serious limitation on crop production. Plants have evolved complex responsive and adaptive mechanisms for acquisition, remobilization and recycling of phosphate (Pi) to maintain P homeostasis. Spatio-temporal molecular, physiological, and biochemical Pi deficiency responses developed by plants are the consequence of local and systemic sensing and signaling pathways. Pi deficiency is sensed locally by the root system where hormones serve as important signaling components in terms of developmental reprogramming, leading to changes in root system architecture. Root-to-shoot and shoot-to-root signals, delivered through the xylem and phloem, respectively, involving Pi itself, hormones, miRNAs, mRNAs, and sucrose, serve to coordinate Pi deficiency responses at the whole-plant level. A combination of chromatin remodeling, transcriptional and posttranslational events contribute to globally regulating a wide range of Pi deficiency responses. In this review, recent advances are evaluated in terms of progress toward developing a comprehensive understanding of the molecular events underlying control over P homeostasis. Application of this knowledge, in terms of developing crop plants having enhanced attributes for P use efficiency, is discussed from the perspective of agricultural sustainability in the face of diminishing global P supplies. PMID:24417933

  13. The Role of Spirituality in Coping with Visual Impairment

    ERIC Educational Resources Information Center

    Yampolsky, Maya A.; Wittich, Walter; Webb, Gail; Overbury, Olga

    2008-01-01

    Spirituality and coping behaviors were measured in 85 individuals with visual impairments aged 23 to 97. A regression analysis indicated that the religious well-being subscale of the Spiritual Well-Being Scale is a significant predictor of adaptive coping behaviors, indicating that higher religious well-being facilitates adaptive coping. (Contains…

  14. Skeletal adaptation to external loads optimizes mechanical properties: fact or fiction

    NASA Technical Reports Server (NTRS)

    Turner, R. T.

    2001-01-01

    The skeleton adapts to a changing mechanical environment but the widely held concept that bone cells are programmed to respond to local mechanical loads to produce an optimal mechanical structure is not consistent with the high frequency of bone fractures. Instead, the author suggests that other important functions of bone compete with mechanical adaptation to determine structure. As a consequence of competing demands, bone architecture never achieves an optimal mechanical structure. c2001 Lippincott Williams & Wilkins, Inc.

  15. Hypothalamic oxytocin mediates adaptation mechanism against chronic stress in rats

    PubMed Central

    Zheng, Jun; Babygirija, Reji; Bülbül, Mehmet; Cerjak, Diana; Ludwig, Kirk

    2010-01-01

    Accumulation of continuous life stress (chronic stress) often causes gastric symptoms. Although central oxytocin has antistress effects, the role of central oxytocin in stress-induced gastric dysmotility remains unknown. Solid gastric emptying was measured in rats receiving acute restraint stress, 5 consecutive days of repeated restraint stress (chronic homotypic stress), and 7 consecutive days of varying types of stress (chronic heterotypic stress). Oxytocin and oxytocin receptor antagonist were administered intracerebroventricularly (icv). Expression of corticotropin-releasing factor (CRF) mRNA and oxytocin mRNA in the paraventricular nucleus (PVN) of the hypothalamus was evaluated by real-time RT-PCR. The changes of oxytocinergic neurons in the PVN were evaluated by immunohistochemistry. Acute stress delayed gastric emptying, and the delayed gastric emptying was completely restored after 5 consecutive days of chronic homotypic stress. In contrast, delayed gastric emptying persisted following chronic heterotypic stress. The restored gastric emptying following chronic homotypic stress was antagonized by icv injection of an oxytocin antagonist. Icv injection of oxytocin restored delayed gastric emptying induced by chronic heterotypic stress. CRF mRNA expression, which was significantly increased in response to acute stress and chronic heterotypic stress, returned to the basal levels following chronic homotypic stress. In contrast, oxytocin mRNA expression was significantly increased following chronic homotypic stress. The number of oxytocin-immunoreactive cells was increased following chronic homotypic stress at the magnocellular part of the PVN. Icv injection of oxytocin reduced CRF mRNA expression induced by acute stress and chronic heterotypic stress. It is suggested that the adaptation mechanism to chronic stress may involve the upregulation of oxytocin expression in the hypothalamus, which in turn attenuates CRF expression. PMID:20689056

  16. Hypothalamic oxytocin mediates adaptation mechanism against chronic stress in rats.

    PubMed

    Zheng, Jun; Babygirija, Reji; Bülbül, Mehmet; Cerjak, Diana; Ludwig, Kirk; Takahashi, Toku

    2010-10-01

    Accumulation of continuous life stress (chronic stress) often causes gastric symptoms. Although central oxytocin has antistress effects, the role of central oxytocin in stress-induced gastric dysmotility remains unknown. Solid gastric emptying was measured in rats receiving acute restraint stress, 5 consecutive days of repeated restraint stress (chronic homotypic stress), and 7 consecutive days of varying types of stress (chronic heterotypic stress). Oxytocin and oxytocin receptor antagonist were administered intracerebroventricularly (icv). Expression of corticotropin-releasing factor (CRF) mRNA and oxytocin mRNA in the paraventricular nucleus (PVN) of the hypothalamus was evaluated by real-time RT-PCR. The changes of oxytocinergic neurons in the PVN were evaluated by immunohistochemistry. Acute stress delayed gastric emptying, and the delayed gastric emptying was completely restored after 5 consecutive days of chronic homotypic stress. In contrast, delayed gastric emptying persisted following chronic heterotypic stress. The restored gastric emptying following chronic homotypic stress was antagonized by icv injection of an oxytocin antagonist. Icv injection of oxytocin restored delayed gastric emptying induced by chronic heterotypic stress. CRF mRNA expression, which was significantly increased in response to acute stress and chronic heterotypic stress, returned to the basal levels following chronic homotypic stress. In contrast, oxytocin mRNA expression was significantly increased following chronic homotypic stress. The number of oxytocin-immunoreactive cells was increased following chronic homotypic stress at the magnocellular part of the PVN. Icv injection of oxytocin reduced CRF mRNA expression induced by acute stress and chronic heterotypic stress. It is suggested that the adaptation mechanism to chronic stress may involve the upregulation of oxytocin expression in the hypothalamus, which in turn attenuates CRF expression. PMID:20689056

  17. Adaptation of spatiotemporal mechanisms by increment and decrement stimuli

    NASA Astrophysics Data System (ADS)

    Purkiss, Todd J.; Demarco, Paul J.

    2002-08-01

    Sawtooth modulation has been used in the past to examine visual sensitivity to luminance increments and decrements. The threshold elevation caused by adaptation depends on the spatial profile of the stimulus field and the polarities of the adaptation and test stimuli. We hypothesized that the adaptation effects reflect a change in the sensitivity of the spatiotemporal channels that detect the stimuli. We used a 2-deg disk centered in a larger surround field. Five levels of contrast between the test field and surround were investigated: equiluminant, three intermediate levels, and dark. At each contrast, observers adapted for 5 s to 2-Hz sawtooth modulation (rapid-on or rapid-off). Immediately after adaptation, thresholds were measured for detection of a single cycle of either a rapid-on or a rapid-off waveform. Varying the contrast of the surround affected observers sensitivity to the polarity of the sawtooth stimulus to the extent that the pattern of sensitivity with the equiluminant surround was the opposite of that with the dark surround. To examine temporal factors, we measured thresholds for slow (500-ms ramps) and fast (8.3-ms pulses) test stimuli. The adaptation effect was preserved with the ramp stimuli but not with the pulse stimuli. Blurring the edge between the test and surround fields in the equiluminant surround condition raised thresholds for all sawtooth test stimuli, suggesting that spatiotemporal channels sensitive to high spatial frequencies and low temporal frequencies facilitate detection in that condition. These findings suggest that adaptation to sawtooth modulation can differentially effect the sensitivity of ON and OFF pathways, but the relative desensitization of each pathway depends on an interaction with the adaptation state of spatiotemporal channels that are involved in detection. 2002 Optical Society of America

  18. Coping Skills.

    ERIC Educational Resources Information Center

    Library of Congress, Washington, DC. National Library Service for the Blind and Physically Handicapped.

    This annotated bibliography lists approximately 150 braille books and 300 audiocassettes of books which address coping skills for people in a variety of situations. All items listed are available in the network library collections provided by the National Library Service for the Blind and Physically Handicapped of the Library of Congress.…

  19. Viewpoints: feeding mechanics, diet, and dietary adaptations in early hominins.

    PubMed

    Daegling, David J; Judex, Stefan; Ozcivici, Engin; Ravosa, Matthew J; Taylor, Andrea B; Grine, Frederick E; Teaford, Mark F; Ungar, Peter S

    2013-07-01

    Inference of feeding adaptation in extinct species is challenging, and reconstructions of the paleobiology of our ancestors have utilized an array of analytical approaches. Comparative anatomy and finite element analysis assist in bracketing the range of capabilities in taxa, while microwear and isotopic analyses give glimpses of individual behavior in the past. These myriad approaches have limitations, but each contributes incrementally toward the recognition of adaptation in the hominin fossil record. Microwear and stable isotope analysis together suggest that australopiths are not united by a single, increasingly specialized dietary adaptation. Their traditional (i.e., morphological) characterization as "nutcrackers" may only apply to a single taxon, Paranthropus robustus. These inferences can be rejected if interpretation of microwear and isotopic data can be shown to be misguided or altogether erroneous. Alternatively, if these sources of inference are valid, it merely indicates that there are phylogenetic and developmental constraints on morphology. Inherently, finite element analysis is limited in its ability to identify adaptation in paleobiological contexts. Its application to the hominin fossil record to date demonstrates only that under similar loading conditions, the form of the stress field in the australopith facial skeleton differs from that in living primates. This observation, by itself, does not reveal feeding adaptation. Ontogenetic studies indicate that functional and evolutionary adaptation need not be conceptually isolated phenomena. Such a perspective helps to inject consideration of mechanobiological principles of bone formation into paleontological inferences. Finite element analysis must employ such principles to become an effective research tool in this context. PMID:23794331

  20. Coping strategies in patients with acquired brain injury: relationships between coping, apathy, depression and lesion location.

    PubMed

    Finset, A; Andersson, S

    2000-10-01

    Coping strategies in individuals suffering severe traumatic brain injury (TBI), cerebrovascular accidents (CVA), or hypoxic brain injury (HBI) were investigated in relation to apathy, depression, and lesion location. Seventy patients (27 with TBI, 30 with CVA, and 13 with HBI) filled in a coping questionnaire (COPE) and were evaluated with respect to apathy and depression. A comparison sample of 71 students also filled in COPE. Patients coping strategies were similar to the comparison group, but patients tended to display less differentiated coping styles. A factor analysis indicated two dimensions of coping in the patient sample; approach oriented and avoidance oriented coping. Approach and avoidance coping sum scores, based on subscales from the two factors, were positively correlated in the patient sample, but not in the comparison group. Lack of active approach oriented coping was associated with apathy, whereas avoidant coping was associated with depression. Coping styles were not related to lesion location. Apathy was related to subcortical and right hemisphere lesions. In bivariate analyses, depression was unrelated to lesion location, but, in a MANCOVA, avoidant coping, apathy and lesion location (left hemisphere lesions) contributed to the variance in positive depressive symptoms. The consistent relationships between coping strategies and neuropsychiatric symptoms were interpreted as two dimensions of adaptational behaviour: an active vs. passive dimension and a depression--distress-avoidance dimension. PMID:11076135

  1. Mechanisms of Motor Adaptation in Reactive Balance Control

    PubMed Central

    Welch, Torrence D. J.; Ting, Lena H.

    2014-01-01

    Balance control must be rapidly modified to provide stability in the face of environmental challenges. Although changes in reactive balance over repeated perturbations have been observed previously, only anticipatory postural adjustments preceding voluntary movements have been studied in the framework of motor adaptation and learning theory. Here, we hypothesized that adaptation occurs in task-level balance control during responses to perturbations due to central changes in the control of both anticipatory and reactive components of balance. Our adaptation paradigm consisted of a Training set of forward support-surface perturbations, a Reversal set of novel countermanding perturbations that reversed direction, and a Washout set identical to the Training set. Adaptation was characterized by a change in a motor variable from the beginning to the end of each set, the presence of aftereffects at the beginning of the Washout set when the novel perturbations were removed, and a return of the variable at the end of the Washout to a level comparable to the end of the Training set. Task-level balance performance was characterized by peak center of mass (CoM) excursion and velocity, which showed adaptive changes with repetitive trials. Only small changes in anticipatory postural control, characterized by body lean and background muscle activity were observed. Adaptation was found in the evoked long-latency muscular response, and also in the sensorimotor transformation mediating that response. Finally, in each set, temporal patterns of muscle activity converged towards an optimum predicted by a trade-off between maximizing motor performance and minimizing muscle activity. Our results suggest that adaptation in balance, as well as other motor tasks, is mediated by altering central sensitivity to perturbations and may be driven by energetic considerations. PMID:24810991

  2. Mechanisms of motor adaptation in reactive balance control.

    PubMed

    Welch, Torrence D J; Ting, Lena H

    2014-01-01

    Balance control must be rapidly modified to provide stability in the face of environmental challenges. Although changes in reactive balance over repeated perturbations have been observed previously, only anticipatory postural adjustments preceding voluntary movements have been studied in the framework of motor adaptation and learning theory. Here, we hypothesized that adaptation occurs in task-level balance control during responses to perturbations due to central changes in the control of both anticipatory and reactive components of balance. Our adaptation paradigm consisted of a Training set of forward support-surface perturbations, a Reversal set of novel countermanding perturbations that reversed direction, and a Washout set identical to the Training set. Adaptation was characterized by a change in a motor variable from the beginning to the end of each set, the presence of aftereffects at the beginning of the Washout set when the novel perturbations were removed, and a return of the variable at the end of the Washout to a level comparable to the end of the Training set. Task-level balance performance was characterized by peak center of mass (CoM) excursion and velocity, which showed adaptive changes with repetitive trials. Only small changes in anticipatory postural control, characterized by body lean and background muscle activity were observed. Adaptation was found in the evoked long-latency muscular response, and also in the sensorimotor transformation mediating that response. Finally, in each set, temporal patterns of muscle activity converged towards an optimum predicted by a trade-off between maximizing motor performance and minimizing muscle activity. Our results suggest that adaptation in balance, as well as other motor tasks, is mediated by altering central sensitivity to perturbations and may be driven by energetic considerations. PMID:24810991

  3. Testing of the coping flexibility hypothesis based on the dual-process theory: Relationships between coping flexibility and depressive Symptoms.

    PubMed

    Kato, Tsukasa

    2015-12-15

    According to the dual-process theory of coping flexibility (Kato, 2012), coping flexibility is the ability to discontinue an ineffective coping strategy (i.e., evaluation coping process) and implement an alternative strategy (i.e., adaptive coping process). The coping flexibility hypothesis (CFH) proposes that the ability to engage in flexible coping is related to better psychological functioning and physical health, including less depression. I the present study, participants were 393 American Whites, 429 Australian Whites, and 496 Chinese, selected from the data pool of the 2013 Coping and Health Survey (see Kato, 2014b). They completed both the Coping Flexibility Scale (Kato, 2012), which is based on the dual-process theory of coping flexibility, and the Center for Epidemiologic Studies Depression Scale (CES-D). For all nationalities and genders, evaluation coping and adaptive coping were significantly correlated with lower levels of depressive symptoms. Structural equation modeling revealed that evaluation coping was associated with lower depressive symptoms for all nationalities and genders, whereas no significant relationships between adaptive coping and depressive symptoms were found for any nationalities. Our results partially supported that the CFH fits with the dual-process theory of coping flexibility. PMID:26342281

  4. Strength and power training: physiological mechanisms of adaptation.

    PubMed

    Kraemer, W J; Fleck, S J; Evans, W J

    1996-01-01

    Adaptations in resistance training are focused on the development and maintenance of the neuromuscular unit needed for force production [97, 136]. The effects of training, when using this system, affect many other physiological systems of the body (e.g., the connective tissue, cardiovascular, and endocrine systems) [16, 18, 37, 77, 83]. Training programs are highly specific to the types of adaptation that occur. Activation of specific patterns of motor units in training dictate what tissue and how other physiological systems will be affected by the exercise training. The time course of the development of the neuromuscular system appears to be dominated in the early phase by neural factors with associated changes in the types of contractile proteins. In the later adaptation phase, muscle protein increases, and the contractile unit begins to contribute the most to the changes in performance capabilities. A host of other factors can affect the adaptations, such as functional capabilities of the individual, age, nutritional status, and behavioral factors (e.g., sleep and health habits). Optimal adaptation appears to be related to the use of specific resistance training programs to meet individual training objectives. PMID:8744256

  5. Personality, Coping Style and Well-Being of Parents Rearing Children with Developmental Disabilities

    ERIC Educational Resources Information Center

    Glidden, L. M.; Billings, F. J.; Jobe, B. M.

    2006-01-01

    Background: Parents with children with developmental disabilities (DD) encounter a variety of stressors associated with rearing their children and must develop effective coping mechanisms in order to adapt successfully to these challenges. Previous research has failed to establish the role of parental individual differences in the reported use of…

  6. Stoichiometric imbalances between terrestrial decomposer communities and their resources: mechanisms and implications of microbial adaptations to their resources.

    PubMed

    Mooshammer, Maria; Wanek, Wolfgang; Zechmeister-Boltenstern, Sophie; Richter, Andreas

    2014-01-01

    Terrestrial microbial decomposer communities thrive on a wide range of organic matter types that rarely ever meet their elemental demands. In this review we synthesize the current state-of-the-art of microbial adaptations to resource stoichiometry, in order to gain a deeper understanding of the interactions between heterotrophic microbial communities and their chemical environment. The stoichiometric imbalance between microbial communities and their organic substrates generally decreases from wood to leaf litter and further to topsoil and subsoil organic matter. Microbial communities can respond to these imbalances in four ways: first, they adapt their biomass composition toward their resource in a non-homeostatic behavior. Such changes are, however, only moderate, and occur mainly because of changes in microbial community structure and less so due to cellular storage of elements in excess. Second, microbial communities can mobilize resources that meet their elemental demand by producing specific extracellular enzymes, which, in turn, is restricted by the C and N requirement for enzyme production itself. Third, microbes can regulate their element use efficiencies (ratio of element invested in growth over total element uptake), such that they release elements in excess depending on their demand (e.g., respiration and N mineralization). Fourth, diazotrophic bacteria and saprotrophic fungi may trigger the input of external N and P to decomposer communities. Theoretical considerations show that adjustments in element use efficiencies may be the most important mechanism by which microbes regulate their biomass stoichiometry. This review summarizes different views on how microbes cope with imbalanced supply of C, N and P, thereby providing a framework for integrating and linking microbial adaptation to resource imbalances to ecosystem scale fluxes across scales and ecosystems. PMID:24550895

  7. Coping with Demotivation: EFL Learners' Remotivation Processes

    ERIC Educational Resources Information Center

    Falout, Joseph

    2012-01-01

    When foreign language education is compulsory, competitive, or coercive, how learners cope with stress can determine outcomes, including value of the subject, persistence on task, and level of proficiency. The development of adaptive or maladaptive coping processes toward situated learning goals is influenced by learners' beliefs about themselves…

  8. Adaptive camouflage in the VIS and IR spectral range: main principles and mechanisms

    NASA Astrophysics Data System (ADS)

    Schwarz, Alexander

    2015-10-01

    This paper presents a survey of main applicable technical principles and mechanisms for adaptive camouflage in the visible (VIS) and infrared (IR) spectral ranges. All principles are described by their operation method and technical data such as the active spectral range, the degree and speed of adaptation, weight, power consumption, robustness, usability, lifetime, technology readiness level (TRL) etc.. The paper allows to compare the different principles and to assess them with regard to an application to an adaptive camouflage system.

  9. Floods and health in Gambella region, Ethiopia: a qualitative assessment of the strengths and weaknesses of coping mechanisms

    PubMed Central

    Wakuma Abaya, Samson; Mandere, Nicodemus; Ewald, Göran

    2009-01-01

    Background Floods are the most frequent and devastating type of natural disaster worldwide, causing unprecedented deaths, diseases, and destruction of property and crops. Flooding has a greater impact in developing countries due to lack of sufficient disaster management structures and a lack of economic resources. Objective This study was conducted with the aim of contributing to the knowledge base of development strategies that reduce flood-related health risks in developing countries. The study focused particularly on assessing the flood risks and health-related issues in the Gambella region of Ethiopia; with the intent of producing relevant information to assist with the improvements in the efficacy of the current flood coping strategies in the region. Methods Data were gathered through interviews with 14 officers from different government and non-governmental organizations and a questionnaire survey given to 35 flood victims in Itang woreda. A qualitative approach was applied and the data were analyzed using content analysis. Results It was found that flooding is a common problem in Gambella region. The findings also indicate that the flood frequency and magnitude has increased rapidly during the last decade. The increase in floods was driven mainly by climate change and changes in land use, specifically deforestation. The reported main impacts of flooding on human health in Gambella region were deaths, injuries, and diseases such as malaria and diarrhea. Another notable consequence of flooding was crop destruction and subsequent malnutrition. Conclusions Three weaknesses that were identified in the current coping strategies for flood-related health impacts in Gambella region were a lack of flood-specific policy, absence of risk assessment, and weak institutional capacity. This study recommends new policy approaches that will increase the effectiveness of the current flood coping strategies to sustainably address the impact of flooding on human health. PMID

  10. Adaptive finite element methods for two-dimensional problems in computational fracture mechanics

    NASA Technical Reports Server (NTRS)

    Min, J. B.; Bass, J. M.; Spradley, L. W.

    1994-01-01

    Some recent results obtained using solution-adaptive finite element methods in two-dimensional problems in linear elastic fracture mechanics are presented. The focus is on the basic issue of adaptive finite element methods for validating the new methodology by computing demonstration problems and comparing the stress intensity factors to analytical results.

  11. Mechanisms of Cardiopulmonary Adaptation to Microgravity. Part 2

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Session TP1 contains short reports concerning: (1) Autonomic Regulation of Circulation and Mechanical Function of Heart at Different Stages of 14th Month Space Flight; (2) Cardiovascular Oxygen Transport in Exercising Humans in Microgravity; (3) Venous Hemodynamic Changes Assessed by Air Plethysmography During a 16-Day Space Flight; (4) Respiratory Mechanics After 180 Days Space Mission (EUROMIR'95); (5) Assessment of the Sympathetic and the Parasympathetic Nervous Activity During Parabolic Flight by Pupillary Light Reflex; and(6) Vascular Response to Different Gravity.

  12. Family Functionality and Coping Attitudes of Patients with Bipolar Disorder.

    PubMed

    Çuhadar, Döndü; Savaş, Haluk Asuman; Ünal, Ahmet; Gökpınar, Fatma

    2015-10-01

    The coping of patients with prodromal syndromes prevents relapses, and the differences in coping strategies affect the results of bipolar disorder. The various functionality levels of bipolar disorder patients such as work, marital relations, parental abilities and social presentation are significantly related with how well they cope. The objective of this study was to determine the family functionality and coping attitudes of bipolar disorder patients. The study planned as a descriptive one was carried with 81 bipolar disorder patients. Personal description form, family assessment device and Coping Attitudes Scale were used as data acquisition tools. It was determined that the adaptive coping attitudes used most frequently by the patients were religious coping, positive reinterpretation, active coping, problem-focused coping and emotional focused coping, beneficial social support use, emotional social support use, planning, suppression of competing activities and restraint coping; maladaptive coping attitudes used most frequently by the patients were "focusing on the problem and venting of emotions and mental disengagement." It was determined that family functions affected the coping attitudes of patients and that the patients who evaluated family functions in a healthy manner made use of adaptive coping strategies more at a statistically significant level. PMID:25086849

  13. Contextual control of inhibition with reinforcement: Adaptation and timing mechanisms

    PubMed Central

    Bouton, Mark E.; Frohardt, Russell J.; Sunsay, Ceyhun; Waddell, Jaylyn; Morris, Richard W.

    2010-01-01

    Four experiments with rats studied the effects of switching the context after Pavlovian conditioning. In three conditioned suppression experiments, a large number of conditioning trials created “inhibition with reinforcement” (IWR), in which fear of the conditional stimulus (CS) reached a maximum and then declined despite continued CS – unconditional stimulus pairings. When IWR occurred, a context switch augmented fear of the CS; IWR and augmentation were highly correlated. Neither IWR nor augmentation resulted from inhibition of delay (IOD): In conditioned suppression, IWR and augmentation occurred without IOD (Experiment 3), and in appetitive conditioning (Experiment 4), IOD occurred without IWR or augmentation. IWR may occur in conditioned suppression because the animal adapts to fear of the CS in a context-specific manner. We discuss several implications. PMID:18426305

  14. Self-* and Adaptive Mechanisms for Large Scale Distributed Systems

    NASA Astrophysics Data System (ADS)

    Fragopoulou, P.; Mastroianni, C.; Montero, R.; Andrjezak, A.; Kondo, D.

    Large-scale distributed computing systems and infrastructure, such as Grids, P2P systems and desktop Grid platforms, are decentralized, pervasive, and composed of a large number of autonomous entities. The complexity of these systems is such that human administration is nearly impossible and centralized or hierarchical control is highly inefficient. These systems need to run on highly dynamic environments, where content, network topologies and workloads are continuously changing. Moreover, they are characterized by the high degree of volatility of their components and the need to provide efficient service management and to handle efficiently large amounts of data. This paper describes some of the areas for which adaptation emerges as a key feature, namely, the management of computational Grids, the self-management of desktop Grid platforms and the monitoring and healing of complex applications. It also elaborates on the use of bio-inspired algorithms to achieve self-management. Related future trends and challenges are described.

  15. Learning to cope with stress modulates anterior cingulate cortex stargazin expression in monkeys and mice.

    PubMed

    Lee, Alex G; Capanzana, Roxanne; Brockhurst, Jacqueline; Cheng, Michelle Y; Buckmaster, Christine L; Absher, Devin; Schatzberg, Alan F; Lyons, David M

    2016-05-01

    Intermittent mildly stressful situations provide opportunities to learn, practice, and improve coping with gains in subsequent emotion regulation. Here we investigate the effects of learning to cope with stress on anterior cingulate cortex gene expression in monkeys and mice. Anterior cingulate cortex is involved in learning, memory, cognitive control, and emotion regulation. Monkeys and mice were randomized to either stress coping or no-stress treatment conditions. Profiles of gene expression were acquired with HumanHT-12v4.0 Expression BeadChip arrays adapted for monkeys. Three genes identified in monkeys by arrays were then assessed in mice by quantitative real-time polymerase chain reaction. Expression of a key gene (PEMT) involved in acetylcholine biosynthesis was increased in monkeys by coping but this result was not verified in mice. Another gene (SPRY2) that encodes a negative regulator of neurotrophic factor signaling was decreased in monkeys by coping but this result was only partly verified in mice. The CACNG2 gene that encodes stargazin (also called TARP gamma-2) was increased by coping in monkeys as well as mice randomized to coping with or without subsequent behavioral tests of emotionality. As evidence of coping effects distinct from repeated stress exposures per se, increased stargazin expression induced by coping correlated with diminished emotionality in mice. Stargazin modulates glutamate receptor signaling and plays a role in synaptic plasticity. Molecular mechanisms of synaptic plasticity that mediate learning and memory in the context of coping with stress may provide novel targets for new treatments of disorders in human mental health. PMID:27003116

  16. Mechanisms of β-cell functional adaptation to changes in workload.

    PubMed

    Wortham, M; Sander, M

    2016-09-01

    Insulin secretion must be tightly coupled to nutritional state to maintain blood glucose homeostasis. To this end, pancreatic β-cells sense and respond to changes in metabolic conditions, thereby anticipating insulin demands for a given physiological context. This is achieved in part through adjustments of nutrient metabolism, which is controlled at several levels including allosteric regulation, post-translational modifications, and altered expression of metabolic enzymes. In this review, we discuss mechanisms of β-cell metabolic and functional adaptation in the context of two physiological states that alter glucose-stimulated insulin secretion: fasting and insulin resistance. We review current knowledge of metabolic changes that occur in the β-cell during adaptation and specifically discuss transcriptional mechanisms that underlie β-cell adaptation. A more comprehensive understanding of how β-cells adapt to changes in nutrient state could identify mechanisms to be co-opted for therapeutically modulating insulin secretion in metabolic disease. PMID:27615135

  17. Fluid Mechanics of Wing Adaptation for Separation Control

    NASA Technical Reports Server (NTRS)

    Chandrasekhara, M. S.; Wilder, M. C.; Carr, L. W.; Davis, Sanford S. (Technical Monitor)

    1997-01-01

    The unsteady fluid mechanics associated with use of a dynamically deforming leading edge airfoil for achieving compressible flow separation control has been experimentally studied. Changing the leading edge curvature at rapid rates dramatically alters the flow vorticity dynamics which is responsible for the many effects observed in the flow.

  18. Micropylar pollen tube guidance and burst: adapted from defense mechanisms?

    PubMed

    Dresselhaus, Thomas; Márton, Mihaela L

    2009-12-01

    After the first description of fertilization in flowering plants some 125 years ago (Strasburger E: Neue-Untersuchungen über den Befruchtungsvorgang bei den Phanerogamen als Grundlage für eine Theorie der Zeugung. Gustav Fischer; 1884), we are finally beginning to understand the various molecular mechanisms leading to sperm delivery and discharge inside the hidden micropylar region of the female gametophyte (embryo sac). The last phase of pollen tube guidance culminating in tube burst and explosive release of tube contents requires extensive crosstalk between both male and female gametophytes. The first molecules identified that play key roles in these processes represent highly polymorphic proteins, similar to major components of the plant innate immune system. Here we summarize recent advances and briefly discuss the underlying molecular mechanisms also in respect to prezygotic barriers of reproductive isolation. PMID:19896414

  19. Genome and Transcriptome Analyses Provide Insight into the Euryhaline Adaptation Mechanism of Crassostrea gigas

    PubMed Central

    Zhang, Linlin; Li, Chunyan; Li, Li; She, Zhicai; Huang, Baoyu; Zhang, Guofan

    2013-01-01

    Background The Pacific oyster, Crassostrea gigas, has developed special mechanisms to regulate its osmotic balance to adapt to fluctuations of salinities in coastal zones. To understand the oyster’s euryhaline adaptation, we analyzed salt stress effectors metabolism pathways under different salinities (salt 5, 10, 15, 20, 25, 30 and 40 for 7 days) using transcriptome data, physiology experiment and quantitative real-time PCR. Results Transcriptome data uncovered 189, 480, 207 and 80 marker genes for monitoring physiology status of oysters and the environment conditions. Three known salt stress effectors (involving ion channels, aquaporins and free amino acids) were examined. The analysis of ion channels and aquaporins indicated that 7 days long-term salt stress inhibited voltage-gated Na+/K+ channel and aquaporin but increased calcium-activated K+ channel and Ca2+ channel. As the most important category of osmotic stress effector, we analyzed the oyster FAAs metabolism pathways (including taurine, glycine, alanine, beta-alanine, proline and arginine) and explained FAAs functional mechanism for oyster low salinity adaptation. FAAs metabolism key enzyme genes displayed expression differentiation in low salinity adapted individuals comparing with control which further indicated that FAAs played important roles for oyster salinity adaptation. A global metabolic pathway analysis (iPath) of oyster expanded genes displayed a co-expansion of FAAs metabolism in C. gigas compared with seven other species, suggesting oyster’s powerful ability regarding FAAs metabolism, allowing it to adapt to fluctuating salinities, which may be one important mechanism underlying euryhaline adaption in oyster. Additionally, using transcriptome data analysis, we uncovered salt stress transduction networks in C. gigas. Conclusions Our results represented oyster salt stress effectors functional mechanisms under salt stress conditions and explained the expansion of FAAs metabolism pathways as

  20. Personality and coping traits: A joint factor analysis.

    PubMed

    Ferguson, Eamonn

    2001-11-01

    OBJECTIVES: The main objective of this paper is to explore the structural similarities between Eysenck's model of personality and the dimensions of the dispositional COPE. Costa et al. {Costa P., Somerfield, M., & McCrae, R. (1996). Personality and coping: A reconceptualisation. In (pp. 44-61) Handbook of coping: Theory, research and applications. New York: Wiley} suggest that personality and coping behaviour are part of a continuum based on adaptation. If this is the case, there should be structural similarities between measures of personality and coping behaviour. This is tested using a joint factor analysis of personality and coping measures. DESIGN: Cross-sectional survey. METHODS: The EPQ-R and the dispositional COPE were administered to 154 participants, and the data were analysed using joint factor analysis and bivariate associations. RESULTS: The joint factor analysis indicated that these data were best explained by a four-factor model. One factor was primarily unrelated to personality. There was a COPE-neurotic-introvert factor (NI-COPE) containing coping behaviours such as denial, a COPE-extroversion (E-COPE) factor containing behaviours such as seeking social support and a COPE-psychoticism factor (P-COPE) containing behaviours such as alcohol use. This factor pattern, especially for NI- and E-COPE, was interpreted in terms of Gray's model of personality {Gray, J. A. (1987) The psychology of fear and stress. Cambridge: Cambridge University Press}. NI-, E-, and P-COPE were shown to be related, in a theoretically consistent manner, to perceived coping success and perceived coping functions. CONCLUSIONS: The results indicate that there are indeed conceptual links between models of personality and coping. It is argued that future research should focus on identifying coping 'trait complexes'. Implications for practice are discussed. PMID:12614507

  1. Molecular mechanisms underlying the exceptional adaptations of batoid fins

    PubMed Central

    Nakamura, Tetsuya; Klomp, Jeff; Pieretti, Joyce; Schneider, Igor; Gehrke, Andrew R.; Shubin, Neil H.

    2015-01-01

    Extreme novelties in the shape and size of paired fins are exemplified by extinct and extant cartilaginous and bony fishes. Pectoral fins of skates and rays, such as the little skate (Batoid, Leucoraja erinacea), show a strikingly unique morphology where the pectoral fin extends anteriorly to ultimately fuse with the head. This results in a morphology that essentially surrounds the body and is associated with the evolution of novel swimming mechanisms in the group. In an approach that extends from RNA sequencing to in situ hybridization to functional assays, we show that anterior and posterior portions of the pectoral fin have different genetic underpinnings: canonical genes of appendage development control posterior fin development via an apical ectodermal ridge (AER), whereas an alternative Homeobox (Hox)–Fibroblast growth factor (Fgf)–Wingless type MMTV integration site family (Wnt) genetic module in the anterior region creates an AER-like structure that drives anterior fin expansion. Finally, we show that GLI family zinc finger 3 (Gli3), which is an anterior repressor of tetrapod digits, is expressed in the posterior half of the pectoral fin of skate, shark, and zebrafish but in the anterior side of the pelvic fin. Taken together, these data point to both highly derived and deeply ancestral patterns of gene expression in skate pectoral fins, shedding light on the molecular mechanisms behind the evolution of novel fin morphologies. PMID:26644578

  2. Molecular mechanisms underlying the exceptional adaptations of batoid fins.

    PubMed

    Nakamura, Tetsuya; Klomp, Jeff; Pieretti, Joyce; Schneider, Igor; Gehrke, Andrew R; Shubin, Neil H

    2015-12-29

    Extreme novelties in the shape and size of paired fins are exemplified by extinct and extant cartilaginous and bony fishes. Pectoral fins of skates and rays, such as the little skate (Batoid, Leucoraja erinacea), show a strikingly unique morphology where the pectoral fin extends anteriorly to ultimately fuse with the head. This results in a morphology that essentially surrounds the body and is associated with the evolution of novel swimming mechanisms in the group. In an approach that extends from RNA sequencing to in situ hybridization to functional assays, we show that anterior and posterior portions of the pectoral fin have different genetic underpinnings: canonical genes of appendage development control posterior fin development via an apical ectodermal ridge (AER), whereas an alternative Homeobox (Hox)-Fibroblast growth factor (Fgf)-Wingless type MMTV integration site family (Wnt) genetic module in the anterior region creates an AER-like structure that drives anterior fin expansion. Finally, we show that GLI family zinc finger 3 (Gli3), which is an anterior repressor of tetrapod digits, is expressed in the posterior half of the pectoral fin of skate, shark, and zebrafish but in the anterior side of the pelvic fin. Taken together, these data point to both highly derived and deeply ancestral patterns of gene expression in skate pectoral fins, shedding light on the molecular mechanisms behind the evolution of novel fin morphologies. PMID:26644578

  3. Dissociative and associative mechanisms of cope rearrangements of fluorinated 1,5-hexadienes and 2,2'-bis-methylenecyclopentanes.

    PubMed

    Black, Kersey A; Wilsey, Sarah; Houk, K N

    2003-06-01

    The effects of fluorine substitution on the Cope rearrangements of 1,5-hexadiene and 2,2'-bis-methylenecyclopentane have been examined computationally using (U)B3LYP/6-31+G(d,p) and CASPT2/6-31G(d) methodology. The calculations indicate that fluorine substituents at the hexadiene termini generally stabilize the transition states relative to the ground states of the chair conformations and destabilize pathways that occur via boat conformations, in accord with the experimental observations of Dolbier. With meso-2,2'-bis(difluoromethylene)cyclopentane, this destabilization is sufficient to favor a relatively dissociative concerted transition state resembling weakly interacting allyl radicals over a normal aromatic concerted boat transition state. This preference is due partly to an increase in the activation enthalpy for the concerted rearrangement coupled with the more favorable entropy for dissociation. In octafluoro- and decafluorohexadienes, the situation is reversed, and reaction through a cyclohexane-1,4-diyl is favored. Even in the octafluoro system with no radical stabilizing substituents at C(2) and C(5), the preference of fluorine for sp(3) centers causes reaction via the cyclohexane-1,4-diyl. In establishing methodology for this study, the conformations of 1,2-difluoroethane and 1,1,2,2-tetrafluoroethane were also examined thoroughly by the B3LYP method using three basis sets. PMID:12769581

  4. Understanding Students' Adaptation to Graduate School: An Integration of Social Support Theory and Social Learning Theory

    ERIC Educational Resources Information Center

    Tsay, Crystal Han-Huei

    2012-01-01

    The contemporary business world demands adaptive individuals (Friedman & Wyman, 2005). Adaptation is essential for any life transition. It often involves developing coping mechanisms, strategies, and seeking of social support. Adaptation occurs in many settings from moving to a new culture, taking a new job, starting or finishing an…

  5. Adaptive implicit-explicit finite element algorithms for fluid mechanics problems

    NASA Technical Reports Server (NTRS)

    Tezduyar, T. E.; Liou, J.

    1988-01-01

    The adaptive implicit-explicit (AIE) approach is presented for the finite-element solution of various problems in computational fluid mechanics. In the AIE approach, the elements are dynamically (adaptively) arranged into differently treated groups. The differences in treatment could be based on considerations such as the cost efficiency, the type of spatial or temporal discretization employed, the choice of field equations, etc. Several numerical tests are performed to demonstrate that this approach can achieve substantial savings in CPU time and memory.

  6. Bone-free: soft mechanics for adaptive locomotion.

    PubMed

    Trimmer, B A; Lin, Huai-ti

    2014-12-01

    Muscular hydrostats (such as mollusks), and fluid-filled animals (such as annelids), can exploit their constant-volume tissues to transfer forces and displacements in predictable ways, much as articulated animals use hinges and levers. Although larval insects contain pressurized fluids, they also have internal air tubes that are compressible and, as a result, they have more uncontrolled degrees of freedom. Therefore, the mechanisms by which larval insects control their movements are expected to reveal useful strategies for designing soft biomimetic robots. Using caterpillars as a tractable model system, it is now possible to identify the biomechanical and neural strategies for controlling movements in such highly deformable animals. For example, the tobacco hornworm, Manduca sexta, can stiffen its body by increasing muscular tension (and therefore body pressure) but the internal cavity (hemocoel) is not iso-barometric, nor is pressure used to directly control the movements of its limbs. Instead, fluid and tissues flow within the hemocoel and the body is soft and flexible to conform to the substrate. Even the gut contributes to the biomechanics of locomotion; it is decoupled from the movements of the body wall and slides forward within the body cavity at the start of each step. During crawling the body is kept in tension for part of the stride and compressive forces are exerted on the substrate along the axis of the caterpillar, thereby using the environment as a skeleton. The timing of muscular activity suggests that crawling is coordinated by proleg-retractor motoneurons and that the large segmental muscles produce anterograde waves of lifting that do not require precise timing. This strategy produces a robust form of locomotion in which the kinematics changes little with orientation. In different species of caterpillar, the presence of prolegs on particular body segments is related to alternative kinematics such as "inching." This suggests a mechanism for the

  7. Adaptive Spontaneous Transitions between Two Mechanisms of Numerical Averaging.

    PubMed

    Brezis, Noam; Bronfman, Zohar Z; Usher, Marius

    2015-01-01

    We investigated the mechanism with which humans estimate numerical averages. Participants were presented with 4, 8 or 16 (two-digit) numbers, serially and rapidly (2 numerals/second) and were instructed to convey the sequence average. As predicted by a dual, but not a single-component account, we found a non-monotonic influence of set-size on accuracy. Moreover, we observed a marked decrease in RT as set-size increases and RT-accuracy tradeoff in the 4-, but not in the 16-number condition. These results indicate that in accordance with the normative directive, participants spontaneously employ analytic/sequential thinking in the 4-number condition and intuitive/holistic thinking in the 16-number condition. When the presentation rate is extreme (10 items/sec) we find that, while performance still remains high, the estimations are now based on intuitive processing. The results are accounted for by a computational model postulating population-coding underlying intuitive-averaging and working-memory-mediated symbolic procedures underlying analytical-averaging, with flexible allocation between the two. PMID:26041580

  8. Adaptive Spontaneous Transitions between Two Mechanisms of Numerical Averaging

    PubMed Central

    Brezis, Noam; Bronfman, Zohar Z.; Usher, Marius

    2015-01-01

    We investigated the mechanism with which humans estimate numerical averages. Participants were presented with 4, 8 or 16 (two-digit) numbers, serially and rapidly (2 numerals/second) and were instructed to convey the sequence average. As predicted by a dual, but not a single-component account, we found a non-monotonic influence of set-size on accuracy. Moreover, we observed a marked decrease in RT as set-size increases and RT-accuracy tradeoff in the 4-, but not in the 16-number condition. These results indicate that in accordance with the normative directive, participants spontaneously employ analytic/sequential thinking in the 4-number condition and intuitive/holistic thinking in the 16-number condition. When the presentation rate is extreme (10 items/sec) we find that, while performance still remains high, the estimations are now based on intuitive processing. The results are accounted for by a computational model postulating population-coding underlying intuitive-averaging and working-memory-mediated symbolic procedures underlying analytical-averaging, with flexible allocation between the two. PMID:26041580

  9. Multidimensional Perfectionism and Coping Resources in Middle School Students.

    ERIC Educational Resources Information Center

    LoCicero, Kenneth A.; Blasko, L. Shane; Ashby, Jeffrey S.; Martin, James L.; Bruner, Linda P.; Edge, Charles A.; Kenny, Mary-Catherine

    A study was designed to investigate the relationship between coping resources and adaptive, maladaptive, and nonperfectionism in middle school students. An hypothesize was made that maladaptive perfectionists would have significantly fewer coping resources to deal with stress than adaptive perfectionists. One hundred and forty-five middle school…

  10. Local adaptive mechanism and hierarchic social entropy in opinion formation on complex networks

    NASA Astrophysics Data System (ADS)

    Cheng, Jie; Hu, Yanqing; Di, Zengru; Fan, Ying

    2010-10-01

    In this paper we study the opinion formation using co-evolution model, in which network's structure interacts with the nodes' opinion. A local adaptive model is proposed to investigate the effects of local information on the opinion formation, including local rewiring and influencing mechanism. The results show that under the local adaptive mechanism, systems could reach steady state of consensus or fragmentation. Considering the local influencing factor only, we find that transition occurs under proper condition and local parameter affects the transition point. At last, the diversity of opinions is considered, and hierarchic social entropy is used as a macroscopic measurement which is proved to be well.

  11. Psychosocial mechanisms of serotonin transporter’s genetic polymorphism in susceptibility to major depressive disorder: mediated by trait coping styles and interacted with life events

    PubMed Central

    Wang, Yanfang; Sun, Ning; Liu, Zhifen; Li, Xinrong; Yang, Chunxia; Zhang, Kerang

    2016-01-01

    The mechanism of 5-HTT genetic polymorphisms related susceptibility of major depressive disorder (MDD) has not been fully understood. Two hundred MDD patients and 199 control subjects were included. A model of two binary logistical regressions with and without controlling for different psychosocial variables, was applied to investigate the possible mediation effects of psychosocial factors in contribution of 5-HTT polymorphisms in MDD development. These psychosocial variables included personality, trait coping style, life events and social support. Then, contribution of interactions between 5-HTT polymorphisms and psychosocial factors in MDD was investigated by a stepwise logistical approach. The results indicated a significant association of 5-HTT LPR with the MDD indicence, but not of VNTR genotype variances with the MDD incidence without counting effects of psychosocial factors. The ss genotype of LPR demonstrated 2.50 (95% CI: 1.11-5.62) times higher odds to develop MDD than ll genotype (p=0.026). After including psychosocial variables, the odds ratio of 5-HTT LPR ss to ll genotype dropped to 1.30 times (95% CI: 0.41-4.10) and became non-significant (p=0.658). While psychosocial variables all showed significant contributions to MDD susceptibility. Our data suggested an intermediator role of this psychosocial variable in LPR genetic pathogenesis of MDD. Whereas, 5-HTT VNTR could significantly affect MDD outcome by interacting with life events (p=0.043). In conclusion, 5-HTT LPR and VNTR polymorphisms could affect MDD susceptibility through mediation by trait coping styles and interaction with severe life events, respectively. The genetic information of 5-HTT can be potentially helpful for diagnosis and further therapy. PMID:27158415

  12. Mid-humerus adaptation in fast pitch softballers and the impact of throwing mechanics

    PubMed Central

    Bogenschutz, Elizabeth D.; Smith, Heather D.; Warden, Stuart J.

    2011-01-01

    Purpose Throwing is a vigorous activity that generates large internal loads. There is limited evidence of the effect of these loads on bone adaptation. The aim of this study was to investigate the: 1) magnitude of bone adaptation within the midshaft humerus of female fast-pitch softball players and 2) influence of throwing mechanics (windmill vs. overhand throwing) on the magnitude of adaptation. Methods Midshaft humeral bone mass, structure and estimated strength were assessed via peripheral quantitative computed tomography in fast-pitch softball players (throwers; n=15) and matched controls (controls; n=15). The effect of throwing was examined by comparing dominant-to-nondominant differences in throwers to controls, while the influence of mechanics was determined by comparing dominant-to-nondominant differences in throwers who primarily play as pitcher (windmill thrower), catcher (overhand thrower) or fielder (overhand thrower). Results Throwers had greater dominant-to-nondominant difference in midshaft humeral bone mass, structure and estimated strength relative to controls (all P<0.05). The largest effect was for estimated torsional strength with throwers having a mean dominant-to-nondominant difference of 22.5% (range, 6.7% to 43.9%) compared to 4.4% (range, -8.3% to 17.5%) in controls (P<0.001). Throwing mechanics appeared to influence the magnitude of skeletal adaptation, with overhand throwers having more than double dominant-to-nondominant difference in midshaft humeral bone mass, structure and estimated strength than windmill throwers (all P<0.05). Conclusion Throwing induces substantial skeletal adaptation at the midshaft humerus of the dominant upper extremity. Throwing mechanics appears to the influence the magnitude of adaptation as catchers and fielders (overhand throwers) had twice as much adaptation as pitchers (windmill throwers). The latter finding may have implications for skeletal injury risk at the midshaft humerus in throwing athletes. PMID

  13. Relations among stress, coping strategies, coping motives, alcohol consumption and related problems: a mediated moderation model.

    PubMed

    Corbin, William R; Farmer, Nicole M; Nolen-Hoekesma, Susan

    2013-04-01

    Although prominent models of alcohol use and abuse implicate stress as an important motivator of alcohol consumption, research has not consistently identified a relationship between stress and drinking outcomes. Presumably stress leads to heavier alcohol consumption and related problems primarily for individuals who lack other adaptive methods for coping effectively with stressful experiences. To test this hypothesis, we examined four adaptive coping approaches (active coping, planning, suppression of competing activities, and restraint), as predictors of alcohol use and related problems as well as moderators of relations between stress and drinking outcomes in an undergraduate population (N=225). Further, we examined coping motives for drinking as potential mediators of the effects of coping strategies as well as stress by coping strategy interactions. Analyses supported both restraint and suppression of competing activities as moderators of the influence of stress on alcohol use but not problems. The stress by restraint interaction was also evident in the prediction of coping motives, and coping motives were related to higher levels of both weekly drinking and alcohol-related problems. Finally, coping motives for drinking served to mediate the stress by restraint interaction on weekly drinking. Overall, these results suggest that efforts to suppress competing activities and restrain impulsive responses in the face of stress may reduce the risk for heavy drinking during the transition from high school to college. PMID:23380486

  14. Coping in Outdoor Recreation: Causes and Consequences of Crowding and Conflict among Community Residents.

    ERIC Educational Resources Information Center

    Manning, Robert E.; Valliere, William A.

    2001-01-01

    Explored coping mechanisms in outdoor recreation in response to crowing and conflict, measuring perceived changes in amounts and types of recreation use occurring at one national park and the extent to which park visitors adopted coping mechanisms. People near the park adopted coping mechanisms at relatively high levels. Coping related to…

  15. Two separate mechanisms of enforced viral replication balance innate and adaptive immune activation.

    PubMed

    Shaabani, Namir; Khairnar, Vishal; Duhan, Vikas; Zhou, Fan; Tur, Rita Ferrer; Häussinger, Dieter; Recher, Mike; Tumanov, Alexei V; Hardt, Cornelia; Pinschewer, Daniel; Christen, Urs; Lang, Philipp A; Honke, Nadine; Lang, Karl S

    2016-02-01

    The induction of innate and adaptive immunity is essential for controlling viral infections. Limited or overwhelming innate immunity can negatively impair the adaptive immune response. Therefore, balancing innate immunity separately from activating the adaptive immune response would result in a better antiviral immune response. Recently, we demonstrated that Usp18-dependent replication of virus in secondary lymphatic organs contributes to activation of the innate and adaptive immune responses. Whether specific mechanisms can balance innate and adaptive immunity separately remains unknown. In this study, using lymphocytic choriomeningitis virus (LCMV) and replication-deficient single-cycle LCMV vectors, we found that viral replication of the initial inoculum is essential for activating virus-specific CD8(+) T cells. In contrast, extracellular distribution of virus along the splenic conduits is necessary for inducing systemic levels of type I interferon (IFN-I). Although enforced virus replication is driven primarily by Usp18, B cell-derived lymphotoxin beta contributes to the extracellular distribution of virus along the splenic conduits. Therefore, lymphotoxin beta regulates IFN-I induction independently of CD8(+) T-cell activity. We found that two separate mechanisms act together in the spleen to guarantee amplification of virus during infection, thereby balancing the activation of the innate and adaptive immune system. PMID:26553386

  16. Mechanism of HSV infection through soluble adapter-mediated virus bridging to the EGF receptor

    SciTech Connect

    Nakano, Kenji; Kobayashi, Masatoshi; Nakamura, Kei-ichiro; Nakanishi, Takeshi; Asano, Ryutaro; Kumagai, Izumi; Tahara, Hideaki; Kuwano, Michihiko; Cohen, Justus B.; Glorioso, Joseph C.

    2011-04-25

    Herpes simplex virus entry into cells requires the binding of envelope glycoprotein D (gD) to an entry receptor. Depending on the cell, entry occurs by different mechanisms, including fusion at the cell surface or endocytosis. Here we examined the entry mechanism through a non-HSV receptor mediated by a soluble bi-specific adapter protein composed of recognition elements for gD and the EGF receptor (EGFR). Virus entered into endosomes using either EGF or an EGFR-specific single chain antibody (scFv) for receptor recognition. Infection was less efficient with the EGF adapter which could be attributed to its weaker binding to a viral gD. Infection mediated by the scFv adapter was pH sensitive, indicating that gD-EGFR bridging alone was insufficient for capsid release from endosomes. We also show that the scFv adapter enhanced infection of EGFR-expressing tumor tissue in vivo. Our results indicate that adapters may retarget HSV infection without drastically changing the entry mechanism.

  17. Controversies Regarding the Psychometric Properties of the Brief COPE: The Case of the Brazilian-Portuguese Version "COPE Breve".

    PubMed

    Brasileiro, Sarah V; Orsini, Mara R C A; Cavalcante, Julianna A; Bartholomeu, Daniel; Montiel, José M; Costa, Paulo S S; Costa, Luciane R

    2016-01-01

    The Brief Coping Orientation to Problems Experienced (COPE) inventory investigates the different ways in which people respond to stressful situations. Knowledge is lacking regarding the coping strategies and styles of people in developing countries, including Brazil. This study aimed to adapt and validate the Brief COPE to Brazilian Portuguese (named COPE Breve) by focusing on dispositional coping. For the cross-cultural adaptation, the original Brief COPE in English (28 items grouped into 14 subscales) was adapted according to a universalistic approach, following these steps: translation, synthesis, back-translation, analysis by an expert panel, and pretest with 30 participants. Then, 237 adults from the community health service responded to the COPE Breve. Psychometric analyses included reliability and exploratory factor analysis. Most of the 14 subscales from the original Brief COPE exhibited problems related to internal consistency. A Velicer's minimum average partial test (MAP) was performed and pointed out 3 factors. Exploratory factor analysis produced a revised 20-item version with a 3-factor solution: religion and positive reframing, distraction and external support. The psychometric properties of the COPE Breve with three factors were appropriate. Limitations of this study as well as suggestions for future studies are presented. The COPE Breve should be used in Brazilian clinics and investigations, but divergences in its psychometrics should be further explored in other contexts. PMID:27007646

  18. Numerical Modeling of Long Bone Adaptation due to Mechanical Loading: Correlation with Experiments

    PubMed Central

    Kumar, Natarajan Chennimalai; Dantzig, Jonathan A.; Jasiuk, Iwona M.; Robling, Alex G.; Turner, Charles H.

    2011-01-01

    The process of external bone adaptation in cortical bone is modeled mathematically using finite element (FE) stress analysis coupled with an evolution model, in which adaptation response is triggered by mechanical stimulus represented by strain energy density. The model is applied to experiments in which a rat ulna is subjected to cyclic loading, and the results demonstrate the ability of the model to predict the bone adaptation response. The FE mesh is generated from micro-computed tomography (μCT) images of the rat ulna, and the stress analysis is carried out using boundary and loading conditions on the rat ulna obtained from the experiments [Robling, A. G., F. M. Hinant, D. B. Burr, and C. H. Turner. J. Bone Miner. Res. 17:1545–1554, 2002]. The external adaptation process is implemented in the model by moving the surface nodes of the FE mesh based on an evolution law characterized by two parameters: one that captures the rate of the adaptation process (referred to as gain); and the other characterizing the threshold value of the mechanical stimulus required for adaptation (referred to as threshold-sensitivity). A parametric study is carried out to evaluate the effect of these two parameters on the adaptation response. We show, following comparison of results from the simulations to the experimental observations of Robling et al. (J. Bone Miner. Res. 17:1545–1554, 2002), that splitting the loading cycles into different number of bouts affects the threshold-sensitivity but not the rate of adaptation. We also show that the threshold-sensitivity parameter can quantify the mechanosensitivity of the osteocytes. PMID:20013156

  19. Adapt

    NASA Astrophysics Data System (ADS)

    Bargatze, L. F.

    2015-12-01

    Active Data Archive Product Tracking (ADAPT) is a collection of software routines that permits one to generate XML metadata files to describe and register data products in support of the NASA Heliophysics Virtual Observatory VxO effort. ADAPT is also a philosophy. The ADAPT concept is to use any and all available metadata associated with scientific data to produce XML metadata descriptions in a consistent, uniform, and organized fashion to provide blanket access to the full complement of data stored on a targeted data server. In this poster, we present an application of ADAPT to describe all of the data products that are stored by using the Common Data File (CDF) format served out by the CDAWEB and SPDF data servers hosted at the NASA Goddard Space Flight Center. These data servers are the primary repositories for NASA Heliophysics data. For this purpose, the ADAPT routines have been used to generate data resource descriptions by using an XML schema named Space Physics Archive, Search, and Extract (SPASE). SPASE is the designated standard for documenting Heliophysics data products, as adopted by the Heliophysics Data and Model Consortium. The set of SPASE XML resource descriptions produced by ADAPT includes high-level descriptions of numerical data products, display data products, or catalogs and also includes low-level "Granule" descriptions. A SPASE Granule is effectively a universal access metadata resource; a Granule associates an individual data file (e.g. a CDF file) with a "parent" high-level data resource description, assigns a resource identifier to the file, and lists the corresponding assess URL(s). The CDAWEB and SPDF file systems were queried to provide the input required by the ADAPT software to create an initial set of SPASE metadata resource descriptions. Then, the CDAWEB and SPDF data repositories were queried subsequently on a nightly basis and the CDF file lists were checked for any changes such as the occurrence of new, modified, or deleted

  20. Microbial community succession mechanism coupling with adaptive evolution of adsorption performance in chalcopyrite bioleaching.

    PubMed

    Feng, Shoushuai; Yang, Hailin; Wang, Wu

    2015-09-01

    The community succession mechanism of Acidithiobacillus sp. coupling with adaptive evolution of adsorption performance were systematically investigated. Specifically, the μmax of attached and free cells was increased and peak time was moved ahead, indicating both cell growth of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans was promoted. In the mixed strains system, the domination courses of A. thiooxidans was dramatically shortened from 22th day to 15th day, although community structure finally approached to the normal system. Compared to A. ferrooxidans, more positive effects of adaptive evolution on cell growth of A. thiooxidans were shown in either single or mixed strains system. Moreover, higher concentrations of sulfate and ferric ions indicated that both sulfur and iron metabolism was enhanced, especially of A. thiooxidans. Consistently, copper ion production was improved from 65.5 to 88.5 mg/L. This new adaptive evolution and community succession mechanism may be useful for guiding similar bioleaching processes. PMID:25978855

  1. Coping Skills: A Goal of Professional Preparation.

    ERIC Educational Resources Information Center

    Wendt, Janice C.

    A sense of crisis in public schools is helping to make teaching a stressful occupation. Prospective teachers should develop the capacity to cope with the institution as it changes to meet societal demands. They should have the ability to analyze problems and choose appropriate coping mechanisms. A positive outlook on teaching, with the support of…

  2. Molecular dynamics modelling of mechanical properties of polymers for adaptive aerospace structures

    NASA Astrophysics Data System (ADS)

    Papanikolaou, Michail; Drikakis, Dimitris; Asproulis, Nikolaos

    2015-02-01

    The features of adaptive structures depend on the properties of the supporting materials. For example, morphing wing structures require wing skin materials, such as rubbers that can withstand the forces imposed by the internal mechanism while maintaining the required aerodynamic properties of the aircraft. In this study, Molecular Dynamics and Minimization simulations are being used to establish well-equilibrated models of Ethylene-Propylene-Diene Monomer (EPDM) elastomer systems and investigate their mechanical properties.

  3. Evolution of time-keeping mechanisms: early emergence and adaptation to photoperiod

    PubMed Central

    Hut, R. A.; Beersma, D. G. M.

    2011-01-01

    Virtually all species have developed cellular oscillations and mechanisms that synchronize these cellular oscillations to environmental cycles. Such environmental cycles in biotic (e.g. food availability and predation risk) or abiotic (e.g. temperature and light) factors may occur on a daily, annual or tidal time scale. Internal timing mechanisms may facilitate behavioural or physiological adaptation to such changes in environmental conditions. These timing mechanisms commonly involve an internal molecular oscillator (a ‘clock’) that is synchronized (‘entrained’) to the environmental cycle by receptor mechanisms responding to relevant environmental signals (‘Zeitgeber’, i.e. German for time-giver). To understand the evolution of such timing mechanisms, we have to understand the mechanisms leading to selective advantage. Although major advances have been made in our understanding of the physiological and molecular mechanisms driving internal cycles (proximate questions), studies identifying mechanisms of natural selection on clock systems (ultimate questions) are rather limited. Here, we discuss the selective advantage of a circadian system and how its adaptation to day length variation may have a functional role in optimizing seasonal timing. We discuss various cases where selective advantages of circadian timing mechanisms have been shown and cases where temporarily loss of circadian timing may cause selective advantage. We suggest an explanation for why a circadian timing system has emerged in primitive life forms like cyanobacteria and we evaluate a possible molecular mechanism that enabled these bacteria to adapt to seasonal variation in day length. We further discuss how the role of the circadian system in photoperiodic time measurement may explain differential selection pressures on circadian period when species are exposed to changing climatic conditions (e.g. global warming) or when they expand their geographical range to different latitudes or

  4. A Neural Mechanism for Time-Window Separation Resolves Ambiguity of Adaptive Coding

    PubMed Central

    Hildebrandt, K. Jannis; Ronacher, Bernhard; Hennig, R. Matthias; Benda, Jan

    2015-01-01

    The senses of animals are confronted with changing environments and different contexts. Neural adaptation is one important tool to adjust sensitivity to varying intensity ranges. For instance, in a quiet night outdoors, our hearing is more sensitive than when we are confronted with the plurality of sounds in a large city during the day. However, adaptation also removes available information on absolute sound levels and may thus cause ambiguity. Experimental data on the trade-off between benefits and loss through adaptation is scarce and very few mechanisms have been proposed to resolve it. We present an example where adaptation is beneficial for one task—namely, the reliable encoding of the pattern of an acoustic signal—but detrimental for another—the localization of the same acoustic stimulus. With a combination of neurophysiological data, modeling, and behavioral tests, we show that adaptation in the periphery of the auditory pathway of grasshoppers enables intensity-invariant coding of amplitude modulations, but at the same time, degrades information available for sound localization. We demonstrate how focusing the response of localization neurons to the onset of relevant signals separates processing of localization and pattern information temporally. In this way, the ambiguity of adaptive coding can be circumvented and both absolute and relative levels can be processed using the same set of peripheral neurons. PMID:25761097

  5. A neural mechanism for time-window separation resolves ambiguity of adaptive coding.

    PubMed

    Hildebrandt, K Jannis; Ronacher, Bernhard; Hennig, R Matthias; Benda, Jan

    2015-03-01

    The senses of animals are confronted with changing environments and different contexts. Neural adaptation is one important tool to adjust sensitivity to varying intensity ranges. For instance, in a quiet night outdoors, our hearing is more sensitive than when we are confronted with the plurality of sounds in a large city during the day. However, adaptation also removes available information on absolute sound levels and may thus cause ambiguity. Experimental data on the trade-off between benefits and loss through adaptation is scarce and very few mechanisms have been proposed to resolve it. We present an example where adaptation is beneficial for one task--namely, the reliable encoding of the pattern of an acoustic signal-but detrimental for another--the localization of the same acoustic stimulus. With a combination of neurophysiological data, modeling, and behavioral tests, we show that adaptation in the periphery of the auditory pathway of grasshoppers enables intensity-invariant coding of amplitude modulations, but at the same time, degrades information available for sound localization. We demonstrate how focusing the response of localization neurons to the onset of relevant signals separates processing of localization and pattern information temporally. In this way, the ambiguity of adaptive coding can be circumvented and both absolute and relative levels can be processed using the same set of peripheral neurons. PMID:25761097

  6. Molecular mechanisms of adaptation emerging from the physics and evolution of nucleic acids and proteins

    PubMed Central

    Goncearenco, Alexander; Ma, Bin-Guang; Berezovsky, Igor N.

    2014-01-01

    DNA, RNA and proteins are major biological macromolecules that coevolve and adapt to environments as components of one highly interconnected system. We explore here sequence/structure determinants of mechanisms of adaptation of these molecules, links between them, and results of their mutual evolution. We complemented statistical analysis of genomic and proteomic sequences with folding simulations of RNA molecules, unraveling causal relations between compositional and sequence biases reflecting molecular adaptation on DNA, RNA and protein levels. We found many compositional peculiarities related to environmental adaptation and the life style. Specifically, thermal adaptation of protein-coding sequences in Archaea is characterized by a stronger codon bias than in Bacteria. Guanine and cytosine load in the third codon position is important for supporting the aerobic life style, and it is highly pronounced in Bacteria. The third codon position also provides a tradeoff between arginine and lysine, which are favorable for thermal adaptation and aerobicity, respectively. Dinucleotide composition provides stability of nucleic acids via strong base-stacking in ApG dinucleotides. In relation to coevolution of nucleic acids and proteins, thermostability-related demands on the amino acid composition affect the nucleotide content in the second codon position in Archaea. PMID:24371267

  7. A genomic perspective on the important genetic mechanisms of upland adaptation of rice

    PubMed Central

    2014-01-01

    Background Cultivated rice consists of two important ecotypes, upland and irrigated, that have respectively adapted to either dry land or irrigated cultivation. Upland rice, widely adopted in rainfed upland areas in virtue of its little water requirement, contains abundant untapped genetic resources, such as genes for drought adaptation. With water shortage exacerbated and population expanding, the need for breeding crop varieties with drought adaptation becomes more and more urgent. However, a previous oversight in upland rice research reveals little information regarding its genetic mechanisms for upland adaption, greatly hindering progress in harnessing its genetic resources for breeding and cultivation. Results In this study, we selected 84 upland and 82 irrigated accessions from all over the world, phenotyped them under both irrigated and dry land environments, and investigated the phylogenetic relations and population structure of the upland ecotype using whole genome variation data. Further comparative analysis yields a list of differentiated genes that may account for the phenotypic and physiological differences between upland and irrigated rice. Conclusions This study represents the first genomic investigation in a large sample of upland rice, providing valuable gene list for understanding upland rice adaptation, especially drought-related adaptation, and its subsequent utilization in modern agriculture. PMID:24920279

  8. A Complexity-Aware Video Adaptation Mechanism for Live Streaming Systems

    NASA Astrophysics Data System (ADS)

    Lu, Meng-Ting; Yao, Jason J.; Chen, Homer H.

    2007-12-01

    The paradigm shift of network design from performance-centric to constraint-centric has called for new signal processing techniques to deal with various aspects of resource-constrained communication and networking. In this paper, we consider the computational constraints of a multimedia communication system and propose a video adaptation mechanism for live video streaming of multiple channels. The video adaptation mechanism includes three salient features. First, it adjusts the computational resource of the streaming server block by block to provide a fine control of the encoding complexity. Second, as far as we know, it is the first mechanism to allocate the computational resource to multiple channels. Third, it utilizes a complexity-distortion model to determine the optimal coding parameter values to achieve global optimization. These techniques constitute the basic building blocks for a successful application of wireless and Internet video to digital home, surveillance, IPTV, and online games.

  9. Perceptions of coping with non-disease-related life stress for women with osteoarthritis: a qualitative analysis

    PubMed Central

    Harris, Melissa L; Byles, Julie E; Townsend, Natalie; Loxton, Deborah

    2016-01-01

    Objective Coping with arthritis-related stress has been extensively studied. However, limited evidence exists regarding coping with stress extraneous to the disease (life stress). This study explored life stress and coping in a subset of older women with osteoarthritis from a larger longitudinal study. Setting An Australian regional university. Design This qualitative study involved semistructured telephone interviews. Potential participants were mailed a letter of invitation/participant information statement by the Australian Longitudinal Study on Women's Health (ALSWH). Invitations were sent out in small batches (primarily 10). Interviews were conducted until data saturation was achieved using a systematic process (n=19). Digitally recorded interviews were transcribed verbatim and deidentified. Data were thematically analysed. Participants Women who indicated being diagnosed or treated for arthritis in the previous 3 years in the fifth survey of the ALSWH (conducted in 2007) provided the sampling frame. Potential participants were randomly sampled by a blinded data manager using a random number generator. Results Coping with life stress involved both attitudinal coping processes developed early in life (ie, stoicism) and transient cognitive and support-based responses. Women also described a dualistic process involving a reduction in the ability to cope with ongoing stress over time, coupled with personal growth. Conclusions This is the first study to examine how individuals cope with non-arthritis-related stress. The findings add to the current understanding of stress and coping, and have implications regarding the prevention of arthritis in women. Importantly, this study highlighted the potential detrimental impact of persistent coping patterns developed early in life. Public health campaigns aimed at stress mitigation and facilitation of adaptive coping mechanisms in childhood and adolescence may assist with arthritis prevention. PMID:27188808

  10. The Role of Adaptation in Body Load-Regulating Mechanisms During Locomotion

    NASA Technical Reports Server (NTRS)

    Ruttley, Tara; Holt, Christopher; Mulavara, Ajitkumar; Bloomberg, Jacob

    2010-01-01

    Body loading is a fundamental parameter that modulates motor output during locomotion, and is especially important for controlling the generation of stepping patterns, dynamic balance, and termination of locomotion. Load receptors that regulate and control posture and stance in locomotion include the Golgi tendon organs and muscle spindles at the hip, knee, and ankle joints, and the Ruffini endings and the Pacinian corpuscles in the soles of the feet. Increased body weight support (BWS) during locomotion results in an immediate reorganization of locomotor control, such as a reduction in stance and double support duration and decreased hip, ankle, and knee angles during the gait cycle. Previous studies on the effect during exposure to increased BWS while walking showed a reduction in lower limb joint angles and gait cycle timing that represents a reorganization of locomotor control. Until now, no studies have investigated how locomotor control responds after a period of exposure to adaptive modification in the body load sensing system. The goal of this research was to determine the adaptive properties of body load-regulating mechanisms in locomotor control during locomotion. We hypothesized that body load-regulating mechanisms contribute to locomotor control, and adaptive changes in these load-regulating mechanisms require reorganization to maintain forward locomotion. Head-torso coordination, lower limb movement patterns, and gait cycle timing were evaluated before and after a 30-minute adaptation session during which subjects walked on a treadmill at 5.4 km/hr with 40% body weight support (BWS). Before and after the adaptation period, head-torso and lower limb 3D kinematic data were obtained while performing a goal directed task during locomotion with 0% BWS using a video-based motion analysis system, and gait cycle timing parameters were collected by foot switches positioned under the heel and toe of the subjects shoes. Subjects showed adaptive modification in

  11. [Mechanisms of natural variability at adaptation of human physiological systems to conditions of space flight].

    PubMed

    Larina, I M; Nosovskiĭ, A M; Grigor'ev, A I

    2012-01-01

    This article analyzes the physiological data using the principle of invariant relationships, to reveal the mechanisms of adaptive variability. It was used physical-chemical, biochemical, and hormonal blood parameters of cosmonauts who have committed short-term and long space flights. These results suggest that application of the methods of fractal geometry to quantitative estimates of homeostasis allows to allocate the processes depending on the increase/decrease of adaptive variability and fix the state of stability or instability of certain physiological regulatory subsystems, due to mobility and to reduce the level of stability which remains stable internal structure of relationships throughout the body. PMID:22679800

  12. Coping with Cold Sores

    MedlinePlus

    ... Here's Help White House Lunch Recipes Coping With Cold Sores KidsHealth > For Kids > Coping With Cold Sores ... sore." What's that? Adam wondered. What Is a Cold Sore? Cold sores are small blisters that is ...

  13. A comparative study on Ca content and distribution in two Gesneriaceae species reveals distinctive mechanisms to cope with high rhizospheric soluble calcium

    PubMed Central

    Li, Wenlong; Xu, Falun; Chen, Shixuan; Zhang, Zhennan; Zhao, Yan; Jin, Yukuan; Li, Meijing; Zhu, Yan; Liu, Yongxiu; Yang, Yi; Deng, Xin

    2014-01-01

    Excessive Ca is toxic to plants thus significantly affects plant growth and species distribution in Ca-rich karst areas. To understand how plants survive high Ca soil, laboratory experiments were established to compare the physiological responses and internal Ca distribution in organ, tissue, cell, and intracellular levels under different Ca levels for Lysionotus pauciflorus and Boea hygrometrica, two karst habitant Gesneriaceae species in Southwest China. In the controlled condition, L. pauciflorus could survive as high as 200 mM rhizospheric soluble Ca, attributed to a series of physiological responses and preferential storage that limited Ca accumulation in chloroplasts of palisade cells. In contrast, B. hygrometrica could survive only 20 mM rhizospheric soluble Ca, but accumulated a high level of internal Ca in both palisade and spongy cells without disturbance on photosynthetic activity. By phenotype screening of transgenic plants expressing high Ca-inducible genes from B. hygrometrica, the expression of BhDNAJC2 in A. thaliana was found to enhance plant growth and photosynthesis under high soluble Ca stress. BhDNAJC2 encodes a recently reported heat shock protein (HSP) 40 family DnaJ-domain protein. The Ca-resistant phenotype of BhDNAJC2 highlights the important role of chaperone-mediated protein quality control in Ca tolerance in B. hygrometrica. Taken together, our results revealed that distinctive mechanisms were employed in the two Gesneriaceae karst habitants to cope with a high Ca environment. PMID:25477893

  14. How to Cope with Bias While Adapting for Inclusion in Physical Education and Sports: A Judgment and Decision-Making Perspective

    ERIC Educational Resources Information Center

    Hutzler, Yeshayahu; Bar-Eli, Michael

    2013-01-01

    The purpose of this article is to describe a theoretical model and practice examples of judgment and decision making bias within the context of inclusion in physical education and sports. After presenting the context of adapting for inclusion, the theoretical roots of judgment and decision are described, and are linked to the practice of physical…

  15. Theory of psychological adaptive modes.

    PubMed

    Lehti, Juha

    2016-05-01

    When an individual is facing a stressor and normal stress-response mechanism cannot guarantee sufficient adaptation, special emotional states, adaptive modes, are activated (for example a depressive reaction). Adaptive modes are involuntary states of mind, they are of comprehensive nature, they interfere with normal functioning, and they cannot be repressed or controlled the same way as many emotions. Their transformational nature differentiates them from other emotional states. The object of the adaptive mode is to optimize the problem-solving abilities according to the situation that has provoked the mode. Cognitions and emotions during the adaptive mode are different than in a normal mental state. These altered cognitions and emotional reactions guide the individual to use the correct coping skills in order to deal with the stressor. Successful adaptation will cause the adaptive mode to fade off since the adaptive mode is no longer necessary, and the process as a whole will lead to raised well-being. However, if the adaptation process is inadequate, then the transformation period is prolonged, and the adaptive mode will turn into a dysfunctional state. Many psychiatric disorders are such maladaptive processes. The maladaptive processes can be turned into functional ones by using adaptive skills that are used in functional adaptive processes. PMID:27063089

  16. Adaptive Response in Animals Exposed to Non-Ionizing Radiofrequency Fields: Some Underlying Mechanisms

    PubMed Central

    Cao, Yi; Tong, Jian

    2014-01-01

    During the last few years, our research group has been investigating the phenomenon of adaptive response in animals exposed to non-ionizing radiofrequency fields. The results from several separate studies indicated a significant increase in survival, decreases in genetic damage as well as oxidative damage and, alterations in several cellular processes in mice pre-exposed to radiofrequency fields and subsequently subjected to sub-lethal or lethal doses of γ-radiation or injected with bleomycin, a radiomimetic chemical mutagen. These observations indicated the induction of adaptive response providing the animals the ability to resist subsequent damage. Similar studies conducted by independent researchers in mice and rats have supported our observation on increased survival. In this paper, we have presented a brief review of all of our own and other independent investigations on radiofrequency fields-induced adaptive response and some underlying mechanisms discussed. PMID:24758897

  17. Terrain Adaptability Mechanism of Large Ruminants' Feet on the Kinematics View

    PubMed Central

    Zhang, Qun; Ding, Xilun; Xu, Kun

    2015-01-01

    Ruminants live in various parts of land. Similar cloven hooves assist ruminants in adapting to different ground environment during locomotion. This paper analyzes the general terrain adaptability of the feet of ruminants using kinematics of the equivalent mechanism model based on screw theory. Cloven hooves could adjust attitude by changing relative positions between two digits in swing phase. This function helps to choose better landing orientation. “Grasping” or “holding” a rock or other object on the ground passively provides extra adhesion force in stance phase. Ruminants could adjust the position of the metacarpophalangeal joint or metatarsophalangeal joint (MTP or MCP) with no relative motion between the tip of feet and the ground, which ensures the adhesion and dexterity in stance phase. These functions are derived from an example from chamois' feet and several assumptions, which are believed to demonstrate the foundation of adaptation of ruminants and ensure a stable and continuous movement. PMID:27019579

  18. Mechanics of pressure-adaptive honeycomb and its application to wing morphing

    NASA Astrophysics Data System (ADS)

    Vos, Roelof; Barrett, Ron

    2011-09-01

    Current, highly active classes of adaptive materials have been considered for use in many different aerospace applications. From adaptive flight control surfaces to wing surfaces, shape-memory alloy (SMA), piezoelectric and electrorheological fluids are making their way into wings, stabilizers and rotor blades. Despite the benefits which can be seen in many classes of aircraft, some profound challenges are ever present, including low power and energy density, high power consumption, high development and installation costs and outright programmatic blockages due to a lack of a materials certification database on FAR 23/25 and 27/29 certified aircraft. Three years ago, a class of adaptive structure was developed to skirt these daunting challenges. This pressure-adaptive honeycomb (PAH) is capable of extremely high performance and is FAA/EASA certifiable because it employs well characterized materials arranged in ways that lend a high level of adaptivity to the structure. This study is centered on laying out the mechanics, analytical models and experimental test data describing this new form of adaptive material. A directionally biased PAH system using an external (spring) force acting on the PAH bending structure was examined. The paper discusses the mechanics of pressure adaptive honeycomb and describes a simple reduced order model that can be used to simplify the geometric model in a finite element environment. The model assumes that a variable stiffness honeycomb results in an overall deformation of the honeycomb. Strains in excess of 50% can be generated through this mechanism without encountering local material (yield) limits. It was also shown that the energy density of pressure-adaptive honeycomb is akin to that of shape-memory alloy, while exhibiting strains that are an order of magnitude greater with an energy efficiency close to 100%. Excellent correlation between theory and experiment is demonstrated in a number of tests. A proof-of-concept wing section

  19. Fibrin Networks Support Recurring Mechanical Loads by Adapting their Structure across Multiple Scales.

    PubMed

    Kurniawan, Nicholas A; Vos, Bart E; Biebricher, Andreas; Wuite, Gijs J L; Peterman, Erwin J G; Koenderink, Gijsje H

    2016-09-01

    Tissues and cells sustain recurring mechanical loads that span a wide range of loading amplitudes and timescales as a consequence of exposure to blood flow, muscle activity, and external impact. Both tissues and cells derive their mechanical strength from fibrous protein scaffolds, which typically have a complex hierarchical structure. In this study, we focus on a prototypical hierarchical biomaterial, fibrin, which is one of the most resilient naturally occurring biopolymers and forms the structural scaffold of blood clots. We show how fibrous networks composed of fibrin utilize irreversible changes in their hierarchical structure at different scales to maintain reversible stress stiffening up to large strains. To trace the origin of this paradoxical resilience, we systematically tuned the microstructural parameters of fibrin and used a combination of optical tweezers and fluorescence microscopy to measure the interactions of single fibrin fibers for the first time, to our knowledge. We demonstrate that fibrin networks adapt to moderate strains by remodeling at the network scale through the spontaneous formation of new bonds between fibers, whereas they adapt to high strains by plastic remodeling of the fibers themselves. This multiscale adaptation mechanism endows fibrin gels with the remarkable ability to sustain recurring loads due to shear flows and wound stretching. Our findings therefore reveal a microscopic mechanism by which tissues and cells can balance elastic nonlinearity and plasticity, and thus can provide microstructural insights into cell-driven remodeling of tissues. PMID:27602730

  20. Coping with Congenital Hand Differences

    PubMed Central

    Franzblau, Lauren E.; Chung, Kevin C.; Carlozzi, Noelle; Chin, Autumn Y. T.; Nellans, Kate W.; Waljee, Jennifer F.

    2015-01-01

    Purpose Although functional outcomes following reconstruction for congenital hand differences are frequently described, much less is known regarding children’s ability to cope with psychosocial effects of these conditions. We qualitatively explored stress and coping mechanisms among children following reconstructive surgery for congenital hand differences. Methods Forty patients and their parents participated in semi-structured interviews examining stress related to hand functioning and appearance, emotional responses to stress, and coping strategies. Interviews were audio-taped, transcribed, and analyzed thematically. A consensus taxonomy for classifying content evolved from comparisons of coding by two reviewers. Themes expressed by participants were studied for patterns of connection and grouped into broader categories. Results In this sample, 58% of children and 40% of parents reported stress related to congenital hand differences, attributed to functional deficits (61%), hand appearance (27%), social interactions (58%), and emotional reactions (46%). Among the 18 children who reported stress, 43% of parents were not aware of the presence of stress. Eight coping strategies emerged, including humor (12%), self-acceptance (21%), avoidance (27%), seeking external support (30%), concealment (30%), educating others (9%), support programs (21%) and religion (24%). Conclusions Although children with congenital hand differences often experience emotional stress related to functional limitations and aesthetic deformities, many apply positive coping mechanisms that enhance self-esteem and self-esteem. Clinicians caring for children with congenital hand differences should inform families about potential sources of stress in order to direct resources toward strengthening coping strategies and support systems. Level of Evidence Level IV-Case series PMID:25502854

  1. Coping with Cancer.

    ERIC Educational Resources Information Center

    Manuel, Gerdenio M.; And Others

    Since the incidence of cancer in this country is high and the cancer survival rates are increasing, it is important to study coping strategies in cancer patients. As survival time lengthens, coping strategies that might affect the quality of a patient's life become increasingly important. A study was conducted to examine coping strategies in newly…

  2. Optimism and coping strategies among Caucasian, Korean, and African American older women.

    PubMed

    Lee, Heesoon; Mason, Derek

    2013-01-01

    Coping strategies and optimism have significant effects on the health of older women. Culture affects coping behaviors used to deal with stress. We examined the relationship between optimism and coping strategies used to manage daily stress and health among community-dwelling Caucasian, Korean American, and African American women. Data were collected from 373 women over the age of 65. Results showed that each group used different coping strategies. The more optimistic used more problem-focused and adaptive copings, while the less optimistic employed more avoidant copings. Differences in cultural background and individual levels of optimism guided their coping strategies. PMID:23865863

  3. Adaptation as a mechanism for gain control in cockroach ON and OFF olfactory receptor neurons.

    PubMed

    Burgstaller, Maria; Tichy, Harald

    2012-02-01

    In many sensory systems adaptation acts as a gain control mechanism that optimizes sensory performance by trading increased sensitivity to low stimulus intensity for decreased sensitivity to high stimulus intensity. Adaptation of insect antennal olfactory receptor neurons (ORNs) has been studied for strong odour concentrations, either pulsed or constant. Here, we report that during slowly oscillating changes in the concentration of the odour of lemon oil, the ON and OFF ORNs on the antenna of the cockroach Periplaneta americana adapt to the actual odour concentration and the rate at which concentration changes. When odour concentration oscillates rapidly with brief periods, adaptation improves gain for instantaneous odour concentration and reduces gain for the rate of concentration change. Conversely, when odour concentration oscillates slowly with long periods, adaptation increases gain for the rate of change at the expense of instantaneous concentration. Without this gain control the ON and OFF ORNs would, at brief oscillation periods, soon reach their saturation level and become insensitive to further concentration increments and decrements. At long oscillation periods, on the other hand, the cue would simply be that the discharge begins to change. Because of the high gain for the rate of change, the cockroach will receive creeping changes in odour concentration, even if they persist in one direction. Gain control permits a high degree of precision at small rates when it counts most, without sacrificing the range of detection and without extending the measuring scale. PMID:22304687

  4. Fungal evolutionary genomics provides insight into the mechanisms of adaptive divergence in eukaryotes.

    PubMed

    Gladieux, Pierre; Ropars, Jeanne; Badouin, Hélène; Branca, Antoine; Aguileta, Gabriela; de Vienne, Damien M; Rodríguez de la Vega, Ricardo C; Branco, Sara; Giraud, Tatiana

    2014-02-01

    Fungi are ideal model organisms for dissecting the genomic bases of adaptive divergence in eukaryotes. They have simple morphologies and small genomes, occupy contrasting, well-identified ecological niches and tend to have short generation times, and many are amenable to experimental approaches. Fungi also display diverse lifestyles, from saprotrophs to pathogens or mutualists, and they play extremely important roles in both ecosystems and human activities, as wood decayers, mycorrhizal fungi, lichens, endophytes, plant and animal pathogens, and in fermentation or drug production. We review here recent insights into the patterns and mechanisms of adaptive divergence in fungi, including sources of divergence, genomic variation and, ultimately, speciation. We outline the various ecological sources of divergent selection and genomic changes, showing that gene loss and changes in gene expression and in genomic architecture are important adaptation processes, in addition to the more widely recognized processes of amino acid substitution and gene duplication. We also review recent findings regarding the interspecific acquisition of genomic variation and suggesting an important role for introgression, hybridization and horizontal gene transfers (HGTs). We show that transposable elements can mediate several of these genomic changes, thus constituting important factors for adaptation. Finally, we review the consequences of divergent selection in terms of speciation, arguing that genetic incompatibilities may not be as widespread as generally thought and that pleiotropy between adaptation and reproductive isolation is an important route of speciation in fungal pathogens. PMID:24341913

  5. Deciphering the salinity adaptation mechanism in Penicilliopsis clavariiformis AP, a rare salt tolerant fungus from mangrove.

    PubMed

    Kashyap, Prem Lal; Rai, Anuradha; Singh, Ruchi; Chakdar, Hillol; Kumar, Sudheer; Srivastava, Alok Kumar

    2016-07-01

    Penicilliopsis clavariiformis AP, a rare salt tolerant fungus reported for the first time from India was identified through polyphasic taxonomy. Scanning electron microscopy showed that the fungus has unique features such as biverticillate penicilli bearing masses of oval to ellipsoidal conidia. The fungus has been characterized for salt tolerance and to understand the relevance of central carbon metabolism in salt stress adaptation. It showed optimal growth at 24 °C and able to tolerate up to 10% (w/v) NaCl. To understand the mechanism of adaptation to high salinity, activities of the key enzymes regulating glycolysis, pentose phosphate pathway, and tricarboxylic acid cycle were investigated under normal (0% NaCl) and saline stress environment (10% NaCl). The results revealed a re-routing of carbon metabolism away from glycolysis to the pentose phosphate pathway (PPP), served as a cellular stress-resistance mechanism in fungi under saline environment. The detection and significant expression of fungus genes (Hsp98, Hsp60, HTB, and RHO) under saline stress suggest that these halotolerance conferring genes from the fungus could have a role in fungus protection and adaptation under saline environment. Overall, the present findings indicate that the rearrangement of the metabolic fluxes distribution and stress related genes play an important role in cell survival and adaptation under saline environment. PMID:26663001

  6. Mechanical Strain Causes Adaptive Change in Bronchial Fibroblasts Enhancing Profibrotic and Inflammatory Responses

    PubMed Central

    Manuyakorn, Wiparat; Smart, David E.; Noto, Antonio; Bucchieri, Fabio; Haitchi, Hans Michael; Holgate, Stephen T.; Howarth, Peter H.; Davies, Donna E.

    2016-01-01

    Asthma is characterized by periodic episodes of bronchoconstriction and reversible airway obstruction; these symptoms are attributable to a number of factors including increased mass and reactivity of bronchial smooth muscle and extracellular matrix (ECM) in asthmatic airways. Literature has suggested changes in cell responses and signaling can be elicited via modulation of mechanical stress acting upon them, potentially affecting the microenvironment of the cell. In this study, we hypothesized that mechanical strain directly affects the (myo)fibroblast phenotype in asthma. Therefore, we characterized responses of bronchial fibroblasts, from 6 normal and 11 asthmatic non-smoking volunteers, exposed to cyclical mechanical strain using flexible silastic membranes. Samples were analyzed for proteoglycans, α-smooth muscle actin (αSMA), collagens I and III, matrix metalloproteinase (MMP) 2 & 9 and interleukin-8 (IL-8) by qRT-PCR, Western blot, zymography and ELISA. Mechanical strain caused a decrease in αSMA mRNA but no change in either αSMA protein or proteoglycan expression. In contrast the inflammatory mediator IL-8, MMPs and interstitial collagens were increased at both the transcriptional and protein level. The results demonstrate an adaptive response of bronchial fibroblasts to mechanical strain, irrespective of donor. The adaptation involves cytoskeletal rearrangement, matrix remodelling and inflammatory cytokine release. These results suggest that mechanical strain could contribute to disease progression in asthma by promoting inflammation and remodelling responses. PMID:27101406

  7. The primary cilium is a self-adaptable, integrating nexus for mechanical stimuli and cellular signaling

    PubMed Central

    Nguyen, An M.; Young, Y.-N.; Jacobs, Christopher R.

    2015-01-01

    ABSTRACT Mechanosensation is crucial for cells to sense and respond to mechanical signals within their local environment. While adaptation allows a sensor to be conditioned by stimuli within the environment and enables its operation in a wide range of stimuli intensities, the mechanisms behind adaptation remain controversial in even the most extensively studied mechanosensor, bacterial mechanosensitive channels. Primary cilia are ubiquitous sensory organelles. They have emerged as mechanosensors across diverse tissues, including kidney, liver and the embryonic node, and deflect with mechanical stimuli. Here, we show that both mechanical and chemical stimuli can alter cilium stiffness. We found that exposure to flow stiffens the cilium, which deflects less in response to subsequent exposures to flow. We also found that through a process involving acetylation, the cell can biochemically regulate cilium stiffness. Finally, we show that this altered stiffness directly affects the responsiveness of the cell to mechanical signals. These results demonstrate a potential mechanism through which the cell can regulate its mechanosensing apparatus. PMID:26603473

  8. Post traumatic stress disorder and coping in a sample of adult survivors of the Italian earthquake.

    PubMed

    Cofini, V; Carbonelli, A; Cecilia, M R; Binkin, N; di Orio, F

    2015-09-30

    The aim was to investigate the prevalence of post traumatic stress disorder (PTSD) in people who had left their damaged homes and were still living in temporary housing more than a year after the April 2009 L'Aquila (Italy) earthquake. In addition, we evaluated the differences in coping strategies implemented by persons who had and who did not have PTSD. A cross-sectional prevalence study was carried out on a sample of 281 people aged >18 years and living in temporary housing after the earthquake. The questionnaires used include the Davidson Trauma Scale and the Brief Cope. The prevalence of PTSD was 43%. Women and the non-employed were more vulnerable to PTSD, while, age and level of education were not associated with PTSD. Those with PTSD symptoms often employed maladaptive coping strategies for dealing with earthquake and had the highest scores in the domains of denial, venting, behavioral disengagement, self-blame. By contrast, those without PTSD generally had more adaptive coping mechanisms. Adults who were living in temporary housing after the earthquake experienced high rates of PTSD. The difference in coping mechanisms between those who have PTSD and those who do not also suggests that they influence the likeliness of developing PTSD. PMID:26162658

  9. Mycobacterial escape from macrophage phagosomes to the cytoplasm represents an alternate adaptation mechanism

    PubMed Central

    Jamwal, Shilpa V.; Mehrotra, Parul; Singh, Archana; Siddiqui, Zaved; Basu, Atanu; Rao, Kanury V.S.

    2016-01-01

    Survival of Mycobacterium tuberculosis (Mtb) within the host macrophage is mediated through pathogen-dependent inhibition of phagosome-lysosome fusion, which enables bacteria to persist within the immature phagosomal compartment. By employing ultrastructural examination of different field isolates supported by biochemical analysis, we found that some of the Mtb strains were in fact poorly adapted for subsistence within endocytic vesicles of infected macrophages. Instead, through a mechanism involving activation of host cytosolic phospholipase A2, these bacteria rapidly escaped from phagosomes, and established residence in the cytoplasm of the host cell. Interestingly, by facilitating an enhanced suppression of host cellular autophagy, this translocation served as an alternate virulence acquisition mechanism. Thus, our studies reveal plasticity in the adaptation strategies employed by Mtb, for survival in the host macrophage. PMID:26980157

  10. Rule-based mechanisms of learning for intelligent adaptive flight control

    NASA Technical Reports Server (NTRS)

    Handelman, David A.; Stengel, Robert F.

    1990-01-01

    How certain aspects of human learning can be used to characterize learning in intelligent adaptive control systems is investigated. Reflexive and declarative memory and learning are described. It is shown that model-based systems-theoretic adaptive control methods exhibit attributes of reflexive learning, whereas the problem-solving capabilities of knowledge-based systems of artificial intelligence are naturally suited for implementing declarative learning. Issues related to learning in knowledge-based control systems are addressed, with particular attention given to rule-based systems. A mechanism for real-time rule-based knowledge acquisition is suggested, and utilization of this mechanism within the context of failure diagnosis for fault-tolerant flight control is demonstrated.

  11. Defensive coping and blood pressure reactivity in medical patients.

    PubMed

    Warrenburg, S; Levine, J; Schwartz, G E; Fontana, A F; Kerns, R D; Delaney, R; Mattson, R

    1989-10-01

    Two defensive coping styles, denial of illness and repressive coping, were studied in two groups of medical patients whose blood pressure (BP) was measured during a stress interview. Denial of illness was measured using the Levine Denial of Illness Scale (LDIS), and repressive coping was measured using a combination of the Marlowe-Crowne (MC) Social Desirability Scale and the SCL-90R anxiety subscale (ANX). Consistent with our prior research indicating that LDIS was associated with adaptive outcomes in the short run, high deniers manifested reduced systolic BP reactivity compared to low deniers. Although not related to repressive coping, systolic BP reactivity was correlated positively with MC and ANX separately. The results demonstrate that LDIS and MC measure different types of defensive coping. Current theories of the MC scale suggest two possible interpretations of the MC findings, one that focuses on avoidant coping and the second on attentional coping in high MC scorers. PMID:2614819

  12. Adaptive kanban control mechanism for a single-stage hybrid system

    NASA Astrophysics Data System (ADS)

    Korugan, Aybek; Gupta, Surendra M.

    2002-02-01

    In this paper, we consider a hybrid manufacturing system with two discrete production lines. Here the output of either production line can satisfy the demand for the same type of product without any penalties. The interarrival times for demand occurrences and service completions are exponentially distributed i.i.d. variables. In order to control this type of manufacturing system we suggest a single stage pull type control mechanism with adaptive kanbans and state independent routing of the production information.

  13. Preferential Osmolyte Accumulation: a Mechanism of Osmotic Stress Adaptation in Diazotrophic Bacteria

    PubMed Central

    Madkour, Magdy A.; Smith, Linda Tombras; Smith, Gary M.

    1990-01-01

    A common cellular mechanism of osmotic-stress adaptation is the intracellular accumulation of organic solutes (osmolytes). We investigated the mechanism of osmotic adaptation in the diazotrophic bacteria Azotobacter chroococcum, Azospirillum brasilense, and Klebsiella pneumoniae, which are adversely affected by high osmotic strength (i.e., soil salinity and/or drought). We used natural-abundance 13C nuclear magnetic resonance spectroscopy to identify all the osmolytes accumulating in these strains during osmotic stress generated by 0.5 M NaCl. Evidence is presented for the accumulation of trehalose and glutamate in Azotobacter chroococcum ZSM4, proline and glutamate in Azospirillum brasilense SHS6, and trehalose and proline in K. pneumoniae. Glycine betaine was accumulated in all strains grown in culture media containing yeast extract as the sole nitrogen source. Alternative nitrogen sources (e.g., NH4Cl or casamino acids) in the culture medium did not result in measurable glycine betaine accumulation. We suggest that the mechanism of osmotic adaptation in these organisms entails the accumulation of osmolytes in hyperosmotically stressed cells resulting from either enhanced uptake from the medium (of glycine betaine, proline, and glutamate) or increased net biosynthesis (of trehalose, proline, and glutamate) or both. The preferred osmolyte in Azotobacter chroococcum ZSM4 shifted from glutamate to trehalose as a consequence of a prolonged osmotic stress. Also, the dominant osmolyte in Azospirillum brasilense SHS6 shifted from glutamate to proline accumulation as the osmotic strength of the medium increased. PMID:16348295

  14. Strategies for adding adaptive learning mechanisms to rule-based diagnostic expert systems

    NASA Technical Reports Server (NTRS)

    Stclair, D. C.; Sabharwal, C. L.; Bond, W. E.; Hacke, Keith

    1988-01-01

    Rule-based diagnostic expert systems can be used to perform many of the diagnostic chores necessary in today's complex space systems. These expert systems typically take a set of symptoms as input and produce diagnostic advice as output. The primary objective of such expert systems is to provide accurate and comprehensive advice which can be used to help return the space system in question to nominal operation. The development and maintenance of diagnostic expert systems is time and labor intensive since the services of both knowledge engineer(s) and domain expert(s) are required. The use of adaptive learning mechanisms to increment evaluate and refine rules promises to reduce both time and labor costs associated with such systems. This paper describes the basic adaptive learning mechanisms of strengthening, weakening, generalization, discrimination, and discovery. Next basic strategies are discussed for adding these learning mechanisms to rule-based diagnostic expert systems. These strategies support the incremental evaluation and refinement of rules in the knowledge base by comparing the set of advice given by the expert system (A) with the correct diagnosis (C). Techniques are described for selecting those rules in the in the knowledge base which should participate in adaptive learning. The strategies presented may be used with a wide variety of learning algorithms. Further, these strategies are applicable to a large number of rule-based diagnostic expert systems. They may be used to provide either immediate or deferred updating of the knowledge base.

  15. An epidemic spreading model on adaptive scale-free networks with feedback mechanism

    NASA Astrophysics Data System (ADS)

    Li, Tao; Liu, Xiongding; Wu, Jie; Wan, Chen; Guan, Zhi-Hong; Wang, Yuanmei

    2016-05-01

    A SIRS epidemic model with feedback mechanism on adaptive scale-free networks is presented. Using the mean field theory the spreading dynamics of the epidemic is studied in detail. The basic reproductive number and equilibriums are derived. Theoretical results indicate that the basic reproductive number is significantly dependent on the topology of the underlying networks. The existence of equilibriums is determined by the basic reproductive number. The global stability of disease-free equilibrium and the epidemic permanence are proved in detail. The feedback mechanism cannot change the basic reproductive number, but it can reduce the endemic level and weaken the epidemic spreading. Numerical simulations confirmed the analytical results.

  16. Coping styles of older adults with ostomies.

    PubMed

    Reynaud, Sheila Normand; Meeker, Bonnie Juve'

    2002-05-01

    Various clinical studies throughout the years have shown that individuals with ostomies are a unique group facing adjustment demands. One of the most important challenges for an individual with an ostomy is coping with the physiological and psychological changes. The purpose of this study was to describe coping styles of older adults after undergoing ostomy surgery and to explore its helpfulness in dealing with the stressors related to having an ostomy. Lazarus and Folkman's theory on stress and coping was used as the framework to guide this study. A sample of 27 participants ranging from age 50 to 84 years was obtained from an ostomy association in southeastern Louisiana. Participants were asked to complete a demographic data form and the Revised Jalowiec Coping Scale. This revised scale measured eight coping styles related to Use and Effectiveness. Findings revealed significant differences existed among the means of the eight measures for both Use and Effectiveness at p < .01. Results demonstrated that the optimistic and self-reliant styles of coping were the most frequently used as effective styles for coping with an ostomy. This indicated a positive outlook and dependence on oneself rather than dependence on others when coping with the stressors of having an ostomy. There were no statistically significant differences related to gender or ostomy type. Also, aging did not appear to be a factor when considering coping styles of older adults with ostomies. The nursing role should include assessment of the individual preoperatively to identify fears, concerns, and stressors related to having an ostomy. Also, nurses can provide education on disease management, assist with identification of ineffective coping mechanisms, and promote effective coping skills and stress management techniques. PMID:12035824

  17. Mechanisms of Host Receptor Adaptation by Severe Acute Respiratory Syndrome Coronavirus

    SciTech Connect

    Wu, Kailang; Peng, Guiqing; Wilken, Matthew; Geraghty, Robert J.; Li, Fang

    2012-12-10

    The severe acute respiratory syndrome coronavirus (SARS-CoV) from palm civets has twice evolved the capacity to infect humans by gaining binding affinity for human receptor angiotensin-converting enzyme 2 (ACE2). Numerous mutations have been identified in the receptor-binding domain (RBD) of different SARS-CoV strains isolated from humans or civets. Why these mutations were naturally selected or how SARS-CoV evolved to adapt to different host receptors has been poorly understood, presenting evolutionary and epidemic conundrums. In this study, we investigated the impact of these mutations on receptor recognition, an important determinant of SARS-CoV infection and pathogenesis. Using a combination of biochemical, functional, and crystallographic approaches, we elucidated the molecular and structural mechanisms of each of these naturally selected RBD mutations. These mutations either strengthen favorable interactions or reduce unfavorable interactions with two virus-binding hot spots on ACE2, and by doing so, they enhance viral interactions with either human (hACE2) or civet (cACE2) ACE2. Therefore, these mutations were viral adaptations to either hACE2 or cACE2. To corroborate the above analysis, we designed and characterized two optimized RBDs. The human-optimized RBD contains all of the hACE2-adapted residues (Phe-442, Phe-472, Asn-479, Asp-480, and Thr-487) and possesses exceptionally high affinity for hACE2 but relative low affinity for cACE2. The civet-optimized RBD contains all of the cACE2-adapted residues (Tyr-442, Pro-472, Arg-479, Gly-480, and Thr-487) and possesses exceptionally high affinity for cACE2 and also substantial affinity for hACE2. These results not only illustrate the detailed mechanisms of host receptor adaptation by SARS-CoV but also provide a molecular and structural basis for tracking future SARS-CoV evolution in animals.

  18. Coping during inpatient stroke rehabilitation: an exploratory study.

    PubMed

    Gillen, Glen

    2006-01-01

    The emotional impact of surviving a stroke has not received the same attention as physical aspects. This is particularly true regarding how stroke survivors cope during inpatient rehabilitation. This study examined the coping strategies used by stroke survivors undergoing inpatient rehabilitation and the relationships between demographic or clinical variables and coping behaviors. This case series examined 16 acute stroke survivors via standardized assessments and a medical records review completed during the first week of inpatient rehabilitation. Stroke survivors used combinations of multiple coping strategies. All stroke survivors used a higher number and frequency of adaptive rather than maladaptive strategies. Women used a higher number of adaptive strategies. Stroke survivors with depression used maladaptive coping strategies more frequently, whereas those presenting with a greater number and severity of comorbidities used adaptive coping strategies more frequently. Stroke survivors with higher levels of coping self-efficacy used the strategies of active coping and positive reframing more frequently. Based on these results, it is recommended direct-care providers place greater emphasis on objectifying the emotional consequences of stroke. Further research is recommended regarding understanding the relationship between coping and outcomes. PMID:16596917

  19. Gene duplication as a mechanism of genomic adaptation to a changing environment

    PubMed Central

    Kondrashov, Fyodor A.

    2012-01-01

    A subject of extensive study in evolutionary theory has been the issue of how neutral, redundant copies can be maintained in the genome for long periods of time. Concurrently, examples of adaptive gene duplications to various environmental conditions in different species have been described. At this point, it is too early to tell whether or not a substantial fraction of gene copies have initially achieved fixation by positive selection for increased dosage. Nevertheless, enough examples have accumulated in the literature that such a possibility should be considered. Here, I review the recent examples of adaptive gene duplications and make an attempt to draw generalizations on what types of genes may be particularly prone to be selected for under certain environmental conditions. The identification of copy-number variation in ecological field studies of species adapting to stressful or novel environmental conditions may improve our understanding of gene duplications as a mechanism of adaptation and its relevance to the long-term persistence of gene duplications. PMID:22977152

  20. Academic Resourcefulness, Coping Strategies and Doubting in University Undergraduates

    ERIC Educational Resources Information Center

    Xuereb, Sharon

    2015-01-01

    This study hypothesised that academic resourcefulness and coping strategies would predict doubting amongst university undergraduates. Doubting refers to the serious consideration of prematurely withdrawing from university. It was predicted that mature students would report higher levels of academic resourcefulness and adaptive coping strategies,…

  1. Teacher Stress and Coping Strategies: A National Snapshot

    ERIC Educational Resources Information Center

    Richards, Jan

    2012-01-01

    This national survey of 1,201 kindergarten through Grade-12-U.S. teachers focused on three related areas: (1) sources of teacher stress, (2) manifestations of stress, and (3) suggested coping strategies. The survey instrument was adapted from the Teacher Stress Inventory and the Coping Scale for Adults. Results indicated that teachers nationwide…

  2. A Qualitative Analysis of the Coping Strategies of Substitute Teachers

    ERIC Educational Resources Information Center

    Vorell, Matthew S.

    2011-01-01

    This study distinguishes whether substitute teachers enact coping strategies that mitigate the source of work-related stress (problem-centered) or coping strategies that enable them to adapt to stress created by work-related stressors (avoidance-centered). The author gathered data for this analysis by conducting 37 in-depth interviews with…

  3. Measuring Coping Skills: Behavioral Observations in Nursery School.

    ERIC Educational Resources Information Center

    Schneider, Eleanor; Scher, Anat

    2000-01-01

    Evaluated the Early Coping Inventory (ECI) as a measure of coping skills in low-risk nursery school children. Findings pointed to significant associations between observers' ratings and teachers' ratings on the Evaluation of Adaptive Behavior in Nursery School. Findings suggest that the ECI may be valuable in early identification of children with…

  4. Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization

    PubMed Central

    Hess, Allison E.; Potter, Kelsey A.; Tyler, Dustin J.; Zorman, Christian A.; Capadona, Jeffrey R.

    2013-01-01

    Implantable microdevices are gaining significant attention for several biomedical applications1-4. Such devices have been made from a range of materials, each offering its own advantages and shortcomings5,6. Most prominently, due to the microscale device dimensions, a high modulus is required to facilitate implantation into living tissue. Conversely, the stiffness of the device should match the surrounding tissue to minimize induced local strain7-9. Therefore, we recently developed a new class of bio-inspired materials to meet these requirements by responding to environmental stimuli with a change in mechanical properties10-14. Specifically, our poly(vinyl acetate)-based nanocomposite (PVAc-NC) displays a reduction in stiffness when exposed to water and elevated temperatures (e.g. body temperature). Unfortunately, few methods exist to quantify the stiffness of materials in vivo15, and mechanical testing outside of the physiological environment often requires large samples inappropriate for implantation. Further, stimuli-responsive materials may quickly recover their initial stiffness after explantation. Therefore, we have developed a method by which the mechanical properties of implanted microsamples can be measured ex vivo, with simulated physiological conditions maintained using moisture and temperature control13,16,17. To this end, a custom microtensile tester was designed to accommodate microscale samples13,17 with widely-varying Young's moduli (range of 10 MPa to 5 GPa). As our interests are in the application of PVAc-NC as a biologically-adaptable neural probe substrate, a tool capable of mechanical characterization of samples at the microscale was necessary. This tool was adapted to provide humidity and temperature control, which minimized sample drying and cooling17. As a result, the mechanical characteristics of the explanted sample closely reflect those of the sample just prior to explantation. The overall goal of this method is to quantitatively assess

  5. Design of a knee joint mechanism that adapts to individual physiology.

    PubMed

    Jiun-Yih Kuan; Pasch, Kenneth A; Herr, Hugh M

    2014-01-01

    This paper describes the design of a new knee joint mechanism, called the Adaptive Coupling Joint (ACJ). The new mechanism has an adaptive trajectory of the center of rotations (COR) that automatically matches those of the attached biological joint. The detailed design is presented as well as characterization results of the ACJ. Conventional exoskeleton and assistive devices usually consider limb joints as a one to three degrees of freedom (DOFs) joint synthesized by multiple one-DOF hinge joints in a single plane. However, the biological joints are complex and usually rotate with respect to a changing COR. As a result, the mismatch between limb joint motion and mechanical interface motion can lead to forces that cause undesired ligament and muscle length changes and internal mechanical changes. These undesired changes contribute to discomfort, as well as to the slippage and sluggish interaction between humans and devices. It is shown that the ACJ can transmit planetary torques from either active or passive devices to the limbs without altering the normal biological joint motion. PMID:25570389

  6. Genomic and transcriptomic analysis of NDM-1 Klebsiella pneumoniae in spaceflight reveal mechanisms underlying environmental adaptability

    PubMed Central

    Li, Jia; Liu, Fei; Wang, Qi; Ge, Pupu; Woo, Patrick C. Y.; Yan, Jinghua; Zhao, Yanlin; Gao, George F.; Liu, Cui Hua; Liu, Changting

    2014-01-01

    The emergence and rapid spread of New Delhi Metallo-beta-lactamase-1 (NDM-1)-producing Klebsiella pneumoniae strains has caused a great concern worldwide. To better understand the mechanisms underlying environmental adaptation of those highly drug-resistant K. pneumoniae strains, we took advantage of the China's Shenzhou 10 spacecraft mission to conduct comparative genomic and transcriptomic analysis of a NDM-1 K. pneumoniae strain (ATCC BAA-2146) being cultivated under different conditions. The samples were recovered from semisolid medium placed on the ground (D strain), in simulated space condition (M strain), or in Shenzhou 10 spacecraft (T strain) for analysis. Our data revealed multiple variations underlying pathogen adaptation into different environments in terms of changes in morphology, H2O2 tolerance and biofilm formation ability, genomic stability and regulation of metabolic pathways. Additionally, we found a few non-coding RNAs to be differentially regulated. The results are helpful for better understanding the adaptive mechanisms of drug-resistant bacterial pathogens. PMID:25163721

  7. Thickening of the knee joint cartilage in elite weightlifters as a potential adaptation mechanism.

    PubMed

    Grzelak, Piotr; Domzalski, Marcin; Majos, Agata; Podgórski, Michal; Stefanczyk, Ludomir; Krochmalski, Marek; Polguj, Michal

    2014-09-01

    Thickening and increase of area of cartilage have been proposed as two alternative mechanisms of cartilage functional adaptation. The latter has been reported in endurance sportsmen. In weightlifters, extreme strain applied to the articular surfaces can result in other forms of adaptation. The aim of this research is to determine whether cartilage thickness is greater in elite weightlifters than in physically inactive men. Weightlifters (13) and 20 controls [age and body mass index (BMI) matched] underwent knee Magnetic Resonance Imaging (MRI). A single sagittal slice of the knee was taken and cartilage thickness was measured in five and six regions of the medial and lateral femoral condyles, respectively. The analyzed segments represented weight-bearing and nonweight-bearing regions. The tibia cartilage in the weight-bearing area was also measured. The time of training onset and its duration in the weightlifter group were recorded. The cartilage was found to be significantly thicker in weightlifters in most of the analyzed regions. The distribution of cartilage thickness on the medial and lateral femoral condyles was similar in both groups. The duration of training was not associated with cartilage thickness, but the time of training onset correlated inversely with cartilage thickness. It is possible that in high-strain sports, joint cartilage can undergo functional adaptation by thickening. Thus, mechanical loading history could exert a postnatal influence on cartilage morphology. PMID:24648385

  8. Genomic and transcriptomic analysis of NDM-1 Klebsiella pneumoniae in spaceflight reveal mechanisms underlying environmental adaptability.

    PubMed

    Li, Jia; Liu, Fei; Wang, Qi; Ge, Pupu; Woo, Patrick C Y; Yan, Jinghua; Zhao, Yanlin; Gao, George F; Liu, Cui Hua; Liu, Changting

    2014-01-01

    The emergence and rapid spread of New Delhi Metallo-beta-lactamase-1 (NDM-1)-producing Klebsiella pneumoniae strains has caused a great concern worldwide. To better understand the mechanisms underlying environmental adaptation of those highly drug-resistant K. pneumoniae strains, we took advantage of the China's Shenzhou 10 spacecraft mission to conduct comparative genomic and transcriptomic analysis of a NDM-1 K. pneumoniae strain (ATCC BAA-2146) being cultivated under different conditions. The samples were recovered from semisolid medium placed on the ground (D strain), in simulated space condition (M strain), or in Shenzhou 10 spacecraft (T strain) for analysis. Our data revealed multiple variations underlying pathogen adaptation into different environments in terms of changes in morphology, H2O2 tolerance and biofilm formation ability, genomic stability and regulation of metabolic pathways. Additionally, we found a few non-coding RNAs to be differentially regulated. The results are helpful for better understanding the adaptive mechanisms of drug-resistant bacterial pathogens. PMID:25163721

  9. Tissue mechanics govern the rapidly adapting and symmetrical response to touch

    PubMed Central

    Eastwood, Amy L.; Sanzeni, Alessandro; Petzold, Bryan C.; Park, Sung-Jin; Vergassola, Massimo; Pruitt, Beth L.

    2015-01-01

    Interactions with the physical world are deeply rooted in our sense of touch and depend on ensembles of somatosensory neurons that invade and innervate the skin. Somatosensory neurons convert the mechanical energy delivered in each touch into excitatory membrane currents carried by mechanoelectrical transduction (MeT) channels. Pacinian corpuscles in mammals and touch receptor neurons (TRNs) in Caenorhabditis elegans nematodes are embedded in distinctive specialized accessory structures, have low thresholds for activation, and adapt rapidly to the application and removal of mechanical loads. Recently, many of the protein partners that form native MeT channels in these and other somatosensory neurons have been identified. However, the biophysical mechanism of symmetric responses to the onset and offset of mechanical stimulation has eluded understanding for decades. Moreover, it is not known whether applied force or the resulting indentation activate MeT channels. Here, we introduce a system for simultaneously recording membrane current, applied force, and the resulting indentation in living C. elegans (Feedback-controlled Application of mechanical Loads Combined with in vivo Neurophysiology, FALCON) and use it, together with modeling, to study these questions. We show that current amplitude increases with indentation, not force, and that fast stimuli evoke larger currents than slower stimuli producing the same or smaller indentation. A model linking body indentation to MeT channel activation through an embedded viscoelastic element reproduces the experimental findings, predicts that the TRNs function as a band-pass mechanical filter, and provides a general mechanism for symmetrical and rapidly adapting MeT channel activation relevant to somatosensory neurons across phyla and submodalities. PMID:26627717

  10. Tissue mechanics govern the rapidly adapting and symmetrical response to touch.

    PubMed

    Eastwood, Amy L; Sanzeni, Alessandro; Petzold, Bryan C; Park, Sung-Jin; Vergassola, Massimo; Pruitt, Beth L; Goodman, Miriam B

    2015-12-15

    Interactions with the physical world are deeply rooted in our sense of touch and depend on ensembles of somatosensory neurons that invade and innervate the skin. Somatosensory neurons convert the mechanical energy delivered in each touch into excitatory membrane currents carried by mechanoelectrical transduction (MeT) channels. Pacinian corpuscles in mammals and touch receptor neurons (TRNs) in Caenorhabditis elegans nematodes are embedded in distinctive specialized accessory structures, have low thresholds for activation, and adapt rapidly to the application and removal of mechanical loads. Recently, many of the protein partners that form native MeT channels in these and other somatosensory neurons have been identified. However, the biophysical mechanism of symmetric responses to the onset and offset of mechanical stimulation has eluded understanding for decades. Moreover, it is not known whether applied force or the resulting indentation activate MeT channels. Here, we introduce a system for simultaneously recording membrane current, applied force, and the resulting indentation in living C. elegans (Feedback-controlled Application of mechanical Loads Combined with in vivo Neurophysiology, FALCON) and use it, together with modeling, to study these questions. We show that current amplitude increases with indentation, not force, and that fast stimuli evoke larger currents than slower stimuli producing the same or smaller indentation. A model linking body indentation to MeT channel activation through an embedded viscoelastic element reproduces the experimental findings, predicts that the TRNs function as a band-pass mechanical filter, and provides a general mechanism for symmetrical and rapidly adapting MeT channel activation relevant to somatosensory neurons across phyla and submodalities. PMID:26627717

  11. Mechanisms for Rapid Adaptive Control of Motion Processing in Macaque Visual Cortex

    PubMed Central

    Baker, Pamela M.; Ahmed, Bashir; Kohn, Adam; Bair, Wyeth

    2015-01-01

    A key feature of neural networks is their ability to rapidly adjust their function, including signal gain and temporal dynamics, in response to changes in sensory inputs. These adjustments are thought to be important for optimizing the sensitivity of the system, yet their mechanisms remain poorly understood. We studied adaptive changes in temporal integration in direction-selective cells in macaque primary visual cortex, where specific hypotheses have been proposed to account for rapid adaptation. By independently stimulating direction-specific channels, we found that the control of temporal integration of motion at one direction was independent of motion signals driven at the orthogonal direction. We also found that individual neurons can simultaneously support two different profiles of temporal integration for motion in orthogonal directions. These findings rule out a broad range of adaptive mechanisms as being key to the control of temporal integration, including untuned normalization and nonlinearities of spike generation and somatic adaptation in the recorded direction-selective cells. Such mechanisms are too broadly tuned, or occur too far downstream, to explain the channel-specific and multiplexed temporal integration that we observe in single neurons. Instead, we are compelled to conclude that parallel processing pathways are involved, and we demonstrate one such circuit using a computer model. This solution allows processing in different direction/orientation channels to be separately optimized and is sensible given that, under typical motion conditions (e.g., translation or looming), speed on the retina is a function of the orientation of image components. SIGNIFICANCE STATEMENT Many neurons in visual cortex are understood in terms of their spatial and temporal receptive fields. It is now known that the spatiotemporal integration underlying visual responses is not fixed but depends on the visual input. For example, neurons that respond selectively to

  12. Older adults coping with vision loss.

    PubMed

    Weber, Joseph A; Wong, Karen B

    2010-07-01

    Age-related vision loss is one of the most commonly cited disabling impairments of adult life. Stressors presented by vision loss can create barriers, threatening the well-being of the individual. This qualitative study of 30 older adults (65 to 95 years of age) investigated vision loss and coping strategies. All participants experienced unexpected sight loss during their adult years. The Adaptation to Age-Related Vision Loss (AVL) Scale was used in this study to examine psychosocial adaptation to vision impairment. The coping strategies of vision impairment were assessed by collecting self-reported reflections toward vision loss and how the change impacted the participant's life. Given the correct balance of support, confidence, and acceptance, older adults can confront the existing barriers and focus on the ability to optimize function with vision loss. Health care service providers and practitioners can provide needed assistance and a helpful guide to assist older adults in successfully coping with vision impairment. PMID:20845173

  13. L-ALLIANCE: a mechanism for adaptive action selection in heterogeneous multi-robot teams

    SciTech Connect

    Parker, L.E.

    1995-11-01

    In practical applications of robotics, it is usually quite difficult, if not impossible, for the system designer to fully predict the environmental states in which the robots will operate. The complexity of the problem is further increased when dealing with teams of robots which themselves may be incompletely known and characterized in advance. It is thus highly desirable for robot teams to be able to adapt their performance during the mission due to changes in the environment, or to changes in other robot team members. In previous work, we introduced a behavior-based mechanism called the ALLIANCE architecture -- that facilitates the fault tolerant cooperative control of multi-robot teams. However, this previous work did not address the issue of how to dynamically update the control parameters during a mission to adapt to ongoing changes in the environment or in the robot team, and to ensure the efficiency of the collective team actions. In this paper, we address this issue by proposing the L-ALLIANCE mechanism, which defines an automated method whereby robots can use knowledge learned from previous experience to continually improve their collective action selection when working on missions composed of loosely coupled, discrete subtasks. This ability to dynamically update robotic control parameters provides a number of distinct advantages: it alleviates the need for human tuning of control parameters, it facilitates the use of custom-designed multi-robot teams for any given application, it improves the efficiency of the mission performance, and It allows robots to continually adapt their performance over time due to changes in the robot team and/or the environment. We describe the L-ALLIANCE mechanism, present the results of various alternative update strategies we investigated, present the formal model of the L-ALLIANCE mechanism, and present the results of a simple proof of concept implementation on a small team of heterogeneous mobile robots.

  14. Molecular Adaptation Mechanisms Employed by Ethanologenic Bacteria in Response to Lignocellulose-derived Inhibitory Compounds

    PubMed Central

    Ibraheem, Omodele; Ndimba, Bongani K.

    2013-01-01

    Current international interest in finding alternative sources of energy to the diminishing supplies of fossil fuels has encouraged research efforts in improving biofuel production technologies. In countries which lack sufficient food, the use of sustainable lignocellulosic feedstocks, for the production of bioethanol, is an attractive option. In the pre-treatment of lignocellulosic feedstocks for ethanol production, various chemicals and/or enzymatic processes are employed. These methods generally result in a range of fermentable sugars, which are subjected to microbial fermentation and distillation to produce bioethanol. However, these methods also produce compounds that are inhibitory to the microbial fermentation process. These compounds include products of sugar dehydration and lignin depolymerisation, such as organic acids, derivatised furaldehydes and phenolic acids. These compounds are known to have a severe negative impact on the ethanologenic microorganisms involved in the fermentation process by compromising the integrity of their cell membranes, inhibiting essential enzymes and negatively interact with their DNA/RNA. It is therefore important to understand the molecular mechanisms of these inhibitions, and the mechanisms by which these microorganisms show increased adaptation to such inhibitors. Presented here is a concise overview of the molecular adaptation mechanisms of ethanologenic bacteria in response to lignocellulose-derived inhibitory compounds. These include general stress response and tolerance mechanisms, which are typically those that maintain intracellular pH homeostasis and cell membrane integrity, activation/regulation of global stress responses and inhibitor substrate-specific degradation pathways. We anticipate that understanding these adaptation responses will be essential in the design of 'intelligent' metabolic engineering strategies for the generation of hyper-tolerant fermentation bacteria strains. PMID:23847442

  15. Molecular adaptation mechanisms employed by ethanologenic bacteria in response to lignocellulose-derived inhibitory compounds.

    PubMed

    Ibraheem, Omodele; Ndimba, Bongani K

    2013-01-01

    Current international interest in finding alternative sources of energy to the diminishing supplies of fossil fuels has encouraged research efforts in improving biofuel production technologies. In countries which lack sufficient food, the use of sustainable lignocellulosic feedstocks, for the production of bioethanol, is an attractive option. In the pre-treatment of lignocellulosic feedstocks for ethanol production, various chemicals and/or enzymatic processes are employed. These methods generally result in a range of fermentable sugars, which are subjected to microbial fermentation and distillation to produce bioethanol. However, these methods also produce compounds that are inhibitory to the microbial fermentation process. These compounds include products of sugar dehydration and lignin depolymerisation, such as organic acids, derivatised furaldehydes and phenolic acids. These compounds are known to have a severe negative impact on the ethanologenic microorganisms involved in the fermentation process by compromising the integrity of their cell membranes, inhibiting essential enzymes and negatively interact with their DNA/RNA. It is therefore important to understand the molecular mechanisms of these inhibitions, and the mechanisms by which these microorganisms show increased adaptation to such inhibitors. Presented here is a concise overview of the molecular adaptation mechanisms of ethanologenic bacteria in response to lignocellulose-derived inhibitory compounds. These include general stress response and tolerance mechanisms, which are typically those that maintain intracellular pH homeostasis and cell membrane integrity, activation/regulation of global stress responses and inhibitor substrate-specific degradation pathways. We anticipate that understanding these adaptation responses will be essential in the design of 'intelligent' metabolic engineering strategies for the generation of hyper-tolerant fermentation bacteria strains. PMID:23847442

  16. Network bursting dynamics in excitatory cortical neuron cultures results from the combination of different adaptive mechanisms.

    PubMed

    Masquelier, Timothée; Deco, Gustavo

    2013-01-01

    In the brain, synchronization among cells of an assembly is a common phenomenon, and thought to be functionally relevant. Here we used an in vitro experimental model of cell assemblies, cortical cultures, combined with numerical simulations of a spiking neural network (SNN) to investigate how and why spontaneous synchronization occurs. In order to deal with excitation only, we pharmacologically blocked GABAAergic transmission using bicuculline. Synchronous events in cortical cultures tend to involve almost every cell and to display relatively constant durations. We have thus named these "network spikes" (NS). The inter-NS-intervals (INSIs) proved to be a more interesting phenomenon. In most cortical cultures NSs typically come in series or bursts ("bursts of NSs", BNS), with short (~1 s) INSIs and separated by long silent intervals (tens of s), which leads to bimodal INSI distributions. This suggests that a facilitating mechanism is at work, presumably short-term synaptic facilitation, as well as two fatigue mechanisms: one with a short timescale, presumably short-term synaptic depression, and another one with a longer timescale, presumably cellular adaptation. We thus incorporated these three mechanisms into the SNN, which, indeed, produced realistic BNSs. Next, we systematically varied the recurrent excitation for various adaptation timescales. Strong excitability led to frequent, quasi-periodic BNSs (CV~0), and weak excitability led to rare BNSs, approaching a Poisson process (CV~1). Experimental cultures appear to operate within an intermediate weakly-synchronized regime (CV~0.5), with an adaptation timescale in the 2-8 s range, and well described by a Poisson-with-refractory-period model. Taken together, our results demonstrate that the INSI statistics are indeed informative: they allowed us to infer the mechanisms at work, and many parameters that we cannot access experimentally. PMID:24146781

  17. Common medial frontal mechanisms of adaptive control in humans and rodents

    PubMed Central

    Frank, Michael J.; Laubach, Mark

    2013-01-01

    In this report, we describe how common brain networks within the medial frontal cortex facilitate adaptive behavioral control in rodents and humans. We demonstrate that low frequency oscillations below 12 Hz are dramatically modulated after errors in humans over mid-frontal cortex and in rats within prelimbic and anterior cingulate regions of medial frontal cortex. These oscillations were phase-locked between medial frontal cortex and motor areas in both rats and humans. In rats, single neurons that encoded prior behavioral outcomes were phase-coherent with low-frequency field oscillations particularly after errors. Inactivating medial frontal regions in rats led to impaired behavioral adjustments after errors, eliminated the differential expression of low frequency oscillations after errors, and increased low-frequency spike-field coupling within motor cortex. Our results describe a novel mechanism for behavioral adaptation via low-frequency oscillations and elucidate how medial frontal networks synchronize brain activity to guide performance. PMID:24141310

  18. COMET-AR User's Manual: COmputational MEchanics Testbed with Adaptive Refinement

    NASA Technical Reports Server (NTRS)

    Moas, E. (Editor)

    1997-01-01

    The COMET-AR User's Manual provides a reference manual for the Computational Structural Mechanics Testbed with Adaptive Refinement (COMET-AR), a software system developed jointly by Lockheed Palo Alto Research Laboratory and NASA Langley Research Center under contract NAS1-18444. The COMET-AR system is an extended version of an earlier finite element based structural analysis system called COMET, also developed by Lockheed and NASA. The primary extensions are the adaptive mesh refinement capabilities and a new "object-like" database interface that makes COMET-AR easier to extend further. This User's Manual provides a detailed description of the user interface to COMET-AR from the viewpoint of a structural analyst.

  19. Fine-scale temporal adaptation within a salmonid population: mechanism and consequences.

    PubMed

    Gharrett, Anthony J; Joyce, John; Smoker, William W

    2013-09-01

    We demonstrate a clear example of local adaptation of seasonal timing of spawning and embryo development. The consequence is a population of pink salmon that is segmented into spawning groups that use the same limited habitat. We synthesize published observations with results of new analyses to demonstrate that genetic variation of these traits results in survival differentials related to that variation, and that density-dependent embryo mortality and seasonally variable juvenile mortality are a mechanism of selection. Most examples of local adaptation in natural systems depend on observed correlations between environments and fitness traits, but do not fully demonstrate local adaptation: that the trait is genetically determined, exhibits different fitness in common environments or across different environments, and its variation is mechanistically connected to fitness differences. The geographic or temporal scales of local adaptation often remain obscure. Here, we show that heritable, fine-scale differences of timing of reproductive migration in a pink salmon (Oncorhynchus gorbuscha) resulted in temporal structure that persisted several generations; the differences enable a density-dependent population to pack more spawners into limited spawning habitat, that is, enhance its fitness. A balanced trade-off of survivals results because embryos from early-migrating fish have a lower freshwater survival (harsh early physical conditions and disturbance by late spawners), but emigrant fry from late-migrating fish have lower marine survivals (timing of their vernal emergence into the estuarine environment). Such fine-scale local adaptations increase the genetic portfolio of the populations and may provide a buffer against the impacts of climate change. PMID:23980763

  20. The role of training in the development of adaptive mechanisms in freedivers.

    PubMed

    Ostrowski, Andrzej; Strzała, Marek; Stanula, Arkadiusz; Juszkiewicz, Mirosław; Pilch, Wanda; Maszczyk, Adam

    2012-05-01

    Freediving is a sport in which athletes aim to achieve the longest or the deepest breath-hold dive. Divers are at risk of gradually increasing hypoxia and hypercapnia due to a long time spent underwater and additionally of increasing hyperoxia while depth diving. Exceeding the limits of hypoxia endurance leads to loss of consciousness or even to death whithout immediate first aid. Often enhanced world records indicate the ability to shape specific to the discipline adaptive mechanisms of cardio-pulmonary system which are individually conditioned. During stay underwater heartbeats decelerating called bradycardia, increase in blood pressure, peripheral blood vessels narrowing and blood centralization in freediver's organism. These mechanisms enhance blood oxygen management as well as transporting it first of all to essential for survival organs, i.e. brain and heart. These mechanisms are supported by spleen and adrenal glands hormonal reactions. PMID:23487544

  1. Lessons in Fundamental Mechanisms and Diverse Adaptations from the 2015 Bacterial Locomotion and Signal Transduction Meeting

    PubMed Central

    Prüβ, Birgit M.; Liu, Jun; Higgs, Penelope I.

    2015-01-01

    In response to rapid changes in their environment, bacteria control a number of processes, including motility, cell division, biofilm formation, and virulence. Research presented in January 2015 at the biennial Bacterial Locomotion and Signal Transduction (BLAST) meeting in Tucson, AZ, illustrates the elegant complexity of the nanoarrays, nanomachines, and networks of interacting proteins that mediate such processes. Studies employing an array of biophysical, genetic, cell biology, and mathematical methods are providing an increasingly detailed understanding of the mechanisms of these systems within well-studied bacteria. Furthermore, comparisons of these processes in diverse bacterial species are providing insight into novel regulatory and functional mechanisms. This review summarizes research presented at the BLAST meeting on these fundamental mechanisms and diverse adaptations, including findings of importance for applications involving bacteria of medical or agricultural relevance. PMID:26195592

  2. The Role of Training in the Development of Adaptive Mechanisms in Freedivers

    PubMed Central

    Ostrowski, Andrzej; Strzała, Marek; Stanula, Arkadiusz; Juszkiewicz, Mirosław; Pilch, Wanda; Maszczyk, Adam

    2012-01-01

    Freediving is a sport in which athletes aim to achieve the longest or the deepest breath-hold dive. Divers are at risk of gradually increasing hypoxia and hypercapnia due to a long time spent underwater and additionally of increasing hyperoxia while depth diving. Exceeding the limits of hypoxia endurance leads to loss of consciousness or even to death whithout immediate first aid. Often enhanced world records indicate the ability to shape specific to the discipline adaptive mechanisms of cardio-pulmonary system which are individually conditioned. During stay underwater heartbeats decelerating called bradycardia, increase in blood pressure, peripheral blood vessels narrowing and blood centralization in freediver’s organism. These mechanisms enhance blood oxygen management as well as transporting it first of all to essential for survival organs, i.e. brain and heart. These mechanisms are supported by spleen and adrenal glands hormonal reactions. PMID:23487544

  3. Farmer Health and Adaptive Capacity in the Face of Climate Change and Variability. Part 1: Health as a Contributor to Adaptive Capacity and as an Outcome from Pressures Coping with Climate Related Adversities

    PubMed Central

    Berry, Helen L.; Hogan, Anthony; Ng, Suan Peng; Parkinson, Anne

    2011-01-01

    This paper examines the role farmers’ health plays as an element of adaptive capacity. The study examines which of twenty aspects of adaptation may be related to overall health outcomes, controlling for demographic and on-farm-factors in health problems. The analysis is based on 3,993 farmers’ responses to a national survey of climate risk and adaptation. Hierarchical linear regression modelling was used examine the extent to which, in a multivariate analysis, the use of adaptive practices was predictively associated with self-assessed health, taking into account the farmer’s rating of whether their health was a barrier to undertaking farm work. We present two models, one excluding pre-existing health (model 1) and one including pre-existing health (model 2). The first model accounted for 21% of the variance. In this model better health was most strongly predicted by an absence of on-farm risk, greater financial viability, greater debt pressures, younger age and a desire to continue farming. Social capital (trust and reciprocity) was moderately associated with health as was the intention to adopt more sustainable practices. The second model (including the farmers’ health as a barrier to undertaking farm work) accounted for 43% of the variance. Better health outcomes were most strongly explained, in order of magnitude, by the absence of pre-existing health problems, greater access to social support, greater financial viability, greater debt pressures, a desire to continue farming and the condition of on-farm resources. Model 2 was a more parsimonious model (only nine predictors, compared with 15 in model 1), and explained twice as much variance in health outcomes. These results suggest that (i) pre-existing health problems are a very important factor to consider when designing adaptation programs and policies and (ii) these problems may mediate or modify the relationship between adaptation and health. PMID:22073027

  4. The mouse fibula as a suitable bone for the study of functional adaptation to mechanical loading

    PubMed Central

    Moustafa, Alaa; Sugiyama, Toshihiro; Saxon, Leanne K.; Zaman, Gul; Sunters, Andrew; Armstrong, Victoria J.; Javaheri, Behzad; Lanyon, Lance E.; Price, Joanna S.

    2009-01-01

    Bones' functionally adaptive responses to mechanical loading can usefully be studied in the tibia by the application of loads between the knee and ankle in normal and genetically modified mice. Such loading also deforms the fibula. Our present study was designed to ascertain whether the fibula adapts to loading in a similar way to the tibia and could thus provide an additional bone in which to study functional adaptation. The right tibiae/fibulae in C57BL/6 mice were subjected to a single period of axial loading (40 cycles at 10 Hz with 10-second intervals between each cycle; approximately 7 min/day, 3 alternate days/week, 2 weeks). The left tibiae/fibulae were used as non-loaded, internal controls. Both left and right fibulae and tibiae were analyzed by micro-computed tomography at the levels of the mid-shaft of the fibula and 25% from its proximal and distal ends. We also investigated the effects of intermittent parathyroid hormone (iPTH) on the (re)modelling response to 2-weeks of loading and the effect of 2-consecutive days of loading on osteocytes' sclerostin expression. These in vivo experiments confirmed that the fibula showed similar loading-related (re)modelling responses to those previously documented in the tibia and similar synergistic increases in osteogenesis between loading and iPTH. The numbers of sclerostin-positive osteocytes at the proximal and middle fibulae were markedly decreased by loading. Collectively, these data suggest that the mouse fibula, as well as the tibia and ulna, is a useful bone in which to assess bone cells' early responses to mechanical loading and the adaptive (re)modelling that this engenders. PMID:19442626

  5. The Interplay Between Strategic And Adaptive Control Mechanisms In Plastic Recalibration Of Locomotor Function

    NASA Technical Reports Server (NTRS)

    Richards, J. T.; Mulavara, A. P.; Bloomberg, J. J.

    2006-01-01

    We have previously shown that viewing simulated rotary self-motion during treadmill locomotion causes immediate strategic modifications (Richards et al. 2004) as well as an after effect reflecting adaptive modification of the control of position and trajectory during over-ground locomotion (Mulavara et al. 2005). The process of sensorimotor adaptation is comprised of both strategic and adaptive control mechanisms. Strategic control involves cognitive, on-line corrections to limb movements once one is aware of a sensory discordance. Over an extended period of exposure to the sensory discordance, new strategic sensorimotor coordination patterns are reinforced until they become more automatic, and therefore adaptive, in nature. The objective of this study was to investigate how strategic changes in trunk control during exposure to simulated rotary self-motion during treadmill walking influences adaptive modification of locomotor heading direction during over-ground stepping. Subjects (n = 10) walked on a motorized linear treadmill while viewing a wide field-of-view virtual scene for 24 minutes. The scene was static for the first 4 minutes and then, for the last 20 minutes, depicted constant rate self-motion equivalent to walking in a counter-clockwise, circular path around the perimeter of a room. Subjects performed five stepping trials both before and after the exposure period to assess after effects. Results from our previous study showed a significant change in heading direction (HD) during post-exposure step tests that was opposite the direction in which the scene rotated during the adaptation period. For the present study, we quantified strategic modifications in trunk movement control during scene exposure using normalized root mean square (R(sub p)) variation of the subject's 3D trunk positions and normalized sum of standard deviations (R(sub o)) variation of 3D trunk orientations during scene rotation relative to that during static scene presentation

  6. Mechanical anisotropy and adaptation of metastatic cells probed by magnetic microbeads

    NASA Astrophysics Data System (ADS)

    Zhang, Zhipeng; Shi, Yanhui; Jhiang, Sissy M.; Menq, Chia-Hsiang

    2010-02-01

    Metastatic cells have the ability to break through the basal lamina, enter the blood vessels, circulate through the vasculature, exit at distant sites, and form secondary tumors. This multi-step process, therefore, clearly indicates the inherent ability of metastatic cells to sense, process, and adapt to the mechanical forces in different surrounding environments. We describe a magnetic probing device that is useful in characterizing the mechanical properties of cells along arbitrary two-dimensional directions. Magnetic force, with the advantages of biocompatibility and specificity, was produced by magnetic poles placed in an octupole configuration and applied to fibronectin-coated magnetic microbeads attached on cell membrane. Cell deformation in response to the applied force was then recorded through the displacement of the microbeads. The motion of the beads was measured by computer processing the video images acquired by a high-speed CMOS camera. Rotating force vectors with constant magnitude while pointing to directions of all 360 degrees were applied to study the mechanical anisotropy of metastatic breast cancer cells MDA-MB-231. The temporal changes in magnitude and directionality of the cellular responses were then analyzed to investigate the cellular adaptation to force stimulation. This probing technology thus has the potential to provide us a better understanding of the mechano-signatures of cells.

  7. Multiple Symbiont Acquisition Strategies as an Adaptive Mechanism in the Coral Stylophora pistillata

    PubMed Central

    Byler, Kristen A.; Carmi-Veal, Maya; Fine, Maoz; Goulet, Tamar L.

    2013-01-01

    In obligate symbioses, the host’s survival relies on the successful acquisition and maintenance of symbionts. Symbionts can either be transferred from parent to offspring via direct inheritance (vertical transmission) or acquired anew each generation from the environment (horizontal transmission). With vertical symbiont transmission, progeny benefit by not having to search for their obligate symbionts, and, with symbiont inheritance, a mechanism exists for perpetuating advantageous symbionts. But, if the progeny encounter an environment that differs from that of their parent, they may be disadvantaged if the inherited symbionts prove suboptimal. Conversely, while in horizontal symbiont acquisition host survival hinges on an unpredictable symbiont source, an individual host may acquire genetically diverse symbionts well suited to any given environment. In horizontal acquisition, however, a potentially advantageous symbiont will not be transmitted to subsequent generations. Adaptation in obligate symbioses may require mechanisms for both novel symbiont acquisition and symbiont inheritance. Using denaturing-gradient gel electrophoresis and real-time PCR, we identified the dinoflagellate symbionts (genus Symbiodinium) hosted by the Red Sea coral Stylophora pistillata throughout its ontogenesis and over depth. We present evidence that S. pistillata juvenile colonies may utilize both vertical and horizontal symbiont acquisition strategies. By releasing progeny with maternally derived symbionts, that are also capable of subsequent horizontal symbiont acquisition, coral colonies may acquire physiologically advantageous novel symbionts that are then perpetuated via vertical transmission to subsequent generations. With symbiont inheritance, natural selection can act upon the symbiotic variability, providing a mechanism for coral adaptation. PMID:23555721

  8. Adaptation of muscle coordination to altered task mechanics during steady-state cycling.

    PubMed

    Neptune, R R; Herzog, W

    2000-02-01

    The objective of this work was to increase our understanding of how motor patterns are produced during movement tasks by quantifying adaptations in muscle coordination in response to altered task mechanics. We used pedaling as our movement paradigm because it is a constrained cyclical movement that allows for a controlled investigation of test conditions such as movement speed and effort. Altered task mechanics were introduced using an elliptical chainring. The kinematics of the crank were changed from a relatively constant angular velocity using a circular chainring to a widely varying angular velocity using an elliptical chainring. Kinetic, kinematic and muscle activity data were collected from eight competitive cyclists using three different chainrings--one circular and two different orientations of an elliptical chainring. We tested the hypotheses that muscle coordination patterns (EMG timing and magnitude), specifically the regions of active muscle force production, would shift towards regions in the crank cycle in which the crank angular velocity, and hence muscle contraction speeds, were favorable to produce muscle power as defined by the skeletal muscle power-velocity relationship. The results showed that our hypothesis with regards to timing was not supported. Although there were statistically significant shifts in muscle timing, the shifts were minor in absolute terms and appeared to be the result of the muscles accounting for the activation dynamics associated with muscle force development (i.e. the delay in muscle force rise and decay). But, significant changes in the magnitude of muscle EMG during regions of slow crank angular velocity for the tibialis anterior and rectus femoris were observed. Thus, the nervous system used adaptations to the muscle EMG magnitude, rather than the timing, to adapt to the altered task mechanics. The results also suggested that cyclists might work on the descending limb of the power-velocity relationship when pedaling at

  9. Mechanisms of regulation of olfactory transduction and adaptation in the olfactory cilium.

    PubMed

    Antunes, Gabriela; Sebastião, Ana Maria; Simoes de Souza, Fabio Marques

    2014-01-01

    Olfactory adaptation is a fundamental process for the functioning of the olfactory system, but the underlying mechanisms regulating its occurrence in intact olfactory sensory neurons (OSNs) are not fully understood. In this work, we have combined stochastic computational modeling and a systematic pharmacological study of different signaling pathways to investigate their impact during short-term adaptation (STA). We used odorant stimulation and electroolfactogram (EOG) recordings of the olfactory epithelium treated with pharmacological blockers to study the molecular mechanisms regulating the occurrence of adaptation in OSNs. EOG responses to paired-pulses of odorants showed that inhibition of phosphodiesterases (PDEs) and phosphatases enhanced the levels of STA in the olfactory epithelium, and this effect was mimicked by blocking vesicle exocytosis and reduced by blocking cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) and vesicle endocytosis. These results suggest that G-coupled receptors (GPCRs) cycling is involved with the occurrence of STA. To gain insights on the dynamical aspects of this process, we developed a stochastic computational model. The model consists of the olfactory transduction currents mediated by the cyclic nucleotide gated (CNG) channels and calcium ion (Ca(2+))-activated chloride (CAC) channels, and the dynamics of their respective ligands, cAMP and Ca(2+), and it simulates the EOG results obtained under different experimental conditions through changes in the amplitude and duration of cAMP and Ca(2+) response, two second messengers implicated with STA occurrence. The model reproduced the experimental data for each pharmacological treatment and provided a mechanistic explanation for the action of GPCR cycling in the levels of second messengers modulating the levels of STA. All together, these experimental and theoretical results indicate the existence of a mechanism of regulation of STA by signaling pathways that control

  10. Mechanisms of Regulation of Olfactory Transduction and Adaptation in the Olfactory Cilium

    PubMed Central

    Antunes, Gabriela; Sebastião, Ana Maria; Simoes de Souza, Fabio Marques

    2014-01-01

    Olfactory adaptation is a fundamental process for the functioning of the olfactory system, but the underlying mechanisms regulating its occurrence in intact olfactory sensory neurons (OSNs) are not fully understood. In this work, we have combined stochastic computational modeling and a systematic pharmacological study of different signaling pathways to investigate their impact during short-term adaptation (STA). We used odorant stimulation and electroolfactogram (EOG) recordings of the olfactory epithelium treated with pharmacological blockers to study the molecular mechanisms regulating the occurrence of adaptation in OSNs. EOG responses to paired-pulses of odorants showed that inhibition of phosphodiesterases (PDEs) and phosphatases enhanced the levels of STA in the olfactory epithelium, and this effect was mimicked by blocking vesicle exocytosis and reduced by blocking cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) and vesicle endocytosis. These results suggest that G-coupled receptors (GPCRs) cycling is involved with the occurrence of STA. To gain insights on the dynamical aspects of this process, we developed a stochastic computational model. The model consists of the olfactory transduction currents mediated by the cyclic nucleotide gated (CNG) channels and calcium ion (Ca2+)-activated chloride (CAC) channels, and the dynamics of their respective ligands, cAMP and Ca2+, and it simulates the EOG results obtained under different experimental conditions through changes in the amplitude and duration of cAMP and Ca2+ response, two second messengers implicated with STA occurrence. The model reproduced the experimental data for each pharmacological treatment and provided a mechanistic explanation for the action of GPCR cycling in the levels of second messengers modulating the levels of STA. All together, these experimental and theoretical results indicate the existence of a mechanism of regulation of STA by signaling pathways that control GPCR

  11. The estimated mechanical advantage of the prosimian ankle joint musculature, and implications for locomotor adaptation.

    PubMed

    Goto, Ryosuke; Kumakura, Hiroo

    2013-05-01

    In this study we compared the power arm lengths and mechanical advantages attributed to 12 lower leg muscles across three prosimian species. The origins and insertions of the lower leg muscles in Garnett's galago, the ring-tailed lemur, and the slow loris were quantified and correlated with positional behaviour. The ankle joint of the galago has a speed-oriented mechanical system, in contrast to that of the slow loris, which exhibits more power-oriented mechanics. The lemur ankle joint exhibited intermediate power arm lengths and an intermediate mechanical advantage relative to the other primates. This result suggests that the mechanical differences in the ankle between the galago and the lemur, taxa that exhibit similar locomotory repertoires, reflect a difference in the kinematics and kinetics of leaping (i.e. generalised vs. specialised leapers). In contrast to leaping primates, lorises have developed a more power-oriented mechanical system as a foot adaptation for positional behaviours such as bridging or cantilevering in their arboreal habitat. PMID:23489408

  12. The Contribution of Experimental in vivo Models to Understanding the Mechanisms of Adaptation to Mechanical Loading in Bone

    PubMed Central

    Meakin, Lee B.; Price, Joanna S.; Lanyon, Lance E.

    2014-01-01

    Changing loading regimens by natural means such as exercise, with or without interference such as osteotomy, has provided useful information on the structure:function relationship in bone tissue. However, the greatest precision in defining those aspects of the overall strain environment that influence modeling and remodeling behavior has been achieved by relating quantified changes in bone architecture to quantified changes in bones’ strain environment produced by direct, controlled artificial bone loading. Jiri Hert introduced the technique of artificial loading of bones in vivo with external devices in the 1960s using an electromechanical device to load rabbit tibiae through transfixing stainless steel pins. Quantifying natural bone strains during locomotion by attaching electrical resistance strain gages to bone surfaces was introduced by Lanyon, also in the 1960s. These studies in a variety of bones in a number of species demonstrated remarkable uniformity in the peak strains and maximum strain rates experienced. Experiments combining strain gage instrumentation with artificial loading in sheep, pigs, roosters, turkeys, rats, and mice has yielded significant insight into the control of strain-related adaptive (re)modeling. This diversity of approach has been largely superseded by non-invasive transcutaneous loading in rats and mice, which is now the model of choice for many studies. Together such studies have demonstrated that over the physiological strain range, bone’s mechanically adaptive processes are responsive to dynamic but not static strains; the size and nature of the adaptive response controlling bone mass is linearly related to the peak loads encountered; the strain-related response is preferentially sensitive to high strain rates and unresponsive to static ones; is most responsive to unusual strain distributions; is maximized by remarkably few strain cycles, and that these are most effective when interrupted by short periods of rest between them

  13. Hybrid numerical method with adaptive overlapping meshes for solving nonstationary problems in continuum mechanics

    NASA Astrophysics Data System (ADS)

    Burago, N. G.; Nikitin, I. S.; Yakushev, V. L.

    2016-06-01

    Techniques that improve the accuracy of numerical solutions and reduce their computational costs are discussed as applied to continuum mechanics problems with complex time-varying geometry. The approach combines shock-capturing computations with the following methods: (1) overlapping meshes for specifying complex geometry; (2) elastic arbitrarily moving adaptive meshes for minimizing the approximation errors near shock waves, boundary layers, contact discontinuities, and moving boundaries; (3) matrix-free implementation of efficient iterative and explicit-implicit finite element schemes; (4) balancing viscosity (version of the stabilized Petrov-Galerkin method); (5) exponential adjustment of physical viscosity coefficients; and (6) stepwise correction of solutions for providing their monotonicity and conservativeness.

  14. Photorespiration and carbon concentrating mechanisms: two adaptations to high O2, low CO2 conditions.

    PubMed

    Moroney, James V; Jungnick, Nadine; Dimario, Robert J; Longstreth, David J

    2013-11-01

    This review presents an overview of the two ways that cyanobacteria, algae, and plants have adapted to high O2 and low CO2 concentrations in the environment. First, the process of photorespiration enables photosynthetic organisms to recycle phosphoglycolate formed by the oxygenase reaction catalyzed by ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Second, there are a number of carbon concentrating mechanisms that increase the CO2 concentration around Rubisco which increases the carboxylase reaction enhancing CO2 fixation. This review also presents possibilities for the beneficial modification of these processes with the goal of improving future crop yields. PMID:23771683

  15. Matrix Metalloproteinases in a Sea Urchin Ligament with Adaptable Mechanical Properties

    PubMed Central

    Ribeiro, Ana R.; Barbaglio, Alice; Oliveira, Maria J.; Ribeiro, Cristina C.; Wilkie, Iain C.; Candia Carnevali, Maria D.; Barbosa, Mário A.

    2012-01-01

    Mutable collagenous tissues (MCTs) of echinoderms show reversible changes in tensile properties (mutability) that are initiated and modulated by the nervous system via the activities of cells known as juxtaligamental cells. The molecular mechanism underpinning this mechanical adaptability has still to be elucidated. Adaptable connective tissues are also present in mammals, most notably in the uterine cervix, in which changes in stiffness result partly from changes in the balance between matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). There have been no attempts to assess the potential involvement of MMPs in the echinoderm mutability phenomenon, apart from studies dealing with a process whose relationship to the latter is uncertain. In this investigation we used the compass depressor ligaments (CDLs) of the sea-urchin Paracentrotus lividus. The effect of a synthetic MMP inhibitor - galardin - on the biomechanical properties of CDLs in different mechanical states (“standard”, “compliant” and “stiff”) was evaluated by dynamic mechanical analysis, and the presence of MMPs in normal and galardin-treated CDLs was determined semi-quantitatively by gelatin zymography. Galardin reversibly increased the stiffness and storage modulus of CDLs in all three states, although its effect was significantly lower in stiff than in standard or compliant CDLs. Gelatin zymography revealed a progressive increase in total gelatinolytic activity between the compliant, standard and stiff states, which was possibly due primarily to higher molecular weight components resulting from the inhibition and degradation of MMPs. Galardin caused no change in the gelatinolytic activity of stiff CDLs, a pronounced and statistically significant reduction in that of standard CDLs, and a pronounced, but not statistically significant, reduction in that of compliant CDLs. Our results provide evidence that MMPs may contribute to the variable tensility of the

  16. The Impact of Childhood Cancer: A Two-Factor Model of Coping.

    ERIC Educational Resources Information Center

    Zevon, Michael A.; Armstrong, Gordon D.

    A review of existing stress and coping models and an analysis of the distress caused by childhood cancer suggest that a broader conceptualization of coping that includes "pleasure management" is needed. Presently, successful coping is identified as the employment of strategies which allow the individual to adapt to stress. Traditional stress…

  17. Family Functioning and Coping Behaviors in Parents of Children with Autism

    ERIC Educational Resources Information Center

    Altiere, Matthew J.; von Kluge, Silvia

    2009-01-01

    We analyzed family dynamics and coping behaviors of parents with a child with an autistic spectrum disorder. Previous research suggests that moderate levels of cohesion and adaptability are associated with higher levels of positive coping, and that the more coping strategies a family implements, the greater their satisfaction with family…

  18. Coping Strategy Use, Personality, and Adjustment of Parents Rearing Children with Developmental Disabilities

    ERIC Educational Resources Information Center

    Glidden, L. M.; Natcher, A. L.

    2009-01-01

    Background: Parents rearing children with developmental disabilities encounter stressors that require coping and adaptation. In Glidden et al. 2006, the use of problem-focused coping strategies was more often associated with positive adjustment outcomes than was the use of emotion-focused coping strategies, and parental personality was shown to…

  19. Adaptive Transgenerational Plasticity in Plants: Case Studies, Mechanisms, and Implications for Natural Populations

    PubMed Central

    Herman, Jacob J.; Sultan, Sonia E.

    2011-01-01

    Plants respond to environmental conditions not only by plastic changes to their own development and physiology, but also by altering the phenotypes expressed by their offspring. This transgenerational plasticity was initially considered to entail only negative effects of stressful parental environments, such as production of smaller seeds by resource- or temperature-stressed parent plants, and was therefore viewed as environmental noise. Recent evolutionary ecology studies have shown that in some cases, these inherited environmental effects can include specific growth adjustments that are functionally adaptive to the parental conditions that induced them, which can range from contrasting states of controlled laboratory environments to the complex habitat variation encountered by natural plant populations. Preliminary findings suggest that adaptive transgenerational effects can be transmitted by means of diverse mechanisms including changes to seed provisioning and biochemistry, and epigenetic modifications such as DNA methylation that can persist across multiple generations. These non-genetically inherited adaptations can influence the ecological breadth and evolutionary dynamics of plant taxa and promote the spread of invasive plants. Interdisciplinary studies that join mechanistic and evolutionary ecology approaches will be an important source of future insights. PMID:22639624

  20. Biological Co-Adaptation of Morphological and Composition Traits Contributes to Mechanical Functionality and Skeletal Fragility

    PubMed Central

    Tommasini, Steven M; Nasser, Philip; Hu, Bin; Jepsen, Karl J

    2008-01-01

    A path analysis was conducted to determine whether functional interactions exist among morphological, compositional, and microstructural traits for young adult human tibias. Data provided evidence that bone traits are co-adapted during ontogeny so that the sets of traits together satisfy physiological loading demands. However, certain sets of traits are expected to perform poorly under extreme load conditions. Introduction Previous data from inbred mouse strains suggested that biological processes within bone co-adapt morphological and compositional traits during ontogeny to satisfy physiological loading demands. Similar work in young adult humans showed that cortical tissue from slender tibias was stiffer, less ductile, and more susceptible to accumulating damage. Here we tested whether the relationships among morphology and tissue level mechanical properties were the result of biological processes that co-adapt physical traits, similar to those observed for the mouse skeleton. Materials and Methods Cross-sectional morphology, bone slenderness (Tt.Ar/Le), and tissue level mechanical properties were measured from tibias from 14 female (22–46 yr old) and 17 male (17–46 yr old) donors. Physical bone traits measured included tissue density, ash content, water content, porosity, and the area fractions of osteonal, interstitial, and circumferential lamellar tissues. Bivariate relationships among traits were determined using linear regression analysis. A path analysis was conducted to test the hypothesis that Tt.Ar/Le is functionally related to mineralization (ash content) and the proportion of total area occupied by cortical bone. Results Ash content correlated negatively with several traits including Tt.Ar/Le and marrow area, indicating that slender bones were constructed of tissue with higher mineralization. Path analysis revealed that slender tibias were compensated by higher mineralization and a greater area fraction of bone. Conclusions The results suggest that

  1. Women's experiences of coping with pregnancy termination for fetal abnormality.

    PubMed

    Lafarge, Caroline; Mitchell, Kathryn; Fox, Pauline

    2013-07-01

    Pregnancy termination for fetal abnormality (TFA) can have significant psychological consequences. Most previous research has been focused on measuring the psychological outcomes of TFA, and little is known about the coping strategies involved. In this article, we report on women's coping strategies used during and after the procedure. Our account is based on experiences of 27 women who completed an online survey. We analyzed the data using interpretative phenomenological analysis. Coping comprised four structures, consistent across time points: support, acceptance, avoidance, and meaning attribution. Women mostly used adaptive coping strategies but reported inadequacies in aftercare, which challenged their resources. The study's findings indicate the need to provide sensitive, nondirective care rooted in the acknowledgment of the unique nature of TFA. Enabling women to reciprocate for emotional support, promoting adaptive coping strategies, highlighting the potential value of spending time with the baby, and providing long-term support (including during subsequent pregnancies) might promote psychological adjustment to TFA. PMID:23558712

  2. Adaptive properties of living beings: proposal for a generic mechanism. (Self-programming machines III).

    PubMed

    Moulin, Jean-Paul

    2006-03-01

    Living systems are capable to have appropriate responses to unpredictable environment. This kind of self-organization seems to operate as a self-programming machine, i.e. an organization able to modify itself. Until now the models of self-organization of living beings proposed are functions solutions of differential systems or transition functions of automata. These functions are fixed and these models are therefore unable to modify their organization. On the other hand, computer science propose a lot of models having the properties of adaptive systems of living beings, but all these models depend on the comparison between a goal and the results and ingenious choices of parameters by programmers, whereas there are no programmer's intention nor choice in the living systems. From two best known examples of adaptive systems of living beings, nervous system and immune system that have in common that the external signals modify the rewriting of their organization and therefore work as self-organizing machines, we devised machines with a finite set of inputs, based upon a recurrence, are able to rewrite their organization (Self-programming machines or m(sp)) whenever external conditions vary and have striking properties of adaptation. M(sp) have similar properties whatever the operation defining the recurrence maybe. These results bring us to make the following statement: adaptive properties of living systems can be explained by their ability to rewrite their organization whenever external conditions vary under the only assumption that the rewriting mechanism be a deterministic constant recurrence in a finite state set. PMID:16545754

  3. Adaptations for economical bipedal running: the effect of limb structure on three-dimensional joint mechanics.

    PubMed

    Rubenson, Jonas; Lloyd, David G; Heliams, Denham B; Besier, Thor F; Fournier, Paul A

    2011-05-01

    The purpose of this study was to examine the mechanical adaptations linked to economical locomotion in cursorial bipeds. We addressed this question by comparing mass-matched humans and avian bipeds (ostriches), which exhibit marked differences in limb structure and running economy. We hypothesized that the nearly 50 per cent lower energy cost of running in ostriches is a result of: (i) lower limb-swing mechanical power, (ii) greater stance-phase storage and release of elastic energy, and (iii) lower total muscle power output. To test these hypotheses, we used three-dimensional joint mechanical measurements and a simple model to estimate the elastic and muscle contributions to joint work and power. Contradictory to our first hypothesis, we found that ostriches and humans generate the same amounts of mechanical power to swing the limbs at a similar self-selected running speed, indicating that limb swing probably does not contribute to the difference in energy cost of running between these species. In contrast, we estimated that ostriches generate 120 per cent more stance-phase mechanical joint power via release of elastic energy compared with humans. This elastic mechanical power occurs nearly exclusively at the tarsometatarso-phalangeal joint, demonstrating a shift of mechanical power generation to distal joints compared with humans. We also estimated that positive muscle fibre power is 35 per cent lower in ostriches compared with humans, and is accounted for primarily by higher capacity for storage and release of elastic energy. Furthermore, our analysis revealed much larger frontal and internal/external rotation joint loads during ostrich running than in humans. Together, these findings support the hypothesis that a primary limb structure specialization linked to economical running in cursorial species is an elevated storage and release of elastic energy in tendon. In the ostrich, energy-saving specializations may also include passive frontal and internal

  4. Molecular mechanisms of Saccharomyces cerevisiae stress adaptation and programmed cell death in response to acetic acid

    PubMed Central

    Giannattasio, Sergio; Guaragnella, Nicoletta; Ždralević, Maša; Marra, Ersilia

    2013-01-01

    Beyond its classical biotechnological applications such as food and beverage production or as a cell factory, the yeast Saccharomyces cerevisiae is a valuable model organism to study fundamental mechanisms of cell response to stressful environmental changes. Acetic acid is a physiological product of yeast fermentation and it is a well-known food preservative due to its antimicrobial action. Acetic acid has recently been shown to cause yeast cell death and aging. Here we shall focus on the molecular mechanisms of S. cerevisiae stress adaptation and programmed cell death in response to acetic acid. We shall elaborate on the intracellular signaling pathways involved in the cross-talk of pro-survival and pro-death pathways underlying the importance of understanding fundamental aspects of yeast cell homeostasis to improve the performance of a given yeast strain in biotechnological applications. PMID:23430312

  5. Molecular mechanisms of Saccharomyces cerevisiae stress adaptation and programmed cell death in response to acetic acid.

    PubMed

    Giannattasio, Sergio; Guaragnella, Nicoletta; Zdralević, Maša; Marra, Ersilia

    2013-01-01

    Beyond its classical biotechnological applications such as food and beverage production or as a cell factory, the yeast Saccharomyces cerevisiae is a valuable model organism to study fundamental mechanisms of cell response to stressful environmental changes. Acetic acid is a physiological product of yeast fermentation and it is a well-known food preservative due to its antimicrobial action. Acetic acid has recently been shown to cause yeast cell death and aging. Here we shall focus on the molecular mechanisms of S. cerevisiae stress adaptation and programmed cell death in response to acetic acid. We shall elaborate on the intracellular signaling pathways involved in the cross-talk of pro-survival and pro-death pathways underlying the importance of understanding fundamental aspects of yeast cell homeostasis to improve the performance of a given yeast strain in biotechnological applications. PMID:23430312

  6. [A mechanism conjugating cellular and individual adaptations could be produced from space biology].

    PubMed

    Atomi, Y

    2001-03-01

    To know a basic mechanism of biological organism on the earth, we can have a standard point to space. An example is hindlimb suspension model that could induce muscle atrophy. This model mimics adaptational changes under zero gravity; in turn the effect of gravity on the biological system developing on the earth. We can understand gravity is a stress from the specific changes of stress protein induced by mechanical stimuli depending on gravity. Recent development of fluorescent microscopy and time-lapse visual system brought us a possibility of analysis to see visualization of dynamic properties of molecular and cellular events in living cells. Especially dynamic fluctuation of cytoskeleton may include new ideas of biological strategy of living organism on the earth and possibly may suggest subtle changes in space. PMID:12101374

  7. Adaptation of Gabor filters for simulation of human preattentive mechanism for a mobile robot

    NASA Astrophysics Data System (ADS)

    Kulkarni, Naren; Naghdy, Golshah A.

    1993-08-01

    Vision guided mobile robot navigation is complex and requires analysis of tremendous amounts of information in real time. In order to simplify the task and reduce the amount of information, human preattentive mechanism can be adapted [Nag90]. During the preattentive search the scene is analyzed rapidly but in sufficient detail for the attention to be focused on the `area of interest.' The `area of interest' can further be scrutinized in more detail for recognition purposes. This `area of interest' can be a text message to facilitate navigation. Gabor filters and an automated turning mechanism are used to isolate the `area of interest.' These regions are subsequently processed with optimal spatial resolution for perception tasks. This method has clear advantages over the global operators in that, after an initial search, it scans each region of interest with optimum resolution. This reduces the volume of information for recognition stages and ensures that no region is over or under estimated.

  8. Poly(ethylene glycol) Hydrogels with Adaptable Mechanical and Degradation Properties for Use in Biomedical Applicationsa

    PubMed Central

    Parlato, Matthew; Reichert, Sarah; Barney, Neal

    2014-01-01

    Requirements of hydrogels for drug delivery, wound dressings, and surgical implantation can be extensive, including suitable mechanical properties and tailorable degradation time frames. Herein, an adaptable PEG-based hydrogel, whose mechanical properties and degradation rate can be systematically adjusted to meet these criteria by altering simple variables such as the PEG molecular weight, is described. The performance of these hydrogels in three physical manipulations (pushing, pulling, and folding), representative of manipulations that they may undergo during typical biomedical use, is also assessed. While not all of these formulations can withstand these manipulations, a subset did, and it is intended to further optimize these formulations for specific clinical applications. Additionally, the outcomes of the physical manipulation tests indicate that simply having a high modulus does not correlate with biomedical applicability. PMID:24949497

  9. Investigating coping strategies and social support among Canadian melanoma patients: A survey approach.

    PubMed

    Kalbfleisch, Melanie; Cyr, Annette; Gregorio, Nancy; Nyhof-Young, Joyce

    2015-01-01

    Complex support needs are involved in coping with a diagnosis of melanoma. The purpose of this study was to determine the perceived social support levels and utilization of adaptive and maladaptive coping strategies by Canadian melanoma patients. The impact of social support level on coping strategy utilization was also examined. Social support and coping strategies were assessed using the Medical Outcomes Study Social Support Survey (MOS-SSS) and the 28-item Brief COPE, respectively. Perceived levels of emotional/informational support were significantly lower than affectionate support and positive social interaction. Acceptance, active coping, and use of emotional support were the most frequently utilized coping strategies. Patients with higher perceived levels of social support had significantly higher adaptive coping scores than patients with lower levels of social support. Health care professionals have an important role in promoting awareness of and access to emotional and informational support resources in order to improve perceived social support levels. PMID:26642495

  10. The Depression Coping Questionnaire.

    ERIC Educational Resources Information Center

    Kleinke, Chris L.

    College students (N=396), chronic pain patients (N=319), and schizophrenic veterans (N=43) completed the Depression Coping Questionnaire (DCQ) and the Beck Depression Inventory (BDI). Factor analysis of the DCQ identified eleven coping responses: social support, problem solving, self-blame/escape, aggression, indulgence, activities, medication,…

  11. Gender Roles and Coping.

    ERIC Educational Resources Information Center

    Patterson, Joan M.; McCubbin, Hamilton I.

    1984-01-01

    Examined the relationship of gender-role orientation and specific behavioral coping responses of wives (N=82) experiencing a long-term separation from their military spouses. Results showed that an androgynous gender-role orientation was significantly associated with four of the five coping patterns identified as helpful to wives managing a…

  12. Influence of background size, luminance and eccentricity on different adaptation mechanisms.

    PubMed

    Gloriani, Alejandro H; Matesanz, Beatriz M; Barrionuevo, Pablo A; Arranz, Isabel; Issolio, Luis; Mar, Santiago; Aparicio, Juan A

    2016-08-01

    Mechanisms of light adaptation have been traditionally explained with reference to psychophysical experimentation. However, the neural substrata involved in those mechanisms remain to be elucidated. Our study analyzed links between psychophysical measurements and retinal physiological evidence with consideration for the phenomena of rod-cone interactions, photon noise, and spatial summation. Threshold test luminances were obtained with steady background fields at mesopic and photopic light levels (i.e., 0.06-110cd/m(2)) for retinal eccentricities from 0° to 15° using three combinations of background/test field sizes (i.e., 10°/2°, 10°/0.45°, and 1°/0.45°). A two-channel Maxwellian view optical system was employed to eliminate pupil effects on the measured thresholds. A model based on visual mechanisms that were described in the literature was optimized to fit the measured luminance thresholds in all experimental conditions. Our results can be described by a combination of visual mechanisms. We determined how spatial summation changed with eccentricity and how subtractive adaptation changed with eccentricity and background field size. According to our model, photon noise plays a significant role to explain contrast detection thresholds measured with the 1/0.45° background/test size combination at mesopic luminances and at off-axis eccentricities. In these conditions, our data reflect the presence of rod-cone interaction for eccentricities between 6° and 9° and luminances between 0.6 and 5cd/m(2). In spite of the increasing noise effects with eccentricity, results also show that the visual system tends to maintain a constant signal-to-noise ratio in the off-axis detection task over the whole mesopic range. PMID:27210038

  13. Marginal adaptation of class V composite restorations submitted to thermal and mechanical cycling

    PubMed Central

    CASSELLI, Denise Sá Maia; FARIA-E-SILVA, André Luis; CASSELLI, Henrique; MARTINS, Luis Roberto Marcondes

    2013-01-01

    Objective: This study evaluated the effect of the margin location and an adhesive system on the marginal adaptation of composite restorations. Material and Methods: Class V cavities were prepared in bovine teeth with the gingival margin on the dentin and the incisal margin on the enamel. The cavities were restored with a micro-hybrid composite resin using an etch-and-rinse [Single Bond 2 (SB)] or a self-etching adhesive [Clearfil SE Bond (CL)]. After finishing and polishing the restorations, epoxy replicas were prepared. The marginal adaptation was analyzed using scanning electronic microscopy (SEM, 500 x magnification). The higher gap width in each margin was recorded (T0). After the first evaluation, the samples were submitted to thermal cycling (2,000 cycles of 5ºC±2ºC followed by 55ºC±2ºC - T1) and mechanical cycling (100,000 cycles of 50 kN and 2 Hz - T2). Replicas of samples were rebuilt after each cycling and analyzed under SEM. The data were submitted to Mann-Whitney, Wilcoxon and Friedman testing (a=0.05). Results: The SB presented higher gaps in the dentin than the enamel, while there was no difference between the substrate for the CL. In the dentin, the CL showed better marginal sealing than the SB. The opposite occurred in the enamel. There were no significant differences between the baseline, thermal and mechanical cycling for any experimental condition. Conclusions: The outcomes of the present study showed that the adhesive system and margin location have an important effect on the marginal adaptation of composite restorations. PMID:23559115

  14. Human monocytes and macrophages differ in their mechanisms of adaptation to hypoxia

    PubMed Central

    2012-01-01

    Introduction Inflammatory arthritis is a progressive disease with chronic inflammation of joints, which is mainly characterized by the infiltration of immune cells and synovial hyperproliferation. Monocytes migrate towards inflamed areas and differentiate into macrophages. In inflamed tissues, much lower oxygen levels (hypoxia) are present in comparison to the peripheral blood. Hence, a metabolic adaptation process must take place. Other studies suggest that Hypoxia Inducible Factor 1-alpha (HIF-1α) may regulate this process, but the mechanism involved for human monocytes is not yet clear. To address this issue, we analyzed the expression and function of HIF-1α in monocytes and macrophages, but also considered alternative pathways involving nuclear factor of kappa light polypeptide gene enhancer in B-cells (NFκB). Methods Isolated human CD14+ monocytes were incubated under normoxia and hypoxia conditions with or without phorbol 12-myristate 13-acetate (PMA) stimulation, respectively. Nuclear and cytosolic fractions were prepared in order to detect HIF-1α and NFκB by immunoblot. For the experiments with macrophages, primary human monocytes were differentiated into human monocyte derived macrophages (hMDM) using human macrophage colony-stimulating factor (hM-CSF). The effects of normoxia and hypoxia on gene expression were compared between monocytes and hMDMs using quantitative PCR (quantitative polymerase chain reaction). Results We demonstrate, using primary human monocytes and hMDM, that the localization of transcription factor HIF-1α during the differentiation process is shifted from the cytosol (in monocytes) into the nucleus (in macrophages), apparently as an adaptation to a low oxygen environment. For this localization change, protein kinase C alpha/beta 1 (PKC-α/β1 ) plays an important role. In monocytes, it is NFκB1, and not HIF-1α, which is of central importance for the expression of hypoxia-adjusted genes. Conclusions These data demonstrate that

  15. A Dopamine- and Protein Kinase A-Dependent Mechanism for Network Adaptation in Retinal Ganglion Cells

    PubMed Central

    Vaquero, C. F.; Pignatelli, A.; Partida, G. J.; Ishida, A. T.

    2011-01-01

    Vertebrates can detect light intensity changes in vastly different photic environments, in part, because post-receptoral neurons undergo “network adaptation”. Previous data implicated dopaminergic, cAMP-dependent inhibition of retinal ganglion cells in this process, yet left unclear how this occurs, and whether this occurs in darkness versus light. To test for light- and dopamine-dependent changes in ganglion cell cAMP levels in situ, we immunostained dark- and light-adapted retinas with anti-cAMP antisera, in the presence and absence of various dopamine receptor ligands. To test for direct effects of dopamine receptor ligands and membrane-permeable protein kinase ligands on ganglion cell excitability, we recorded spikes from isolated ganglion cells in perforated-patch whole-cell mode, before and during application of these agents by microperfusion. Our immunostainings show that light, endogenous dopamine, and exogenous dopamine elevate ganglion cell cAMP levels in situ by activating D1-type dopamine receptors. Our spike recordings show that D1-type agonists and 8-bromo cAMP reduce spike frequency and curtail sustained spike firing, and that these effects entail protein kinase A activation. These effects resemble those of background light on ganglion cell responses to light flashes. Network adaptation could thus be produced, to some extent, by dopaminergic modulation of ganglion cell spike generation, a mechanism distinct from modulation of transmitter release onto ganglion cells or of transmitter-gated currents in ganglion cells. Combining these observations, with results obtained in studies of photoreceptor, bipolar, and horizontal cells, indicates that all three layers of neurons in the retina are equipped with mechanisms for adaptation to ambient light. PMID:11606650

  16. Identifying core features of adaptive metabolic mechanisms for chronic heat stress attenuation contributing to systems robustness.

    PubMed

    Gu, Jenny; Weber, Katrin; Klemp, Elisabeth; Winters, Gidon; Franssen, Susanne U; Wienpahl, Isabell; Huylmans, Ann-Kathrin; Zecher, Karsten; Reusch, Thorsten B H; Bornberg-Bauer, Erich; Weber, Andreas P M

    2012-05-01

    The contribution of metabolism to heat stress may play a significant role in defining robustness and recovery of systems; either by providing the energy and metabolites required for cellular homeostasis, or through the generation of protective osmolytes. However, the mechanisms by which heat stress attenuation could be adapted through metabolic processes as a stabilizing strategy against thermal stress are still largely unclear. We address this issue through metabolomic and transcriptomic profiles for populations along a thermal cline where two seagrass species, Zostera marina and Zostera noltii, were found in close proximity. Significant changes captured by these profile comparisons could be detected, with a larger response magnitude observed in northern populations to heat stress. Sucrose, fructose, and myo-inositol were identified to be the most responsive of the 29 analyzed organic metabolites. Many key enzymes in the Calvin cycle, glycolysis and pentose phosphate pathways also showed significant differential expression. The reported comparison suggests that adaptive mechanisms are involved through metabolic pathways to dampen the impacts of heat stress, and interactions between the metabolome and proteome should be further investigated in systems biology to understand robust design features against abiotic stress. PMID:22402787

  17. [PROTEOMIC ANALYSIS OF ADAPTIVE MECHANISMS TO SALINITY STRESS IN MARINE GASTROPODS LITTORINA SAXATILIS].

    PubMed

    Muraeva, O A; Maltseva, A L; Mikhailova, N A; Granovitch, A I

    2015-01-01

    Salinity is one of the most important abiotic environmental factors affecting marine animals. If salinity deviate from optimum, adaptive mechanisms switch on to maintain organism's physiological activity. In this study, the reaction of the snails Littorina saxatilis from natural habitats and in response to experimental salinity decreasing was analyzed on proteomic level. The isolation of all snails inside their shells and gradually declining mortality was observed under acute experimental salinity decrease (down to 10 per hundred). Proteomic changes were evaluated in the surviving experimental mollusks compared to control individual using differential 2D gel-electrophoresis (DIGE) and subsequent LC-MS/MS-identification of proteins. Approximately 10% of analyzed proteins underwent up- or down regulation during the experiment. Proteins of folding, antioxidant response, intercellular matrix, cell adhesion, cell signaling and metabolic enzymes were identified among them. Proteome changes observed in experimental hypoosmotic stress partially reproduced in the proteomes of mollusks that live in conditions of natural freshening (estuaries). Possible mechanisms involved in the adaptation process of L. saxatilis individuals to hypo-osmotic stress are discussed. PMID:26995971

  18. Coping profiles characterize individual flourishing, languishing, and depression.

    PubMed

    Faulk, Kathryn E; Gloria, Christian T; Steinhardt, Mary A

    2013-01-01

    According to the broaden-and-build theory of positive emotions, negative emotions narrow one's thought-action repertoire. In contrast, positive emotions have a broadening effect, expanding cognitive capacity, increasing potential coping strategies that come to mind, and enhancing decision-making, reaction, and adaptation to adversity. Fredrickson and Losada determined that a positivity ratio - the ratio of experienced positive to negative emotions - at or above 2.9 promotes human flourishing. A ratio below 2.9 is indicative of languishing individuals, whereas a ratio below 1.0 is a marker of depression. This study examined whether adaptive and maladaptive coping profiles differentiated those who flourish, languish, or are depressed in two convenience samples - military spouses (n =367) and public school teachers (n=267). Results were consistent with the theoretical predictions, as coping profiles of the groups differed significantly, with flourishing individuals favoring adaptive coping strategies more than those who were languishing or depressed. Conversely, depressed individuals reported greater use of maladaptive coping strategies than those who were languishing or flourishing. These results provide further empirical support for the mathematical model of Fredrickson and Losada, as the set of positivity criteria were predictive of coping profiles in two samples where successful coping and adaptation are important. PMID:22853921

  19. Acclimation of leaf cohorts expanded under light and water stresses: an adaptive mechanism of Eucryphia cordifolia to face changes in climatic conditions?

    PubMed

    Morales, Loreto V; Coopman, Rafael E; Rojas, Roke; Escandón, Antonio B; Flexas, Jaume; Galmés, Jeroni; García-Plazaola, José I; Gago, Jorge; Cabrera, Hernán M; Corcuera, Luis J

    2014-12-01

    Eucryphia cordifolia Cav. is a long-lived evergreen tree species, commonly found as a canopy emergent tree in the Chilean temperate rain forest. This species displays successive leaf cohorts throughout the entire growing season. Thus, full leaf expansion occurs under different environmental conditions during growing such as air temperature, vapor pressure deficit and the progress of moderate water stress (WS). These climate variations can be reflected as differences in anatomical and physiological characteristics among leaf cohorts. Thus, we investigated the potential adaptive role of different co-existing leaf cohorts in seedlings grown under shade, drought stress or a combination of the two. Photosynthetic and anatomical traits were measured in the first displayed leaf cohort and in a subsequent leaf cohort generated during the mid-season. Although most anatomical and photosynthetic pigments did not vary between cohorts, photosynthetic acclimation did occur in the leaf cohort and was mainly driven by biochemical processes such as leaf nitrogen content, Rubisco carboxylation capacity and maximal Photosystem II electron transport rather than CO2 diffusion conductance. Cohort acclimation could be relevant in the context of climate change, as this temperate rainforest will likely face some degree of summer WS even under low light conditions. We suggest that the acclimation of the photosynthetic capacity among current leaf cohorts represents a well-tuned mechanism helping E. cordifolia seedlings to face a single stress like shade or drought stress, but is insufficient to cope with simultaneous stresses. PMID:25398632

  20. Nonreligious coping and religious coping as predictors of expressed emotion in relatives of patients with schizophrenia

    PubMed Central

    Wasserman, Stephanie; Weisman, Amy; Suro, Giulia

    2012-01-01

    Expressed emotion (EE) is a measure of the amount of criticism and emotional over involvement expressed by a key relative towards a relative with a disorder or illness (Hooley, 2007). Research has established that living in a high EE environment, which is characterized by increased levels of critical and emotionally exaggerated communication, leads to a poorer prognosis for patients with a mental illness when compared to low EE environments. Despite evidence that EE is a strong predictor of course of illness, there continue to be questions concerning why some family members express excessive levels of high EE attitudes about their mentally ill relatives while others do not. Based on indirect evidence from previous research, the current study tested whether religious and nonreligious coping serve as predictors of EE. A sample of 72 family members of patients with schizophrenia completed an EE interview, along with questionnaires assessing situational nonreligious coping and religious coping. In line with hypotheses, results indicated that nonreligious coping predicted EE. Specifically, less use of adaptive emotion-focused coping predicted high EE. Also consistent with predictions, maladaptive religious coping predicted high EE above and beyond nonreligious coping. PMID:23393424

  1. A comparative study of marginal fit of copings prepared with various techniques on different implant abutments.

    PubMed

    Koç, Esra; Öngül, Değer; Şermet, Bülent

    2016-01-01

    This study evaluated fabrication techniques of recently introduced all-ceramic copings' marginal adaptation on two different implant abutments with different finish lines. Five different copings were prepared (Casted chrome-cobalt metal coping, Zirkonzahn, Cercon, In Ceram Alumina and IPS e.max Press) on two cementable implant abutments with two marginal designs. Ten samples for each coping group were prepared (totally 100 samples). Copings were cemented to implant abutments and marginal gap measurements were done from 24 points with stereomicroscope and the datas were analyzed by the Kruskal-Wallis test before cementation. Cercon copings showed the lowest marginal fit scores and metal copings showed the highest scores. After cementation, all marginal gap values have been increased. All marginal gap values obtained from crown copings can be considered in clinically acceptable limits (<120 µm) except metal copings after cementation on abutment with 135 degrees shoulder group (123 µm). PMID:27252001

  2. Controversies Regarding the Psychometric Properties of the Brief COPE: The Case of the Brazilian-Portuguese Version “COPE Breve”

    PubMed Central

    Orsini, Mara R. C. A.; Bartholomeu, Daniel; Montiel, José M.

    2016-01-01

    The Brief Coping Orientation to Problems Experienced (COPE) inventory investigates the different ways in which people respond to stressful situations. Knowledge is lacking regarding the coping strategies and styles of people in developing countries, including Brazil. This study aimed to adapt and validate the Brief COPE to Brazilian Portuguese (named COPE Breve) by focusing on dispositional coping. For the cross-cultural adaptation, the original Brief COPE in English (28 items grouped into 14 subscales) was adapted according to a universalistic approach, following these steps: translation, synthesis, back-translation, analysis by an expert panel, and pretest with 30 participants. Then, 237 adults from the community health service responded to the COPE Breve. Psychometric analyses included reliability and exploratory factor analysis. Most of the 14 subscales from the original Brief COPE exhibited problems related to internal consistency. A Velicer's minimum average partial test (MAP) was performed and pointed out 3 factors. Exploratory factor analysis produced a revised 20-item version with a 3-factor solution: religion and positive reframing, distraction and external support. The psychometric properties of the COPE Breve with three factors were appropriate. Limitations of this study as well as suggestions for future studies are presented. The COPE Breve should be used in Brazilian clinics and investigations, but divergences in its psychometrics should be further explored in other contexts. PMID:27007646

  3. Mechanically adaptive intracortical implants improve the proximity of neuronal cell bodies

    NASA Astrophysics Data System (ADS)

    Harris, J. P.; Capadona, J. R.; Miller, R. H.; Healy, B. C.; Shanmuganathan, K.; Rowan, S. J.; Weder, C.; Tyler, D. J.

    2011-10-01

    The hypothesis is that the mechanical mismatch between brain tissue and microelectrodes influences the inflammatory response. Our unique, mechanically adaptive polymer nanocomposite enabled this study within the cerebral cortex of rats. The initial tensile storage modulus of 5 GPa decreases to 12 MPa within 15 min under physiological conditions. The response to the nanocomposite was compared to surface-matched, stiffer implants of traditional wires (411 GPa) coated with the identical polymer substrate and implanted on the contralateral side. Both implants were tethered. Fluorescent immunohistochemistry labeling examined neurons, intermediate filaments, macrophages, microglia and proteoglycans. We demonstrate, for the first time, a system that decouples the mechanical and surface chemistry components of the neural response. The neuronal nuclei density within 100 µm of the device at four weeks post-implantation was greater for the compliant nanocomposite compared to the stiff wire. At eight weeks post-implantation, the neuronal nuclei density around the nanocomposite was maintained, but the density around the wire recovered to match that of the nanocomposite. The glial scar response to the compliant nanocomposite was less vigorous than it was to the stiffer wire. The results suggest that mechanically associated factors such as proteoglycans and intermediate filaments are important modulators of the response of the compliant nanocomposite.

  4. Ectomycorrhizal fungi decompose soil organic matter using oxidative mechanisms adapted from saprotrophic ancestors.

    PubMed

    Shah, Firoz; Nicolás, César; Bentzer, Johan; Ellström, Magnus; Smits, Mark; Rineau, Francois; Canbäck, Björn; Floudas, Dimitrios; Carleer, Robert; Lackner, Gerald; Braesel, Jana; Hoffmeister, Dirk; Henrissat, Bernard; Ahrén, Dag; Johansson, Tomas; Hibbett, David S; Martin, Francis; Persson, Per; Tunlid, Anders

    2016-03-01

    Ectomycorrhizal fungi are thought to have a key role in mobilizing organic nitrogen that is trapped in soil organic matter (SOM). However, the extent to which ectomycorrhizal fungi decompose SOM and the mechanism by which they do so remain unclear, considering that they have lost many genes encoding lignocellulose-degrading enzymes that are present in their saprotrophic ancestors. Spectroscopic analyses and transcriptome profiling were used to examine the mechanisms by which five species of ectomycorrhizal fungi, representing at least four origins of symbiosis, decompose SOM extracted from forest soils. In the presence of glucose and when acquiring nitrogen, all species converted the organic matter in the SOM extract using oxidative mechanisms. The transcriptome expressed during oxidative decomposition has diverged over evolutionary time. Each species expressed a different set of transcripts encoding proteins associated with oxidation of lignocellulose by saprotrophic fungi. The decomposition 'toolbox' has diverged through differences in the regulation of orthologous genes, the formation of new genes by gene duplications, and the recruitment of genes from diverse but functionally similar enzyme families. The capacity to oxidize SOM appears to be common among ectomycorrhizal fungi. We propose that the ancestral decay mechanisms used primarily to obtain carbon have been adapted in symbiosis to scavenge nutrients instead. PMID:26527297

  5. Adaptedness and coping in dysphagic students.

    PubMed

    Gustafsson, B; Theorell, T

    1995-01-01

    Using a definition based on Bowlby and Pörn, an effort is made to interpret adaptedness and coping in 87 dysphagic students (corresponding to a prevalence of dysphagia in 9% of the boys and 12% of the girls) found in a screening study utilizing a questionnaire. Coping patterns and methods of adaptation were explored in a telephone interview with dysphagic students. Those who stated that their dysphagia influenced their daily living were classified as subjectively maladapted (S-maladapted; n = 9). Compared with the S-adapted students, the S-maladapted students reported more defects in ability to eat, more inappropriate beliefs about the causes and management of dysphagia, and greater desires regarding eating than S-adapted students (p < 0.05). The environmental conditions more often impaired the eating ability in S-maladapted students (p < 0.05). Anxiety at mealtime was reported more frequently than in S-adapted students (p < 0.05). Every second S-maladapted student had reduced self-esteem because of dysphagia (p < 0.05). The S-maladapted students had talked about their dysphagia with parents and/or friends and visited a school physician because of dysphagia more often than S-adapted students (p < 0.05). Two of 9 students felt confirmed by the physician and experienced help. There was concordance between the students' own beliefs regarding the causes of dysphagia and corresponding coping strategy. PMID:7600858

  6. Influence of resveratrol release on the tissue response to mechanically adaptive cortical implants.

    PubMed

    Nguyen, Jessica K; Jorfi, Mehdi; Buchanan, Kelly L; Park, Daniel J; Foster, E Johan; Tyler, Dustin J; Rowan, Stuart J; Weder, Christoph; Capadona, Jeffrey R

    2016-01-01

    The stability and longevity of recordings obtained from intracortical microelectrodes continues to remain an area of concern for neural interfacing applications. The limited longevity of microelectrode performance has been associated with the integrity of the blood brain barrier (BBB) and the neuroinflammatory response to the microelectrode. Here, we report the investigation of an additive approach that targets both mechanical and chemical factors believed to contribute to chronic BBB instability and the neuroinflammatory response associated with implanted intracortical microelectrodes. The implants investigated were based on a mechanically adaptive, compliant nanocomposite (NC), which reduces the tissue response and tissue strain. This material was doped with various concentrations of the antioxidant resveratrol with the objective of local and rapid delivery. In vitro analysis of resveratrol release, antioxidant activity, and cytotoxicity suggested that a resveratrol content of 0.01% was optimal for in vivo assessment. Thus, probes made from the neat NC reference and probes containing resveratrol (NC Res) were implanted into the cortical tissue of rats for up to sixteen weeks. Histochemical analysis suggested that at three days post-implantation, neither materials nor therapeutic approaches (independently or in combination) could alter the initial wound healing response. However, at two weeks post-implantation, the NC Res implant showed a reduction in activated microglia/macrophages and improvement in neuron density at the tissue-implant interface when compared to the neat NC reference. However, sixteen weeks post-implantation, when the antioxidant was exhausted, NC Res and the neat NC reference exhibited similar tissue responses. The data show that NC Res provides short-term, short-lived benefits due to the antioxidant release, and a long-term reduction in neuroinflammation on account of is mechanical adaptive, compliant nature. Together, these results

  7. Molecular Mechanisms Mediating the Adaptive Regulation of Intestinal Riboflavin Uptake Process

    PubMed Central

    Subramanian, Veedamali S.; Ghosal, Abhisek; Kapadia, Rubina; Nabokina, Svetlana M.; Said, Hamid M.

    2015-01-01

    The intestinal absorption process of vitamin B2 (riboflavin, RF) is carrier-mediated, and all three known human RF transporters, i.e., hRFVT-1, -2, and -3 (products of the SLC52A1, 2 & 3 genes, respectively) are expressed in the gut. We have previously shown that the intestinal RF uptake process is adaptively regulated by substrate level, but little is known about the molecular mechanism(s) involved. Using human intestinal epithelial NCM460 cells maintained under RF deficient and over-supplemented (OS) conditions, we now show that the induction in RF uptake in RF deficiency is associated with an increase in expression of the hRFVT-2 & -3 (but not hRFVT-1) at the protein and mRNA levels. Focusing on hRFVT-3, the predominant transporter in the intestine, we also observed an increase in the level of expression of its hnRNA and activity of its promoter in the RF deficiency state. An increase in the level of expression of the nuclear factor Sp1 (which is important for activity of the SLC52A3 promoter) was observed in RF deficiency, while mutating the Sp1/GC site in the SLC52A3 promoter drastically decreased the level of induction in SLC52A3 promoter activity in RF deficiency. We also observed specific epigenetic changes in the SLC52A3 promoter in RF deficiency. Finally, an increase in hRFVT-3 protein expression at the cell surface was observed in RF deficiency. Results of these investigations show, for the first time, that transcriptional and post-transcriptional mechanisms are involved in the adaptive regulation of intestinal RF uptake by the prevailing substrate level. PMID:26121134

  8. How Older Female Spouses Cope with Partners' Coronary Artery Bypass Graft Surgery

    PubMed Central

    Marnocha, Suzanne; Marnocha, Mark

    2013-01-01

    This research sought to better understand how older female spouses cope with a partner's coronary artery bypass graft surgery and to explore coping's relationships with life-change stress, cognitive appraisal, resilience, social support, and aspects of spouse's surgery. A sample of 96 women, aged from 55 to 81 years, completed surveys after their partner's surgery. Folkman and Lazarus' ways of coping (WCQ) scales yielded two factors in this sample—reactive coping and adaptive coping. Reactive coping, including more emotion-focused ways of coping from the WCQ, was associated only with more time spent anticipating spouses' surgeries. Women described the greatest use of ways of coping labeled adaptive, which in turn had significant relationships with greater resilience, social support, and positive appraisal of the surgical experience. Stepwise multiple regression found greater resilience, more frequent religious participation, and fewer children to be distinct predictors of adaptive coping. Nursing staff are encouraged to accept and normalize reactive coping, while facilitating adaptive coping with surgical stresses. PMID:23634299

  9. Mechanisms Underlying Adaptation to Life in Hydrogen Sulfide-Rich Environments.

    PubMed

    Kelley, Joanna L; Arias-Rodriguez, Lenin; Patacsil Martin, Dorrelyn; Yee, Muh-Ching; Bustamante, Carlos D; Tobler, Michael

    2016-06-01

    Hydrogen sulfide (H2S) is a potent toxicant interfering with oxidative phosphorylation in mitochondria and creating extreme environmental conditions in aquatic ecosystems. The mechanistic basis of adaptation to perpetual exposure to H2S remains poorly understood. We investigated evolutionarily independent lineages of livebearing fishes that have colonized and adapted to springs rich in H2S and compared their genome-wide gene expression patterns with closely related lineages from adjacent, nonsulfidic streams. Significant differences in gene expression were uncovered between all sulfidic and nonsulfidic population pairs. Variation in the number of differentially expressed genes among population pairs corresponded to differences in divergence times and rates of gene flow, which is consistent with neutral drift driving a substantial portion of gene expression variation among populations. Accordingly, there was little evidence for convergent evolution shaping large-scale gene expression patterns among independent sulfide spring populations. Nonetheless, we identified a small number of genes that was consistently differentially expressed in the same direction in all sulfidic and nonsulfidic population pairs. Functional annotation of shared differentially expressed genes indicated upregulation of genes associated with enzymatic H2S detoxification and transport of oxidized sulfur species, oxidative phosphorylation, energy metabolism, and pathways involved in responses to oxidative stress. Overall, our results suggest that modification of processes associated with H2S detoxification and toxicity likely complement each other to mediate elevated H2S tolerance in sulfide spring fishes. Our analyses allow for the development of novel hypotheses about biochemical and physiological mechanisms of adaptation to extreme environments. PMID:26861137

  10. Mechanisms Underlying Adaptation to Life in Hydrogen Sulfide–Rich Environments

    PubMed Central

    Kelley, Joanna L.; Arias-Rodriguez, Lenin; Patacsil Martin, Dorrelyn; Yee, Muh-Ching; Bustamante, Carlos D.; Tobler, Michael

    2016-01-01

    Hydrogen sulfide (H2S) is a potent toxicant interfering with oxidative phosphorylation in mitochondria and creating extreme environmental conditions in aquatic ecosystems. The mechanistic basis of adaptation to perpetual exposure to H2S remains poorly understood. We investigated evolutionarily independent lineages of livebearing fishes that have colonized and adapted to springs rich in H2S and compared their genome-wide gene expression patterns with closely related lineages from adjacent, nonsulfidic streams. Significant differences in gene expression were uncovered between all sulfidic and nonsulfidic population pairs. Variation in the number of differentially expressed genes among population pairs corresponded to differences in divergence times and rates of gene flow, which is consistent with neutral drift driving a substantial portion of gene expression variation among populations. Accordingly, there was little evidence for convergent evolution shaping large-scale gene expression patterns among independent sulfide spring populations. Nonetheless, we identified a small number of genes that was consistently differentially expressed in the same direction in all sulfidic and nonsulfidic population pairs. Functional annotation of shared differentially expressed genes indicated upregulation of genes associated with enzymatic H2S detoxification and transport of oxidized sulfur species, oxidative phosphorylation, energy metabolism, and pathways involved in responses to oxidative stress. Overall, our results suggest that modification of processes associated with H2S detoxification and toxicity likely complement each other to mediate elevated H2S tolerance in sulfide spring fishes. Our analyses allow for the development of novel hypotheses about biochemical and physiological mechanisms of adaptation to extreme environments. PMID:26861137

  11. Interrelatedness of Proactive Coping, Reactive Coping, and Learned Resourcefulness

    ERIC Educational Resources Information Center

    Moring, John; Fuhrman, Robert; Zauszniewski, Jaclene A.

    2011-01-01

    Research has identified that coping strategies used by individuals depend on temporal locations of stressors. Dispositional attributes are also identified as predictors of coping. The current study identified commonalities of proactive coping, reactive coping, and learned resourcefulness measures. The analysis yielded three factors reflective of…

  12. Indirect adaptive output feedback control of a biorobotic AUV using pectoral-like mechanical fins.

    PubMed

    Naik, Mugdha S; Singh, Sahjendra N; Mittal, Rajat

    2009-06-01

    This paper treats the question of servoregulation of autonomous underwater vehicles (AUVs) in the yaw plane using pectoral-like mechanical fins. The fins attached to the vehicle have oscillatory swaying and yawing motion. The bias angle of the angular motion of the fin is used for the purpose of control. Of course, the design approach considered here is applicable to AUVs for other choices of oscillation patterns of the fins, which produce periodic forces and moments. It is assumed that the vehicle parameters, hydrodynamic coefficients, as well the fin forces and moments are unknown. For the trajectory control of the yaw angle, a sampled-data indirect adaptive control system using output (yaw angle) feedback is derived. The control system has a modular structure, which includes a parameter identifier and a stabilizer. For the control law derivation, an internal model of the exosignals (reference signal (constant or ramp) and constant disturbance) is included. Unlike the direct adaptive control scheme, the derived control law is applicable to minimum as well as nonminimum phase biorobotic AUVs (BAUVs). This is important, because for most of the fin locations on the vehicle, the model is a nonminimum phase. In the closed-loop system, the yaw angle trajectory tracking error converges to zero and the remaining state variables remain bounded. Simulation results are presented which show that the derived modular control system accomplishes precise set point yaw angle control and turning maneuvers in spite of the uncertainties in the system parameters using only yaw angle feedback. PMID:19276512

  13. Integrated physiological mechanisms of exercise performance, adaptation, and maladaptation to heat stress.

    PubMed

    Sawka, Michael N; Leon, Lisa R; Montain, Scott J; Sonna, Larry A

    2011-10-01

    This article emphasizes significant recent advances regarding heat stress and its impact on exercise performance, adaptations, fluid electrolyte imbalances, and pathophysiology. During exercise-heat stress, the physiological burden of supporting high skin blood flow and high sweating rates can impose considerable cardiovascular strain and initiate a cascade of pathophysiological events leading to heat stroke. We examine the association between heat stress, particularly high skin temperature, on diminishing cardiovascular/aerobic reserves as well as increasing relative intensity and perceptual cues that degrade aerobic exercise performance. We discuss novel systemic (heat acclimation) and cellular (acquired thermal tolerance) adaptations that improve performance in hot and temperate environments and protect organs from heat stroke as well as other dissimilar stresses. We delineate how heat stroke evolves from gut underperfusion/ischemia causing endotoxin release or the release of mitochondrial DNA fragments in response to cell necrosis, to mediate a systemic inflammatory syndrome inducing coagulopathies, immune dysfunction, cytokine modulation, and multiorgan damage and failure. We discuss how an inflammatory response that induces simultaneous fever and/or prior exposure to a pathogen (e.g., viral infection) that deactivates molecular protective mechanisms interacts synergistically with the hyperthermia of exercise to perhaps explain heat stroke cases reported in low-risk populations performing routine activities. Importantly, we question the "traditional" notion that high core temperature is the critical mediator of exercise performance degradation and heat stroke. Published 2011. This article is a U.S. Government work and is in the public domain in the USA. PMID:23733692

  14. An Adaptive Jitter Mechanism for Reactive Route Discovery in Sensor Networks

    PubMed Central

    Cordero, Juan Antonio; Yi, Jiazi; Clausen, Thomas

    2014-01-01

    This paper analyses the impact of jitter when applied to route discovery in reactive (on-demand) routing protocols. In multi-hop non-synchronized wireless networks, jitter—a small, random variation in the timing of message emission—is commonly employed, as a means to avoid collisions of simultaneous transmissions by adjacent routers over the same channel. In a reactive routing protocol for sensor and ad hoc networks, jitter is recommended during the route discovery process, specifically, during the network-wide flooding of route request messages, in order to avoid collisions. Commonly, a simple uniform jitter is recommended. Alas, this is not without drawbacks: when applying uniform jitter to the route discovery process, an effect called delay inversion is observed. This paper, first, studies and quantifies this delay inversion effect. Second, this paper proposes an adaptive jitter mechanism, designed to alleviate the delay inversion effect and thereby to reduce the route discovery overhead and (ultimately) allow the routing protocol to find more optimal paths, as compared to uniform jitter. This paper presents both analytical and simulation studies, showing that the proposed adaptive jitter can effectively decrease the cost of route discovery and increase the path quality. PMID:25111238

  15. Integrity of the osteocyte bone cell network in osteoporotic fracture: Implications for mechanical load adaptation

    NASA Astrophysics Data System (ADS)

    Kuliwaba, J. S.; Truong, L.; Codrington, J. D.; Fazzalari, N. L.

    2010-06-01

    The human skeleton has the ability to modify its material composition and structure to accommodate loads through adaptive modelling and remodelling. The osteocyte cell network is now considered to be central to the regulation of skeletal homeostasis; however, very little is known of the integrity of the osteocyte cell network in osteoporotic fragility fracture. This study was designed to characterise osteocyte morphology, the extent of osteocyte cell apoptosis and expression of sclerostin protein (a negative regulator of bone formation) in trabecular bone from the intertrochanteric region of the proximal femur, for postmenopausal women with fragility hip fracture compared to age-matched women who had not sustained fragility fracture. Osteocyte morphology (osteocyte, empty lacunar, and total lacunar densities) and the degree of osteocyte apoptosis (percent caspase-3 positive osteocyte lacunae) were similar between the fracture patients and non-fracture women. The fragility hip fracture patients had a lower proportion of sclerostin-positive osteocyte lacunae in comparison to sclerostin-negative osteocyte lacunae, in contrast to similar percent sclerostin-positive/sclerostin-negative lacunae for non-fracture women. The unexpected finding of decreased sclerostin expression in trabecular bone osteocytes from fracture cases may be indicative of elevated bone turnover and under-mineralisation, characteristic of postmenopausal osteoporosis. Further, altered osteocytic expression of sclerostin may be involved in the mechano-responsiveness of bone. Optimal function of the osteocyte cell network is likely to be a critical determinant of bone strength, acting via mechanical load adaptation, and thus contributing to osteoporotic fracture risk.

  16. An adaptive jitter mechanism for reactive route discovery in sensor networks.

    PubMed

    Cordero, Juan Antonio; Yi, Jiazi; Clausen, Thomas

    2014-01-01

    This paper analyses the impact of jitter when applied to route discovery in reactive (on-demand) routing protocols. In multi-hop non-synchronized wireless networks, jitter--a small, random variation in the timing of message emission--is commonly employed, as a means to avoid collisions of simultaneous transmissions by adjacent routers over the same channel. In a reactive routing protocol for sensor and ad hoc networks, jitter is recommended during the route discovery process, specifically, during the network-wide flooding of route request messages, in order to avoid collisions. Commonly, a simple uniform jitter is recommended. Alas, this is not without drawbacks: when applying uniform jitter to the route discovery process, an effect called delay inversion is observed. This paper, first, studies and quantifies this delay inversion effect. Second, this paper proposes an adaptive jitter mechanism, designed to alleviate the delay inversion effect and thereby to reduce the route discovery overhead and (ultimately) allow the routing protocol to find more optimal paths, as compared to uniform jitter. This paper presents both analytical and simulation studies, showing that the proposed adaptive jitter can effectively decrease the cost of route discovery and increase the path quality. PMID:25111238

  17. Differential gene retention as an evolutionary mechanism to generate biodiversity and adaptation in yeasts

    PubMed Central

    Morel, Guillaume; Sterck, Lieven; Swennen, Dominique; Marcet-Houben, Marina; Onesime, Djamila; Levasseur, Anthony; Jacques, Noémie; Mallet, Sandrine; Couloux, Arnaux; Labadie, Karine; Amselem, Joëlle; Beckerich, Jean-Marie; Henrissat, Bernard; Van de Peer, Yves; Wincker, Patrick; Souciet, Jean-Luc; Gabaldón, Toni; Tinsley, Colin R.; Casaregola, Serge

    2015-01-01

    The evolutionary history of the characters underlying the adaptation of microorganisms to food and biotechnological uses is poorly understood. We undertook comparative genomics to investigate evolutionary relationships of the dairy yeast Geotrichum candidum within Saccharomycotina. Surprisingly, a remarkable proportion of genes showed discordant phylogenies, clustering with the filamentous fungus subphylum (Pezizomycotina), rather than the yeast subphylum (Saccharomycotina), of the Ascomycota. These genes appear not to be the result of Horizontal Gene Transfer (HGT), but to have been specifically retained by G. candidum after the filamentous fungi–yeasts split concomitant with the yeasts’ genome contraction. We refer to these genes as SRAGs (Specifically Retained Ancestral Genes), having been lost by all or nearly all other yeasts, and thus contributing to the phenotypic specificity of lineages. SRAG functions include lipases consistent with a role in cheese making and novel endoglucanases associated with degradation of plant material. Similar gene retention was observed in three other distantly related yeasts representative of this ecologically diverse subphylum. The phenomenon thus appears to be widespread in the Saccharomycotina and argues that, alongside neo-functionalization following gene duplication and HGT, specific gene retention must be recognized as an important mechanism for generation of biodiversity and adaptation in yeasts. PMID:26108467

  18. Local adaptation: Mechanical fit between floral ecotypes of Nerine humilis (Amaryllidaceae) and pollinator communities.

    PubMed

    Newman, Ethan; Manning, John; Anderson, Bruce

    2015-09-01

    Geographic variation in floral morphology is often assumed to reflect geographic variation in pollinator communities and associated divergence in selective pressures. We studied populations of Nerine humilis (Amaryllidaceae) to assess whether geographic variation in floral form is the result of local adaptation to different pollinator communities. We first tested for associations between floral traits and visitor communities, and found that populations with similar floral morphologies were visited by similar insect communities. Mean style length in each population was also closely associated with the mean body length of the local visitor community. A reciprocal translocation experiment demonstrated that native phenotypes set more seed than translocated phenotypes. Single visitation experiments showed that native flowers received more pollen, and set more seed per visit, than introduced phenotypes in both populations. This suggests that the effectiveness of pollinator visits is determined by the degree of mechanical fit between flowers and visitors. We provide strong evidence that the observed among-population variation in floral traits is an adaptive response to geographic variation in the pollinator community. PMID:26194119

  19. CHANNEL MODULATION AND THE MECHANISM OF LIGHT ADAPTATION IN MOUSE RODS

    PubMed Central

    Chen, Jeannie; Woodruff, Michael L.; Wang, Tian; Concepcion, Francis A.; Tranchina, Daniel; Fain, Gordon L.

    2010-01-01

    Vertebrate photoreceptors are thought to adapt to light by a change in Ca2+, which is postulated to mediate modulation of (1) excited rhodopsin (Rh*) by Ca2+-dependent binding of recoverin, (2) guanylyl cyclase activity via Ca2+-dependent GCAP proteins, and (3) cyclic nucleotide-gated channels by binding of Ca2+-calmodulin. Previous experiments genetically deleted recoverin and the GCAPs and showed that significant regulation of sensitivity survives removal of (1) and (2). We genetically deleted the channel Ca2+-calmodulin binding site in the mouse Mus musculus and find that removal of (3) alters response waveform, but removal of (3) or of (2) and (3) together still leaves much of adaptation intact. These experiments demonstrate that an important additional mechanism is required, which other experiments indicate may be regulation of phosphodiesterase (PDE6). We therefore constructed a kinetic model in which light produces a Ca2+-mediated decrease in PDE6 decay rate, with the novel feature that both spontaneously activated and light-activated PDE6 are modulated. This model together with Ca2+-dependent acceleration of guanylyl cyclase can successfully account for changes in sensitivity and response waveform in background light. PMID:21123569

  20. Mechanisms of adaptation to chronic respiratory acidosis in the rabbit proximal tubule.

    PubMed Central

    Krapf, R

    1989-01-01

    The hyperbicarbonatemia of chronic respiratory acidosis is maintained by enhanced bicarbonate reabsorption in the proximal tubule. To investigate the cellular mechanisms involved in this adaptation, cell and luminal pH were measured microfluorometrically using (2",7')-bis(carboxyethyl)-(5,6)-carboxyfluorescein in isolated, microperfused S2 proximal convoluted tubules from control and acidotic rabbits. Chronic respiratory acidosis was induced by exposure to 10% CO2 for 52-56 h. Tubules from acidotic rabbits had a significantly lower luminal pH after 1-mm perfused length (7.03 +/- 0.09 vs. 7.26 +/- 0.06 in controls, perfusion rate = 10 nl/min). Chronic respiratory acidosis increased the initial rate of cell acidification (dpHi/dt) in response to luminal sodium removal by 63% and in response to lowering luminal pH (7.4-6.8) by 69%. Chronic respiratory acidosis also increased dpHi/dt in response to peritubular sodium removal by 63% and in response to lowering peritubular pH by 73%. In conclusion, chronic respiratory acidosis induces a parallel increase in the rates of the luminal Na/H antiporter and the basolateral Na/(HCO3)3 cotransporter. Therefore, the enhanced proximal tubule reabsorption of bicarbonate in chronic respiratory acidosis may be, at least in part, mediated by a parallel adaptation of these transporters. PMID:2537851

  1. Intra-plastid protein trafficking; how plant cells adapted prokaryotic mechanisms to the eukaryotic condition

    PubMed Central

    Celedon, Jose M.; Cline, Kenneth

    2012-01-01

    Protein trafficking and localization in plastids involves a complex interplay between ancient (prokaryotic) and novel (eukaryotic) translocases and targeting machineries. During evolution, ancient systems acquired new functions and novel translocation machineries were developed to facilitate the correct localization of nuclear encoded proteins targeted to the chloroplast. Because of its post-translational nature, targeting and integration of membrane proteins posed the biggest challenge to the organelle to avoid aggregation in the aqueous compartments. Soluble proteins faced a different kind of problem since some had to be transported across three membranes to reach their destination. Early studies suggested that chloroplasts addressed these issues by adapting ancient-prokaryotic machineries and integrating them with novel-eukaryotic systems, a process called ‘conservative sorting’. In the last decade, detailed biochemical, genetic, and structural studies have unraveled the mechanisms of protein targeting and localization in chloroplasts, suggesting a highly integrated scheme where ancient and novel systems collaborate at different stages of the process. In this review we focus on the differences and similarities between chloroplast ancestral translocases and their prokaryotic relatives to highlight known modifications that adapted them to the eukaryotic situation. PMID:22750312

  2. Non-Invasive Investigation of Bone Adaptation in Humans to Mechanical Loading

    NASA Technical Reports Server (NTRS)

    Whalen, R.

    1999-01-01

    Experimental studies have identified peak cyclic forces, number of loading cycles, and loading rate as contributors to the regulation of bone metabolism. We have proposed a theoretical model that relates bone density to a mechanical stimulus derived from average daily cumulative peak cyclic 'effective' tissue stresses. In order to develop a non-invasive experimental model to test the theoretical model we need to: (1) monitor daily cumulative loading on a bone, (2) compute the internal stress state(s) resulting from the imposed loading, and (3) image volumetric bone density accurately, precisely, and reproducibly within small contiguous volumes throughout the bone. We have chosen the calcaneus (heel) as an experimental model bone site because it is loaded by ligament, tendon and joint contact forces in equilibrium with daily ground reaction forces that we can measure; it is a peripheral bone site and therefore more easily and accurately imaged with computed tomography; it is composed primarily of cancellous bone; and it is a relevant site for monitoring bone loss and adaptation in astronauts and the general population. This paper presents an overview of our recent advances in the areas of monitoring daily ground reaction forces, biomechanical modeling of the forces on the calcaneus during gait, mathematical modeling of calcaneal bone adaptation in response to cumulative daily activity, accurate and precise imaging of the calcaneus with quantitative computed tomography (QCT), and application to long duration space flight.

  3. A graph-based approach to developing adaptive representations of complex reaction mechanisms

    SciTech Connect

    He, Kaiyuan; Ierapetritou, Marianthi G.; Androulakis, Ioannis P.

    2008-12-15

    An effective adaptive mechanism reduction approach based on flux graph clustering is proposed in this paper. The instantaneous element flux is quantified and considered as a proxy for describing the reactive propensities of the system. Our underlying hypothesis is that even though particular conditions may be characterized by a multitude of combinations of species mass fraction, T, and P, the essential chemistry, and hence the reaction propensity of the mixture that is active under this family of conditions, is the same. Therefore, we opt to use the instantaneous fluxes through the active reactions as an intrinsic property of the system. Flux graphs are first constructed for the chemical reaction system under numerous conditions aiming at capturing the attainable region. Similarity between flux graphs is quantified through the distances between corresponding vectors, using the cosine coefficient and a novel graph-distance metric taking into account the magnitude of each flux and the activity distribution of different fluxes. A hierarchical clustering algorithm is implemented to group similar instantaneous flux graphs into clusters, and consequently a reduced mechanism is generated for each cluster. A search algorithm is defined afterward to assign a new query point to a particular flux graph cluster, and subsequently the reduced mechanism associated with this cluster is used to describe the system at this time point. Finally, the methodology is demonstrated using n-pentane combustion in an adiabatic plug flow reactor model and a pairwise mixing stirred reactor model. (author)

  4. Simultaneous optimization of actuator position and control parameter for adaptive mechanical structures

    NASA Astrophysics Data System (ADS)

    Weber, Christian-Toralf; Gabbert, Ulrich; Enzmann, Marc R.

    1998-07-01

    The design of adaptive mechanical structures is divided into three parts: the structural design, the controller design and the placement of actuators and sensors. The objective of the design is to create a mechanical structure, which corresponds with the physical and technical requirements. The controller design includes the definition of the optimal controller law and the parameters required to create an actuator adjustment from the perceptible signals of the structural answer. The placement of the actuators and of the sensors give an answer to the question about the optimal distribution of the actuators and sensors in the structure. The sensor placement determines which signals are available to the automatic controller. The position of the actuators in the mechanical structure determines at which points control forces may act to influence the structural behavior in a suitable manner. The determination of the optimal position of the actuators require information about the controller design, the sensor position and the layout and the behavior of the structure. Based on the ideas of the shape optimization and topology optimization, a procedure will be presented, to handle simultaneously the discrete positions of the actuators and the continuous parameters of the controller. The method is based on an augmented Lagrangian function to include additional conditions and the discontinuity of the discrete variables into the objective function. The method will be demonstrated by an test example.

  5. Mechano-adaptive sensory mechanism of α-catenin under tension

    PubMed Central

    Maki, Koichiro; Han, Sung-Woong; Hirano, Yoshinori; Yonemura, Shigenobu; Hakoshima, Toshio; Adachi, Taiji

    2016-01-01

    The contractile forces in individual cells drive the tissue processes, such as morphogenesis and wound healing, and maintain tissue integrity. In these processes, α-catenin molecule acts as a tension sensor at cadherin-based adherens junctions (AJs), accelerating the positive feedback of intercellular tension. Under tension, α-catenin is activated to recruit vinculin, which recruits actin filaments to AJs. In this study, we revealed how α-catenin retains its activated state while avoiding unfolding under tension. Using single-molecule force spectroscopy employing atomic force microscopy (AFM), we found that mechanically activated α-catenin fragment had higher mechanical stability than a non-activated fragment. The results of our experiments using mutated and segmented fragments showed that the key intramolecular interactions acted as a conformational switch. We also found that the conformation of α-catenin was reinforced by vinculin binding. We demonstrate that α-catenin adaptively changes its conformation under tension to a stable intermediate state, binds to vinculin, and finally settles into a more stable state reinforced by vinculin binding. Our data suggest that the plastic characteristics of α-catenin, revealed in response to both mechanical and biochemical cues, enable the functional-structural dynamics at the cellular and tissue levels. PMID:27109499

  6. Mechano-adaptive sensory mechanism of α-catenin under tension.

    PubMed

    Maki, Koichiro; Han, Sung-Woong; Hirano, Yoshinori; Yonemura, Shigenobu; Hakoshima, Toshio; Adachi, Taiji

    2016-01-01

    The contractile forces in individual cells drive the tissue processes, such as morphogenesis and wound healing, and maintain tissue integrity. In these processes, α-catenin molecule acts as a tension sensor at cadherin-based adherens junctions (AJs), accelerating the positive feedback of intercellular tension. Under tension, α-catenin is activated to recruit vinculin, which recruits actin filaments to AJs. In this study, we revealed how α-catenin retains its activated state while avoiding unfolding under tension. Using single-molecule force spectroscopy employing atomic force microscopy (AFM), we found that mechanically activated α-catenin fragment had higher mechanical stability than a non-activated fragment. The results of our experiments using mutated and segmented fragments showed that the key intramolecular interactions acted as a conformational switch. We also found that the conformation of α-catenin was reinforced by vinculin binding. We demonstrate that α-catenin adaptively changes its conformation under tension to a stable intermediate state, binds to vinculin, and finally settles into a more stable state reinforced by vinculin binding. Our data suggest that the plastic characteristics of α-catenin, revealed in response to both mechanical and biochemical cues, enable the functional-structural dynamics at the cellular and tissue levels. PMID:27109499

  7. Genomic Mechanisms Accounting for the Adaptation to Parasitism in Nematode-Trapping Fungi

    PubMed Central

    Meerupati, Tejashwari; Andersson, Karl-Magnus; Friman, Eva; Kumar, Dharmendra; Tunlid, Anders; Ahrén, Dag

    2013-01-01

    Orbiliomycetes is one of the earliest diverging branches of the filamentous ascomycetes. The class contains nematode-trapping fungi that form unique infection structures, called traps, to capture and kill free-living nematodes. The traps have evolved differently along several lineages and include adhesive traps (knobs, nets or branches) and constricting rings. We show, by genome sequencing of the knob-forming species Monacrosporium haptotylum and comparison with the net-forming species Arthrobotrys oligospora, that two genomic mechanisms are likely to have been important for the adaptation to parasitism in these fungi. Firstly, the expansion of protein domain families and the large number of species-specific genes indicated that gene duplication followed by functional diversification had a major role in the evolution of the nematode-trapping fungi. Gene expression indicated that many of these genes are important for pathogenicity. Secondly, gene expression of orthologs between the two fungi during infection indicated that differential regulation was an important mechanism for the evolution of parasitism in nematode-trapping fungi. Many of the highly expressed and highly upregulated M. haptotylum transcripts during the early stages of nematode infection were species-specific and encoded small secreted proteins (SSPs) that were affected by repeat-induced point mutations (RIP). An active RIP mechanism was revealed by lack of repeats, dinucleotide bias in repeats and genes, low proportion of recent gene duplicates, and reduction of recent gene family expansions. The high expression and rapid divergence of SSPs indicate a striking similarity in the infection mechanisms of nematode-trapping fungi and plant and insect pathogens from the crown groups of the filamentous ascomycetes (Pezizomycotina). The patterns of gene family expansions in the nematode-trapping fungi were more similar to plant pathogens than to insect and animal pathogens. The observation of RIP activity

  8. Grid coupling mechanism in the semi-implicit adaptive Multi-Level Multi-Domain method

    NASA Astrophysics Data System (ADS)

    Innocenti, M. E.; Tronci, C.; Markidis, S.; Lapenta, G.

    2016-05-01

    The Multi-Level Multi-Domain (MLMD) method is a semi-implicit adaptive method for Particle-In-Cell plasma simulations. It has been demonstrated in the past in simulations of Maxwellian plasmas, electrostatic and electromagnetic instabilities, plasma expansion in vacuum, magnetic reconnection [1, 2, 3]. In multiple occasions, it has been commented on the coupling between the coarse and the refined grid solutions. The coupling mechanism itself, however, has never been explored in depth. Here, we investigate the theoretical bases of grid coupling in the MLMD system. We obtain an evolution law for the electric field solution in the overlap area of the MLMD system which highlights a dependance on the densities and currents from both the coarse and the refined grid, rather than from the coarse grid alone: grid coupling is obtained via densities and currents.

  9. Genome analysis of three Pneumocystis species reveals adaptation mechanisms to life exclusively in mammalian hosts.

    PubMed

    Ma, Liang; Chen, Zehua; Huang, Da Wei; Kutty, Geetha; Ishihara, Mayumi; Wang, Honghui; Abouelleil, Amr; Bishop, Lisa; Davey, Emma; Deng, Rebecca; Deng, Xilong; Fan, Lin; Fantoni, Giovanna; Fitzgerald, Michael; Gogineni, Emile; Goldberg, Jonathan M; Handley, Grace; Hu, Xiaojun; Huber, Charles; Jiao, Xiaoli; Jones, Kristine; Levin, Joshua Z; Liu, Yueqin; Macdonald, Pendexter; Melnikov, Alexandre; Raley, Castle; Sassi, Monica; Sherman, Brad T; Song, Xiaohong; Sykes, Sean; Tran, Bao; Walsh, Laura; Xia, Yun; Yang, Jun; Young, Sarah; Zeng, Qiandong; Zheng, Xin; Stephens, Robert; Nusbaum, Chad; Birren, Bruce W; Azadi, Parastoo; Lempicki, Richard A; Cuomo, Christina A; Kovacs, Joseph A

    2016-01-01

    Pneumocystis jirovecii is a major cause of life-threatening pneumonia in immunosuppressed patients including transplant recipients and those with HIV/AIDS, yet surprisingly little is known about the biology of this fungal pathogen. Here we report near complete genome assemblies for three Pneumocystis species that infect humans, rats and mice. Pneumocystis genomes are highly compact relative to other fungi, with substantial reductions of ribosomal RNA genes, transporters, transcription factors and many metabolic pathways, but contain expansions of surface proteins, especially a unique and complex surface glycoprotein superfamily, as well as proteases and RNA processing proteins. Unexpectedly, the key fungal cell wall components chitin and outer chain N-mannans are absent, based on genome content and experimental validation. Our findings suggest that Pneumocystis has developed unique mechanisms of adaptation to life exclusively in mammalian hosts, including dependence on the lungs for gas and nutrients and highly efficient strategies to escape both host innate and acquired immune defenses. PMID:26899007

  10. Genome analysis of three Pneumocystis species reveals adaptation mechanisms to life exclusively in mammalian hosts

    PubMed Central

    Ma, Liang; Chen, Zehua; Huang, Da Wei; Kutty, Geetha; Ishihara, Mayumi; Wang, Honghui; Abouelleil, Amr; Bishop, Lisa; Davey, Emma; Deng, Rebecca; Deng, Xilong; Fan, Lin; Fantoni, Giovanna; Fitzgerald, Michael; Gogineni, Emile; Goldberg, Jonathan M.; Handley, Grace; Hu, Xiaojun; Huber, Charles; Jiao, Xiaoli; Jones, Kristine; Levin, Joshua Z.; Liu, Yueqin; Macdonald, Pendexter; Melnikov, Alexandre; Raley, Castle; Sassi, Monica; Sherman, Brad T.; Song, Xiaohong; Sykes, Sean; Tran, Bao; Walsh, Laura; Xia, Yun; Yang, Jun; Young, Sarah; Zeng, Qiandong; Zheng, Xin; Stephens, Robert; Nusbaum, Chad; Birren, Bruce W.; Azadi, Parastoo; Lempicki, Richard A.; Cuomo, Christina A.; Kovacs, Joseph A.

    2016-01-01

    Pneumocystis jirovecii is a major cause of life-threatening pneumonia in immunosuppressed patients including transplant recipients and those with HIV/AIDS, yet surprisingly little is known about the biology of this fungal pathogen. Here we report near complete genome assemblies for three Pneumocystis species that infect humans, rats and mice. Pneumocystis genomes are highly compact relative to other fungi, with substantial reductions of ribosomal RNA genes, transporters, transcription factors and many metabolic pathways, but contain expansions of surface proteins, especially a unique and complex surface glycoprotein superfamily, as well as proteases and RNA processing proteins. Unexpectedly, the key fungal cell wall components chitin and outer chain N-mannans are absent, based on genome content and experimental validation. Our findings suggest that Pneumocystis has developed unique mechanisms of adaptation to life exclusively in mammalian hosts, including dependence on the lungs for gas and nutrients and highly efficient strategies to escape both host innate and acquired immune defenses. PMID:26899007

  11. Ca2+-Dependent Regulations and Signaling in Skeletal Muscle: From Electro-Mechanical Coupling to Adaptation

    PubMed Central

    Gehlert, Sebastian; Bloch, Wilhelm; Suhr, Frank

    2015-01-01

    Calcium (Ca2+) plays a pivotal role in almost all cellular processes and ensures the functionality of an organism. In skeletal muscle fibers, Ca2+ is critically involved in the innervation of skeletal muscle fibers that results in the exertion of an action potential along the muscle fiber membrane, the prerequisite for skeletal muscle contraction. Furthermore and among others, Ca2+ regulates also intracellular processes, such as myosin-actin cross bridging, protein synthesis, protein degradation and fiber type shifting by the control of Ca2+-sensitive proteases and transcription factors, as well as mitochondrial adaptations, plasticity and respiration. These data highlight the overwhelming significance of Ca2+ ions for the integrity of skeletal muscle tissue. In this review, we address the major functions of Ca2+ ions in adult muscle but also highlight recent findings of critical Ca2+-dependent mechanisms essential for skeletal muscle-regulation and maintenance. PMID:25569087

  12. Adaptive response of bacteria: Multiple hurdles, cross-tolerance and tools to illustrate underlying mechanisms

    NASA Astrophysics Data System (ADS)

    Paramythiotis, Spyridon; Skandamis, Panagiotis N.

    2015-01-01

    A basic principle in the bacterial resistance against lethal stresses is that exposure of microbial cells to a sublethal hurdle (e.g., pH 5.0, 3% NaCl, or 48°C) may induce resistance to lethal level of the same or different stress. The latter is called "cross-tolerance" and the bacteria experiencing such situations are termed "stress-hardened". The majority of scientific reports on the adaptive responses of bacteria to stresses have recently addressed the need to elucidate the underlying mechanisms controlling bacterial stress response. This in turn, will assist in the efficient application of the multiple hurdle approach, e.g., by selecting specific sanitizers, combining stress treatments or antimicrobials, especially in mild processing, against specific cellular targets, eliminating the possibility of the development of stress adapted cells. Common scientific approaches for studying the link between phenotype (e.g., inactivation, survival, or growth) and physiology is the assessment of global transcriptional changes (up- or down-regulation) or those of certain genes, as well as of proteins involved in certain metabolic pathways, occurring during exposure to stress. This may also be performed in parallel to comparative evaluation of the phenotypic response of wild and mutant strains. The post-genomics research on foodborne pathogens has extended our knowledge beyond their phenotypic behavior and may offer mechanistic insights in the following: (i) the top-down approach (induction), which is the search of the underlying mechanisms (low level) responsible for a specific phenotype based on "-omic" studies; and (ii) the bottom-up approach (deduction), which starts from intracellular level and forms a mechanistic (functional) basis for the cellular response. All these may eventually enable the development of mechanistic microbial models and efficient strategies for controlling survival and growth of pathogens in foods.

  13. Time Course of Pathogenic and Adaptation Mechanisms in Cystinotic Mouse Kidneys

    PubMed Central

    Gaide Chevronnay, Héloïse P.; Janssens, Virginie; Van Der Smissen, Patrick; N’Kuli, Francisca; Nevo, Nathalie; Guiot, Yves; Levtchenko, Elena; Marbaix, Etienne; Pierreux, Christophe E.; Cherqui, Stéphanie; Antignac, Corinne; Courtoy, Pierre J.

    2014-01-01

    Cystinosis, a main cause of Fanconi syndrome, is reproduced in congenic C57BL/6 cystinosin knockout (KO) mice. To identify the sequence of pathogenic and adaptation mechanisms of nephropathic cystinosis, we defined the onset of Fanconi syndrome in KO mice between 3 and 6 months of age and analyzed the correlation with structural and functional changes in proximal tubular cells (PTCs), with focus on endocytosis of ultrafiltrated disulfide-rich proteins as a key source of cystine. Despite considerable variation between mice at the same age, typical event sequences were delineated. At the cellular level, amorphous lysosomal inclusions preceded cystine crystals and eventual atrophy without crystals. At the nephron level, lesions started at the glomerulotubular junction and then extended distally. In situ hybridization and immunofluorescence revealed progressive loss of expression of megalin, cubilin, sodium-glucose cotransporter 2, and type IIa sodium-dependent phosphate cotransporter, suggesting apical dedifferentiation accounting for Fanconi syndrome before atrophy. Injection of labeled proteins revealed that defective endocytosis in S1 PTCs led to partial compensatory uptake by S3 PTCs, suggesting displacement of endocytic load and injury by disulfide-rich cargo. Increased PTC apoptosis allowed luminal shedding of cystine crystals and was partially compensated for by tubular proliferation. We conclude that lysosomal storage triggered by soluble cystine accumulation induces apical PTC dedifferentiation, which causes transfer of the harmful load of disulfide-rich proteins to more distal cells, possibly explaining longitudinal progression of swan-neck lesions. Furthermore, our results suggest that subsequent adaptation mechanisms include lysosomal clearance of free and crystalline cystine into urine and ongoing tissue repair. PMID:24525030

  14. Relationship Between Resilience and Coping Strategies in Competitive Sport.

    PubMed

    Secades, Xabel García; Molinero, Olga; Salguero, Alfonso; Barquín, Roberto Ruíz; de la Vega, Ricardo; Márquez, Sara

    2016-02-01

    Resilience is important in sport performers to withstand the pressure they experience. This study analyzed the relationship among resilient qualities and coping strategies in 235 Spanish athletes (126 males, 109 females; M age = 20.7 yr) who practiced different sports (79.1% team sports, 20.9% individual sports). They were evaluated at the beginning of the last competitive mesocycle and after an important competition. Coping strategies and level of resilient qualities were measured by the Coping Inventory for Competitive Sport and the Resilience Scale. There was no significant difference in resilience scores between evaluations performed during the last mesocycle or competition. A significant increase occurred in the scores for emotion-oriented and distraction-oriented coping during competition. Resilience scores correlated positively to task-oriented coping and negatively to disengagement- and distraction-oriented coping during both periods. Analysis of variance indicated that athletes with high individual resilient qualities reached higher scores in task-oriented coping, using to a lower extent disengagement- and distraction-oriented coping. Results obtained suggest that resilient characteristics may associate in athletes to the use of more potentially adaptative coping strategies. PMID:27420325

  15. Coping with the Unthinkable.

    ERIC Educational Resources Information Center

    Scholzman, Steven C.

    2001-01-01

    Describes the symptoms of posttraumatic stress disorder in students. Suggests ways that teachers can help students cope with catastrophic events such as the September 11 terrorist attack on the World Trade Center and the Pentagon. (PKP)

  16. Coping with the Crunch.

    ERIC Educational Resources Information Center

    Sturgeon, Julie

    2000-01-01

    Examines housing strategies several college facilities managers used to cope with the problem of overcrowded residence halls. Also highlighted are tips to help facilities managers determine if their solution is to build additional housing. (GR)

  17. Adapting Vocational Psychology To Cope with Change.

    ERIC Educational Resources Information Center

    Hesketh, Beryl

    2001-01-01

    The interdisciplinary tradition of vocational psychology is a strength, but it has been slow to respond to technology. Strategic issues to be addressed include implications of human genome research, inclusion of goal setting and metacognition in career development, virtual work organizations, and time as an important dimension of career research.…

  18. [Parents' coping with a diabetic child].

    PubMed

    Seppänen, S; Kyngäs, H; Nikkonen, M

    1997-01-01

    parents adapted to the diagnosis of diabetes and the care of the diabetic child. The parents felt that the life of the family became normalized and controlled. The important parental coping responses consisted of concrete models of functioning, which they developed to control the demands caused by the child's diabetes. PMID:9429344

  19. Caregivers--Who Copes How?

    ERIC Educational Resources Information Center

    Chappell, Neena L.; Dujela, Carren

    2009-01-01

    Within gerontological caregiving research, there is a major emphasis on stresses and burdens of this role. Yet there has been little attention directed toward the coping strategies that caregivers engage in to cope with this role and the factors that influence their adoption of different coping strategies. This article examines coping strategies…

  20. Heritable variation in heat shock gene expression: a potential mechanism for adaptation to thermal stress in embryos of sea turtles.

    PubMed

    Tedeschi, J N; Kennington, W J; Tomkins, J L; Berry, O; Whiting, S; Meekan, M G; Mitchell, N J

    2016-01-13

    The capacity of species to respond adaptively to warming temperatures will be key to their survival in the Anthropocene. The embryos of egg-laying species such as sea turtles have limited behavioural means for avoiding high nest temperatures, and responses at the physiological level may be critical to coping with predicted global temperature increases. Using the loggerhead sea turtle (Caretta caretta) as a model, we used quantitative PCR to characterise variation in the expression response of heat-shock genes (hsp60, hsp70 and hsp90; molecular chaperones involved in cellular stress response) to an acute non-lethal heat shock. We show significant variation in gene expression at the clutch and population levels for some, but not all hsp genes. Using pedigree information, we estimated heritabilities of the expression response of hsp genes to heat shock and demonstrated both maternal and additive genetic effects. This is the first evidence that the heat-shock response is heritable in sea turtles and operates at the embryonic stage in any reptile. The presence of heritable variation in the expression of key thermotolerance genes is necessary for sea turtles to adapt at a molecular level to warming incubation environments. PMID:26763709

  1. Multifractal entropy based adaptive multiwavelet construction and its application for mechanical compound-fault diagnosis

    NASA Astrophysics Data System (ADS)

    He, Shuilong; Chen, Jinglong; Zhou, Zitong; Zi, Yanyang; Wang, Yanxue; Wang, Xiaodong

    2016-08-01

    Compound-fault diagnosis of mechanical equipment is still challenging at present because of its complexity, multiplicity and non-stationarity. In this work, an adaptive redundant multiwavelet packet (ARMP) method is proposed for the compound-fault diagnosis. Multiwavelet transform has two or more base functions and many excellent properties, making it suitable for detecting all the features of compound-fault simultaneously. However, on the other hand, the fixed basis function used in multiwavelet transform may decrease the accuracy of fault extraction; what's more, the multi-resolution analysis of multiwavelet transform in low frequency band may also leave out the useful features. Thus, the minimum sum of normalized multifractal entropy is adopted as the optimization criteria for the proposed ARMP method, while the relative energy ratio of the characteristic frequency is utilized as an effective way in automatically selecting the sensitive frequency bands. Then, The ARMP technique combined with Hilbert transform demodulation analysis is then applied to detect the compound-fault of bevel gearbox and planetary gearbox. The results verify that the proposed method can effectively identify and detect the compound-fault of mechanical equipment.

  2. Animal activity around the clock with no overt circadian rhythms: patterns, mechanisms and adaptive value

    PubMed Central

    Bloch, Guy; Barnes, Brian M.; Gerkema, Menno P.; Helm, Barbara

    2013-01-01

    Circadian rhythms are ubiquitous in many organisms. Animals that are forced to be active around the clock typically show reduced performance, health and survival. Nevertheless, we review evidence of animals showing prolonged intervals of activity with attenuated or nil overt circadian rhythms and no apparent ill effects. We show that around-the-clock and ultradian activity patterns are more common than is generally appreciated, particularly in herbivores, in animals inhabiting polar regions and habitats with constant physical environments, in animals during specific life-history stages (such as migration or reproduction), and in highly social animals. The underlying mechanisms are diverse, but studies suggest that some circadian pacemakers continue to measure time in animals active around the clock. The prevalence of around-the-clock activity in diverse animals and habitats, and an apparent diversity of underlying mechanisms, are consistent with convergent evolution. We suggest that the basic organizational principles of the circadian system and its complexity encompass the potential for chronobiological plasticity. There may be trade-offs between benefits of persistent daily rhythms versus plasticity, which for reasons still poorly understood make overt daily arrhythmicity functionally adaptive only in selected habitats and for selected lifestyles. PMID:23825202

  3. Mechanisms of sensing and adaptive responses to low oxygen conditions in mammals and yeasts.

    PubMed

    Trendeleva, T A; Aliverdieva, D A; Zvyagilskaya, R A

    2014-08-01

    Oxygen is required for effective production of ATP and plays a key role in the maintenance of life for all organisms, excepting strict anaerobes. The ability of aerobic organisms to sense and respond to changes in oxygen level is a basic requirement for their survival. Eukaryotes have developed adaptive mechanisms to sense and respond to decreased oxygen concentrations (hypoxia) through adjustment of oxygen homeostasis by upregulating hypoxic and downregulating aerobic nuclear genes. This review summarizes recent data on mechanisms of cells sensing and responding to changes in oxygen availability in mammals and in yeasts. In the first part of the review, prominence is given to functional regulation and stabilization of hypoxia-inducible factors (HIFs), HIF-mediated regulation of electron transport flux and repression of lipogenesis, as well as to hypoxia-induced mitochondrial permeability transition (pore) opening, cell death, and autophagy. In the second part of the review emphasis is placed on oxygen sensing in nonpathogenic yeasts by heme, unsaturated fatty acids, and sterols, as well as on responses to hypoxia in fungal pathogens. PMID:25365485

  4. Mechanisms Underlying the Regulation of Innate and Adaptive Immunity by Vitamin D

    PubMed Central

    Wei, Ran; Christakos, Sylvia

    2015-01-01

    Non-classical actions of vitamin D were first suggested over 30 years ago when receptors for the active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), were detected in various tissues and cells that are not associated with the regulation of calcium homeostasis, including activated human inflammatory cells. The question that remained was the biological significance of the presence of vitamin D receptors in the different tissues and cells and, with regard to the immune system, whether or not vitamin D plays a role in the normal immune response and in modifying immune mediated diseases. In this article findings indicating that vitamin D is a key factor regulating both innate and adaptive immunity are reviewed with a focus on the molecular mechanisms involved. In addition, the physiological significance of vitamin D action, as suggested by in vivo studies in mouse models is discussed. Together, the findings indicate the importance of 1,25(OH)2D3 as a regulator of key components of the immune system. An understanding of the mechanisms involved will lead to potential therapeutic applications for the treatment of immune mediated diseases. PMID:26404359

  5. Evolution of the fruit endocarp: molecular mechanisms underlying adaptations in seed protection and dispersal strategies

    PubMed Central

    Dardick, Chris; Callahan, Ann M.

    2014-01-01

    Plant evolution is largely driven by adaptations in seed protection and dispersal strategies that allow diversification into new niches. This is evident by the tremendous variation in flowering and fruiting structures present both across and within different plant lineages. Within a single plant family a staggering variety of fruit types can be found such as fleshy fruits including berries, pomes, and drupes and dry fruit structures like achenes, capsules, and follicles. What are the evolutionary mechanisms that enable such dramatic shifts to occur in a relatively short period of time? This remains a fundamental question of plant biology today. On the surface it seems that these extreme differences in form and function must be the consequence of very different developmental programs that require unique sets of genes. Yet as we begin to decipher the molecular and genetic basis underlying fruit form it is becoming apparent that simple genetic changes in key developmental regulatory genes can have profound anatomical effects. In this review, we discuss recent advances in understanding the molecular mechanisms of fruit endocarp tissue differentiation that have contributed to species diversification within three plant lineages. PMID:25009543

  6. Animal activity around the clock with no overt circadian rhythms: patterns, mechanisms and adaptive value.

    PubMed

    Bloch, Guy; Barnes, Brian M; Gerkema, Menno P; Helm, Barbara

    2013-08-22

    Circadian rhythms are ubiquitous in many organisms. Animals that are forced to be active around the clock typically show reduced performance, health and survival. Nevertheless, we review evidence of animals showing prolonged intervals of activity with attenuated or nil overt circadian rhythms and no apparent ill effects. We show that around-the-clock and ultradian activity patterns are more common than is generally appreciated, particularly in herbivores, in animals inhabiting polar regions and habitats with constant physical environments, in animals during specific life-history stages (such as migration or reproduction), and in highly social animals. The underlying mechanisms are diverse, but studies suggest that some circadian pacemakers continue to measure time in animals active around the clock. The prevalence of around-the-clock activity in diverse animals and habitats, and an apparent diversity of underlying mechanisms, are consistent with convergent evolution. We suggest that the basic organizational principles of the circadian system and its complexity encompass the potential for chronobiological plasticity. There may be trade-offs between benefits of persistent daily rhythms versus plasticity, which for reasons still poorly understood make overt daily arrhythmicity functionally adaptive only in selected habitats and for selected lifestyles. PMID:23825202

  7. Do common mechanisms of adaptation mediate color discrimination and appearance? Uniform backgrounds

    PubMed Central

    Hillis, James M.; Brainard, David H.

    2007-01-01

    Color vision is useful for detecting surface boundaries and identifying objects. Are the signals used to perform these two functions processed by common mechanisms, or has the visual system optimized its processing separately for each task? We measured the effect of mean chromaticity and luminance on color discriminability and on color appearance under well-matched stimulus conditions. In the discrimination experiments, a pedestal spot was presented in one interval and a pedestal + test in a second. Observers indicated which interval contained the test. In the appearance experiments, observers matched the appearance of test spots across a change in background. We analyzed the data using a variant of Fechner's proposal, that the rate of apparent stimulus change is proportional to visual sensitivity. We found that saturating visual response functions together with a model of adaptation that included multiplicative gain control and a subtractive term accounted for data from both tasks. This result suggests that effects of the contexts we studied on color appearance and discriminability are controlled by the same underlying mechanism. PMID:16277280

  8. Electronics and mechanisms control system for FRIDA (inFRared Imager and Dissector for Adaptive optics)

    NASA Astrophysics Data System (ADS)

    Flores-Meza, R.; Cuevas, S.; Díaz, J. J.; Espejo, C.; Keiman, C.; Lara, G.; Sánchez, B.; Uribe, J.

    2012-09-01

    FRIDA will be a common-user near infrared imager and integral field spectrograph covering the wavelength range from 0.9 to 2.5 microns. Primary observing modes driven the instrument design are two: direct imaging and integral field spectroscopy. FRIDA will be installed at the Nasmyth-B platform of the Gran Telescopio Canarias (GTC) behind the GTC Adaptive Optics (GTCAO) system. Instrument will use diffraction-limited optics to avoid degrading the high Strehl ratios derived by the GTCAO system in the near infrared. High-performance astronomical instruments with a high reconfiguration degree as FRIDA, not only depends on optical and mechanical efficient designs but also on the good quality of its electronics and control systems design. In fact, astronomical instruments operating performance on telescope greatly relies on electronics and control system. This paper describes the main design topics for the FRIDA electronics and mechanisms control system, pointing on the development that these areas have reached on the project status. FRIDA Critical Design Review (CDR) was held on September 2011.

  9. Do common mechanisms of adaptation mediate color discrimination and appearance? Uniform backgrounds

    NASA Astrophysics Data System (ADS)

    Hillis, James M.; Brainard, David H.

    2005-10-01

    Color vision is useful for detecting surface boundaries and identifying objects. Are the signals used to perform these two functions processed by common mechanisms, or has the visual system optimized its processing separately for each task? We measured the effect of mean chromaticity and luminance on color discriminability and on color appearance under well-matched stimulus conditions. In the discrimination experiments, a pedestal spot was presented in one interval and a pedestal + test in a second. Observers indicated which interval contained the test. In the appearance experiments, observers matched the appearance of test spots across a change in background. We analyzed the data using a variant of Fechner's proposal, that the rate of apparent stimulus change is proportional to visual sensitivity. We found that saturating visual response functions together with a model of adaptation that included multiplicative gain control and a subtractive term accounted for data from both tasks. This result suggests that effects of the contexts we studied on color appearance and discriminability are controlled by the same underlying mechanism.

  10. The Coexistence of Coping Resources and Specific Coping Styles in Stress: Evidence from Full Information Item Bifactor Analysis

    PubMed Central

    Cui, Meng; Wu, Qing; Zhu, Xia; Miao, Danmin; Zhang, Yan; Feng, Xi; Xiao, Wei

    2014-01-01

    Background Knowledge of coping styles is useful in clinical diagnosis and suggesting specific therapeutic interventions. However, the latent structures and relationships between different aspects of coping styles have not been fully clarified. A full information item bifactor model will be beneficial to future research. Objective One goal of this study is identification of the best fit statistical model of coping styles. A second goal is entails extended analyses of latent relationships among different coping styles. In general, such research should offer greater understanding of the mechanisms of coping styles and provide insights into coping with stress. Methods Coping Styles Questionnaire (CSQ) and Generalized Self-Efficacy Scale (GSES) were administrated to officers suffering from military stress. Confirmatory Factor Analyses was performed to indentify the best fit model. A hierarchical item response model (bifactor model) was adopted to analyze the data. Additionally, correlations among coping styles and self-efficacy were compared using both original and bifactor models. Results Results showed a bifactor model best fit the data. Item loadings on general and specific factors varied among different coping styles. All items loaded significantly on the general factor, and most items also had moderate to large loadings on specific factors. The correlation between coping styles and self-efficacy and the correlation among different coping styles changed significantly after extracting the general factor of coping stress using bifactor analysis. This was seen in changes from positive (r = 0.714, p<0.01) correlation to negative (r = −0.335, p<0.01) and also from negative (r = −0.296, p<0.01) to positive (r = 0.331, p<0.01). Conclusion Our results reveal that coping styles have a bifactor structure. They also provide direct evidence of coexisting coping resources and styles. This further clarifies that dimensions of coping styles should include

  11. Evidence for Retromutagenesis as a Mechanism for Adaptive Mutation in Escherichia coli.

    PubMed

    Morreall, Jordan; Kim, Alice; Liu, Yuan; Degtyareva, Natalya; Weiss, Bernard; Doetsch, Paul W

    2015-08-01

    Adaptive mutation refers to the continuous outgrowth of new mutants from a non-dividing cell population during selection, in apparent violation of the neo-Darwinian principle that mutation precedes selection. One explanation is that of retromutagenesis, in which a DNA lesion causes a transcriptional mutation that yields a mutant protein, allowing escape from selection. This enables a round of DNA replication that establishes heritability. Because the model requires that gene expression precedes DNA replication, it predicts that during selection, new mutants will arise from damage only to the transcribed DNA strand. As a test, we used a lacZ amber mutant of Escherichia coli that can revert by nitrous acid-induced deamination of adenine residues on either strand of the TAG stop codon, each causing different DNA mutations. When stationary-phase, mutagenized cells were grown in rich broth before being plated on lactose-selective media, only non-transcribed strand mutations appeared in the revertants. This result was consistent with the known high sensitivity to deamination of the single-stranded DNA in a transcription bubble, and it provided an important control because it demonstrated that the genetic system we would use to detect transcribed-strand mutations could also detect a bias toward the non-transcribed strand. When residual lacZ transcription was blocked beforehand by catabolite repression, both strands were mutated about equally, but if revertants were selected immediately after nitrous acid exposure, transcribed-strand mutations predominated among the revertants, implicating retromutagenesis as the mechanism. This result was not affected by gene orientation. Retromutagenesis is apt to be a universal method of evolutionary adaptation, which enables the emergence of new mutants from mutations acquired during counterselection rather than beforehand, and it may have roles in processes as diverse as the development of antibiotic resistance and neoplasia. PMID

  12. Structures and Mechanisms Design Concepts for Adaptive Deployable Entry Placement Technology

    NASA Technical Reports Server (NTRS)

    Yount, Bryan C.; Arnold, James O.; Gage, Peter J.; Mockelman, Jeffrey; Venkatapathy, Ethiraj

    2012-01-01

    System studies have shown that large deployable aerodynamic decelerators such as the Adaptive Deployable Entry and Placement Technology (ADEPT) concept can revolutionize future robotic and human exploration missions involving atmospheric entry, descent and landing by significantly reducing the maximum heating rate, total heat load, and deceleration loads experienced by the spacecraft during entry [1-3]. ADEPT and the Hypersonic Inflatable Aerodynamic Decelerator (HIAD) [4] share the approach of stowing the entry system in the shroud of the launch vehicle and deploying it to a much larger diameter prior to entry. The ADEPT concept provides a low ballistic coefficient for planetary entry by employing an umbrella-like deployable structure consisting of ribs, struts and a fabric cover that form an aerodynamic decelerator capable of undergoing hypersonic flight. The ADEPT "skin" is a 3-D woven carbon cloth that serves as a thermal protection system (TPS) and as a structural surface that transfers aerodynamic forces to the underlying ribs [5]. This paper focuses on design activities associated with integrating ADEPT components (cloth, ribs, struts and mechanisms) into a system that can function across all configurations and environments of a typical mission concept: stowed during launch, in-space deployment, entry, descent, parachute deployment and separation from the landing payload. The baseline structures and mechanisms were selected via trade studies conducted during the summer and fall of 2012. They are now being incorporated into the design of a ground test article (GTA) that will be fabricated in 2013. It will be used to evaluate retention of the stowed configuration in a launch environment, mechanism operation for release, deployment and locking, and static strength of the deployed decelerator. Of particular interest are the carbon cloth interfaces, underlying hot structure, (Advanced Carbon- Carbon ribs) and other structural components (nose cap, struts, and

  13. A review of adaptive mechanisms in cell responses towards oxidative stress caused by dental resin monomers.

    PubMed

    Krifka, Stephanie; Spagnuolo, Gianrico; Schmalz, Gottfried; Schweikl, Helmut

    2013-06-01

    Dental composite resins are biomaterials commonly used to aesthetically restore the structure and function of teeth impaired by caries, erosion, or fracture. Residual monomers released from resin restorations as a result of incomplete polymerization processes interact with living oral tissues. Monomers like triethylene glycol dimethacrylate (TEGDMA) or 2-hydroxylethyl methacrylate (HEMA) are cytotoxic via apoptosis, induce genotoxic effects, and delay the cell cycle. Monomers also influence the response of cells of the innate immune system, inhibit specific odontoblast cell functions, or delay the odontogenic differentiation and mineralization processes in pulp-derived cells including stem cells. These observations indicate that resin monomers act as environmental stressors which inevitably disturb regulatory cellular networks through interference with signal transduction pathways. We hypothesize that an understanding of the cellular mechanisms underlying these phenomena will provide a better estimation of the consequences associated with dental therapy using composite materials, and lead to innovative therapeutic strategies and improved materials being used at tissue interfaces within the oral cavity. Current findings strongly suggest that monomers enhance the formation of reactive oxygen species (ROS), which is most likely the cause of biological reactions activated by dental composites and resin monomers. The aim of the present review manuscript is to discuss adaptive cell responses to oxidative stress caused by monomers. The particular significance of a tightly controlled network of non-enzymatic as well as enzymatic antioxidants for the regulation of cellular redox homeostasis and antioxidant defense in monomer-exposed cells will be addressed. The expression of ROS-metabolizing antioxidant enzymes like superoxide dismutase (SOD1), glutathione peroxidase (GPx1/2), and catalase in cells exposed to monomers will be discussed with particular emphasis on the role

  14. Time scale matters: genetic analysis does not support adaptation-by-time as the mechanism for adaptive seasonal declines in kokanee reproductive life span

    PubMed Central

    Morbey, Yolanda E; Jensen, Evelyn L; Russello, Michael A

    2014-01-01

    Seasonal declines of fitness-related traits are often attributed to environmental effects or individual-level decisions about reproductive timing and effort, but genetic variation may also play a role. In populations of Pacific salmon (Oncorhynchus spp.), seasonal declines in reproductive life span have been attributed to adaptation-by-time, in which divergent selection for different traits occurs among reproductively isolated temporal components of a population. We evaluated this hypothesis in kokanee (freshwater obligate Oncorhynchus nerka) by testing for temporal genetic structure in neutral and circadian-linked loci. We detected no genetic differences in presumably neutral loci among kokanee with different arrival and maturation dates within a spawning season. Similarly, we detected no temporal genetic structure in OtsClock1b, Omy1009uw, or OmyFbxw11, candidate loci associated with circadian function. The genetic evidence from this study and others indicates a lack of support for adaptation-by-time as an important evolutionary mechanism underlying seasonal declines in reproductive life span and a need for greater consideration of other mechanisms such as time-dependent, adaptive adjustment of reproductive effort. PMID:25478160

  15. Segregation of tracked and wheeled ground vehicle mobility mechanisms through in-situ adaptation of seismic features

    NASA Astrophysics Data System (ADS)

    Park, Christopher G.; Fitzgerald, James; Power, Dennis

    2008-04-01

    The ability to perform generalized ground vehicle classification by unattended ground sensors (UGS) is an important facet of data analysis performed by modern unattended sensor systems. Large variation in seismic signature propagation from one location to another renders exploiting seismic measurements to classify vehicles a significant challenge. This paper presents the results of using an adaptive methodology to distinguish between tracked and wheeled ground vehicle mobility mechanisms. The methodology is a passive in-situ learning process that does not rely upon an explicit calibration process but does require an estimated range to the target. Furthermore, the benefits of the seismic feature adaptation are realized with a sparse information set. There exist scenarios in which the adaptation fails to provide information when implemented as an independent process. These situations, however, may be mitigated by sharing information with other classification algorithms. Once properly initialized, the in-situ adaptation process correctly categorizes over 95% of ground vehicles.

  16. A New Mechanism for Adaptation to Changes in Light Intensity and Quality in the Red Alga Porphyra perforata1

    PubMed Central

    Satoh, Kazuhiko; Fork, David C.

    1983-01-01

    In the red alga Porphyra perforata, the level of chlorophyll fluorescence in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) decreased during illumination of the thallus. The results showed that: (a) this decay was related to the photooxidative activity of photosystem I; (b) Q, the primary electron acceptor of photosystem II, became oxidized during the decay of the fluorescence; (c) reagents which inhibit the back reaction of photosystem II inhibited the decay. From these results, it is suggested that, when conditions in the chloroplasts of this red alga become too oxidative, excess light energy can be converted to heat as a result of an accelerated back reaction of photosystem II. This may be one of the mechanisms by which this alga can cope with the high salt and high light conditions that can occur in its natural habitat. PMID:16662886

  17. Saccade Adaptation Abnormalities Implicate Dysfunction of Cerebellar-Dependent Learning Mechanisms in Autism Spectrum Disorders (ASD)

    PubMed Central

    Mosconi, Matthew W.; Luna, Beatriz; Kay-Stacey, Margaret; Nowinski, Caralynn V.; Rubin, Leah H.; Scudder, Charles; Minshew, Nancy; Sweeney, John A.

    2013-01-01

    The cerebellar vermis (lobules VI-VII) has been implicated in both postmortem and neuroimaging studies of autism spectrum disorders (ASD). This region maintains the consistent accuracy of saccadic eye movements and plays an especially important role in correcting systematic errors in saccade amplitudes such as those induced by adaptation paradigms. Saccade adaptation paradigms have not yet been used to study ASD. Fifty-six individuals with ASD and 53 age-matched healthy controls performed an intrasaccadic target displacement task known to elicit saccadic adaptation reflected in an amplitude reduction. The rate of amplitude reduction and the variability of saccade amplitude across 180 adaptation trials were examined. Individuals with ASD adapted slower than healthy controls, and demonstrated more variability of their saccade amplitudes across trials prior to, during and after adaptation. Thirty percent of individuals with ASD did not significantly adapt, whereas only 6% of healthy controls failed to adapt. Adaptation rate and amplitude variability impairments were related to performance on a traditional neuropsychological test of manual motor control. The profile of impaired adaptation and reduced consistency of saccade accuracy indicates reduced neural plasticity within learning circuits of the oculomotor vermis that impedes the fine-tuning of motor behavior in ASD. These data provide functional evidence of abnormality in the cerebellar vermis that converges with previous reports of cellular and gross anatomic dysmorphology of this brain region in ASD. PMID:23704934

  18. The Influence of Emotional Intelligence (EI) on Coping and Mental Health in Adolescence: Divergent Roles for Trait and Ability EI

    ERIC Educational Resources Information Center

    Davis, Sarah K.; Humphrey, Neil

    2012-01-01

    Theoretically, trait and ability emotional intelligence (EI) should mobilise coping processes to promote adaptation, plausibly operating as personal resources determining choice and/or implementation of coping style. However, there is a dearth of research deconstructing if/how EI impacts mental health via multiple coping strategies in adolescence.…

  19. Use of Ultrasound to Monitor Biceps Femoris Mechanical Adaptations after Injury in a Professional Soccer Player.

    PubMed

    Kellis, Eleftherios; Galanis, Nikiforos; Chrysanthou, Chrysanthos; Kofotolis, Nikolaos

    2016-03-01

    This study examined the use of ultrasound to monitor changes in the long head of the biceps femoris (BF) architecture of aprofessional soccer player with acute first-time hamstring strain. The player followed a 14 session physiotherapy treatment until return to sport. The pennation angle and aponeurosis strain of the long head of the biceps femoris (BF) were monitored at 6 occasions (up until 1 year) after injury. The size of the scar / hematoma was reduced by 63.56% (length) and 67.9% (width) after the intervention and it was almost non-traceable one year after injury. The pennation angle of the fascicles underneath the scar showed a decline of 51.4% at the end of the intervention while an increase of 109.2% of the fascicles which were closer to deep aponeurosis was observed. In contrast, pennation angle of fascicles located away from the injury site were relatively unaffected. The treatment intervention resulted in a 57.9% to 77.3% decline of maximum strain per unit of MVC moment and remained similar one year after the intervention. This study provided an example of the potential use of ultrasound-based parameters to link the mechanical adaptations of the injured muscle to specific therapeutic intervention. Key pointsChanges in fascicle orientation after biceps femoris mild tear were reduced after a 28 day intervention and remained similar one year after injury.Tendon/aponeurosis strain per unit of moment of force decreased during the course of the therapeutic intervention.Future studies could utilize ultrasonography to monitor mechanical responses after various types of hamstring injury and interventions in order to improve criteria for a safe return to sport. PMID:26957929

  20. Feedback of mechanical effectiveness induces adaptations in motor modules during cycling.

    PubMed

    De Marchis, Cristiano; Schmid, Maurizio; Bibbo, Daniele; Castronovo, Anna Margherita; D'Alessio, Tommaso; Conforto, Silvia

    2013-01-01

    Recent studies have reported evidence that the motor system may rely on a modular organization, even if this behavior has yet to be confirmed during motor adaptation. The aim of the present study is to investigate the modular motor control mechanisms underlying the execution of pedaling by untrained subjects in different biomechanical conditions. We use the muscle synergies framework to characterize the muscle coordination of 11 subjects pedaling under two different conditions. The first one consists of a pedaling exercise with a strategy freely chosen by the subjects (Preferred Pedaling Technique, PPT), while the second condition constrains the gesture by means of a real time visual feedback of mechanical effectiveness (Effective Pedaling Technique, EPT). Pedal forces, recorded using a pair of instrumented pedals, were used to calculate the Index of Effectiveness (IE). EMG signals were recorded from eight muscles of the dominant leg and Non-negative Matrix Factorization (NMF) was applied for the extraction of muscle synergies. All the synergy vectors, extracted cycle by cycle for each subject, were pooled across subjects and conditions and underwent a 2-dimensional Sammon's non-linear mapping. Seven representative clusters were identified on the Sammon's projection, and the corresponding eight-dimensional synergy vectors were used to reconstruct the repertoire of muscle activation for all subjects and all pedaling conditions (VAF > 0.8 for each individual muscle pattern). Only 5 out of the 7 identified modules were used by the subjects during the PPT pedaling condition, while 2 additional modules were found specific for the pedaling condition EPT. The temporal recruitment of three identified modules was highly correlated with IE. The structure of the identified modules was found similar to that extracted in other studies of human walking, partly confirming the existence of shared and task specific muscle synergies, and providing further evidence on the modularity

  1. Use of Ultrasound to Monitor Biceps Femoris Mechanical Adaptations after Injury in a Professional Soccer Player

    PubMed Central

    Kellis, Eleftherios; Galanis, Nikiforos; Chrysanthou, Chrysanthos; Kofotolis, Nikolaos

    2016-01-01

    This study examined the use of ultrasound to monitor changes in the long head of the biceps femoris (BF) architecture of aprofessional soccer player with acute first-time hamstring strain. The player followed a 14 session physiotherapy treatment until return to sport. The pennation angle and aponeurosis strain of the long head of the biceps femoris (BF) were monitored at 6 occasions (up until 1 year) after injury. The size of the scar / hematoma was reduced by 63.56% (length) and 67.9% (width) after the intervention and it was almost non-traceable one year after injury. The pennation angle of the fascicles underneath the scar showed a decline of 51.4% at the end of the intervention while an increase of 109.2% of the fascicles which were closer to deep aponeurosis was observed. In contrast, pennation angle of fascicles located away from the injury site were relatively unaffected. The treatment intervention resulted in a 57.9% to 77.3% decline of maximum strain per unit of MVC moment and remained similar one year after the intervention. This study provided an example of the potential use of ultrasound-based parameters to link the mechanical adaptations of the injured muscle to specific therapeutic intervention. Key points Changes in fascicle orientation after biceps femoris mild tear were reduced after a 28 day intervention and remained similar one year after injury. Tendon/aponeurosis strain per unit of moment of force decreased during the course of the therapeutic intervention. Future studies could utilize ultrasonography to monitor mechanical responses after various types of hamstring injury and interventions in order to improve criteria for a safe return to sport. PMID:26957929

  2. Feedback of mechanical effectiveness induces adaptations in motor modules during cycling

    PubMed Central

    De Marchis, Cristiano; Schmid, Maurizio; Bibbo, Daniele; Castronovo, Anna Margherita; D'Alessio, Tommaso; Conforto, Silvia

    2013-01-01

    Recent studies have reported evidence that the motor system may rely on a modular organization, even if this behavior has yet to be confirmed during motor adaptation. The aim of the present study is to investigate the modular motor control mechanisms underlying the execution of pedaling by untrained subjects in different biomechanical conditions. We use the muscle synergies framework to characterize the muscle coordination of 11 subjects pedaling under two different conditions. The first one consists of a pedaling exercise with a strategy freely chosen by the subjects (Preferred Pedaling Technique, PPT), while the second condition constrains the gesture by means of a real time visual feedback of mechanical effectiveness (Effective Pedaling Technique, EPT). Pedal forces, recorded using a pair of instrumented pedals, were used to calculate the Index of Effectiveness (IE). EMG signals were recorded from eight muscles of the dominant leg and Non-negative Matrix Factorization (NMF) was applied for the extraction of muscle synergies. All the synergy vectors, extracted cycle by cycle for each subject, were pooled across subjects and conditions and underwent a 2-dimensional Sammon's non-linear mapping. Seven representative clusters were identified on the Sammon's projection, and the corresponding eight-dimensional synergy vectors were used to reconstruct the repertoire of muscle activation for all subjects and all pedaling conditions (VAF > 0.8 for each individual muscle pattern). Only 5 out of the 7 identified modules were used by the subjects during the PPT pedaling condition, while 2 additional modules were found specific for the pedaling condition EPT. The temporal recruitment of three identified modules was highly correlated with IE. The structure of the identified modules was found similar to that extracted in other studies of human walking, partly confirming the existence of shared and task specific muscle synergies, and providing further evidence on the modularity

  3. Oxygen sensing by the carotid body: mechanisms and role in adaptation to hypoxia.

    PubMed

    López-Barneo, José; González-Rodríguez, Patricia; Gao, Lin; Fernández-Agüera, M Carmen; Pardal, Ricardo; Ortega-Sáenz, Patricia

    2016-04-15

    Oxygen (O2) is fundamental for cell and whole-body homeostasis. Our understanding of the adaptive processes that take place in response to a lack of O2(hypoxia) has progressed significantly in recent years. The carotid body (CB) is the main arterial chemoreceptor that mediates the acute cardiorespiratory reflexes (hyperventilation and sympathetic activation) triggered by hypoxia. The CB is composed of clusters of cells (glomeruli) in close contact with blood vessels and nerve fibers. Glomus cells, the O2-sensitive elements in the CB, are neuron-like cells that contain O2-sensitive K(+)channels, which are inhibited by hypoxia. This leads to cell depolarization, Ca(2+)entry, and the release of transmitters to activate sensory fibers terminating at the respiratory center. The mechanism whereby O2modulates K(+)channels has remained elusive, although several appealing hypotheses have been postulated. Recent data suggest that mitochondria complex I signaling to membrane K(+)channels plays a fundamental role in acute O2sensing. CB activation during exposure to low Po2is also necessary for acclimatization to chronic hypoxia. CB growth during sustained hypoxia depends on the activation of a resident population of stem cells, which are also activated by transmitters released from the O2-sensitive glomus cells. These advances should foster further studies on the role of CB dysfunction in the pathogenesis of highly prevalent human diseases. PMID:26764048

  4. Adaptive Physiological Response to Perceived Scarcity as a Mechanism of Sensory Modulation of Life Span.

    PubMed

    Waterson, Michael J; Chan, Tammy P; Pletcher, Scott D

    2015-09-01

    Chemosensation is a potent modulator of organismal physiology and longevity. In Drosophila, loss of recognition of diverse tastants has significant and bidirectional life-span effects. Recently published results revealed that when flies were unable to taste water, they increased its internal generation, which may have subsequently altered life span. To determine whether similar adaptive responses occur in other contexts, we explored the impact of sensory deficiency of other metabolically important molecules. Trehalose is a major circulating carbohydrate in the fly that is recognized by the gustatory receptor Gr5a. Gr5a mutant flies are short lived, and we found that they specifically increased whole-body and circulating levels of trehalose, but not other carbohydrates, likely through upregulation of de novo synthesis. dILP2 transcript levels were increased in Gr5a mutants, a possible response intended to reduce hypertrehalosemia, and likely a contributing factor to their reduced life span. Together, these data suggest that compensatory physiological responses to perceived environmental scarcity, which are designed to alleviate the ostensive shortage, may be a common outcome of sensory manipulation. We suggest that future investigations into the mechanisms underlying sensory modulation of aging may benefit by focusing on direct or indirect consequences of physiological changes that are designed to correct perceived disparity with the environment. PMID:25878032

  5. Adaptation and detoxification mechanisms of Vetiver grass (Chrysopogon zizanioides) growing on gold mine tailings.

    PubMed

    Melato, F A; Mokgalaka, N S; McCrindle, R I

    2016-01-01

    Vetiver grass (Chrysopogon zizanioides) was investigated for its potential use in the rehabilitation of gold mine tailings, its ability to extract and accumulate toxic metals from the tailings and its metal tolerant strategies. Vetiver grass was grown on gold mine tailings soil, in a hothouse, and monitored for sixteen weeks. The mine tailings were highly acidic and had high electrical conductivity. Vetiver grass was able to grow and adapt well on gold mine tailings. The results showed that Vetiver grass accumulated large amounts of metals in the roots and restricted their translocation to the shoots. This was confirmed by the bioconcentration factor of Zn, Cu, and Ni of >1 and the translocation factor of <1 for all the metals. This study revealed the defense mechanisms employed by Vetiver grass against metal stress that include: chelation of toxic metals by phenolics, glutathione S-tranferase, and low molecular weight thiols; sequestration and accumulation of metals within the cell wall that was revealed by the scanning electron microscopy that showed closure of stomata and thickened cell wall and was confirmed by high content of cell wall bound phenolics. Metal induced reactive oxygen species are reduced or eliminated by catalase, superoxide dismutase and peroxidase dismutase. PMID:26588814

  6. Exploration of intraclonal adaptation mechanisms of Pseudomonas brassicacearum facing cadmium toxicity

    PubMed Central

    Pagès, Delphine; Sanchez, Lisa; Conrod, Sandrine; Gidrol, Xavier; Fekete, Agnes; Schmitt-Kopplin, Philippe; Heulin, Thierry; Achouak, Wafa

    2007-01-01

    Pseudomonas brassicacearum forms phenotypic variants in vitro as well as in planta during root colonization under natural conditions, leading to subpopulations (phase I and II cells) that differ in colony morphology and production of exoenzymes/secondary metabolites. The maximal concentration of cadmium allowing both variants growth was 25 μM; however, phase II cells accumulated fivefold higher Cd than phase I cells, even though both variants showed the same growth rate and kinetics, comprising a long stasis period (50 h). The whole transcriptome analysis of both variants in response to Cd was investigated using the home-made DNA microarrays. This analysis revealed completely different adaptation mechanisms developed by each variant to withstand and grow in the presence of the toxic. A re-organization of the cell wall to limit Cd entrance was noticed for phase I cells, as genes encoding levan exopolymers were downregulated at the expense of an upregulation of genes encoding alginate, and an upregulation of transporters such as cadA, and a downregulation of copper transporters. Phase II cells were unable to prevent Cd entrance and recruited genes under the control of oxyR and soxR regulation to face osmotic and oxidant stresses generated by Cd. Putrescine and spermidine metabolism appeared to play a central role in Cd tolerance. Microarray data were validated by biological analyses such as motility, oxidative stress assay, metabolite profiling with ICR-FT/MS and UPLC, capillary electrophoresis analysis of biogenic amines. PMID:17922765

  7. From tetrapods to primates: conserved developmental mechanisms in diverging ecological adaptations.

    PubMed

    Aboitiz, Francisco; Montiel, Juan F

    2012-01-01

    Primates are endowed with a brain about twice the size that of a mammal with the same body size, and humans have the largest brain relative to body size of all animals. This increase in brain size may be related to the acquisition of higher cognitive skills that permitted more complex social interactions, the evolution of culture, and the eventual ability to manipulate the environment. Nevertheless, in its internal structure, the primate brain shares a very conserved design with other mammals, being covered by a six-layered neocortex that, although expands disproportionately to other brain components, it does so following relatively well-defined allometric trends. Thus, the most fundamental events generating the basic design of the primate and human brain took place before the appearance of the first primate-like animal. Presumably, the earliest mammals already displayed a brain morphology radically different from that of their ancestors and that of their sister group, the reptiles, being characterized by the presence of an incipient neocortex that underwent an explosive growth in subsequent mammal evolution. In this chapter, we propose an integrative hypothesis for the origin of the mammalian neocortex, by considering the developmental modifications, functional networks, and ecological adaptations involved in the generation of this structure during the cretaceous period. Subsequently, the expansion of the primate brain is proposed to have relied on the amplification of the same, or very similar, developmental mechanisms as those involved in its primary origins, even in different ecological settings. PMID:22230620

  8. Facets and mechanisms of adaptive pain behavior: predictive regulation and action

    PubMed Central

    Morrison, India; Perini, Irene; Dunham, James

    2013-01-01

    Neural mechanisms underlying nociception and pain perception are considered to serve the ultimate goal of limiting tissue damage. However, since pain usually occurs in complex environments and situations that call for elaborate control over behavior, simple avoidance is insufficient to explain a range of mammalian pain responses, especially in the presence of competing goals. In this integrative review we propose a Predictive Regulation and Action (PRA) model of acute pain processing. It emphasizes evidence that the nervous system is organized to anticipate potential pain and to adjust behavior before the risk of tissue damage becomes critical. Regulatory processes occur on many levels, and can be dynamically influenced by local interactions or by modulation from other brain areas in the network. The PRA model centers on neural substrates supporting the predictive nature of pain processing, as well as on finely-calibrated yet versatile regulatory processes that ultimately affect behavior. We outline several operational categories of pain behavior, from spinally-mediated reflexes to adaptive voluntary action, situated at various neural levels. An implication is that neural processes that track potential tissue damage in terms of behavioral consequences are an integral part of pain perception. PMID:24348358

  9. Reproductive trade-offs in extant hunter-gatherers suggest adaptive mechanism for the Neolithic expansion.

    PubMed

    Page, Abigail E; Viguier, Sylvain; Dyble, Mark; Smith, Daniel; Chaudhary, Nikhil; Salali, Gul Deniz; Thompson, James; Vinicius, Lucio; Mace, Ruth; Migliano, Andrea Bamberg

    2016-04-26

    The Neolithic demographic transition remains a paradox, because it is associated with both higher rates of population growth and increased morbidity and mortality rates. Here we reconcile the conflicting evidence by proposing that the spread of agriculture involved a life history quality-quantity trade-off whereby mothers traded offspring survival for increased fertility, achieving greater reproductive success despite deteriorating health. We test this hypothesis by investigating fertility, mortality, health, and overall reproductive success in Agta hunter-gatherers whose camps exhibit variable levels of sedentarization, mobility, and involvement in agricultural activities. We conducted blood composition tests in 345 Agta and found that viral and helminthic infections as well as child mortality rates were significantly increased with sedentarization. Nonetheless, both age-controlled fertility and overall reproductive success were positively affected by sedentarization and participation in cultivation. Thus, we provide the first empirical evidence, to our knowledge, of an adaptive mechanism in foragers that reconciles the decline in health and child survival with the observed demographic expansion during the Neolithic. PMID:27071109

  10. The local enhancement conundrum: in search of the adaptive value of a social learning mechanism.

    PubMed

    Arbilly, Michal; Laland, Kevin N

    2014-02-01

    Social learning mechanisms are widely thought to vary in their degree of complexity as well as in their prevalence in the natural world. While learning the properties of a stimulus that generalize to similar stimuli at other locations (stimulus enhancement) prima facie appears more useful to an animal than learning about a specific stimulus at a specific location (local enhancement), empirical evidence suggests that the latter is much more widespread in nature. Simulating populations engaged in a producer-scrounger game, we sought to deploy mathematical models to identify the adaptive benefits of reliance on local enhancement and/or stimulus enhancement, and the alternative conditions favoring their evolution. Surprisingly, we found that while stimulus enhancement readily evolves, local enhancement is advantageous only under highly restricted conditions: when generalization of information was made unreliable or when error in social learning was high. Our results generate a conundrum over how seemingly conflicting empirical and theoretical findings can be reconciled. Perhaps the prevalence of local enhancement in nature is due to stimulus enhancement costs independent of the learning task itself (e.g. predation risk), perhaps natural habitats are often characterized by unreliable yet highly rewarding payoffs, or perhaps local enhancement occurs less frequently, and stimulus enhancement more frequently, than widely believed. PMID:24044984

  11. How they cope: a qualitative study of the coping skills of hospice volunteers.

    PubMed

    Brown, Mary V

    2011-09-01

    The purpose of this phenomenological study was to examine the coping techniques utilized by hospice volunteers. Individual semi-structured interviews were conducted with 15 hospice volunteers who had at least 1 year of experience, working as a hospice volunteer with direct patient care. The interviews were digitally recorded, transcribed, and analyzed utilizing qualitative research methods. The results indicated the volunteers used problem-focused coping (seeking advice from members of the hospice interdisciplinary team), emotion-focused coping (talking with others, going to funerals), meaning making through appraisal (religious beliefs, downward comparison), and physical techniques (walking, deep breathing). The most significant coping mechanism utilized for the volunteer was talking with the volunteer coordinator. Implications for hospice volunteer coordinators are also discussed. PMID:21262760

  12. An investigation of coping styles of hemodialysis patients

    PubMed Central

    Dehkordi, Leila Mardanian; Shahgholian, Nahid

    2013-01-01

    Background: Hemodialysis patients are exposed to different stressful factors and have to use coping strategies as supportive processes. The goal of the present study is to investigate coping styles of hemodialysis patients. Materials and Methods: This is a descriptive analytical study conducted on 96 patients referring to hemodialysis centers affiliated to Isfahan University of Medical Sciences in 2011. The data, collected by a questionnaire including two sections of demographic characteristics and patients’ coping with the disease, were analyzed by parametric and non- parametric statistical tests. Results: Patients used emotion focused coping strategies more (mean = 20.07, SD = 4.39) to adapt with the disease compared to problem focused coping strategies (mean = 14.65, SD = 5.08). There was a significant association in coping (P = 0.027) and emotion focused dimension (P = 0.008) in various ages, but there was no significant association in problem focused dimension (P = 0.134). Conclusion: Since most of the hemodialysis patients use emotion focused coping styles, it is suggested to consider educational programs on application of problem focused coping styles for these patients in order to decrease the pressures of the disease and treatment, and to promote their mental health, quality of life and efficiency. PMID:23983727

  13. Coping With Stress Strategies in HIV-infected Iranian Patients.

    PubMed

    Mahmoudi, Maryam; Dehdari, Tahereh; Shojaeezadeh, Davoud; Abbasian, Ladan

    2015-01-01

    Stress has significant adverse impacts on health outcomes of HIV-infected patients. Our study explored coping with stress strategies by HIV-infected Iranian patients. A qualitative content analysis study was conducted at the Consultation Clinic of HIV at the Imam Khomeini Hospital in Tehran, Iran in 2012. Twenty-six semi-structured in-depth interviews were done. Participants were asked about coping strategies for stress. After the first interview, continuous analysis of data was started and continued up to data saturation. Results showed that participants used two categories of strategies (emotion-based coping and problem-based coping) to cope with stress. Emotion-based coping had two sub-themes: adaptive and maladaptive. The problem-based coping category had three sub-themes: participation in education sessions, adherence to medication, and efforts to maintain a healthy lifestyle. Explanations of different strategies available to HIV-infected patients to cope with stress may help develop tailored interventions to improve the psychological conditions of people living with HIV. PMID:25769759

  14. Curcumin-releasing mechanically adaptive intracortical implants improve the proximal neuronal density and blood-brain barrier stability.

    PubMed

    Potter, Kelsey A; Jorfi, Mehdi; Householder, Kyle T; Foster, E Johan; Weder, Christoph; Capadona, Jeffrey R

    2014-05-01

    The cellular and molecular mechanisms by which neuroinflammatory pathways respond to and propagate the reactive tissue response to intracortical microelectrodes remain active areas of research. We previously demonstrated that both the mechanical mismatch between rigid implants and the much softer brain tissue, as well as oxidative stress, contribute to the neurodegenerative reactive tissue response to intracortical implants. In this study, we utilize physiologically responsive, mechanically adaptive polymer implants based on poly(vinyl alcohol) (PVA), with the capability to also locally administer the antioxidant curcumin. The goal of this study is to investigate if the combination of two independently effective mechanisms - softening of the implant and antioxidant release - leads to synergistic effects in vivo. Over the first 4weeks of the implantation, curcumin-releasing, mechanically adaptive implants were associated with higher neuron survival and a more stable blood-brain barrier at the implant-tissue interface than the neat PVA controls. 12weeks post-implantation, the benefits of the curcumin release were lost, and both sets of compliant materials (with and without curcumin) had no statistically significant differences in neuronal density distribution profiles. Overall, however, the curcumin-releasing softening polymer implants cause minimal implant-mediated neuroinflammation, and embody the new concept of localized drug delivery from mechanically adaptive intracortical implants. PMID:24468582

  15. Vestibulospinal adaptation to microgravity

    NASA Technical Reports Server (NTRS)

    Paloski, W. H.

    1998-01-01

    Human balance control is known to be transiently disrupted after spaceflight; however, the mechanisms responsible for postflight postural ataxia are still under investigation. In this report, we propose a conceptual model of vestibulospinal adaptation based on theoretical adaptive control concepts and supported by the results from a comprehensive study of balance control recovery after spaceflight. The conceptual model predicts that immediately after spaceflight the balance control system of a returning astronaut does not expect to receive gravity-induced afferent inputs and that descending vestibulospinal control of balance is disrupted until the central nervous system is able to cope with the newly available vestibular otolith information. Predictions of the model are tested using data from a study of the neurosensory control of balance in astronauts immediately after landing. In that study, the mechanisms of sensorimotor balance control were assessed under normal, reduced, and/or altered (sway-referenced) visual and somatosensory input conditions. We conclude that the adaptive control model accurately describes the neurobehavioral responses to spaceflight and that similar models of altered sensory, motor, or environmental constraints are needed clinically to predict responses that patients with sensorimotor pathologies may have to various visual-vestibular or changing stimulus environments.

  16. Stress in College Athletics: Causes, Consequences, Coping.

    ERIC Educational Resources Information Center

    Humphrey, James H.; Yow, Deborah A.; Bowden, William W.

    This book addresses the causes and consequences of stress in college sports and offers effective coping mechanisms to help individuals understand and control stressors and emotions in their environment. The chapters are: (1) "Understanding Stress"; (2) "Perceptions of Stress in College Athletics"; (3) "Stress among College Athletes"; (4) "Stress…

  17. [Urbanization mechanisms in bird species: population systems transformations or adaptations at the individual level?].

    PubMed

    Fridman, V S; Eremkin, G S; Zakharova-Kubareva, N Iu

    2008-01-01

    The present research deals with urbanization of wild bird and mammal species. Forms and mechanisms of population steadiness in the urban landscape have been examined. The urbanization process turned out to be a directed change of the population system forming de novo in the urbolandscape leading to a sustainable organization peculiar for the particular environment. The population organization of different types in urbolandscape is found to provide its stability under conditions of directed and fast changes accompanied with instability and heterogenous structure of habitats. It is shown that the same type of population organization meets the corresponding demands among different species settling in the urban environment. Its features are "openness" and "flowage" of the groups, far order of settlement levels and other units of population system, constant movements of the individuals between the groups as a respond to the signals of urboenvironment significant changes. The "urban" variant of the population system organization turns out to be opposite to that of the same species in the non-urban habitats. After formation of the urban types by the species and successful developing of the town, the urban population becomes separated from the maternal local population and begins to exist independently in the urban landscape. The variety of adaptation aberrations in ecology, behavior, and mode of life of urban birds is the population system stability function in the urban landscape and is not a results of individual selection. It is shown that the urbanization process of the species goes firstly on the population level being the system structure transformation developed by the species towards the most stable state in the town (city) territory. Only after the appearance of stable urban population, the urban individuals show the rapid growth of different changes in ecology, behavior, mode of life that was traditionally described by naturalists as species adaptation to the

  18. Mistakes were made: neural mechanisms for the adaptive control of action initiation by the medial prefrontal cortex.

    PubMed

    Laubach, Mark; Caetano, Marcelo S; Narayanan, Nandakumar S

    2015-01-01

    Studies in rats, monkeys and humans have established that the medial prefrontal cortex is crucial for the ability to exert adaptive control over behavior. Here, we review studies on the role of the rat medial prefrontal cortex in adaptive control, with a focus on simple reaction time tasks that can be easily used across species and have clinical relevance. The performance of these tasks is associated with neural activity in the medial prefrontal cortex that reflects stimulus detection, action timing, and outcome monitoring. We describe rhythmic neural activity that occurs when animals initiate a temporally extended action. Such rhythmic activity is coterminous with major changes in population spike activity. Testing animals over a series of sessions with varying pre-stimulus intervals showed that the signals adapt to the current temporal demands of the task. Disruptions of rhythmic neural activity occur on error trials (premature responding) and lead to a persistent encoding of the error and a subsequent change in behavioral performance (i.e. post-error slowing). Analysis of simultaneously recorded spike activity suggests that the presence of strong theta rhythms is coterminous with altered network dynamics, and might serve as a mechanism for adaptive control. Computational modeling suggests that these signals may enable learning from errors. Together, our findings contribute to an emerging literature and provide a new perspective on the neuronal mechanisms for the adaptive control of action. PMID:25636373

  19. Coping with Jealousy: The Association between Maladaptive Aspects of Jealousy and Drinking Problems are Mediated by Drinking to Cope

    PubMed Central

    DiBello, Angelo M.; Neighbors, Clayton; Rodriguez, Lindsey M.; Lindgren, Kristen

    2013-01-01

    Previous research has shown that both alcohol use and jealousy are related to negative relationship outcomes. Little work, however, has examined direct associations between alcohol use and jealousy. The current study aimed to build upon existing research examining alcohol use and jealousy. More specifically, findings from current jealousy literature indicate that jealousy is a multifaceted construct with both maladaptive and adaptive aspects. The current study examined the association between maladaptive and adaptive feelings of jealousy and alcohol-related problems in the context of drinking to cope. Given the relationship between coping motives and alcohol-related problems, our primary interest was in predicting alcohol-related problems, but alcohol consumption was also investigated. Undergraduate students at a large Northwestern university (N = 657) in the US participated in the study. They completed measures of jealousy, drinking to cope, alcohol use, and alcohol-related problems. Analyses examined associations between jealousy subscales, alcohol use, drinking to cope, and drinking problems. Results indicated that drinking to cope mediated the association between some, but not all, aspects of jealousy and problems with alcohol use. In particular, the more negative or maladaptive aspects of jealousy were related to drinking to cope and drinking problems, while the more adaptive aspects were not, suggesting a more complex view of jealousy than previously understood. PMID:24138965

  20. Impact of Age, and Cognitive and Coping Resources on Coping

    ERIC Educational Resources Information Center

    Trouillet, Raphael; Doan-Van-Hay, Loane-Martine; Launay, Michel; Martin, Sophie

    2011-01-01

    To explore the predictive value of cognitive and coping resources for problem- and emotion-focused coping with age, we collected data from community-dwelling adults between 20 and 90 years old. We hypothesized that age, perceived stress, self-efficacy, working-memory capacity, and mental flexibility were predictors of coping. We collected data…

  1. At Home with MS: Adapting Your Environment

    MedlinePlus

    ... of things you almost never need. Your storage adaptations may include hanging baskets, rolling storage carts, peg ... living at home with a disability. n Any adaptation or renovation to help you cope with MS ...

  2. Coping Style and Quality of Life in Elderly Patients with Vision Disturbances

    PubMed Central

    Oles, Maria

    2014-01-01

    Purpose. This study aims at evaluating coping style and quality of life in patients with glaucoma and cataract. Methods. The participants were patients (N = 237, 130F; mean age: M = 67,8; SD = 9,5) with low vision caused by cataract (N = 188) and glaucoma (N = 49) who answered the Quality of Life Questionnaire (QOLQ) by Schalock and Keith. The participants were divided by means of cluster analysis (k-means) according to coping styles measured by CISS (Endler and Parker) into three groups: (1) high mobilization for coping, (2) task-oriented coping, and (3) low mobilization for coping. Results. In all the group, a general quality of life was moderately lowered; however, in task-oriented group it was relatively high. Moreover, task-oriented group had significantly lower level of anxiety (STAI), hopelessness (HS), and loneliness (UCLA LS-R) and higher level of self-esteem (SES) in comparison to the patients from high mobilization and low mobilization for coping. Conclusions. In an old age, adaptive coping with vision disturbances does not necessarily mean flexibility in combining all coping styles, but rather task-oriented coping and an ability to use social support. Extreme mobilization for coping seems not adaptive similarly like low mobilization for coping because it violates balance between environmental requirements and personal resources. PMID:25215225

  3. Design of an Adaptive Power Regulation Mechanism and a Nozzle for a Hydroelectric Power Plant Turbine Test Rig

    NASA Astrophysics Data System (ADS)

    Mert, Burak; Aytac, Zeynep; Tascioglu, Yigit; Celebioglu, Kutay; Aradag, Selin; ETU Hydro Research Center Team

    2014-11-01

    This study deals with the design of a power regulation mechanism for a Hydroelectric Power Plant (HEPP) model turbine test system which is designed to test Francis type hydroturbines up to 2 MW power with varying head and flow(discharge) values. Unlike the tailor made regulation mechanisms of full-sized, functional HEPPs; the design for the test system must be easily adapted to various turbines that are to be tested. In order to achieve this adaptability, a dynamic simulation model is constructed in MATLAB/Simulink SimMechanics. This model acquires geometric data and hydraulic loading data of the regulation system from Autodesk Inventor CAD models and Computational Fluid Dynamics (CFD) analysis respectively. The dynamic model is explained and case studies of two different HEPPs are performed for validation. CFD aided design of the turbine guide vanes, which is used as input for the dynamic model, is also presented. This research is financially supported by Turkish Ministry of Development.

  4. Coping by Caring.

    ERIC Educational Resources Information Center

    Lidstone, Sheila S.

    1992-01-01

    Describes a Texas elementary school's efforts to cope with the special needs of Kenneth, a fourth grader slowly dying of kidney cancer. Besides learning their subjects like other students, Kenneth's classmates learned how to care. Every student volunteered to be Kenneth's assistant and was enriched by the boy's positive attitude and determination…

  5. Coping with Computing Success.

    ERIC Educational Resources Information Center

    Breslin, Richard D.

    Elements of computing success of Iona College, the challenges it currently faces, and the strategies conceived to cope with future computing needs are discussed. The college has mandated computer literacy for students and offers nine degrees in the computerized information system/management information system areas. Since planning is needed in…

  6. Incarceration, Coping, and Support.

    ERIC Educational Resources Information Center

    Carlson, Bonnie E.; Cervera, Neil J.

    1991-01-01

    Examined effects of incarceration on family life among 63 inmates and 38 inmate wives. Contrasted those who participated in Family Reunion (conjugal visits) Program with nonparticipants. Found that coping was in normal range for both groups of inmates and wives and, except for measures of wives' passive appraisal, did not differ according to…

  7. Molecular adaptations in Antarctic fish and bacteria

    NASA Astrophysics Data System (ADS)

    Russo, Roberta; Riccio, Alessia; di Prisco, Guido; Verde, Cinzia; Giordano, Daniela

    2010-08-01

    Marine organisms, living in the cold waters of the Southern Ocean, are exposed to high oxygen concentrations. Cold-adapted organisms have developed networks of defence mechanisms to protect themselves against oxidative stress. The dominant suborder Notothenioidei of the Southern Ocean is one of the most interesting models, within vertebrates, to study the evolutionary biological responses to extreme environment. Within bacteria, the psychrophilic Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 gives the opportunity to explore the cellular strategies adopted in vivo by cold-adapted microorganisms to cope with cold and high oxygen concentration. Understanding the molecular mechanisms underlying how a range of Antarctic organisms have responded to climate change in the past will enable predictions as to how they and other species will adapt to global climate change, in terms of physiological function, distribution patterns and ecosystem balance.

  8. Agricultural Intensification as a Mechanism of Adaptation to Climate Change Impacts

    NASA Astrophysics Data System (ADS)

    Kyle, P.; Calvin, K. V.; le Page, Y.; Patel, P.; West, T. O.; Wise, M. A.

    2015-12-01

    The research, policy, and NGO communities have devoted significant attention to the potential for agricultural intensification, or closure of "yield gaps," to alleviate future global hunger, poverty, climate change impacts, and other threats. However, because the research to this point has focused on biophysically attainable yields—assuming optimal choices under ideal conditions—the presently available work has not yet addressed the likely responses of the agricultural sector to real-world conditions in the future. This study investigates endogenous agricultural intensification in response to global climate change impacts—that is, intensification independent of policies or other exogenous interventions to promote yield gap closure. The framework for the analysis is a set of scenarios to 2100 in the GCAM global integrated assessment model, enhanced to include endogenous irrigation, fertilizer application, and yields, in each of 283 land use regions, with maximum yields based on the 95th percentile of attainable yields in a recent global assessment. We assess three levels of agricultural climate impacts, using recent global gridded crop model datasets: none, low (LPJmL), and high (Pegasus). Applying formulations for decomposition of climate change impacts response developed in prior AgMIP work, we find that at the global level, availability of high-yielding technologies mitigates price shocks and shifts the agricultural sector's climate response modestly towards intensification, away from cropland expansion and reduced production. At the regional level, the behavior is more complex; nevertheless, availability of high-yielding production technologies enhances the inter-regional shifts in agricultural production that are induced by climate change, complemented by commensurate changes in trade patterns. The results highlight the importance of policies to facilitate yield gap closure and inter-regional trade as mechanisms for adapting to climate change

  9. Adaptation of the Black Yeast Wangiella dermatitidis to Ionizing Radiation: Molecular and Cellular Mechanisms

    PubMed Central

    Robertson, Kelly L.; Mostaghim, Anahita; Cuomo, Christina A.; Soto, Carissa M.; Lebedev, Nikolai; Bailey, Robert F.; Wang, Zheng

    2012-01-01

    Observations of enhanced growth of melanized fungi under low-dose ionizing radiation in the laboratory and in the damaged Chernobyl nuclear reactor suggest they have adapted the ability to survive or even benefit from exposure to ionizing radiation. However, the cellular and molecular mechanism of fungal responses to such radiation remains poorly understood. Using the black yeast Wangiella dermatitidis as a model, we confirmed that ionizing radiation enhanced cell growth by increasing cell division and cell size. Using RNA-seq technology, we compared the transcriptomic profiles of the wild type and the melanin-deficient wdpks1 mutant under irradiation and non-irradiation conditions. It was found that more than 3000 genes were differentially expressed when these two strains were constantly exposed to a low dose of ionizing radiation and that half were regulated at least two fold in either direction. Functional analysis indicated that many genes for amino acid and carbohydrate metabolism and cell cycle progression were down-regulated and that a number of antioxidant genes and genes affecting membrane fluidity were up-regulated in both irradiated strains. However, the expression of ribosomal biogenesis genes was significantly up-regulated in the irradiated wild-type strain but not in the irradiated wdpks1 mutant, implying that melanin might help to contribute radiation energy for protein translation. Furthermore, we demonstrated that long-term exposure to low doses of radiation significantly increased survivability of both the wild-type and the wdpks1 mutant, which was correlated with reduced levels of reactive oxygen species (ROS), increased production of carotenoid and induced expression of genes encoding translesion DNA synthesis. Our results represent the first functional genomic study of how melanized fungal cells respond to low dose ionizing radiation and provide clues for the identification of biological processes, molecular pathways and individual genes

  10. Adaptation of the black yeast Wangiella dermatitidis to ionizing radiation: molecular and cellular mechanisms.

    PubMed

    Robertson, Kelly L; Mostaghim, Anahita; Cuomo, Christina A; Soto, Carissa M; Lebedev, Nikolai; Bailey, Robert F; Wang, Zheng

    2012-01-01

    Observations of enhanced growth of melanized fungi under low-dose ionizing radiation in the laboratory and in the damaged Chernobyl nuclear reactor suggest they have adapted the ability to survive or even benefit from exposure to ionizing radiation. However, the cellular and molecular mechanism of fungal responses to such radiation remains poorly understood. Using the black yeast Wangiella dermatitidis as a model, we confirmed that ionizing radiation enhanced cell growth by increasing cell division and cell size. Using RNA-seq technology, we compared the transcriptomic profiles of the wild type and the melanin-deficient wdpks1 mutant under irradiation and non-irradiation conditions. It was found that more than 3000 genes were differentially expressed when these two strains were constantly exposed to a low dose of ionizing radiation and that half were regulated at least two fold in either direction. Functional analysis indicated that many genes for amino acid and carbohydrate metabolism and cell cycle progression were down-regulated and that a number of antioxidant genes and genes affecting membrane fluidity were up-regulated in both irradiated strains. However, the expression of ribosomal biogenesis genes was significantly up-regulated in the irradiated wild-type strain but not in the irradiated wdpks1 mutant, implying that melanin might help to contribute radiation energy for protein translation. Furthermore, we demonstrated that long-term exposure to low doses of radiation significantly increased survivability of both the wild-type and the wdpks1 mutant, which was correlated with reduced levels of reactive oxygen species (ROS), increased production of carotenoid and induced expression of genes encoding translesion DNA synthesis. Our results represent the first functional genomic study of how melanized fungal cells respond to low dose ionizing radiation and provide clues for the identification of biological processes, molecular pathways and individual genes

  11. Innate and adaptive T cells in asthmatic patients: Relationship to severity and disease mechanisms

    PubMed Central

    Hinks, Timothy S.C.; Zhou, Xiaoying; Staples, Karl J.; Dimitrov, Borislav D.; Manta, Alexander; Petrossian, Tanya; Lum, Pek Y.; Smith, Caroline G.; Ward, Jon A.; Howarth, Peter H.; Walls, Andrew F.; Gadola, Stephan D.; Djukanović, Ratko

    2015-01-01

    Background Asthma is a chronic inflammatory disease involving diverse cells and mediators whose interconnectivity and relationships to asthma severity are unclear. Objective We performed a comprehensive assessment of TH17 cells, regulatory T cells, mucosal-associated invariant T (MAIT) cells, other T-cell subsets, and granulocyte mediators in asthmatic patients. Methods Sixty patients with mild-to-severe asthma and 24 control subjects underwent detailed clinical assessment and provided induced sputum, endobronchial biopsy, bronchoalveolar lavage, and blood samples. Adaptive and invariant T-cell subsets, cytokines, mast cells, and basophil mediators were analyzed. Results Significant heterogeneity of T-cell phenotypes was observed, with levels of IL-13–secreting T cells and type 2 cytokines increased at some, but not all, asthma severities. TH17 cells and γδ-17 cells, proposed drivers of neutrophilic inflammation, were not strongly associated with asthma, even in severe neutrophilic forms. MAIT cell frequencies were strikingly reduced in both blood and lung tissue in relation to corticosteroid therapy and vitamin D levels, especially in patients with severe asthma in whom bronchoalveolar lavage regulatory T-cell numbers were also reduced. Bayesian network analysis identified complex relationships between pathobiologic and clinical parameters. Topological data analysis identified 6 novel clusters that are associated with diverse underlying disease mechanisms, with increased mast cell mediator levels in patients with severe asthma both in its atopic (type 2 cytokine–high) and nonatopic forms. Conclusion The evidence for a role for TH17 cells in patients with severe asthma is limited. Severe asthma is associated with a striking deficiency of MAIT cells and high mast cell mediator levels. This study provides proof of concept for disease mechanistic networks in asthmatic patients with clusters that could inform the development of new therapies. PMID:25746968

  12. Musical training generalises across modalities and reveals efficient and adaptive mechanisms for reproducing temporal intervals.

    PubMed

    Aagten-Murphy, David; Cappagli, Giulia; Burr, David

    2014-03-01

    Expert musicians are able to time their actions accurately and consistently during a musical performance. We investigated how musical expertise influences the ability to reproduce auditory intervals and how this generalises across different techniques and sensory modalities. We first compared various reproduction strategies and interval length, to examine the effects in general and to optimise experimental conditions for testing the effect of music, and found that the effects were robust and consistent across different paradigms. Focussing on a 'ready-set-go' paradigm subjects reproduced time intervals drawn from distributions varying in total length (176, 352 or 704 ms) or in the number of discrete intervals within the total length (3, 5, 11 or 21 discrete intervals). Overall, Musicians performed more veridical than Non-Musicians, and all subjects reproduced auditory-defined intervals more accurately than visually-defined intervals. However, Non-Musicians, particularly with visual stimuli, consistently exhibited a substantial and systematic regression towards the mean interval. When subjects judged intervals from distributions of longer total length they tended to regress more towards the mean, while the ability to discriminate between discrete intervals within the distribution had little influence on subject error. These results are consistent with a Bayesian model that minimizes reproduction errors by incorporating a central tendency prior weighted by the subject's own temporal precision relative to the current distribution of intervals. Finally a strong correlation was observed between all durations of formal musical training and total reproduction errors in both modalities (accounting for 30% of the variance). Taken together these results demonstrate that formal musical training improves temporal reproduction, and that this improvement transfers from audition to vision. They further demonstrate the flexibility of sensorimotor mechanisms in adapting to

  13. Children Coping with Chronic Illness.

    ERIC Educational Resources Information Center

    Perez, Lissette M.

    Children who live with chronic illness are confronted with challenges that frequently force them to cope in myriad ways. The ways in which children face chronic illness are summarized in this literature review. Also covered, are how the effects of family can influence coping strategies and how family members, especially parents, cope with their…

  14. Adult Coping with Childhood Sexual Abuse: A Theoretical and Empirical Review

    PubMed Central

    Walsh, Kate; Fortier, Michelle A.; DiLillo, David

    2009-01-01

    Coping has been suggested as an important element in understanding the long-term functioning of individuals with a history of child sexual abuse (CSA). The present review synthesizes the literature on coping with CSA, first by examining theories of coping with trauma, and, second by examining how these theories have been applied to studies of coping in samples of CSA victims. Thirty-nine studies were reviewed, including eleven descriptive studies of the coping strategies employed by individuals with a history of CSA, eighteen correlational studies of the relationship between coping strategies and long-term functioning of CSA victims, and ten investigations in which coping was examined as a mediational factor in relation to long-term outcomes. These studies provide initial information regarding early sexual abuse and subsequent coping processes. However, this literature is limited by several theoretical and methodological issues, including a failure to specify the process of coping as it occurs, a disparity between theory and research, and limited applicability to clinical practice. Future directions of research are discussed and include the need to understand coping as a process, identification of coping in relation to adaptive outcomes, and considerations of more complex mediational and moderational processes in the study of coping with CSA. PMID:20161502

  15. Black Canadians' Coping Responses to Racial Discrimination

    ERIC Educational Resources Information Center

    Joseph, Justine; Kuo, Ben C. H.

    2009-01-01

    On the basis of a cultural coping framework, the present study examined coping responses to racial discrimination among 190 Black Canadians. The study assessed the respondents' coping with both general (i.e., problem- and emotion-focused coping) and Africultural coping strategies (i.e., spiritual-centered, collective, and ritual-centered coping)…

  16. Coping strategies of Spanish pregnant women and their impact on anxiety and depression.

    PubMed

    Peñacoba-Puente, Cecilia; Carmona-Monge, Francisco Javier; Marín-Morales, Dolores; Naber, Katharina

    2013-02-01

    The aims of this study were to analyze the coping strategies used by women in the first trimester of low-risk pregnancies, their relationships to sociodemographic and pregnancy variables, and their ability to predict anxiety and depression in the third trimester. Participants in the first trimester were 285 Spanish pregnant women, of whom 122 were followed into the third trimester. The use of problem-focused coping was stable, whereas variations occurred in emotion-focused coping. Age, educational level, employment, planned pregnancy, previous childbirth, and previous miscarriage were associated with adaptive coping. Coping strategies predicting anxiety and depressive symptoms were overt emotional expression and social support seeking. Coping through religion predicted anxiety. Coping is a complex process influenced by sociodemographic and obstetric factors that can contribute to the onset of psychological symptoms. PMID:23080536

  17. Neural adaptations to resistive exercise: mechanisms and recommendations for training practices.

    PubMed

    Gabriel, David A; Kamen, Gary; Frost, Gail

    2006-01-01

    It is generally accepted that neural factors play an important role in muscle strength gains. This article reviews the neural adaptations in strength, with the goal of laying the foundations for practical applications in sports medicine and rehabilitation. An increase in muscular strength without noticeable hypertrophy is the first line of evidence for neural involvement in acquisition of muscular strength. The use of surface electromyographic (SEMG) techniques reveal that strength gains in the early phase of a training regimen are associated with an increase in the amplitude of SEMG activity. This has been interpreted as an increase in neural drive, which denotes the magnitude of efferent neural output from the CNS to active muscle fibres. However, SEMG activity is a global measure of muscle activity. Underlying alterations in SEMG activity are changes in motor unit firing patterns as measured by indwelling (wire or needle) electrodes. Some studies have reported a transient increase in motor unit firing rate. Training-related increases in the rate of tension development have also been linked with an increased probability of doublet firing in individual motor units. A doublet is a very short interspike interval in a motor unit train, and usually occurs at the onset of a muscular contraction. Motor unit synchronisation is another possible mechanism for increases in muscle strength, but has yet to be definitely demonstrated. There are several lines of evidence for central control of training-related adaptation to resistive exercise. Mental practice using imagined contractions has been shown to increase the excitability of the cortical areas involved in movement and motion planning. However, training using imagined contractions is unlikely to be as effective as physical training, and it may be more applicable to rehabilitation. Retention of strength gains after dissipation of physiological effects demonstrates a strong practice effect. Bilateral contractions are

  18. Diversity of CRISPR-Cas-Mediated Mechanisms of Adaptive Immunity in Prokaryotes and Their Application in Biotechnology.

    PubMed

    Savitskaya, E E; Musharova, O S; Severinov, K V

    2016-07-01

    CRISPR-Cas systems of adaptive immunity in prokaryotes consist of CRISPR arrays (clusters of short repeated genomic DNA fragments separated by unique spacer sequences) and cas (CRISPR-associated) genes that provide cells with resistance against bacteriophages and plasmids containing protospacers, i.e. sequences complementary to CRISPR array spacers. CRISPR-Cas systems are responsible for two different cellular phenomena: CRISPR adaptation and CRISPR interference. CRISPR adaptation is cell genome modification by integration of new spacers that represents a unique case of Lamarckian inheritance. CRISPR interference involves specific recognition of protospacers in foreign DNA followed by introduction of breaks into this DNA and its destruction. According to the mechanisms of action, CRISPR-Cas systems have been subdivided into two classes, five types, and numerous subtypes. The development of techniques based on CRISPR interference mediated by the Type II system Cas9 protein has revolutionized the field of genome editing because it allows selective, efficient, and relatively simple introduction of directed breaks into target DNA loci. However, practical applications of CRISPR-Cas systems are not limited only to genome editing. In this review, we focus on the variety of CRISPR interference and CRISPR adaptation mechanisms and their prospective use in biotechnology. PMID:27449612

  19. Development of the PROMIS® Coping Expectancies of Smoking Item Banks

    PubMed Central

    Edelen, Maria Orlando; Tucker, Joan S.; Stucky, Brian D.; Hansen, Mark; Cai, Li

    2014-01-01

    Objective: Smoking is a coping strategy for many smokers who then have difficulty finding new ways to cope with negative affect when they quit. This paper describes analyses conducted to develop and evaluate item banks for assessing the coping expectancies of smoking for daily and nondaily smokers. Methods: Using data from a large sample of daily (N = 4,201) and nondaily (N = 1,183) smokers, we conducted a series of item factor analyses, item response theory analyses, and differential item functioning (DIF) analyses (according to gender, age, and ethnicity) to arrive at a unidimensional set of items for daily and nondaily smokers. We also evaluated performance of short forms (SFs) and computer adaptive tests (CATs) for assessing coping expectancies of smoking. Results: For both daily and nondaily smokers, the unidimensional Coping Expectancies item banks (21 items) are relatively DIF free and are highly reliable (0.96 and 0.97, respectively). A common 4-item SF for daily and nondaily smokers also showed good reliability (0.85). Adaptive tests required an average of 4.3 and 3.7 items for simulated daily and nondaily respondents, respectively, and achieved reliabilities of 0.91 for both when the maximum test length was 10 items. Conclusions: This research provides a new set of items that can be used to reliably assess coping expectancies of smoking, through a SF, CAT, or a tailored set selected for a specific research purpose. PMID:25118227

  20. Adaptive mechanisms of insect pests against plant protease inhibitors and future prospects related to crop protection: a review.

    PubMed

    Macedo, Maria L R; de Oliveira, Caio F R; Costa, Poliene M; Castelhano, Elaine C; Silva-Filho, Marcio C

    2015-01-01

    The overwhelming demand for food requires the application of technology on field. An important issue that limits the productivity of crops is related to insect attacks. Hence, several studies have evaluated the application of different compounds to reduce the field losses, especially insecticide compounds from plant sources. Among them, plant protease inhibitors (PIs) have been studied in both basic and applied researches, displaying positive results in control of some insects. However, certain species are able to bypass the insecticide effects exerted by PIs. In this review, we disclosed the adaptive mechanisms showed by lepidopteran and coleopteran insects, the most expressive insect orders related to crop predation. The structural aspects involved in adaptation mechanisms are presented as well as the newest alternatives for pest control. The application of biotechnological tools in crop protection will be mandatory in agriculture, and it will be up to researchers to find the best candidates for effective control in long-term. PMID:25329404

  1. Chronic sorrow and coping in families of children with epilepsy.

    PubMed

    Hobdell, Elizabeth F; Grant, Mitzie L; Valencia, Ignacio; Mare, Jane; Kothare, Sanjeev V; Legido, Agustin; Khurana, Divya S

    2007-04-01

    Epilepsy, a common problem in child neurology, affects the entire family. There is a potential for such psychosocial consequences as parental chronic sorrow and alterations in coping. In this study, 67 parents completed brief questionnaires about their sorrow and coping styles. Results demonstrated chronic sorrow as measured by the Adapted Burke Questionnaire (10.45 +/- 7.9). Interestingly, the total score was not significantly different between parents of children with refractory and nonrefractory epilepsy or parents of children with comorbid or without comorbid conditions. Selection of the individual item disbelief, however, was significantly increased in parents of children with nonrefractory epilepsy, and selection of the item anger was significantly increased in parents of children with comorbid conditions. Parental coping styles were similar to those reported in the normative data for the instrument used, the Coping Health Inventory for Parents (CHIP). The correlation between chronic sorrow and coping was significant between the grief component of sorrow and Coping Pattern II of the CHIP. Implications for practice include earlier identification of parental feelings of sorrow and coping styles, which may contribute to a positive outcome. PMID:17477221

  2. Insights into Mechanisms and Proteomic Characterisation of Pseudomonas aeruginosa Adaptation to a Novel Antimicrobial Substance

    PubMed Central

    Cierniak, Peter; Jübner, Martin; Müller, Stefan; Bender, Katja

    2013-01-01

    Antibiotic resistance has been reported since the introduction of synthetic antibiotics. Bacteria, such as one of the most common nosocomial pathogens P. aeruginosa, adapt quickly to changing environmental conditions, due to their short generation time. Thus microevolutional changes can be monitored in situ. In this study, the microevolutional process of Pseudomonas aeruginosa PAO1 resistance against a recently developed novel antibacterial zinc Schiff-base (ZSB) was investigated at the proteome level. After extended exposure to ZSB the passaged strain differed in tolerance against ZSB, with the adapted P. aeruginosa PAO1 exhibiting 1.6 times higher minimal inhibitory concentration. Using Two-dimensional Difference Gel Electrophoresis, the changes in the proteome of ZSB adapted P. aeruginosa PAO1 were examined by comparison with the non-adapted P. aeruginosa PAO1. The proteome of the adapted P. aeruginosa PAO1 strain differed significantly from the non-adapted in the abundance of two proteins when both strains were grown under stressing conditions. One protein could be identified as the outer membrane protein D that plays a role in uptake of basic amino acids as well as in carbapeneme resistance. The second protein has been identified as alkyl peroxide reductase subunit F. Our data indicated a slight increase in abundance of alkyl peroxide reductase F (AhpF) in the case of ZSB passaged P. aeruginosa PAO1. Higher abundance of Ahp has been discussed in the literature as a promoter of accelerated detoxification of benzene derivatives. The observed up-regulated AhpF thus appears to be connected to an increased tolerance against ZSB. Changes in the abundance of proteins connected to oxidative stress were also found after short-time exposure of P. aeruginosa PAO1 to the ZSB. Furthermore, adapted P. aeruginosa PAO1 showed increased tolerance against hydrogen peroxide and, in addition, showed accelerated degradation of ZSB, as determined by HPLC measurements. PMID:23869205

  3. Mindfulness Training Improves Problem-Focused Coping in Psychology and Medical Students: Results from a Randomized Controlled Trial

    ERIC Educational Resources Information Center

    Halland, E.; De Vibe, M.; Solhaug, I.; Friborg, O.; Rosenvinge, J. H.; Tyssen, R.; Sørlie, T.; Bjørndal, A.

    2015-01-01

    Background: Students of clinical psychology and medicine experience high levels of mental distress and low levels of life satisfaction. Using adaptive coping strategies can modify the negative effect of stressors on health. Mindfulness, it has been claimed, more adaptive coping with stress, yet few studies have investigated whether mindfulness…

  4. Contributions of Maternal Adult Attachment to Socialization of Coping

    PubMed Central

    Abaied, Jamie L.; Rudolph, Karen D.

    2011-01-01

    This research examined whether maternal adult attachment predicted the coping suggestions mothers made to their children. A sample of 157 youth (M age = 12.42, SD = 1.20) and their maternal caregivers completed semi-structured interviews and questionnaires in a two-wave longitudinal study. Results revealed that maternal insecure attachment predicted fewer engagement coping suggestions (orienting toward stress) and heightened disengagement coping suggestions (avoiding or denying stress) both concurrently and over time. These associations were found after adjusting for other relevant characteristics of the child, mother, and family context. This study contributes to our understanding of the implications of adult attachment for parenting behavior, suggesting that insecure attachment undermines a parent’s ability to provide adaptive coping guidance to their children. PMID:21892245

  5. Coping style, health beliefs, and breast self-examination.

    PubMed

    Barron, C R; Houfek, J F; Foxall, M J

    1997-01-01

    The purpose of this study was to determine the role of coping style in women's practice of breast self-examination (BSE). The framework was adapted from the Cognitive Transactional Model of Stress and Coping and the Health Belief Model. The convenience sample consisted of 269 women recruited from an employee list of a medical center and a membership list of a professional nurses' group. Survey booklets were distributed via interdepartmental or U.S. mail and contained measures of trait anxiety and defensiveness and questions related to health beliefs, BSE practice, and demographics. The sample was categorized by coping style (i.e., repressive, true high anxious, defensive high anxious, or true low anxious), and data were analyzed via MANOVAs, ANOVAs, and hierarchical regression. Results indicated that coping style predicted BSE practice (i.e., proficiency, frequency) and health beliefs of barriers, confidence, seriousness, and susceptibility. The findings provide nurses with information for developing interventions to foster BSE. PMID:9233171

  6. Coping Styles of Female Adolescent Cancer Patients with Potential Fertility Loss

    PubMed Central

    Murphy, Devin; Knapp, Caprice A.; Christie, Juliette; Phares, Vicky; Wells, Kristen J.

    2013-01-01

    Purpose The purpose of this qualitative study was to assess the coping styles of female adolescent cancer patients regarding potential loss of fertility. Expectations and desires for the future, coping styles in typical adolescence, and coping styles when faced with potential loss of fertility due to cancer treatment are discussed. Methods Female adolescents diagnosed with cancer aged 12–18 years at study (N=14) were administered a 10-item values clarification tool to pilot test the readability and relevance of the items on reproductive concerns, followed by a cognitive debriefing interview asking participants how they would respond to each item. These qualitative responses were assessed for coping style type using the constant comparative approach. Results All adolescent participants reported having a strong desire for biological children in the future. Reactions to questions regarding the loss of fertility fell into two categories of coping styles: emotion-focused coping or problem-focused (engagement) coping. Within emotion-focused coping, there were three distinct styles: externalizing attribution style, internalizing attribution style, and repressive adaptation. Problem-focused coping adolescents displayed optimism. Conclusion Successful interventions aimed at promoting adaptive coping styles should seek to uncover adolescents' values about future parenthood and reproduction. Development of an age-appropriate assessment to stimulate dialogue regarding fertility and initiate an adolescent's cognitive processing of potential fertility loss is warranted. PMID:23781403

  7. Examining Behavioural Coping Strategies as Mediators between Work-Family Conflict and Psychological Distress

    PubMed Central

    Shamsuddin, Khadijah

    2015-01-01

    We examined the mediating role of behavioral coping strategies in the association between work-family conflict and psychological distress. In particular, we examined the two directions of work-family conflict, namely, work interference into family and family interference into work. Furthermore, two coping styles in this study were adaptive and maladaptive coping strategies. This cross-sectional study was conducted among 429 Malaysian working women using self-reported data. The results of mediational analysis in the present study showed that adaptive coping strategy does not significantly mediate the effect of work-family conflict on psychological distress. However, maladaptive coping strategies significantly mediate the effect of work-family conflict on psychological distress. These results show that adaptive coping strategies, which aimed to improve the stressful situation, are not effective in managing stressor such as work-family conflict. We found that experiencing interrole conflict steers employees toward frequent use of maladaptive coping strategies which in turn lead to psychological distress. Interventions targeted at improvement of coping skills which are according to individual's needs and expectation may help working women to balance work and family demands. The important issue is to keep in mind that effective coping strategies are to control the situations not to eliminate work-family conflict. PMID:25695097

  8. Examining behavioural coping strategies as mediators between work-family conflict and psychological distress.

    PubMed

    Aazami, Sanaz; Shamsuddin, Khadijah; Akmal, Syaqirah

    2015-01-01

    We examined the mediating role of behavioral coping strategies in the association between work-family conflict and psychological distress. In particular, we examined the two directions of work-family conflict, namely, work interference into family and family interference into work. Furthermore, two coping styles in this study were adaptive and maladaptive coping strategies. This cross-sectional study was conducted among 429 Malaysian working women using self-reported data. The results of mediational analysis in the present study showed that adaptive coping strategy does not significantly mediate the effect of work-family conflict on psychological distress. However, maladaptive coping strategies significantly mediate the effect of work-family conflict on psychological distress. These results show that adaptive coping strategies, which aimed to improve the stressful situation, are not effective in managing stressor such as work-family conflict. We found that experiencing interrole conflict steers employees toward frequent use of maladaptive coping strategies which in turn lead to psychological distress. Interventions targeted at improvement of coping skills which are according to individual's needs and expectation may help working women to balance work and family demands. The important issue is to keep in mind that effective coping strategies are to control the situations not to eliminate work-family conflict. PMID:25695097

  9. Mechanical, hormonal, and hypertrophic adaptations to 10 weeks of eccentric and stretch-shortening cycle exercise training in old males.

    PubMed

    Váczi, Márk; Nagy, Szilvia A; Kőszegi, Tamás; Ambrus, Míra; Bogner, Péter; Perlaki, Gábor; Orsi, Gergely; Tóth, Katalin; Hortobágyi, Tibor

    2014-10-01

    The growth promoting effects of eccentric (ECC) contractions are well documented but it is unknown if the rate of stretch per se plays a role in such muscular responses in healthy aging human skeletal muscle. We tested the hypothesis that exercise training of the quadriceps muscle with low rate ECC and high rate ECC contractions in the form of stretch-shortening cycles (SSCs) but at equal total mechanical work would produce rate-specific adaptations in healthy old males age 60-70. Both training programs produced similar improvements in maximal voluntary isometric (6%) and ECC torque (23%) and stretch-shortening cycle function (reduced contraction duration [24%] and enhanced elastic energy storage [12%]) (p<0.05). The rate of torque development increased 30% only after SSC exercise (p<0.05). Resting testosterone and cortisol levels were unchanged but after each program the acute exercise-induced cortisol levels were 12-15% lower (p<0.05). Both programs increased quadriceps size 2.5% (p<0.05). It is concluded that both ECC and SSC exercise training produces favorable adaptations in healthy old males' quadriceps muscle. Although the rate of muscle tension during the SSC vs. ECC contractions was about 4-fold greater, the total mechanical work seems to regulate the hypetrophic, hormonal, and most of the mechanical adaptations. However, SSC exercise was uniquely effective in improving a key deficiency of aging muscle, i.e., its ability to produce force rapidly. PMID:25064038

  10. Chaos control of the micro-electro-mechanical resonator by using adaptive dynamic surface technology with extended state observer

    NASA Astrophysics Data System (ADS)

    Luo, Shaohua; Sun, Quanping; Cheng, Wei

    2016-04-01

    This paper addresses chaos control of the micro-electro- mechanical resonator by using adaptive dynamic surface technology with extended state observer. To reveal the mechanism of the micro- electro-mechanical resonator, the phase diagrams and corresponding time histories are given to research the nonlinear dynamics and chaotic behavior, and Homoclinic and heteroclinic chaos which relate closely with the appearance of chaos are presented based on the potential function. To eliminate the effect of chaos, an adaptive dynamic surface control scheme with extended state observer is designed to convert random motion into regular motion without precise system model parameters and measured variables. Putting tracking differentiator into chaos controller solves the `explosion of complexity' of backstepping and poor precision of the first-order filters. Meanwhile, to obtain high performance, a neural network with adaptive law is employed to approximate unknown nonlinear function in the process of controller design. The boundedness of all the signals of the closed-loop system is proved in theoretical analysis. Finally, numerical simulations are executed and extensive results illustrate effectiveness and robustness of the proposed scheme.

  11. Illness Adaptation: Clarifying the Concept and Validating a Scale.

    ERIC Educational Resources Information Center

    Young, Rosalie F.; Kahana, Eva

    Traditionally, coping and adaptation have been considered synonymous in individual's responses to illness and other stressful situations. The Illness Adaptation Scale (IAS) is a 12-item instrument which was designed to assess adaptational outcomes in illness situations as well as four coping modes (instrumental-self oriented, instrumental-other…

  12. Mechanism of Cell Culture Adaptation of an Enteric Calicivirus, the Porcine Sapovirus Cowden Strain

    PubMed Central

    Lu, Zhongyan; Yokoyama, Masaru; Chen, Ning; Oka, Tomoichiro; Jung, Kwonil; Chang, Kyeong-Ok; Annamalai, Thavamathi

    2015-01-01

    ABSTRACT The porcine sapovirus (SaV) (PoSaV) Cowden strain is one of only a few culturable enteric caliciviruses. Compared to the wild-type (WT) PoSaV Cowden strain, tissue culture-adapted (TC) PoSaV has two conserved amino acid substitutions in the RNA-dependent RNA polymerase (RdRp) and six in the capsid protein (VP1). By using the reverse-genetics system, we identified that 4 amino acid substitutions in VP1 (residues 178, 289, 324, and 328), but not the substitutions in the RdRp region, were critical for the cell culture adaptation of the PoSaV Cowden strain. The other two substitutions in VP1 (residues 291 and 295) reduced virus replication in vitro. Three-dimensional (3D) structural analysis of VP1 showed that residue 178 was located near the dimer-dimer interface, which may affect VP1 assembly and oligomerization; residues 289, 291, 324, and 328 were located at protruding subdomain 2 (P2) of VP1, which may influence virus binding to cellular receptors; and residue 295 was located at the interface of two monomeric VP1 proteins, which may influence VP1 dimerization. Although reversion of the mutation at residue 291 or 295 from that of the TC strain to that of the WT reduced virus replication in vitro, it enhanced virus replication in vivo, and the revertants induced higher-level serum and mucosal antibody responses than those induced by the TC PoSaV Cowden strain. Our findings reveal the molecular basis for PoSaV adaptation to cell culture. These findings may provide new, critical information for the cell culture adaptation of other PoSaV strains and human SaVs or noroviruses. IMPORTANCE The tissue culture-adapted porcine sapovirus Cowden strain is one of only a few culturable enteric caliciviruses. We discovered that 4 amino acid substitutions in VP1 (residues 178, 289, 324, and 328) were critical for its adaptation to LLC-PK cells. Two substitutions in VP1 (residues 291 and 295) reduced virus replication in vitro but enhanced virus replication and induced

  13. The Development and Psychometric Evaluation of the Brief Resilient Coping Scale

    ERIC Educational Resources Information Center

    Sinclair, Vaughn G.; Wallston, Kenneth A.

    2004-01-01

    This article introduces the Brief Resilient Coping Scale (BRCS), a 4-item measure designed to capture tendencies to cope with stress in a highly adaptive manner. Two samples of individuals with rheumatoid arthritis (ns = 90 and 140) provide evidence for the reliability and validity of the BRCS. The BRCS has adequate internal consistency and…

  14. Age and Gender Differences in Coping Style across Various Problems: Omani Adolescents' Perspective

    ERIC Educational Resources Information Center

    Al-Bahrani, Muna; Aldhafri, Said; Alkharusi, Hussain; Kazem, Ali; Alzubiadi, Abdulqawi

    2013-01-01

    This study examines adolescents' coping styles, with relation to their gender and age and level, of six types of problems. The participants were 1843 adolescents (51.7% female and 48.3% male) from the Sultanate of Oman with a mean age of 15.75. Two scales examining general adaptive and maladaptive coping styles and levels of school, economic,…

  15. Stress Constellations and Coping Styles of Older Adults with Age-Related Visual Impairment

    ERIC Educational Resources Information Center

    Lee, Kyoung Othelia; Brennan, Mark

    2006-01-01

    Narrative data from two earlier studies of adaptation to age-related visual impairment were examined for constellations of stressors and coping styles. In the course of previous qualitative analyses, the researchers identified stress and coping codes according to behavioral, psychological, and social domains using a grounded theory approach. In…

  16. Coping strategies in a sample of anxiety patients: factorial analysis and associations with psychopathology

    PubMed Central

    Pozzi, Gino; Frustaci, Alessandra; Tedeschi, Daniela; Solaroli, Silvia; Grandinetti, Paolo; Di Nicola, Marco; Janiri, Luigi

    2015-01-01

    Background The relationship between coping styles and mental disorders has received considerable attention and instruments have been developed to assess coping strategies. The measurement by means of category systems has been criticized and a functional hierarchy of action types linked to the adaptive processes is preferred. We aimed to determine which factors may exist within the Brief-COPE (Brief Coping Orientation to Problems Experienced – COPE – Inventory) in an Italian sample of patients with anxiety disorders; and if these factors correlate with the severity of psychopathology or with other characteristics. Methods A total sample of 148 patients was recruited. The Brief-COPE inventory, the Symptom Check List 90-Revised, the Penn State Worry Questionnaire, the Zung Anxiety Status Inventory and the Zung Self-Rating Anxiety Scale were administered. Results Factor analysis of the Brief-COPE yielded nine factors accounting for 65.48% of the variance. Patients scored higher on Searching Support, followed by Acceptance, Changing Perspective, and Problem Solving. Associations between measures of psychopathology and factors of coping strategies, mostly Searching support and Avoidance, were found. Conclusions Data of the present study support a nine-factor structure of the Brief-COPE that includes five broad dimensions of coping. Psychopathology was mostly related to Searching support and Avoidance factors, showing that these strategies may reflect ineffective ways of coping; Problem solving and Changing perspective could be a valid approach to moderate anxiety/depression symptoms and psychopathology in general. PMID:26356192

  17. Evolution of the fruit endocarp: molecular mechanisms underlying adaptations in seed protection and dispersal strategies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant evolution is largely driven by adaptations in seed protection and dispersal strategies that allow diversification into new niches. This is evident by the tremendous variation in flowering and fruiting structures present both across and within different plant lineages. Within a single plant f...

  18. A striking reduction of simple loudness adaptation in autism

    PubMed Central

    Lawson, Rebecca P.; Aylward, Jessica; White, Sarah; Rees, Geraint

    2015-01-01

    Reports of sensory disturbance, such as loudness sensitivity or sound intolerance, are ubiquitous in Autism Spectrum Disorder (ASD) but a mechanistic explanation for these perceptual differences is lacking. Here we tested adaptation to loudness, a process that regulates incoming sensory input, in adults with ASD and matched controls. Simple loudness adaptation (SLA) is a fundamental adaptive process that reduces the subjective loudness of quiet steady-state sounds in the environment over time, whereas induced loudness adaptation (ILA) is a means of generating a reduction in the perceived volume of louder sounds. ASD participants showed a striking reduction in magnitude and rate of SLA relative to age and ability-matched typical adults, but in contrast ILA remained intact. Furthermore, rate of SLA predicted sensory sensitivity coping strategies in the ASD group. These results provide the first evidence that compromised neural mechanisms governing fundamental adaptive processes might account for sound sensitivity in ASD. PMID:26537694

  19. Light and dark adaptation mechanisms in the compound eyes of Myrmecia ants that occupy discrete temporal niches.

    PubMed

    Narendra, Ajay; Greiner, Birgit; Ribi, Willi A; Zeil, Jochen

    2016-08-15

    Ants of the Australian genus Myrmecia partition their foraging niche temporally, allowing them to be sympatric with overlapping foraging requirements. We used histological techniques to study the light and dark adaptation mechanisms in the compound eyes of diurnal (Myrmecia croslandi), crepuscular (M. tarsata, M. nigriceps) and nocturnal ants (M. pyriformis). We found that, except in the day-active species, all ants have a variable primary pigment cell pupil that constricts the crystalline cone in bright light to control for light flux. We show for the nocturnal M. pyriformis that the constriction of the crystalline cone by the primary pigment cells is light dependent whereas the opening of the aperture is regulated by an endogenous rhythm. In addition, in the light-adapted eyes of all species, the retinular cell pigment granules radially migrate towards the rhabdom, a process that in both the day-active M. croslandi and the night-active M. pyriformis is driven by ambient light intensity. Visual system properties thus do not restrict crepuscular and night-active ants to their temporal foraging niche, while day-active ants require high light intensities to operate. We discuss the ecological significance of these adaptation mechanisms and their role in temporal niche partitioning. PMID:27535985

  20. Utilizing micro-electro-mechanical systems (MEMS) micro-shutter designs for adaptive coded aperture imaging (ACAI) technologies

    NASA Astrophysics Data System (ADS)

    Ledet, Mary M.; Starman, LaVern A.; Coutu, Ronald A., Jr.; Rogers, Stanley

    2009-08-01

    Coded aperture imaging (CAI) has been used in both the astronomical and medical communities for years due to its ability to image light at short wavelengths and thus replacing conventional lenses. Where CAI is limited, adaptive coded aperture imaging (ACAI) can recover what is lost. The use of photonic micro-electro-mechanical-systems (MEMS) for creating adaptive coded apertures has been gaining momentum since 2007. Successful implementation of micro-shutter technologies would potentially enable the use of adaptive coded aperture imaging and non-imaging systems in current and future military surveillance and intelligence programs. In this effort, a prototype of MEMS microshutters has been designed and fabricated onto a 3 mm x 3 mm square of silicon substrate using the PolyMUMPSTM process. This prototype is a line-drivable array using thin flaps of polysilicon to cover and uncover an 8 x 8 array of 20 μm apertures. A characterization of the micro-shutters to include mechanical, electrical and optical properties is provided. This prototype, its actuation scheme, and other designs for individual microshutters have been modeled and studied for feasibility purposes. In addition, microshutters fabricated from an Al-Au alloy on a quartz wafer were optically tested and characterized with a 632 nm HeNe laser.

  1. Transcriptomes reveal the genetic mechanisms underlying ionic regulatory adaptations to salt in the crab-eating frog

    PubMed Central

    Shao, Yong; Wang, Li-Jun; Zhong, Li; Hong, Mei-Ling; Chen, Hong-Man; Murphy, Robert W.; Wu, Dong-Dong; Zhang, Ya-Ping; Che, Jing

    2015-01-01

    The crab-eating frog, Fejervarya cancrivora, is the only frog that lives near seas. It tolerates increased environmental concentrations of sodium, chloride and potassium partly by raising ion and urea levels in its blood plasma. The molecular mechanism of the adaptation remains rarely documented. Herein, we analyze transcriptomes of the crab-eating frog and its closely related saline-intolerant species, F. limnocharis, to explore the molecular basis of adaptations to such extreme environmental conditions. Analyses reveal the potential genetic mechanism underlying the adaptation to salinity for the crab-eating frog. Genes in categories associated with ion transport appear to have evolved rapidly in F. cancrivora. Both positively selected and differentially expressed genes exhibit enrichment in the GO category regulation of renal sodium excretion. In this category, the positively selected sites of ANPEP and AVPR2 encode CD13 and V2 receptors, respectively; they fall precisely on conserved domains. More differentially expressed rapidly evolved genes occur in the kidney of F. cancrivora than in F. limnocharis. Four genes involved in the regulation of body fluid levels show signs of positive selection and increased expression. Significant up-regulation occurs in several genes of F. cancrivora associated with renin-angiotensin system and aldosterone-regulated sodium reabsorption pathways, which relate to osmotic regulation. PMID:26619819

  2. Transcriptomes reveal the genetic mechanisms underlying ionic regulatory adaptations to salt in the crab-eating frog.

    PubMed

    Shao, Yong; Wang, Li-Jun; Zhong, Li; Hong, Mei-Ling; Chen, Hong-Man; Murphy, Robert W; Wu, Dong-Dong; Zhang, Ya-Ping; Che, Jing

    2015-01-01

    The crab-eating frog, Fejervarya cancrivora, is the only frog that lives near seas. It tolerates increased environmental concentrations of sodium, chloride and potassium partly by raising ion and urea levels in its blood plasma. The molecular mechanism of the adaptation remains rarely documented. Herein, we analyze transcriptomes of the crab-eating frog and its closely related saline-intolerant species, F. limnocharis, to explore the molecular basis of adaptations to such extreme environmental conditions. Analyses reveal the potential genetic mechanism underlying the adaptation to salinity for the crab-eating frog. Genes in categories associated with ion transport appear to have evolved rapidly in F. cancrivora. Both positively selected and differentially expressed genes exhibit enrichment in the GO category regulation of renal sodium excretion. In this category, the positively selected sites of ANPEP and AVPR2 encode CD13 and V2 receptors, respectively; they fall precisely on conserved domains. More differentially expressed rapidly evolved genes occur in the kidney of F. cancrivora than in F. limnocharis. Four genes involved in the regulation of body fluid levels show signs of positive selection and increased expression. Significant up-regulation occurs in several genes of F. cancrivora associated with renin-angiotensin system and aldosterone-regulated sodium reabsorption pathways, which relate to osmotic regulation. PMID:26619819

  3. The Cellie Coping Kit for Sickle Cell Disease: Initial acceptability and feasibility

    PubMed Central

    Marsac, Meghan L.; Klingbeil, Olivia G.; Hildenbrand, Aimee K.; Alderfer, Melissa A.; Kassam-Adams, Nancy; Smith-Whitley, Kim; Barakat, Lamia P.

    2014-01-01

    Sickle Cell Disease (SCD) and its treatment can place physical and psychosocial strain on children and their families, underlining the need for behavioral and emotional support. Much of SCD is often managed at home, which may prevent children from obtaining supportive services from medical and psychosocial teams. Children with SCD report a restricted number of coping strategies specific to managing SCD and may benefit from education on adaptive coping. To address this unmet need, a coping tool for children with cancer (Cellie Cancer Coping Kit) was adapted for children with SCD. The Cellie Coping Kit for SCD (Cellie Coping Kit) includes a stuffed “Cellie” toy, coping cards for children, and a book for caregivers. This study sought to assess the acceptability and feasibility of an intervention utilizing the Cellie Coping Kit. Fifteen children with SCD (ages 6-14) and their caregivers participated in a baseline assessment including semi-structured interviews to examine SCD-related stressors and coping strategies. Next, families received a brief introduction to the Cellie Coping Kit and were provided with a kit to use independently over the next four weeks before completing a follow-up assessment. Results indicated strong intervention acceptability overall. While families reported using and learning information and skills from the Cellie Coping Kit, several challenges were identified (e.g., child's living situation, busy schedules). The Cellie Coping Kit is a promising tool to support children with SCD and their families. Future research should examine whether use of the Cellie Coping Kit impacts behavioral change and improved health outcomes. PMID:25664228

  4. Robust adaptive control modeling of human arm movements subject to altered gravity and mechanical loads

    NASA Astrophysics Data System (ADS)

    Tryfonidis, Michail

    It has been observed that during orbital spaceflight the absence of gravitation related sensory inputs causes incongruence between the expected and the actual sensory feedback resulting from voluntary movements. This incongruence results in a reinterpretation or neglect of gravity-induced sensory input signals. Over time, new internal models develop, gradually compensating for the loss of spatial reference. The study of adaptation of goal-directed movements is the main focus of this thesis. The hypothesis is that during the adaptive learning process the neural connections behave in ways that can be described by an adaptive control method. The investigation presented in this thesis includes two different sets of experiments. A series of dart throwing experiments took place onboard the space station Mir. Experiments also took place at the Biomechanics lab at MIT, where the subjects performed a series of continuous trajectory tracking movements while a planar robotic manipulandum exerted external torques on the subjects' moving arms. The experimental hypothesis for both experiments is that during the first few trials the subjects will perform poorly trying to follow a prescribed trajectory, or trying to hit a target. A theoretical framework is developed that is a modification of the sliding control method used in robotics. The new control framework is an attempt to explain the adaptive behavior of the subjects. Numerical simulations of the proposed framework are compared with experimental results and predictions from competitive models. The proposed control methodology extends the results of the sliding mode theory to human motor control. The resulting adaptive control model of the motor system is robust to external dynamics, even those of negative gain, uses only position and velocity feedback, and achieves bounded steady-state error without explicit knowledge of the system's nonlinearities. In addition, the experimental and modeling results demonstrate that

  5. On Everyday Stress and Coping Strategies among Elementary School Children

    ERIC Educational Resources Information Center

    Sotardi, Valerie A.

    2013-01-01

    Elementary school students are confronted with a variety of everyday challenges ranging from comprehension obstacles to interpersonal conflict. Learning to cope effectively with moments of tension is an important part of a child's education because adaptation to stress is likely to influence academic and developmental success. However,…

  6. Flexible Applications of the Coping Cat Program for Anxious Youth

    ERIC Educational Resources Information Center

    Beidas, Rinad S.; Benjamin, Courtney L.; Puleo, Connor M.; Edmunds, Julie M.; Kendall, Philip C.

    2010-01-01

    The current article offers suggestions for ways to adapt empirically supported treatments (ESTs). A specific manualized EST (Coping Cat; Kendall & Hedtke, 2006a) is used to illustrate the concept of "flexibility within fidelity" (Kendall & Beidas, 2007; Kendall, Gosch, Furr, & Sood, 2008). Flexibility within fidelity stresses the importance of…

  7. Adaptive engineering of a hyperthermophilic archaeon on CO and discovering the underlying mechanism by multi-omics analysis

    PubMed Central

    Lee, Seong Hyuk; Kim, Min-Sik; Lee, Jae-Hak; Kim, Tae Wan; Bae, Seung Seob; Lee, Sung-Mok; Jung, Hae Chang; Yang, Tae-Jun; Choi, Ae Ran; Cho, Yong-Jun; Lee, Jung-Hyun; Kwon, Kae Kyoung; Lee, Hyun Sook; Kang, Sung Gyun

    2016-01-01

    The hyperthermophilic archaeon Thermococcus onnurineus NA1 can grow and produce H2 on carbon monoxide (CO) and its H2 production rates have been improved through metabolic engineering. In this study, we applied adaptive evolution to enhance H2 productivity. After over 150 serial transfers onto CO medium, cell density, CO consumption rate and H2 production rate increased. The underlying mechanism for those physiological changes could be explained by using multi-omics approaches including genomic, transcriptomic and epigenomic analyses. A putative transcriptional regulator was newly identified to regulate the expression levels of genes related to CO oxidation. Transcriptome analysis revealed significant changes in the transcript levels of genes belonging to the categories of transcription, translation and energy metabolism. Our study presents the first genome-scale methylation pattern of hyperthermophilic archaea. Adaptive evolution led to highly enhanced H2 productivity at high CO flow rates using synthesis gas produced from coal gasification. PMID:26975345

  8. Adaptive engineering of a hyperthermophilic archaeon on CO and discovering the underlying mechanism by multi-omics analysis.

    PubMed

    Lee, Seong Hyuk; Kim, Min-Sik; Lee, Jae-Hak; Kim, Tae Wan; Bae, Seung Seob; Lee, Sung-Mok; Jung, Hae Chang; Yang, Tae-Jun; Choi, Ae Ran; Cho, Yong-Jun; Lee, Jung-Hyun; Kwon, Kae Kyoung; Lee, Hyun Sook; Kang, Sung Gyun

    2016-01-01

    The hyperthermophilic archaeon Thermococcus onnurineus NA1 can grow and produce H2 on carbon monoxide (CO) and its H2 production rates have been improved through metabolic engineering. In this study, we applied adaptive evolution to enhance H2 productivity. After over 150 serial transfers onto CO medium, cell density, CO consumption rate and H2 production rate increased. The underlying mechanism for those physiological changes could be explained by using multi-omics approaches including genomic, transcriptomic and epigenomic analyses. A putative transcriptional regulator was newly identified to regulate the expression levels of genes related to CO oxidation. Transcriptome analysis revealed significant changes in the transcript levels of genes belonging to the categories of transcription, translation and energy metabolism. Our study presents the first genome-scale methylation pattern of hyperthermophilic archaea. Adaptive evolution led to highly enhanced H2 productivity at high CO flow rates using synthesis gas produced from coal gasification. PMID:26975345

  9. Vocal learning beyond imitation: mechanisms of adaptive vocal development in songbirds and human infants

    PubMed Central

    Tchernichovski, Ofer; Marcus, Gary

    2014-01-01

    Studies of vocal learning in songbirds typically focus on the acquisition of sensory templates for song imitation and on the consequent process of matching song production to templates. However, functional vocal development also requires the capacity to adaptively diverge from sensory templates, and to flexibly assemble vocal units. Examples of adaptive divergence include the corrective imitation of abnormal songs, and the decreased tendency to copy overabundant syllables. Such frequency-dependent effects might mirror tradeoffs between the assimilation of group identity (culture) while establishing individual and flexibly expressive songs. Intriguingly, although the requirements for vocal plasticity vary across songbirds, and more so between birdsong and language, the capacity to flexibly assemble vocal sounds develops in a similar, stepwise manner across species. Therefore, universal features of vocal learning go well beyond the capacity to imitate. PMID:25005823

  10. Mechanisms of thermal adaptation revealed from the genomes of the Antarctic

    SciTech Connect

    Saunders, Neil F.W.; Thomas, Torsten; Curmi, Paul M.G.; Mattick, John S.; Kuczek, Elizabeth; Slade, Rob; Davis, John; Franzmann, Peter; Boone, David; Rusterholtz, Karl; Feldman, Robert; Gates, Chris; Bench, Shellie; Sowers, Kevin; Kadner, Kristen; Aerts, Andrea; Dehal, Paramvir; Detter, Chris; Glavina, Tijana; Lucas, Susan; Richardson, Paul; Larimer, Frank; Hauser , Frank; Hauser, Loren; Land, Miriam; Cavicchioli, Richard

    2003-03-01

    We generated draft genome sequences for two cold-adapted Archaea, Methanogenium frigidum and Methanococcoides burtonii, to identify genotypic characteristics that distinguish them from Archaea with a higher optimal growth temperature (OGT). Comparative genomics revealed trends in amino acid and tRNA composition, and structural features of proteins. Proteins from the cold-adapted Archaea are characterized by a higher content of non-charged polar amino acids, particularly Gln and Thr and a lower content of hydrophobic amino acids, particularly Leu. Sequence data from nine methanogen genomes (OGT 15-98 C) was used to generate 1 111 modeled protein structures. Analysis of the models from the cold-adapted Archaea showed a strong tendency in the solvent accessible area for more Gln, Thr an hydrophobic residues and fewer charged residues. A cold shock domain (CSD) protein (CspA homolog) was identified in M. frigidum, two hypothetical proteins with CSD-folds in M. burtonii, and a unique winged helix DNA-binding domain protein in M. burtonii. This suggests that these types of nucleic acid binding proteins have a critical role in cold-adapted Archaea. Structural analysis of tRNA sequences from the Archaea indicated that GC content is the major factor influencing tRNA stability in hyperthermophiles, but not in the psychrophiles, mesophiles or moderate thermophiles. Below an OGT of 60 C, the GC content in tRNA was largely unchanged, indicating that any requirement for flexibility of tRNA in psychrophiles is mediated by other means. This is the first time that comparisons have been performed with genome data from Archaea spanning the growth temperature extremes from psychrophiles to hyperthermophiles.

  11. Studying citizen science through adaptive management and learning feedbacks as mechanisms for improving conservation.

    PubMed

    Jordan, Rebecca; Gray, Steven; Sorensen, Amanda; Newman, Greg; Mellor, David; Newman, Greg; Hmelo-Silver, Cindy; LaDeau, Shannon; Biehler, Dawn; Crall, Alycia

    2016-06-01

    Citizen science has generated a growing interest among scientists and community groups, and citizen science programs have been created specifically for conservation. We examined collaborative science, a highly interactive form of citizen science, which we developed within a theoretically informed framework. In this essay, we focused on 2 aspects of our framework: social learning and adaptive management. Social learning, in contrast to individual-based learning, stresses collaborative and generative insight making and is well-suited for adaptive management. Adaptive-management integrates feedback loops that are informed by what is learned and is guided by iterative decision making. Participants engaged in citizen science are able to add to what they are learning through primary data collection, which can result in the real-time information that is often necessary for conservation. Our work is particularly timely because research publications consistently report a lack of established frameworks and evaluation plans to address the extent of conservation outcomes in citizen science. To illustrate how our framework supports conservation through citizen science, we examined how 2 programs enacted our collaborative science framework. Further, we inspected preliminary conservation outcomes of our case-study programs. These programs, despite their recent implementation, are demonstrating promise with regard to positive conservation outcomes. To date, they are independently earning funds to support research, earning buy-in from local partners to engage in experimentation, and, in the absence of leading scientists, are collecting data to test ideas. We argue that this success is due to citizen scientists being organized around local issues and engaging in iterative, collaborative, and adaptive learning. PMID:26585836

  12. Placental, Matrilineal, and Epigenetic Mechanisms Promoting Environmentally Adaptive Development of the Mammalian Brain

    PubMed Central

    Broad, Kevin D.; Rocha-Ferreira, Eridan; Hristova, Mariya

    2016-01-01

    The evolution of intrauterine development, vivipary, and placentation in eutherian mammals has introduced new possibilities and constraints in the regulation of neural plasticity and development which promote neural function that is adaptive to the environment that a developing brain is likely to encounter in the future. A range of evolutionary adaptations associated with placentation transfers disproportionate control of this process to the matriline, a period unique in mammalian development in that there are three matrilineal genomes interacting in the same organism at the same time (maternal, foetal, and postmeiotic oocytes). The interactions between the maternal and developing foetal hypothalamus and placenta can provide a template by which a mother can transmit potentially adaptive information concerning potential future environmental conditions to the developing brain. In conjunction with genomic imprinting, it also provides a template to integrate epigenetic information from both maternal and paternal lineages. Placentation also hands ultimate control of genomic imprinting and intergenerational epigenetic information transfer to the matriline as epigenetic markers undergo erasure and reprogramming in the developing oocyte. These developments, in conjunction with an expanded neocortex, provide a unique evolutionary template by which matrilineal transfer of maternal care, resources, and culture can be used to promote brain development and infant survival. PMID:27069693

  13. Dimensions of Family Coping with Head Injury.

    ERIC Educational Resources Information Center

    Kosciulek, John F.

    1994-01-01

    Examined dimensions underlying family coping with head injury. Data from 150 families with a member with a head injury identified 3 dimensions of coping: individual-to-family versus family-to-community coping; family-respite versus head-injury-focused coping; and cognitive versus behavioral coping. Findings have implications for family stress and…

  14. Coping as Part of Motivational Resilience in School: A Multidimensional Measure of Families, Allocations, and Profiles of Academic Coping

    ERIC Educational Resources Information Center

    Skinner, Ellen; Pitzer, Jennifer; Steele, Joel

    2013-01-01

    A study was designed to examine a multidimensional measure of children's coping in the academic domain as part of a larger model of motivational resilience. Using items tapping multiple ways of dealing with academic problems, including five adaptive ways (strategizing, help-seeking, comfort-seeking, self-encouragement, and commitment) and six…

  15. Amplifying effect of a release mechanism for fast adaptation in the hair bundle.

    PubMed

    Sul, Bora; Iwasa, Kuni H

    2009-07-01

    A "release" mechanism, which has been experimentally observed as the fast component in the hair bundle's response to mechanical stimulation, appears similar to common mechanical relaxation with a damping effect. This observation is puzzling because such a response is expected to have an amplifying role in the mechanoelectrical transduction process in hair cells. Here it is shown that a release mechanism can indeed have a role in amplification, if it is associated with negative stiffness due to the gating of the mechonoelectric transducer channel. PMID:19603855

  16. En las Manos de Dios [in God’s Hands]: Religious and Other Forms of Coping Among Latinos With Arthritis

    PubMed Central

    Abraído-Lanza, Ana F.; Vásquez, Elizabeth; Echeverría, Sandra E.

    2013-01-01

    This study tested a theoretical model concerning religious, passive, and active coping; pain; and psychological adjustment among a sample of 200 Latinos with arthritis. Respondents reported using high levels of religious coping. A path analysis indicated that religious coping was correlated with active but not with passive coping. Religious coping was directly related to psychological well-being. Passive coping was associated with greater pain and worse adjustment. The effects of active coping on pain, depression, and psychological well-being were entirely indirect, mediated by acceptance of illness and self-efficacy. These findings warrant more research on the mechanisms that mediate the relationship between coping and health. This study contributes to a growing literature on religious coping among people with chronic illness, as well as contributing to a historically under-studied ethnic group. PMID:14756618

  17. Adaptive coupling between damage mechanics and peridynamics: A route for objective simulation of material degradation up to complete failure

    NASA Astrophysics Data System (ADS)

    Han, Fei; Lubineau, Gilles; Azdoud, Yan

    2016-09-01

    The objective (mesh-independent) simulation of evolving discontinuities, such as cracks, remains a challenge. Current techniques are highly complex or involve intractable computational costs, making simulations up to complete failure difficult. We propose a framework as a new route toward solving this problem that adaptively couples local-continuum damage mechanics with peridynamics to objectively simulate all the steps that lead to material failure: damage nucleation, crack formation and propagation. Local-continuum damage mechanics successfully describes the degradation related to dispersed microdefects before the formation of a macrocrack. However, when damage localizes, it suffers spurious mesh dependency, making the simulation of macrocracks challenging. On the other hand, the peridynamic theory is promising for the simulation of fractures, as it naturally allows discontinuities in the displacement field. Here, we present a hybrid local-continuum damage/peridynamic model. Local-continuum damage mechanics is used to describe "volume" damage before localization. Once localization is detected at a point, the remaining part of the energy is dissipated through an adaptive peridynamic model capable of the transition to a "surface" degradation, typically a crack. We believe that this framework, which actually mimics the real physical process of crack formation, is the first bridge between continuum damage theories and peridynamics. Two-dimensional numerical examples are used to illustrate that an objective simulation of material failure can be achieved by this method.

  18. Utilizing Matrix-Filler Interactions in the Design of Stimuli-Responsive, Mechanically-Adaptive Electrospun Composites

    NASA Astrophysics Data System (ADS)

    Wanasekara, Nandula; Stone, David; Wnek, Gary; Korley, Lashanda

    2013-03-01

    A new class of all-organic, stimuli-responsive and mechanically-adaptive electrospun nanocomposites, which have the ability to alter their stiffness upon hydration, were developed. These materials were fabricated by incorporating an electrospun mat of poly(vinyl alcohol) (PVA) as the filler in a polymeric matrix consisting of either poly(vinyl acetate) (PVAc) or ethylene oxide-epicholorohydrin copolymer (EO-EPI). The incorporation of high stiffness, high aspect ratio PVA filler mat significantly enhanced the tensile storage modulus of EO-EPI based composites, while modulus enhancement was only noticed above the glass transition for PVAc-based composites. Composite materials based on a rubbery EO-EPI host polymer and PVA filler exhibit an irreversible reduction by a factor of 12 of the tensile modulus upon hydration. In contrast, composites comprised of PVAc show a reversible reduction of modulus by a factor of 280 upon water uptake. The mechanical morphing of the electrospun composites is the result of the filler crystallinity, and matrix-filler interactions facilitated by the surface hydroxyl groups of the PVA filler. The choice of polymer matrix and electrospun nanofiber fillers allow control of matrix-filler interactions in a new series of all-organic composites to achieve desired stimuli-responsiveness and mechanical-adaptability upon exposure to various stimuli.

  19. A comparison of the level of functioning in chronic schizophrenia with coping and burden in caregivers

    PubMed Central

    Creado, Dean A.; Parkar, Shubhangi R.; Kamath, Ravindra M.

    2006-01-01

    Background: A chronic mental illness such as schizophrenia is a challenging task for caregivers especially in the current era of de-institutionalization. In India, few studies have attempted to directly determine the relationship between coping mechanisms and burden; in the West, studies have found that improved coping in family members can decrease the perceived burden. Aim: To evaluate the burden and coping of caregivers in relation to the level of functioning in patients with chronic schizophrenia. Methods: The sample was 100 patients with their primary caregivers attending a Psychiatry OPD. Patients were assessed on the Global Assessment of Functioning (GAF) scale while caregivers were administered the Burden Assessment Schedule (BAS) and Mechanisms of Coping (MOC) scale. Results: Fatalism and problem-solving were the two most preferred ways of coping. Problem-focused coping, i.e. problem-solving and expressive-action decreased the burden of caregivers, while emotion-focused coping, i.e. fatalism and passivity, increased it. As the level of functioning of the patient decreased, the significance with which the coping mechanisms influenced the burden, increased. The use of problem-solving coping by caregivers showed a significant correlation with higher level of functioning in patients. Conclusion: Coping mechanisms such as problem-solving can decrease the burden of illness on caregivers and may even improve the level of functioning of patients. PMID:20703411

  20. Ventricular structure, function, and mechanics at high altitude: chronic remodeling in Sherpa vs. short-term lowlander adaptation

    PubMed Central

    Ainslie, Philip N.; Hughes, Michael G.; Stöhr, Eric J.; Cotter, James D.; Nio, Amanda Q. X.; Shave, Rob

    2014-01-01

    Short-term, high-altitude (HA) exposure raises pulmonary artery systolic pressure (PASP) and decreases left-ventricular (LV) volumes. However, relatively little is known of the long-term cardiac consequences of prolonged exposure in Sherpa, a highly adapted HA population. To investigate short-term adaptation and potential long-term cardiac remodeling, we studied ventricular structure and function in Sherpa at 5,050 m (n = 11; 31 ± 13 yr; mass 68 ± 10 kg; height 169 ± 6 cm) and lowlanders at sea level (SL) and following 10 ± 3 days at 5,050 m (n = 9; 34 ± 7 yr; mass 82 ± 10 kg; height 177 ± 6 cm) using conventional and speckle-tracking echocardiography. At HA, PASP was higher in Sherpa and lowlanders compared with lowlanders at SL (both P < 0.05). Sherpa had smaller right-ventricular (RV) and LV stroke volumes than lowlanders at SL with lower RV systolic strain (P < 0.05) but similar LV systolic mechanics. In contrast to LV systolic mechanics, LV diastolic, untwisting velocity was significantly lower in Sherpa compared with lowlanders at both SL and HA. After partial acclimatization, lowlanders demonstrated no change in the RV end-diastolic area; however, both RV strain and LV end-diastolic volume were reduced. In conclusion, short-term hypoxia induced a reduction in RV systolic function that was also evident in Sherpa following chronic exposure. We propose that this was consequent to a persistently higher PASP. In contrast to the RV, remodeling of LV volumes and normalization of systolic mechanics indicate structural and functional adaptation to HA. However, altered LV diastolic relaxation after chronic hypoxic exposure may reflect differential remodeling of systolic and diastolic LV function. PMID:24876358

  1. Ventricular structure, function, and mechanics at high altitude: chronic remodeling in Sherpa vs. short-term lowlander adaptation.

    PubMed

    Stembridge, Mike; Ainslie, Philip N; Hughes, Michael G; Stöhr, Eric J; Cotter, James D; Nio, Amanda Q X; Shave, Rob

    2014-08-01

    Short-term, high-altitude (HA) exposure raises pulmonary artery systolic pressure (PASP) and decreases left-ventricular (LV) volumes. However, relatively little is known of the long-term cardiac consequences of prolonged exposure in Sherpa, a highly adapted HA population. To investigate short-term adaptation and potential long-term cardiac remodeling, we studied ventricular structure and function in Sherpa at 5,050 m (n = 11; 31 ± 13 yr; mass 68 ± 10 kg; height 169 ± 6 cm) and lowlanders at sea level (SL) and following 10 ± 3 days at 5,050 m (n = 9; 34 ± 7 yr; mass 82 ± 10 kg; height 177 ± 6 cm) using conventional and speckle-tracking echocardiography. At HA, PASP was higher in Sherpa and lowlanders compared with lowlanders at SL (both P < 0.05). Sherpa had smaller right-ventricular (RV) and LV stroke volumes than lowlanders at SL with lower RV systolic strain (P < 0.05) but similar LV systolic mechanics. In contrast to LV systolic mechanics, LV diastolic, untwisting velocity was significantly lower in Sherpa compared with lowlanders at both SL and HA. After partial acclimatization, lowlanders demonstrated no change in the RV end-diastolic area; however, both RV strain and LV end-diastolic volume were reduced. In conclusion, short-term hypoxia induced a reduction in RV systolic function that was also evident in Sherpa following chronic exposure. We propose that this was consequent to a persistently higher PASP. In contrast to the RV, remodeling of LV volumes and normalization of systolic mechanics indicate structural and functional adaptation to HA. However, altered LV diastolic relaxation after chronic hypoxic exposure may reflect differential remodeling of systolic and diastolic LV function. PMID:24876358

  2. Genome Sequencing of the Perciform Fish Larimichthys crocea Provides Insights into Molecular and Genetic Mechanisms of Stress Adaptation

    PubMed Central

    Shi, Qiong; Zhu, Lv-Yun; Li, Ting; Ding, Yang; Nie, Li; Li, Qiuhua; Dong, Wei-ren; Jiang, Liang; Sun, Bing; Zhang, XinHui; Li, Mingyu; Zhang, Hai-Qi; Xie, ShangBo; Zhu, YaBing; Jiang, XuanTing; Wang, Xianhui; Mu, Pengfei; Chen, Wei; Yue, Zhen; Wang, Zhuo; Wang, Jun; Shao, Jian-Zhong; Chen, Xinhua

    2015-01-01

    The large yellow croaker Larimichthys crocea (L. crocea) is one of the most economically important marine fish in China and East Asian countries. It also exhibits peculiar behavioral and physiological characteristics, especially sensitive to various environmental stresses, such as hypoxia and air exposure. These traits may render L. crocea a good model for investigating the response mechanisms to environmental stress. To understand the molecular and genetic mechanisms underlying the adaptation and response of L. crocea to environmental stress, we sequenced and assembled the genome of L. crocea using a bacterial artificial chromosome and whole-genome shotgun hierarchical strategy. The final genome assembly was 679 Mb, with a contig N50 of 63.11 kb and a scaffold N50 of 1.03 Mb, containing 25,401 protein-coding genes. Gene families underlying adaptive behaviours, such as vision-related crystallins, olfactory receptors, and auditory sense-related genes, were significantly expanded in the genome of L. crocea relative to those of other vertebrates. Transcriptome analyses of the hypoxia-exposed L. crocea brain revealed new aspects of neuro-endocrine-immune/metabolism regulatory networks that may help the fish to avoid cerebral inflammatory injury and maintain energy balance under hypoxia. Proteomics data demonstrate that skin mucus of the air-exposed L. crocea had a complex composition, with an unexpectedly high number of proteins (3,209), suggesting its multiple protective mechanisms involved in antioxidant functions, oxygen transport, immune defence, and osmotic and ionic regulation. Our results reveal the molecular and genetic basis of fish adaptation and response to hypoxia and air exposure. The data generated by this study will provide valuable resources for the genetic improvement of stress resistance and yield potential in L. crocea. PMID:25835551

  3. The complete genome and proteome of Laribacter hongkongensis reveal potential mechanisms for adaptations to different temperatures and habitats.

    PubMed

    Woo, Patrick C Y; Lau, Susanna K P; Tse, Herman; Teng, Jade L L; Curreem, Shirly O T; Tsang, Alan K L; Fan, Rachel Y Y; Wong, Gilman K M; Huang, Yi; Loman, Nicholas J; Snyder, Lori A S; Cai, James J; Huang, Jian-Dong; Mak, William; Pallen, Mark J; Lok, Si; Yuen, Kwok-Yung

    2009-03-01

    Laribacter hongkongensis is a newly discovered Gram-negative bacillus of the Neisseriaceae family associated with freshwater fish-borne gastroenteritis and traveler's diarrhea. The complete genome sequence of L. hongkongensis HLHK9, recovered from an immunocompetent patient with severe gastroenteritis, consists of a 3,169-kb chromosome with G+C content of 62.35%. Genome analysis reveals different mechanisms potentially important for its adaptation to diverse habitats of human and freshwater fish intestines and freshwater environments. The gene contents support its phenotypic properties and suggest that amino acids and fatty acids can be used as carbon sources. The extensive variety of transporters, including multidrug efflux and heavy metal transporters as well as genes involved in chemotaxis, may enable L. hongkongensis to survive in different environmental niches. Genes encoding urease, bile salts efflux pump, adhesin, catalase, superoxide dismutase, and other putative virulence factors-such as hemolysins, RTX toxins, patatin-like proteins, phospholipase A1, and collagenases-are present. Proteomes of L. hongkongensis HLHK9 cultured at 37 degrees C (human body temperature) and 20 degrees C (freshwater habitat temperature) showed differential gene expression, including two homologous copies of argB, argB-20, and argB-37, which encode two isoenzymes of N-acetyl-L-glutamate kinase (NAGK)-NAGK-20 and NAGK-37-in the arginine biosynthesis pathway. NAGK-20 showed higher expression at 20 degrees C, whereas NAGK-37 showed higher expression at 37 degrees C. NAGK-20 also had a lower optimal temperature for enzymatic activities and was inhibited by arginine probably as negative-feedback control. Similar duplicated copies of argB are also observed in bacteria from hot springs such as Thermus thermophilus, Deinococcus geothermalis, Deinococcus radiodurans, and Roseiflexus castenholzii, suggesting that similar mechanisms for temperature adaptation may be employed by other

  4. The development and psychometric evaluation of the Brief Resilient Coping Scale.

    PubMed

    Sinclair, Vaughn G; Wallston, Kenneth A

    2004-03-01

    This article introduces the Brief Resilient Coping Scale (BRCS), a 4-item measure designed to capture tendencies to cope with stress in a highly adaptive manner. Two samples of individuals with rheumatoid arthritis (ns = 90 and 140) provide evidence for the reliability and validity of the BRCS. The BRCS has adequate internal consistency and test-retest reliability. Convergent validity of the scale is demonstrated by predictable correlations with measures of personal coping resources (e.g., optimism, helplessness, self-efficacy), pain coping behaviors, and psychological well-being. Resilient coping, as assessed by the BRCS, also buffers the effects of high levels of arthritis-related and non-arthritis-related stressors on depressive symptoms. The sensitivity of the BRCS to changes associated with a cognitive-behavioral intervention is also demonstrated. The BCRS may be useful for identifying individuals in need of interventions designed to enhance resilient coping skills. PMID:14994958

  5. Cold adaptation mechanisms in the ghost moth Hepialus xiaojinensis: Metabolic regulation and thermal compensation.

    PubMed

    Zhu, Wei; Zhang, Huan; Li, Xuan; Meng, Qian; Shu, Ruihao; Wang, Menglong; Zhou, Guiling; Wang, Hongtuo; Miao, Lin; Zhang, Jihong; Qin, Qilian

    2016-02-01

    Ghost moths (Lepidoptera: Hepialidae) are cold-adapted stenothermal species inhabiting alpine meadows on the Tibetan Plateau. They have an optimal developmental temperature of 12-16°C but can maintain feeding and growth at 0°C. Their survival strategies have received little attention, but these insects are a promising model for environmental adaptation. Here, biochemical adaptations and energy metabolism in response to cold were investigated in larvae of the ghost moth Hepialus xiaojinensis. Metabolic rate and respiratory quotient decreased dramatically with decreasing temperature (15-4°C), suggesting that the energy metabolism of ghost moths, especially glycometabolism, was sensitive to cold. However, the metabolic rate at 4°C increased with the duration of cold exposure, indicating thermal compensation to sustain energy budgets under cold conditions. Underlying regulation strategies were studied by analyzing metabolic differences between cold-acclimated (4°C for 48h) and control larvae (15°C). In cold-acclimated larvae, the energy generating pathways of carbohydrates, instead of the overall consumption of carbohydrates, was compensated in the fat body by improving the transcription of related enzymes. The mobilization of lipids was also promoted, with higher diacylglycerol, monoacylglycerol and free fatty acid content in hemolymph. These results indicated that cold acclimation induced a reorganization on metabolic structure to prioritise energy metabolism. Within the aerobic process, flux throughout the tricarboxylic acid (TCA) cycle was encouraged in the fat body, and the activity of α-ketoglutarate dehydrogenase was the likely compensation target. Increased mitochondrial cristae density was observed in the midgut of cold-acclimated larvae. The thermal compensation strategies in this ghost moth span the entire process of energy metabolism, including degration of metabolic substrate, TCA cycle and oxidative phosphorylation, and from an energy budget

  6. Genomic analysis identified a potential novel molecular mechanism for high-altitude adaptation in sheep at the Himalayas.

    PubMed

    Gorkhali, Neena Amatya; Dong, Kunzhe; Yang, Min; Song, Shen; Kader, Adiljian; Shrestha, Bhola Shankar; He, Xiaohong; Zhao, Qianjun; Pu, Yabin; Li, Xiangchen; Kijas, James; Guan, Weijun; Han, Jianlin; Jiang, Lin; Ma, Yuehui

    2016-01-01

    Sheep has successfully adapted to the extreme high-altitude Himalayan region. To identify genes underlying such adaptation, we genotyped genome-wide single nucleotide polymorphisms (SNPs) of four major sheep breeds living at different altitudes in Nepal and downloaded SNP array data from additional Asian and Middle East breeds. Using a di value-based genomic comparison between four high-altitude and eight lowland Asian breeds, we discovered the most differentiated variants at the locus of FGF-7 (Keratinocyte growth factor-7), which was previously reported as a good protective candidate for pulmonary injuries. We further found a SNP upstream of FGF-7 that appears to contribute to the divergence signature. First, the SNP occurred at an extremely conserved site. Second, the SNP showed an increasing allele frequency with the elevated altitude in Nepalese sheep. Third, the electrophoretic mobility shift assays (EMSA) analysis using human lung cancer cells revealed the allele-specific DNA-protein interactions. We thus hypothesized that FGF-7 gene potentially enhances lung function by regulating its expression level in high-altitude sheep through altering its binding of specific transcription factors. Especially, FGF-7 gene was not implicated in previous studies of other high-altitude species, suggesting a potential novel adaptive mechanism to high altitude in sheep at the Himalayas. PMID:27444145

  7. Genomic analysis identified a potential novel molecular mechanism for high-altitude adaptation in sheep at the Himalayas

    PubMed Central

    Gorkhali, Neena Amatya; Dong, Kunzhe; Yang, Min; Song, Shen; Kader, Adiljian; Shrestha, Bhola Shankar; He, Xiaohong; Zhao, Qianjun; Pu, Yabin; Li, Xiangchen; Kijas, James; Guan, Weijun; Han, Jianlin; Jiang, Lin; Ma, Yuehui

    2016-01-01

    Sheep has successfully adapted to the extreme high-altitude Himalayan region. To identify genes underlying such adaptation, we genotyped genome-wide single nucleotide polymorphisms (SNPs) of four major sheep breeds living at different altitudes in Nepal and downloaded SNP array data from additional Asian and Middle East breeds. Using a di value-based genomic comparison between four high-altitude and eight lowland Asian breeds, we discovered the most differentiated variants at the locus of FGF-7 (Keratinocyte growth factor-7), which was previously reported as a good protective candidate for pulmonary injuries. We further found a SNP upstream of FGF-7 that appears to contribute to the divergence signature. First, the SNP occurred at an extremely conserved site. Second, the SNP showed an increasing allele frequency with the elevated altitude in Nepalese sheep. Third, the electrophoretic mobility shift assays (EMSA) analysis using human lung cancer cells revealed the allele-specific DNA-protein interactions. We thus hypothesized that FGF-7 gene potentially enhances lung function by regulating its expression level in high-altitude sheep through altering its binding of specific transcription factors. Especially, FGF-7 gene was not implicated in previous studies of other high-altitude species, suggesting a potential novel adaptive mechanism to high altitude in sheep at the Himalayas. PMID:27444145

  8. Structural Insight into and Mutational Analysis of Family 11 Xylanases: Implications for Mechanisms of Higher pH Catalytic Adaptation

    PubMed Central

    Bai, Wenqin; Zhou, Cheng; Zhao, Yueju; Wang, Qinhong; Ma, Yanhe

    2015-01-01

    To understand the molecular basis of higher pH catalytic adaptation of family 11 xylanases, we compared the structures of alkaline, neutral, and acidic active xylanases and analyzed mutants of xylanase Xyn11A-LC from alkalophilic Bacillus sp. SN5. It was revealed that alkaline active xylanases have increased charged residue content, an increased ratio of negatively to positively charged residues, and decreased Ser, Thr, and Tyr residue content relative to non-alkaline active counterparts. Between strands β6 and β7, alkaline xylanases substitute an α-helix for a coil or turn found in their non-alkaline counterparts. Compared with non-alkaline xylanases, alkaline active enzymes have an inserted stretch of seven amino acids rich in charged residues, which may be beneficial for xylanase function in alkaline conditions. Positively charged residues on the molecular surface and ionic bonds may play important roles in higher pH catalytic adaptation of family 11 xylanases. By structure comparison, sequence alignment and mutational analysis, six amino acids (Glu16, Trp18, Asn44, Leu46, Arg48, and Ser187, numbering based on Xyn11A-LC) adjacent to the acid/base catalyst were found to be responsible for xylanase function in higher pH conditions. Our results will contribute to understanding the molecular mechanisms of higher pH catalytic adaptation in family 11 xylanases and engineering xylanases to suit industrial applications. PMID:26161643

  9. An adaptive compensation algorithm for temperature drift of micro-electro-mechanical systems gyroscopes using a strong tracking Kalman filter.

    PubMed

    Feng, Yibo; Li, Xisheng; Zhang, Xiaojuan

    2015-01-01

    We present an adaptive algorithm for a system integrated with micro-electro-mechanical systems (MEMS) gyroscopes and a compass to eliminate the influence from the environment, compensate the temperature drift precisely, and improve the accuracy of the MEMS gyroscope. We use a simplified drift model and changing but appropriate model parameters to implement this algorithm. The model of MEMS gyroscope temperature drift is constructed mostly on the basis of the temperature sensitivity of the gyroscope. As the state variables of a strong tracking Kalman filter (STKF), the parameters of the temperature drift model can be calculated to adapt to the environment under the support of the compass. These parameters change intelligently with the environment to maintain the precision of the MEMS gyroscope in the changing temperature. The heading error is less than 0.6° in the static temperature experiment, and also is kept in the range from 5° to -2° in the dynamic outdoor experiment. This demonstrates that the proposed algorithm exhibits strong adaptability to a changing temperature, and performs significantly better than KF and MLR to compensate the temperature drift of a gyroscope and eliminate the influence of temperature variation. PMID:25985165

  10. An Adaptive Compensation Algorithm for Temperature Drift of Micro-Electro-Mechanical Systems Gyroscopes Using a Strong Tracking Kalman Filter

    PubMed Central

    Feng, Yibo; Li, Xisheng; Zhang, Xiaojuan

    2015-01-01

    We present an adaptive algorithm for a system integrated with micro-electro-mechanical systems (MEMS) gyroscopes and a compass to eliminate the influence from the environment, compensate the temperature drift precisely, and improve the accuracy of the MEMS gyroscope. We use a simplified drift model and changing but appropriate model parameters to implement this algorithm. The model of MEMS gyroscope temperature drift is constructed mostly on the basis of the temperature sensitivity of the gyroscope. As the state variables of a strong tracking Kalman filter (STKF), the parameters of the temperature drift model can be calculated to adapt to the environment under the support of the compass. These parameters change intelligently with the environment to maintain the precision of the MEMS gyroscope in the changing temperature. The heading error is less than 0.6° in the static temperature experiment, and also is kept in the range from 5° to −2° in the dynamic outdoor experiment. This demonstrates that the proposed algorithm exhibits strong adaptability to a changing temperature, and performs significantly better than KF and MLR to compensate the temperature drift of a gyroscope and eliminate the influence of temperature variation. PMID:25985165

  11. Coping and social support of parents with a diabetic child.

    PubMed

    Seppänen, S M; Kyngäs, H A; Nikkonen, M J

    1999-03-01

    The purpose of this study is to describe and understand the parental coping and the social support received by the parents of diabetic children. The parental coping process was followed for a 4-week period after the diagnosis of diabetes. The parents of two girls, whose diabetes was diagnosed in early childhood, served as study subjects. Data were collected by interviewing and observing the parents over four separate periods. The data were analyzed by the time series and content analysis methods. Six phases of parental coping were identified: disbelief, lack of information and guilt, learning to care, normalization, uncertainty and reorganization. In the different phases of parental coping, the parents' experience of stress, coping strategies and sense of control varied. In the phase of disbelief, the parents tried to reject the child's diabetes by questioning the diagnosis. The initial information given to the parents regarding their child's diabetes proved to be important for parental coping. In the phase of lack of information and guilt, the parents sought reasons for their child's diabetes and felt guilty about it. As coping responses, the parents sought support from each other and from people who had experienced the same. In the learning to care phase, they recognized the demands caused by diabetes and took responsibility for the child's care. The parents appreciated supervision based on their problems. In the normalization phase, the parents prepared to return home with the diabetic child. Getting back to normal life was one of the most effective parental coping responses. In the uncertainty phase, the care to be given to the diabetic child changed the daily routines of the family. In the reorganization phase, the parents adapted to the diagnosis of diabetes and to the care of their diabetic child. The parents felt that the life of the family normalized and was able to be controlled. PMID:10894653

  12. School Principals' Emotional Coping Process

    ERIC Educational Resources Information Center

    Poirel, Emmanuel; Yvon, Frédéric

    2014-01-01

    The present study examines the emotional coping of school principals in Quebec. Emotional coping was measured by stimulated recall; six principals were filmed during a working day and presented a week later with their video showing stressful encounters. The results show that school principals experience anger because of reproaches from staff…

  13. Intergenerational Child Abuse and Coping

    ERIC Educational Resources Information Center

    Robboy, Juliet; Anderson, Kristen G.

    2011-01-01

    Many studies have investigated the consequences of child sexual abuse (CSA) but few have examined the intergenerational effects of poly-victimization and maladaptive coping. The purpose of this investigation was to examine patterns of maltreatment and maladaptive coping among second-generation CSA survivors. It is hypothesized that: (a) maternal…

  14. Comparing residue clusters from thermophilic and mesophilic enzymes reveals adaptive mechanisms

    DOE PAGESBeta

    Sammond, Deanne W.; Kastelowitz, Noah; Himmel, Michael E.; Yin, Hang; Crowley, Michael F.; Bomble, Yannick J.

    2016-01-07

    Understanding how proteins adapt to function at high temperatures is important for deciphering the energetics that dictate protein stability and folding. While multiple principles important for thermostability have been identified, we lack a unified understanding of how internal protein structural and chemical environment determine qualitative or quantitative impact of evolutionary mutations. In this work we compare equivalent clusters of spatially neighboring residues between paired thermophilic and mesophilic homologues to evaluate adaptations under the selective pressure of high temperature. We find the residue clusters in thermophilic enzymes generally display improved atomic packing compared to mesophilic enzymes, in agreement with previous research.more » Unlike residue clusters from mesophilic enzymes, however, thermophilic residue clusters do not have significant cavities. In addition, anchor residues found in many clusters are highly conserved with respect to atomic packing between both thermophilic and mesophilic enzymes. As a result, the improvements in atomic packing observed in thermophilic homologues are not derived from these anchor residues but from neighboring positions, which may serve to expand optimized protein core regions.« less

  15. Mechanisms Underlying Adaptation of Respiratory Network Activity to Modulatory Stimuli in the Mouse Embryo

    PubMed Central

    Chevalier, Marc; De Sa, Rafaël; Cardoit, Laura; Thoby-Brisson, Muriel

    2016-01-01

    Breathing is a rhythmic behavior that requires organized contractions of respiratory effector muscles. This behavior must adapt to constantly changing conditions in order to ensure homeostasis, proper body oxygenation, and CO2/pH regulation. Respiratory rhythmogenesis is controlled by neural networks located in the brainstem. One area considered to be essential for generating the inspiratory phase of the respiratory rhythm is the preBötzinger complex (preBötC). Rhythmogenesis emerges from this network through the interplay between the activation of intrinsic cellular properties (pacemaker properties) and intercellular synaptic connections. Respiratory activity continuously changes under the impact of numerous modulatory substances depending on organismal needs and environmental conditions. The preBötC network has been shown to become active during the last third of gestation. But only little is known regarding the modulation of inspiratory rhythmicity at embryonic stages and even less on a possible role of pacemaker neurons in this functional flexibility during the prenatal period. By combining electrophysiology and calcium imaging performed on embryonic brainstem slice preparations, we provide evidence showing that embryonic inspiratory pacemaker neurons are already intrinsically sensitive to neuromodulation and external conditions (i.e., temperature) affecting respiratory network activity, suggesting a potential role of pacemaker neurons in mediating rhythm adaptation to modulatory stimuli in the embryo. PMID:27239348

  16. Comparing Residue Clusters from Thermophilic and Mesophilic Enzymes Reveals Adaptive Mechanisms

    PubMed Central

    Sammond, Deanne W.; Kastelowitz, Noah; Himmel, Michael E.; Yin, Hang; Crowley, Michael F.; Bomble, Yannick J.

    2016-01-01

    Understanding how proteins adapt to function at high temperatures is important for deciphering the energetics that dictate protein stability and folding. While multiple principles important for thermostability have been identified, we lack a unified understanding of how internal protein structural and chemical environment determine qualitative or quantitative impact of evolutionary mutations. In this work we compare equivalent clusters of spatially neighboring residues between paired thermophilic and mesophilic homologues to evaluate adaptations under the selective pressure of high temperature. We find the residue clusters in thermophilic enzymes generally display improved atomic packing compared to mesophilic enzymes, in agreement with previous research. Unlike residue clusters from mesophilic enzymes, however, thermophilic residue clusters do not have significant cavities. In addition, anchor residues found in many clusters are highly conserved with respect to atomic packing between both thermophilic and mesophilic enzymes. Thus the improvements in atomic packing observed in thermophilic homologues are not derived from these anchor residues but from neighboring positions, which may serve to expand optimized protein core regions. PMID:26741367

  17. Adaptive mechanisms during food restriction in Acomys russatus: the use of torpor for desert survival.

    PubMed

    Ehrhardt, N; Heldmaier, G; Exner, C

    2005-04-01

    The golden spiny mouse (Acomys russatus) is an omnivorous desert rodent that does not store food, but can store large amounts of body fat. Thus, it provides a good animal model to study physiological and behavioural adaptations to changes in food availability. The aim of this study was to investigate the time course of metabolic and behavioural responses to prolonged food restriction. Spiny mice were kept at an ambient temperature of 27 degrees C and for 3 weeks their food was reduced individually to 30% of their previous ad libitum food intake. When fed ad libitum, their average metabolic rate was 82.77+/-3.72 ml O(2) h(-1) during the photophase and 111.19+/-4.30 ml O(2) h(-1) during the scotophase. During food restriction they displayed episodes of daily torpor when the minimal metabolic rate gradually decreased to 16.07+/-1.07 ml O(2) h(-1), i.e. a metabolic rate depression of approximately 83%. During the hypometabolic bouts the minimum average body temperature T(b), decreased gradually from 32.6+/-0.1 degrees C to 29.0+/-0.4 degrees C, with increasing duration of consecutive bouts. In parallel, the animals increased their activity during the remaining daytime. Torpor as well as hyperactivity was suppressed immediately by refeeding. Thus golden spiny mice used two simultaneous strategies to adapt to shortened food supply, namely energysaving torpor during their resting period and an increase in locomotor activity pattern during their activity period. PMID:15742195

  18. MTPA control of mechanical sensorless IPMSM based on adaptive nonlinear control.

    PubMed

    Najjar-Khodabakhsh, Abbas; Soltani, Jafar

    2016-03-01

    In this paper, an adaptive nonlinear control scheme has been proposed for implementing maximum torque per ampere (MTPA) control strategy corresponding to interior permanent magnet synchronous motor (IPMSM) drive. This control scheme is developed in the rotor d-q axis reference frame using adaptive input-output state feedback linearization (AIOFL) method. The drive system control stability is supported by Lyapunov theory. The motor inductances are online estimated by an estimation law obtained by AIOFL. The estimation errors of these parameters are proved to be asymptotically converged to zero. Based on minimizing the motor current amplitude, the MTPA control strategy is performed by using the nonlinear optimization technique while considering the online reference torque. The motor reference torque is generated by a conventional rotor speed PI controller. By performing MTPA control strategy, the generated online motor d-q reference currents were used in AIOFL controller to obtain the SV-PWM reference voltages and the online estimation of the motor d-q inductances. In addition, the stator resistance is online estimated using a conventional PI controller. Moreover, the rotor position is detected using the online estimation of the stator flux and online estimation of the motor q-axis inductance. Simulation and experimental results obtained prove the effectiveness and the capability of the proposed control method. PMID:26830002

  19. Network-based integration of molecular and physiological data elucidates regulatory mechanisms underlying adaptation to high-fat diet.

    PubMed

    Derous, Davina; Kelder, Thomas; van Schothorst, Evert M; van Erk, Marjan; Voigt, Anja; Klaus, Susanne; Keijer, Jaap; Radonjic, Marijana

    2015-07-01

    Health is influenced by interplay of molecular, physiological and environmental factors. To effectively maintain health and prevent disease, health-relevant relations need to be understood at multiple levels of biological complexity. Network-based methods provide a powerful platform for integration and mining of data and knowledge characterizing different aspects of health. Previously, we have reported physiological and gene expression changes associated with adaptation of murine epididymal white adipose tissue (eWAT) to 5 days and 12 weeks of high-fat diet (HFD) and low-fat diet feeding (Voigt et al. in Mol Nutr Food Res 57:1423-1434, 2013. doi: 10.1002/mnfr.201200671 ). In the current study, we apply network analysis on this dataset to comprehensively characterize mechanisms driving the short- and long-term adaptation of eWAT to HFD across multiple levels of complexity. We built a three-layered interaction network comprising enriched biological processes, their transcriptional regulators and associated changes in physiological parameters. The multi-layered network model reveals that early eWAT adaptation to HFD feeding involves major changes at a molecular level, including activation of TGF-β signalling pathway, immune and stress response and downregulation of mitochondrial functioning. Upon prolonged HFD intake, initial transcriptional response tails off, mitochondrial functioning is even further diminished, and in turn the relation between eWAT gene expression and physiological changes becomes more prominent. In particular, eWAT weight and total energy intake negatively correlate with cellular respiration process, revealing mitochondrial dysfunction as a hallmark of late eWAT adaptation to HFD. Apart from global understanding of the time-resolved adaptation to HFD, the multi-layered network model allows several novel mechanistic hypotheses to emerge: (1) early activation of TGF-β signalling as a trigger for structural and morphological changes in

  20. Full-Body Gaze Control Mechanisms Elicited During Locomotion: Effects Of VOR Adaptation

    NASA Technical Reports Server (NTRS)

    Mulavara, A. P.; Houser, J.; Peters, B.; Miller, C.; Richards, J.; Marshburn, A.; Brady, R.; Cohen, H.; Bloomberg, J. J.

    2004-01-01

    Control of locomotion requires precise interaction between several sensorimotor subsystems. During locomotion the performer must satisfy two performance criteria: maintain stable forward translation and to stabilize gaze (McDonald, et al., 1997). Precise coordination demands integration of multiple sensorimotor subsystems for fulfilling both criteria. In order to test the general hypothesis that the whole body can serve as an integrated gaze stabilization system, we have previously investigated how the multiple, interdependent full-body sensorimotor subsystems respond to changes in gaze stabilization task constraints during locomotion (Mulavara and Bloomberg, 2003). The results suggest that the full body contributes to gaze stabilization during locomotion, and that its different functional elements respond to changes in visual task constraints. The goal of this study was to determine how the multiple, interdependent, full-body sensorimotor subsystems aiding gaze stabilization during locomotion are functionally coordinated after the vestibulo-ocular reflex (VOR) gain has been altered. We investigated the potential of adaptive remodeling of the full-body gaze control system following exposure to visual-vestibular conflict known to adaptively reduce the VOR. Subjects (n=14) walked (6.4 km/h) on the treadmill before and after they were exposed to 0.5X manifying lenses worn for 30 minutes during self-generated sinusoidal vertical head rotations performed while seated. In this study we measured: temporal parameters of gait, full body sagittal plane segmental kinematics of the head, trunk, thigh, shank and foot, accelerations along the vertical axis at the head and the shank, and the vertical forces acting on the support surface. Results indicate that, following exposure to the 0.5X minifying lenses, there was a significant increase in the duration of stance and stride times, alteration in the amplitude of head movement with respect to space and a significant increase in

  1. Changes in Pain Coping, Catastrophizing and Coping Efficacy after Cognitive-Behavioral Therapy in Children and Adolescents with Juvenile Fibromyalgia

    PubMed Central

    Kashikar-Zuck, Susmita; Sil, Soumitri; Lynch-Jordan, Anne M.; Ting, Tracy V.; Peugh, James; Schikler, Kenneth N.; Hashkes, Philip J.; Arnold, Lesley M.; Passo, Murray; Richards, Margaret M.; Powers, Scott W.; Lovell, Daniel J.

    2013-01-01

    A recent randomized multi-site clinical trial found that cognitive-behavioral therapy (CBT) was significantly more effective than fibromyalgia education (FE) in reducing functional disability in adolescents with juvenile fibromyalgia (JFM). The primary objective of this study was to examine the psychological processes of CBT effectiveness by evaluating changes in pain coping, catastrophizing, and coping efficacy and test these changes as mediators of continued improvements in functional disability and depressive symptoms at 6-month follow-up. One hundred adolescents (11–18 years old) with JFM completed the clinical trial. Coping, catastrophizing, and coping efficacy (Pain Coping Questionnaire) and the outcomes of functional disability (Functional Disability Inventory) and depressive symptoms (Children’s Depression Inventory) were measured at baseline, post-treatment, and 6-month follow-up. Participants in both conditions showed significant improvement in coping, catastrophizing, and efficacy by the end of the study, but significantly greater improvements were found immediately following treatment for those who received CBT. Treatment gains were maintained at follow-up. Baseline to post-treatment changes in coping, catastrophizing, and efficacy were not found to mediate improvements in functional disability or depressive symptoms from post-treatment to follow-up. Future directions for understanding mechanisms of CBT effectiveness in adolescents with chronic pain are discussed. PMID:23541069

  2. ["Coping... and the person with chronic pain"].

    PubMed

    Ribeiro, Leonor Ana; Santos, Céila

    2008-01-01

    We intend to present some aspects related with the coping process in a person with chronic pain. The presence of pain has implications in daily life activities, such as eating, drinking, sleeping or selfcare. Pain can unchain responses in the person, namely depression, anxiety, isolation, fear of pain and pessimistic thoughts. Thus we verify that in his/her adaptation process to the condition of chronic pain the person needs to integrate some strategies to manage his/her day by day activities. In this article we try to systematize the process where nurses based on Lazarus and Folkman's Model: Stress processing and Coping, can systematize care. In fact, nurses try to help people in the identification of their personal resources as well as the socio-ecological resources. The sense the care process has as a goal is the improvement of the quality of life through pain control and the person's adaptation of his/her condition of health, through development of his/her knowledge and capacities to use the resources, be they personal as instrumental or social. PMID:19341045

  3. Tenderization effect of cold-adapted collagenolytic protease MCP-01 on beef meat at low temperature and its mechanism.

    PubMed

    Zhao, Guo-Yan; Zhou, Ming-Yang; Zhao, Hui-Lin; Chen, Xiu-Lan; Xie, Bin-Bin; Zhang, Xi-Ying; He, Hai-Lun; Zhou, Bai-Cheng; Zhang, Yu-Zhong

    2012-10-15

    The enzymes currently used to increase meat tenderness are all mesophilic or thermophilic proteases. This study provides insight into the tenderization effect and the mechanism of a cold-adapted collagenolytic enzyme MCP-01 on beef meat at low temperatures. MCP-01 (10 U of caseinolytic activity) reduced the meat shear force by 23% and increased the relative myofibrillar fragmentation index of the meat by 91.7% at 4 °C, and it also kept the fresh colour and moisture of the meat. Compared to the commercially used tenderizers papain and bromelain, MCP-01 showed a unique tenderization mechanism. MCP-01 had a strong selectivity for degrading collagen at 4 °C, showed a distinct digestion pattern on the myofibrillar proteins, and had a different disruption pattern on the muscle fibres under scanning electron micrograph. These results suggest that the cold-adapted collagenolytic protease MCP-01 may be promising for use as a meat tenderizer at low and moderate temperatures. PMID:23442615

  4. Mechanisms of mindfulness: The dynamics of affective adaptation during open monitoring.

    PubMed

    Uusberg, Helen; Uusberg, Andero; Talpsep, Teri; Paaver, Marika

    2016-07-01

    Mindfulness - the nonjudgmental awareness of the present experience - is thought to facilitate affective adaptation through increased exposure to emotions and faster extinction of habitual responses. To test this framework, the amplification of the Late Positive Potential (LPP) by negative relative to neutral images was analyzed across stimulus repetitions while 37 novices performed an open monitoring mindfulness exercise. Compared to two active control conditions where attention was either diverted to a distracting task or the stimuli were attended without mindfulness instructions, open monitoring enhanced the initial LPP response to negative stimuli, indicating increased emotional exposure. Across successive repetitions, mindfulness reduced and ultimately removed the affective LPP amplification, suggesting extinction of habitual emotional reactions. This effect arose from reduced negative as well enlarged neutral LPPs. Unlike stimuli from control conditions, the images previously viewed with mindfulness instructions did not elicit affective LPP amplification during subsequent re-exposure, suggesting reconsolidation of stimulus meaning. PMID:27211913

  5. Adaptive Breast Radiation Therapy Using Modeling of Tissue Mechanics: A Breast Tissue Segmentation Study

    SciTech Connect

    Juneja, Prabhjot; Harris, Emma J.; Kirby, Anna M.; Evans, Philip M.

    2012-11-01

    Purpose: To validate and compare the accuracy of breast tissue segmentation methods applied to computed tomography (CT) scans used for radiation therapy planning and to study the effect of tissue distribution on the segmentation accuracy for the purpose of developing models for use in adaptive breast radiation therapy. Methods and Materials: Twenty-four patients receiving postlumpectomy radiation therapy for breast cancer underwent CT imaging in prone and supine positions. The whole-breast clinical target volume was outlined. Clinical target volumes were segmented into fibroglandular and fatty tissue using the following algorithms: physical density thresholding; interactive thresholding; fuzzy c-means with 3 classes (FCM3) and 4 classes (FCM4); and k-means. The segmentation algorithms were evaluated in 2 stages: first, an approach based on the assumption that the breast composition should be the same in both prone and supine position; and second, comparison of segmentation with tissue outlines from 3 experts using the Dice similarity coefficient (DSC). Breast datasets were grouped into nonsparse and sparse fibroglandular tissue distributions according to expert assessment and used to assess the accuracy of the segmentation methods and the agreement between experts. Results: Prone and supine breast composition analysis showed differences between the methods. Validation against expert outlines found significant differences (P<.001) between FCM3 and FCM4. Fuzzy c-means with 3 classes generated segmentation results (mean DSC = 0.70) closest to the experts' outlines. There was good agreement (mean DSC = 0.85) among experts for breast tissue outlining. Segmentation accuracy and expert agreement was significantly higher (P<.005) in the nonsparse group than in the sparse group. Conclusions: The FCM3 gave the most accurate segmentation of breast tissues on CT data and could therefore be used in adaptive radiation therapy-based on tissue modeling. Breast tissue segmentation

  6. Testing a model of family stress and coping based on war and non-war stressors, family resources and coping among Lebanese families.

    PubMed

    Farhood, L F

    1999-08-01

    This study was undertaken to describe the objective stressors, perceived stress, coping, and resources of families living in Beirut during the Lebanese war (1975-1991) and to test a model predicting the relationships of these variables to family adaptation. The sample consisted of 438 families chosen at random. Independent variables included objective stressors and perceived stress. The mediating variables were family resources and coping strategies. The dependent variables were health and interactional indicators of family adaptation: physical and psychological health, depression, and interpersonal and marital relationships. Findings provided support for the theoretical framework. Multiple regression analyses revealed that perceived stress, rather than the objective occurrence of events, predicted family adaptation. Family resources, particularly social support, positively impacted family adaptation and was associated with increased use of cognitive coping. The findings provide a theoretical model which, on further testing, can serve as a basis for practice by health professionals when working with traumatized families. PMID:10478497

  7. Coping with Overload and Stress: Men and Women in Dual-Earner Families

    ERIC Educational Resources Information Center

    Higgins, Chris A.; Duxbury, Linda E.; Lyons, Sean T.

    2010-01-01

    This study tested gender differences in a model positing relationships between work and family demands, overload, 4 coping mechanisms, and stress. The coping mechanisms were hypothesized to moderate the relationship between overload and stress. The sample consisted of 1,404 men and 1,623 women in dual-earner families. Respondents relied on 2…

  8. Mechanical adaptability of the Bouligand-type structure in natural dermal armour.

    PubMed

    Zimmermann, Elizabeth A; Gludovatz, Bernd; Schaible, Eric; Dave, Neil K N; Yang, Wen; Meyers, Marc A; Ritchie, Robert O

    2013-01-01

    Arapaima gigas, a fresh water fish found in the Amazon Basin, resist predation by piranhas through the strength and toughness of their scales, which act as natural dermal armour. Arapaima scales consist of a hard, mineralized outer shell surrounding a more ductile core. This core region is composed of aligned mineralized collagen fibrils arranged in distinct lamellae. Here we show how the Bouligand-type (twisted plywood) arrangement of collagen fibril lamellae has a key role in developing their unique protective properties, by using in situ synchrotron small-angle X-ray scattering during mechanical tensile tests to observe deformation mechanisms in the fibrils. Specifically, the Bouligand-type structure allows the lamellae to reorient in response to the loading environment; remarkably, most lamellae reorient towards the tensile axis and deform in tension through stretching/sliding mechanisms, whereas other lamellae sympathetically rotate away from the tensile axis and compress, thereby enhancing the scale's ductility and toughness to prevent fracture. PMID:24129554

  9. Mechanical adaptability of the Bouligand-type structure in natural dermal armour

    NASA Astrophysics Data System (ADS)

    Zimmermann, Elizabeth A.; Gludovatz, Bernd; Schaible, Eric; Dave, Neil K. N.; Yang, Wen; Meyers, Marc A.; Ritchie, Robert O.

    2013-10-01

    Arapaima gigas, a fresh water fish found in the Amazon Basin, resist predation by piranhas through the strength and toughness of their scales, which act as natural dermal armour. Arapaima scales consist of a hard, mineralized outer shell surrounding a more ductile core. This core region is composed of aligned mineralized collagen fibrils arranged in distinct lamellae. Here we show how the Bouligand-type (twisted plywood) arrangement of collagen fibril lamellae has a key role in developing their unique protective properties, by using in situ synchrotron small-angle X-ray scattering during mechanical tensile tests to observe deformation mechanisms in the fibrils. Specifically, the Bouligand-type structure allows the lamellae to reorient in response to the loading environment; remarkably, most lamellae reorient towards the tensile axis and deform in tension through stretching/sliding mechanisms, whereas other lamellae sympathetically rotate away from the tensile axis and compress, thereby enhancing the scale’s ductility and toughness to prevent fracture.

  10. Examining the Coping Response to Peer Relational Aggression Victimization

    PubMed Central

    Gomes, Melissa M.

    2011-01-01

    Purpose. Relational aggression, rumor spreading, backstabbing, and social isolation, is psychologically damaging for adolescent girls. The purpose of this study was to provide an explanation of victimization response after experiencing peer relational aggression victimization. Methods. Grounded theory techniques were used to gain an understanding of the victimization experience and the coping responses used. Findings. A theory of coping after experiencing peer relational aggression victimization was generated. Girls voiced feelings of hurt and anger after the experience and expressed the following ways of coping as a result: distancing from others, retaliation against the aggressor, discussing their feelings with friends and family, writing their feelings down, and/or confronting the aggressor. Clinical Implications. Nurses should be aware of the phenomenon and asses, for incidences of relational aggression victimization so that they may provide strategies to assist the adolescent and her family with positive coping mechanisms in order to prevent maladaptive responses. PMID:21994828

  11. Stress and glucocorticoid receptor-dependent mechanisms in long-term memory: from adaptive responses to psychopathologies

    PubMed Central

    Finsterwald, Charles; Alberini, Cristina M.

    2013-01-01

    A proper response against stressors is critical for survival. In mammals, the stress response is primarily mediated by secretion of glucocorticoids via the hypothalamic-pituitaryadrenocortical (HPA) axis and release of catecholamines through adrenergic neurotransmission. Activation of these pathways results in a quick physical response to the stress and, in adaptive conditions, mediates long-term changes in the brain that lead to the formation of long-term memories of the experience. These long-term memories are an essential adaptive mechanism that allows an animal to effectively face similar demands again. Indeed, a moderate stress level has a strong positive effect on memory and cognition, as a single arousing or moderately stressful event can be remembered for up to a lifetime. Conversely, exposure to extreme, traumatic, or chronic stress can have the opposite effect and cause memory loss, cognitive impairments, and stress-related psychopathologies such as anxiety disorders, depression and post-traumatic stress disorder (PTSD). While more effort has been devoted to the understanding of the effects of the negative effects of chronic stress, much less has been done thus far on the identification of the mechanisms engaged in the brain when stress promotes long-term memory formation. Understanding these mechanisms will provide critical information for use in ameliorating memory processes in both normal and pathological conditions. Here, we will review the role of glucocorticoids and glucocorticoid receptors (GRs) in memory formation and modulation. Furthermore, we will discuss recent findings on the molecular cascade of events underlying the effect of GR activation in adaptive levels of stress that leads to strong, long-lasting memories. Our recent data indicate that the positive effects of GR activation on memory consolidation critically engage the brain-derived neurotrophic factor (BDNF) pathway. We propose and will discuss the hypothesis that stress promotes the

  12. Stress and glucocorticoid receptor-dependent mechanisms in long-term memory: from adaptive responses to psychopathologies.

    PubMed

    Finsterwald, Charles; Alberini, Cristina M

    2014-07-01

    A proper response against stressors is critical for survival. In mammals, the stress response is primarily mediated by secretion of glucocorticoids via the hypothalamic-pituitary-adrenocortical (HPA) axis and release of catecholamines through adrenergic neurotransmission. Activation of these pathways results in a quick physical response to the stress and, in adaptive conditions, mediates long-term changes in the brain that lead to the formation of long-term memories of the experience. These long-term memories are an essential adaptive mechanism that allows an animal to effectively face similar demands again. Indeed, a moderate stress level has a strong positive effect on memory and cognition, as a single arousing or moderately stressful event can be remembered for up to a lifetime. Conversely, exposure to extreme, traumatic, or chronic stress can have the opposite effect and cause memory loss, cognitive impairments, and stress-related psychopathologies such as anxiety disorders, depression and post-traumatic stress disorder (PTSD). While more effort has been devoted to the understanding of the negative effects of chronic stress, much less has been done thus far on the identification of the mechanisms engaged in the brain when stress promotes long-term memory formation. Understanding these mechanisms will provide critical information for use in ameliorating memory processes in both normal and pathological conditions. Here, we will review the role of glucocorticoids and glucocorticoid receptors (GRs) in memory formation and modulation. Furthermore, we will discuss recent findings on the molecular cascade of events underlying the effect of GR activation in adaptive levels of stress that leads to strong, long-lasting memories. Our recent data indicate that the positive effects of GR activation on memory consolidation critically engage the brain-derived neurotrophic factor (BDNF) pathway. We propose and will discuss the hypothesis that stress promotes the formation of

  13. Mechanisms of psychological resiliency in women after mastectomy

    PubMed Central

    Sęk, Helena; Ziarko, Michał; Marzec, Marta

    2012-01-01

    Aim of the study To investigate into the mechanisms of resiliency in women after mastectomy. We hypothesized that the mechanism of resiliency in women with breast cancer would involve facilitation of adaptive coping strategies and inhibition of maladaptive strategies. We tested a mediational model in which resiliency was related to satisfaction with life through coping strategies. Material and methods Thirty women after mastectomy aged 28–69 years (M = 53.23, SD = 9.00) completed the Ego Resiliency Scale, Mental Adjustment to Cancer Scale, and Satisfaction with Life Scale. Results The bootstrapping technique revealed that there were significant indirect effects for positive reframing (95% CI: 0.01–0.36), hopelessness/helplessness (95% CI: 0.18–0.83) and anxious preoccupation (95% CI: 0.001–0.55) but not for fighting spirit. The models explained up to 33% of the variance in satisfaction with life. Conclusions Coping strategies fully explain the effect of resiliency on satisfaction with life in women after mastectomy. This finding provides additional evidence of the fundamental role of coping strategies in the mechanisms of resiliency. We obtained similar results in patients with type II diabetes and rheumatoid arthritis. The lack of significant associations of fighting spirit with resiliency suggests that this coping strategy may be beneficial for somatic health but its contribution to the mechanisms of psychological resiliency is complex. PMID:23788906

  14. A Bayesian Tutoring System for Newtonian Mechanics: Can It Adapt to Different Learners?

    ERIC Educational Resources Information Center

    Pek, Peng-Kiat; Poh, Kim-Leng

    2004-01-01

    Newtonian mechanics is a core module in technology courses, but is difficult for many students to learn. Computerized tutoring can assist the teachers to provide individualized instruction. This article presents the application of decision theory to develop a tutoring system, "iTutor", to select optimal tutoring actions under uncertainty of…

  15. Rate perception adapts across the senses: evidence for a unified timing mechanism.

    PubMed

    Levitan, Carmel A; Ban, Yih-Hsin A; Stiles, Noelle R B; Shimojo, Shinsuke

    2015-01-01

    The brain constructs a representation of temporal properties of events, such as duration and frequency, but the underlying neural mechanisms are under debate. One open question is whether these mechanisms are unisensory or multisensory. Duration perception studies provide some evidence for a dissociation between auditory and visual timing mechanisms; however, we found active crossmodal interaction between audition and vision for rate perception, even when vision and audition were never stimulated together. After exposure to 5 Hz adaptors, people perceived subsequent test stimuli centered around 4 Hz to be slower, and the reverse after exposure to 3 Hz adaptors. This aftereffect occurred even when the adaptor and test were different modalities that were never presented together. When the discrepancy in rate between adaptor and test increased, the aftereffect was attenuated, indicating that the brain uses narrowly-tuned channels to process rate information. Our results indicate that human timing mechanisms for rate perception are not entirely segregated between modalities and have substantial implications for models of how the brain encodes temporal features. We propose a model of multisensory channels for rate perception, and consider the broader implications of such a model for how the brain encodes timing. PMID:25748443

  16. Coping strategies in melanoma patients.

    PubMed

    Trapp, Michael; Trapp, Eva-Maria; Richtig, Erika; Egger, Josef Wilhelm; Zampetti, Anna; Sampogna, Francesca; Rohrer, Peter Michael; Komericki, Peter; Strimitzer, Tanja; Linder, Michael Dennis

    2012-11-01

    An observational, questionnaire-based, cross-sectional study was performed to assess whether differences in coping behaviour (positive and negative strategies) between patients with either a recent diagnosis of malignant melanoma (MM) or with benign dermatological disease, were predictive of the diagnosis. Coping strategies were assessed with the German version of the stress-coping questionnaire (SVF 120) in 46 inpatients for whom surgery was planned at the Department of Dermatology, Medical University of Graz, Austria. Subjects were divided into two groups: patients with non-metastatic MM, and patients with benign dermatological diseases (controls). The risk for the diagnosis "melanoma" decreased with higher values of "situation control" (p = 0.007) and increased with higher values of resignation (p = 0.035) and trivialisation (p = 0.039). More-over, the risk for having a MM with thickness > 1 mm decreased in patients with higher values in positive coping strategies (p < 0.34). These results suggest differences in coping behaviour between patients with MM and those with benign skin diseases and, amidst patients with MM, between patients with different MM thickness; the results may hence lead to earlier, more specific and more effective psychological interventions to improve coping in patients with MM, as differences in coping behaviour seem to appear even in the non-metastatic stage of the disease. PMID:22772950

  17. Biomechanical stability of novel mechanically adapted open-porous titanium scaffolds in metatarsal bone defects of sheep.

    PubMed

    Wieding, Jan; Lindner, Tobias; Bergschmidt, Philipp; Bader, Rainer

    2015-04-01

    Open-porous titanium scaffolds for large segmental bone defects offer advantages like early weight-bearing and limited risk of implant failure. The objective of this experimental study was to determine the biomechanical behavior of novel open-porous titanium scaffolds with mechanical-adapted properties in vivo. Two types of the custom-made, open-porous scaffolds made of Ti6Al4V (Young's modulus: 6-8 GPa and different pore sizes) were implanted into a 20 mm segmental defect in the mid-diaphysis of the metatarsus of sheep, and were stabilized with an osteosynthesis plate. After 12 and 24 weeks postoperatively, torsional testing was performed on the implanted bone and compared to the contralateral non-treated side. Maximum torque, maximum angle, torsional stiffness, fracture energy, shear modulus and shear stress were investigated. Furthermore, bone mineral density (BMD) of the newly formed bone was determined. Mechanical loading capabilities for both scaffolds were similar and about 50% after 12 weeks (e.g., max. torque of approximately 20 Nm). A further increase after 24 weeks was found for most of the investigated parameters. Results for torsional stiffness and shear modulus as well as bone formation depended on the type of scaffold. Increased BMD after 24 weeks was found for one scaffold type but remained constant for the other one. The present data showed the capability of mechanically adapted open-porous titanium scaffolds to function as bone scaffolds for large segmental defects and the influence of the scaffold's stiffness. A further increase in the biomechanical stability can be assumed for longer observation periods of greater than six months. PMID:25678114

  18. Mechanisms underlying the adaptive response against spontaneous neoplastic transformation induced by low doses of low LET radiation, Final Technical Report

    SciTech Connect

    J. Leslie Redpath, Ph.D.

    2006-01-23

    The goal of this project was to investigate mechanisms underlying the adaptive response seen following exposure of HeLa x skin fibroblast human hybrid cells to low doses of low LET radiation. It was proposed to investigate the contributions of three possible mechanisms. These were: 1. Upregulation of cellular antioxidant status. 2. Upregulation of DNA repair. 3. Upregulation of gap junction intracellular communication. We have completed the study of the role of upregulation of reduced glutathione (GSH) as a possible mechanism underlying our observed suppression of transformation frequency at low radiation doses. We have also completed our study of the possible role of upregulation of DNA repair in the observed adaptive response against neoplastic transformation. We concluded that upregulation of DNA repair may be more important in modulating transformation at the higher dose. A manuscript describing the above studies has been submitted published in Carcinogenesis 24:1961-1965, 2003. Finally, we have completed two studies of the possible role of upregulation of gap junction intercellular communication (GJIC) in modulating transformation frequency at low doses of low LET radiation. This research was published in Radiation Research 162:646-654, 2004. In order to optimize the opportunity for GJIC, we then carried out a study where confluent cultures were irradiated. The results indicated, that while the degree of low dose suppression was somewhat reduced compared to that seen for subconfluent cultures, it was not completely absent. This research has been submitted for publication. Our research program was of sufficient interest to generate two invited reviews, and five invited presentations.

  19. Adolescent vulnerability and the distress of rejection: Associations of adjustment problems and gender with control, emotions, and coping.

    PubMed

    Zimmer-Gembeck, Melanie J; Skinner, Ellen A

    2015-12-01

    We examined adjustment problems as risks for patterns of emotions, appraisals, and coping with rejection, and explored whether these processes could account for sex (boy/girl) differences in coping. Young adolescents (N = 669, grades 6-8) completed questionnaires, which assessed responses to peer rejection threat with two short scenarios. Using structural equation modeling to test a multivariate process model, adolescents with heightened social anxiety had the most maladaptive responses to rejection threat, including elevated emotional reactions, more self-blame, and coping using more social isolation, rumination and opposition. Adolescents reporting more depressive symptoms felt less control and anticipated using less adaptive coping (less support seeking, distraction, and negotiation), whereas aggressive adolescents responded with more anger and coped via opposition. Moreover, as anticipated, sex differences in coping, symptoms, emotions, and appraisals were found. However, coping differences between boys and girls were mostly nonsignificant after accounting for symptoms, aggression, emotional reactions, and appraisals. PMID:26439867

  20. Discovery of intramolecular trans-sialidases in human gut microbiota suggests novel mechanisms of mucosal adaptation

    PubMed Central

    Tailford, Louise E.; Owen, C. David; Walshaw, John; Crost, Emmanuelle H.; Hardy-Goddard, Jemma; Le Gall, Gwenaelle; de Vos, Willem M.; Taylor, Garry L.; Juge, Nathalie

    2015-01-01

    The gastrointestinal mucus layer is colonized by a dense community of microbes catabolizing dietary and host carbohydrates during their expansion in the gut. Alterations in mucosal carbohydrate availability impact on the composition of microbial species. Ruminococcus gnavus is a commensal anaerobe present in the gastrointestinal tract of >90% of humans and overrepresented in inflammatory bowel diseases (IBD). Using a combination of genomics, enzymology and crystallography, we show that the mucin-degrader R. gnavus ATCC 29149 strain produces an intramolecular trans-sialidase (IT-sialidase) that cleaves off terminal α2-3-linked sialic acid from glycoproteins, releasing 2,7-anhydro-Neu5Ac instead of sialic acid. Evidence of IT-sialidases in human metagenomes indicates that this enzyme occurs in healthy subjects but is more prevalent in IBD metagenomes. Our results uncover a previously unrecognized enzymatic activity in the gut microbiota, which may contribute to the adaptation of intestinal bacteria to the mucosal environment in health and disease. PMID:26154892