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Sample records for depression explains nonlinear

  1. Depression of nonlinearity in decaying isotropic turbulence

    International Nuclear Information System (INIS)

    Kraichnan, R.H.; Panda, R.

    1988-01-01

    Simulations of decaying isotropic Navier--Stokes turbulence exhibit depression of the normalized mean-square nonlinear term to 57% of the value for a Gaussianly distributed velocity field with the same instantaneous velocity spectrum. Similar depression is found for dynamical models with random coupling coefficients (modified Betchov models). This suggests that the depression is dynamically generic rather than specifically driven by alignment of velocity and vorticity

  2. Do sex differences in rumination explain sex differences in depression?

    Science.gov (United States)

    Shors, Tracey J; Millon, Emma M; Chang, Han Yan M; Olson, Ryan L; Alderman, Brandon L

    2017-01-02

    It is generally accepted that women tend to ruminate more than men do and these thought patterns are often associated with depressive symptoms (Nolen-Hoeksema et al., ). Based on these findings, we considered whether the relationship between rumination and depression is stronger in women than in men and if so, whether this might explain the higher prevalence of major depressive disorder (MDD) in women and finally, whether the association can be disrupted through a mind/body intervention. Adult men and women, most of whom were clinically depressed, participated in an intervention known as MAP Training, which combines "mental" training with silent meditation and "physical" training with aerobic exercise (Shors et al., ). After eight weeks of training, both men and women reported significantly fewer symptoms of depression and fewer ruminative thoughts (Alderman et al., ). Statistical correlations between depressive symptoms and ruminative thoughts were strong and significant (rho > 0.50; p depressive symptoms relate to "reflective" ruminations, which involve analyses of past events, feelings, and behaviors. This is also the only relationship that dissipated after the intervention. In general, these analyses suggest that the strength of the relationship between depressive symptoms and rumination does not necessarily explain sex differences in depression; but because the relationship is strong, targeting rumination through intervention can reduce the incidence of MDD, which is more prevalent among women. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  3. Explaining social class differences in depression and well-being.

    Science.gov (United States)

    Stansfeld, S A; Head, J; Marmot, M G

    1998-01-01

    Work characteristics, including skill discretion and decision authority, explain most of the socioeconomic status gradient in well-being and depression in middle-aged British civil servants from the Whitehall II Study, London. Social support explained about one-third of the gradient, life events and material difficulties less than one-third. Socioeconomic status was measured by employment grade. Work characteristics were based on the Karasek model, social support was measured by the Close Persons Questionnaire, depression by the General Health Questionnaire and well-being by the Affect Balance Scale. Despite a small contribution from social selective factors measured by upward mobility, the psychosocial work environment explained most of the cross-sectional socioeconomic status gradient in well-being and depression.

  4. Explaining ecological clusters of maternal depression in South Western Sydney.

    Science.gov (United States)

    Eastwood ED, John; Kemp, Lynn; Jalaludin, Bin

    2014-01-24

    The aim of the qualitative study reported here was to: 1) explain the observed clustering of postnatal depressive symptoms in South Western Sydney; and 2) identify group-level mechanisms that would add to our understanding of the social determinants of maternal depression. Critical realism provided the methodological underpinning for the study. The setting was four local government areas in South Western Sydney, Australia. Child and Family practitioners and mothers in naturally occurring mothers groups were interviewed. Using an open coding approach to maximise emergence of patterns and relationships we have identified seven theoretical concepts that might explain the observed spatial clustering of maternal depression. The theoretical concepts identified were: Community-level social networks; Social Capital and Social Cohesion; "Depressed community"; Access to services at the group level; Ethnic segregation and diversity; Supportive social policy; and Big business. We postulate that these regional structural, economic, social and cultural mechanisms partially explain the pattern of maternal depression observed in families and communities within South Western Sydney. We further observe that powerful global economic and political forces are having an impact on the local situation. The challenge for policy and practice is to support mothers and their families within this adverse regional and global-economic context.

  5. Explaining ecological clusters of maternal depression in South Western Sydney

    Science.gov (United States)

    2014-01-01

    Background The aim of the qualitative study reported here was to: 1) explain the observed clustering of postnatal depressive symptoms in South Western Sydney; and 2) identify group-level mechanisms that would add to our understanding of the social determinants of maternal depression. Methods Critical realism provided the methodological underpinning for the study. The setting was four local government areas in South Western Sydney, Australia. Child and Family practitioners and mothers in naturally occurring mothers groups were interviewed. Results Using an open coding approach to maximise emergence of patterns and relationships we have identified seven theoretical concepts that might explain the observed spatial clustering of maternal depression. The theoretical concepts identified were: Community-level social networks; Social Capital and Social Cohesion; "Depressed community"; Access to services at the group level; Ethnic segregation and diversity; Supportive social policy; and Big business. Conclusions We postulate that these regional structural, economic, social and cultural mechanisms partially explain the pattern of maternal depression observed in families and communities within South Western Sydney. We further observe that powerful global economic and political forces are having an impact on the local situation. The challenge for policy and practice is to support mothers and their families within this adverse regional and global-economic context. PMID:24460690

  6. Social Factors Explaining Children's Subjective Happiness and Depressive Symptoms

    Science.gov (United States)

    Uusitalo-Malmivaara, Lotta; Lehto, Juhani E.

    2013-01-01

    In this study happiness and depression in 737 12-year-old Finnish children were predicted by relationships with family members and other people, the number of close friends and their experiences of parental fighting and drinking. There were no differences in happiness between the genders, but the girls were more depressed than the boys. Low…

  7. Pathways of disadvantage: Explaining the relationship between maternal depression and children's problem behaviors.

    Science.gov (United States)

    Turney, Kristin

    2012-11-01

    A large body of literature documents that children of depressed mothers have impaired cognitive, behavioral, and health outcomes throughout the life course, though much less is known about the mechanisms linking maternal depression to children's outcomes. In this paper, I use data from the Fragile Families and Child Wellbeing Study to estimate and explain the consequences of maternal depression for 5-year-old children's internalizing and externalizing problem behaviors. Ordinary least squared (OLS) regression models and propensity score models show that children exposed to both chronic and intermittent maternal depression have more problem behaviors than their counterparts with never depressed mothers. Results also show that economic resources and maternal parenting behaviors mediate much of the association between maternal depression and children's problem behaviors, but that relationships with romantic partners and social support do little to explain this association. This research extends past literature by illuminating some mechanisms through which maternal depression matters for children; by utilizing longitudinal measures of depression; by employing rigorous statistical techniques to lend confidence to the findings; and by using a large, diverse, and non-clinical sample of children most susceptible to maternal depression. Given that early childhood problem behaviors lay a crucial foundation for short- and long-term life trajectories, the social consequences of maternal depression may be far-reaching. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Unequal Depression for Equal Work? How the wage gap explains gendered disparities in mood disorders

    OpenAIRE

    Platt, Jonathan; Prins, Seth; Bates, Lisa; Keyes, Katherine

    2015-01-01

    Mood disorders, such as depression and anxiety, are more prevalent among women than men. This disparity may be partially due to the effects of structural gender discrimination in the work force, which acts to perpetuate gender differences in opportunities and resources and may manifest as the gender wage gap. We sought to quantify and operationalize the wage gap in order to explain the gender disparity in depression and anxiety disorders, using data from a 2001–2002 US nationally representati...

  9. Depressive status explains a significant amount of the variance in COPD assessment test (CAT) scores.

    Science.gov (United States)

    Miravitlles, Marc; Molina, Jesús; Quintano, José Antonio; Campuzano, Anna; Pérez, Joselín; Roncero, Carlos

    2018-01-01

    COPD assessment test (CAT) is a short, easy-to-complete health status tool that has been incorporated into the multidimensional assessment of COPD in order to guide therapy; therefore, it is important to understand the factors determining CAT scores. This is a post hoc analysis of a cross-sectional, observational study conducted in respiratory medicine departments and primary care centers in Spain with the aim of identifying the factors determining CAT scores, focusing particularly on the cognitive status measured by the Mini-Mental State Examination (MMSE) and levels of depression measured by the short Beck Depression Inventory (BDI). A total of 684 COPD patients were analyzed; 84.1% were men, the mean age of patients was 68.7 years, and the mean forced expiratory volume in 1 second (%) was 55.1%. Mean CAT score was 21.8. CAT scores correlated with the MMSE score (Pearson's coefficient r =-0.371) and the BDI ( r =0.620), both p CAT scores and explained 45% of the variability. However, a model including only MMSE and BDI scores explained up to 40% and BDI alone explained 38% of the CAT variance. CAT scores are associated with clinical variables of severity of COPD. However, cognitive status and, in particular, the level of depression explain a larger percentage of the variance in the CAT scores than the usual COPD clinical severity variables.

  10. Explaining risk for suicidal ideation in adolescent offspring of mothers with depression.

    Science.gov (United States)

    Hammerton, G; Zammit, S; Thapar, A; Collishaw, S

    2016-01-01

    It is well-established that offspring of depressed mothers are at increased risk for suicidal ideation. However, pathways involved in the transmission of risk for suicidal ideation from depressed mothers to offspring are poorly understood. The aim of this study was to examine the contribution of potential mediators of this association, including maternal suicide attempt, offspring psychiatric disorder and the parent-child relationship. Data were utilized from a population-based birth cohort (ALSPAC). Three distinct classes of maternal depression symptoms across the first 11 years of the child's life had already been identified (minimal, moderate, chronic-severe). Offspring suicidal ideation was assessed at age 16 years. Data were analysed using structural equation modelling. There was evidence for increased risk of suicidal ideation in offspring of mothers with chronic-severe depression symptoms compared to offspring of mothers with minimal symptoms (odds ratio 3.04, 95% confidence interval 2.19-4.21). The majority of this association was explained through maternal suicide attempt and offspring psychiatric disorder. There was also evidence for an independent indirect effect via the parent-child relationship in middle childhood. There was no longer evidence of a direct effect of maternal depression on offspring suicidal ideation after accounting for all three mediators. The pattern of results was similar when examining mechanisms for maternal moderate depression symptoms. Findings highlight that suicide prevention efforts in offspring of depressed mothers should be particularly targeted at both offspring with a psychiatric disorder and offspring whose mothers have made a suicide attempt. Interventions aimed at improving the parent-child relationship may also be beneficial.

  11. Does Discrimination Explain High Risk of Depression among High-Income African American Men?

    Science.gov (United States)

    Assari, Shervin; Lankarani, Maryam Moghani; Caldwell, Cleopatra Howard

    2018-04-19

    Background: Higher socioeconomic status is known to decrease the risk for poor mental health overall. However, African American males of higher socioeconomic status (SES) are at an increased risk for having a major depressive episode (MDE). It is not known whether perceived discrimination (PD) explains this risk. The current study used nationally representative data to explore the role of PD in explaining the association between high-SES and having MDE among African American men. Methods: The National Survey of American Life (NSAL), 2003, included 4461 American adults including 1271 African American men. SES indicators (i.e., household income, educational attainment, employment status, and marital status) were the independent variables. 12-month MDE measured using the Composite International Diagnostic Interview (CIDI) was the outcome. Age, gender, and region were the covariates. PD was the potential mediator. For data analysis, we used logistic regression. Results: Among African American men, household income was positively associated with odds of 12-month MDE. The positive association between household income and odds of MDE remained unchanged after adding PD to the model, suggesting that PD may not explain why high-income African American men are at a higher risk of MDE. Conclusions: Perceived discrimination does not explain the increased risk for depression among African American males of higher SES. Future research should explore the role of other potential mechanisms such as stress, coping, social isolation, and/or negative social interaction that may increase psychological costs of upward social mobility for African American males.

  12. Does Discrimination Explain High Risk of Depression among High-Income African American Men?

    Directory of Open Access Journals (Sweden)

    Shervin Assari

    2018-04-01

    Full Text Available Background: Higher socioeconomic status is known to decrease the risk for poor mental health overall. However, African American males of higher socioeconomic status (SES are at an increased risk for having a major depressive episode (MDE. It is not known whether perceived discrimination (PD explains this risk. The current study used nationally representative data to explore the role of PD in explaining the association between high-SES and having MDE among African American men. Methods: The National Survey of American Life (NSAL, 2003, included 4461 American adults including 1271 African American men. SES indicators (i.e., household income, educational attainment, employment status, and marital status were the independent variables. 12-month MDE measured using the Composite International Diagnostic Interview (CIDI was the outcome. Age, gender, and region were the covariates. PD was the potential mediator. For data analysis, we used logistic regression. Results: Among African American men, household income was positively associated with odds of 12-month MDE. The positive association between household income and odds of MDE remained unchanged after adding PD to the model, suggesting that PD may not explain why high-income African American men are at a higher risk of MDE. Conclusions: Perceived discrimination does not explain the increased risk for depression among African American males of higher SES. Future research should explore the role of other potential mechanisms such as stress, coping, social isolation, and/or negative social interaction that may increase psychological costs of upward social mobility for African American males.

  13. Unequal Depression for Equal Work? How the wage gap explains gendered disparities in mood disorders

    Science.gov (United States)

    Platt, Jonathan; Prins, Seth; Bates, Lisa; Keyes, Katherine

    2016-01-01

    Mood disorders, such as depression and anxiety, are more prevalent among women than men. This disparity may be partially due to the effects of structural gender discrimination in the work force, which acts to perpetuate gender differences in opportunities and resources and may manifest as the gender wage gap. We sought to quantify and operationalize the wage gap in order to explain the gender disparity in depression and anxiety disorders, using data from a 2001–2002 US nationally representative survey of 22,581 working adults ages 30–65. Using established Oaxaca-Blinder decomposition methods to account for gender differences in individual-level productivity, our models reduced the wage gap in our sample by 13.5%, from 54% of men’s pay to 67.5% of men’s pay. We created a propensity-score matched sample of productivity indicators to test if the direction of the wage gap moderated the effects of gender on depression or anxiety. Where female income was less than the matched male counterpart, odds of both disorders were significantly higher among women versus men (major depressive disorder OR: 2.43, 95% CI: 1.95–3.04; generalized anxiety disorder OR: 4.11, 95% CI: 2.80–6.02). Where female income was greater than the matched male, the higher odds ratios for women for both disorders were significantly attenuated (Major Depressive Disorder OR: 1.20; 95% CI: 0.96–1.52) (Generalized Anxiety Disorder OR: 1.5; 95% CI: 1.04–2.29). The test for effect modification by sex and wage gap direction was statistically significant for both disorders. Structural forms of discrimination may explain mental health disparities at the population level. Beyond prohibiting overt gender discrimination, policies must be created to address embedded inequalities in procedures surrounding labor markets and compensation in the workplace. PMID:26689629

  14. Unequal depression for equal work? How the wage gap explains gendered disparities in mood disorders.

    Science.gov (United States)

    Platt, Jonathan; Prins, Seth; Bates, Lisa; Keyes, Katherine

    2016-01-01

    Mood disorders, such as depression and anxiety, are more prevalent among women than men. This disparity may be partially due to the effects of structural gender discrimination in the work force, which acts to perpetuate gender differences in opportunities and resources and may manifest as the gender wage gap. We sought to quantify and operationalize the wage gap in order to explain the gender disparity in depression and anxiety disorders, using data from a 2001-2002 US nationally representative survey of 22,581 working adults ages 30-65. Using established Oaxaca-Blinder decomposition methods to account for gender differences in individual-level productivity, our models reduced the wage gap in our sample by 13.5%, from 54% of men's pay to 67.5% of men's pay. We created a propensity-score matched sample of productivity indicators to test if the direction of the wage gap moderated the effects of gender on depression or anxiety. Where female income was less than the matched male counterpart, odds of both disorders were significantly higher among women versus men (major depressive disorder OR: 2.43, 95% CI: 1.95-3.04; generalized anxiety disorder OR: 4.11, 95% CI: 2.80-6.02). Where female income was greater than the matched male, the higher odds ratios for women for both disorders were significantly attenuated (Major Depressive Disorder OR: 1.20; 95% CI: 0.96-1.52) (Generalized Anxiety Disorder OR: 1.5; 95% CI: 1.04-2.29). The test for effect modification by sex and wage gap direction was statistically significant for both disorders. Structural forms of discrimination may explain mental health disparities at the population level. Beyond prohibiting overt gender discrimination, policies must be created to address embedded inequalities in procedures surrounding labor markets and compensation in the workplace. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Classifying depression patients and normal subjects using machine learning techniques and nonlinear features from EEG signal.

    Science.gov (United States)

    Hosseinifard, Behshad; Moradi, Mohammad Hassan; Rostami, Reza

    2013-03-01

    Diagnosing depression in the early curable stages is very important and may even save the life of a patient. In this paper, we study nonlinear analysis of EEG signal for discriminating depression patients and normal controls. Forty-five unmedicated depressed patients and 45 normal subjects were participated in this study. Power of four EEG bands and four nonlinear features including detrended fluctuation analysis (DFA), higuchi fractal, correlation dimension and lyapunov exponent were extracted from EEG signal. For discriminating the two groups, k-nearest neighbor, linear discriminant analysis and logistic regression as the classifiers are then used. Highest classification accuracy of 83.3% is obtained by correlation dimension and LR classifier among other nonlinear features. For further improvement, all nonlinear features are combined and applied to classifiers. A classification accuracy of 90% is achieved by all nonlinear features and LR classifier. In all experiments, genetic algorithm is employed to select the most important features. The proposed technique is compared and contrasted with the other reported methods and it is demonstrated that by combining nonlinear features, the performance is enhanced. This study shows that nonlinear analysis of EEG can be a useful method for discriminating depressed patients and normal subjects. It is suggested that this analysis may be a complementary tool to help psychiatrists for diagnosing depressed patients. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  16. Factors explaining the North-South differentials in contraceptive use in Nigeria: A nonlinear decomposition analysis

    Directory of Open Access Journals (Sweden)

    Stella Babalola

    2018-01-01

    Full Text Available Background: Northern Nigeria has some of the worst reproductive health indicators worldwide. Conspicuous North-South variations exist in contraceptive use; not much is known about the drivers of contraceptive use disparities in the North compared to the South. Objective: In this study, we examine the relative weights of the factors that contribute to this North-South gap in contraceptive prevalence. Methods: Using the women's 2013 Demographic Health Survey dataset, we applied a nonlinear decomposition technique to determine the contribution of sociodemographic and socioeconomic characteristics, conjugal relationship dynamics, intimate partner violence, ideational variables, and Islamic culture to the North-South disparities in contraceptive use. Results: There was a gap of 12.4 percentage points in contraceptive prevalence between the north and south of Nigeria (5.2Š vs 17.6Š. The largest contributors to the gap were ideational characteristics (explaining 42.0Š of the gap and socio-economic profiles (explaining 42.6Š. Patterns of conjugal relationship dynamics (11.1Š, socio-demographic characteristics (‒11.0Š, Islamic religious culture (7.6Š, and exposure to family planning messaging (6.1Š were also significant contributors. Conclusions: Effective interventions to increase contraceptive use in northern Nigeria should aim at addressing socioeconomic disadvantage in the North, impacting ideational characteristics and specifically targeting poor women and those with low levels of education. Working with Islamic religious leaders is also critical to bridging the gap. Contribution: This paper broadens the knowledge on the determinants of contraceptive use in Nigeria by identifying contextual factors that operate differently in the North compared to the South.

  17. As fathers and felons: explaining the effects of current and recent incarceration on major depression.

    Science.gov (United States)

    Turney, Kristin; Wildeman, Christopher; Schnittker, Jason

    2012-01-01

    Dramatic increases in the American imprisonment rate since the mid-1970s have important implications for the life chances of minority men with low educational attainment, including for their health. Although a large literature has considered the collateral consequences of incarceration for a variety of outcomes, studies concerned with health have several limitations: Most focus exclusively on physical health; those concerned with mental health only consider current incarceration or previous incarceration, but never both; some are cross-sectional; many fail to consider mechanisms; and virtually all neglect the role of family processes, thereby overlooking the social roles current and former prisoners inhabit. In this article, we use stress process theory to extend this research by first considering the association between incarceration and major depression and then considering potential mechanisms that explain this association. Results from the Fragile Families and Child Wellbeing Study (N = 3,107) show current and recent incarceration are substantially associated with the risk of major depression, suggesting both immediate and short-term implications. In addition, consistent with stress proliferation theory, the results show the well-known consequences of incarceration for socioeconomic status and family functioning partly explain these associations, suggesting the link between incarceration and depression depends heavily on the consequences of incarceration for economic and social reintegration, not only the direct psychological consequences of confinement.

  18. Are depressive persons capable of describing changes in their reactions without being able to explain them? A proof of a cybernetic hypothesis of depression.

    Science.gov (United States)

    Leibetseder, Max; Kamolz, Thomas

    2004-01-01

    Many studies on the autobiographical memory and the explanation of reasons for success and failure proved that persons suffering from major depression tend to overgeneralize. This study examines the hypothesis that changes of reactions caused by a depressive disorder can be described by the affected persons but not explained. Persons suffering from major depression and persons with posttraumatic stress disorder or disturbance of accommodation with depressive mood (= reactive form of a depressive disorder) were presented with a list of modalities (behaviour, emotional and physical reactions) characteristic for depression. They were asked to identify modalities applicable to them and to describe and explain them. Their responses were analysed using a content analysis and assigned to the categories description and explanation. Persons with a major depression tended to use explanations or evaluations rather than descriptions for their depression-related modalities. Those persons suffering from a reactive form of depressive disorder tended to prefer evaluations. These results support the assumption that states of depression cause general descriptions of depression-relevant behaviour. The specific characteristics that have been perceived confirm the general concepts, which however make the patient prone to the respective selective perceptions. Persons suffering from a reactive form of depressive mood cannot be assumed to have this tendency of self-affirmation. Their depressive state may be maintained by perseverating general pessimistic schemes. It must however be conceded that it was not possible to control the physical comorbidity methodically and to take its effects into consideration, even though only persons without serious illnesses were included in the samples. This study did not verify whether other clinical groups, like patients suffering from anxiety, show the same patterns of explaining and describing their problems. It should furthermore be reviewed how other

  19. Nonlinear Effects in Piezoelectric Transformers Explained by Thermal-Electric Model Based on a Hypothesis of Self-Heating

    DEFF Research Database (Denmark)

    Andersen, Thomas; Andersen, Michael A. E.; Thomsen, Ole Cornelius

    2012-01-01

    As the trend within power electronic still goes in the direction of higher power density and higher efficiency, it is necessary to develop new topologies and push the limit for the existing technology. Piezoelectric transformers are a fast developing technology to improve efficiency and increase ...... is developed to explain nonlinearities as voltage jumps and voltage saturation and thereby avoid the complex theory of electro elasticity. The model is based on the hypothesis of self-heating and tested with measurements with good correlation....

  20. Chaos and the quantum: how nonlinear effects can explain certain quantum paradoxes

    Energy Technology Data Exchange (ETDEWEB)

    McHarris, Wm C, E-mail: mcharris@chemistry.msu.edu [Departments of Chemistry and Physics/Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2011-07-08

    In recent years we have suggested that many of the so-called paradoxes resulting from the Copenhagen interpretation of quantum mechanics could well have more logical parallels based in nonlinear dynamics and chaos theory. Perhaps quantum mechanics might not be strictly linear as has been commonly postulated, and indeed, during the past year experimentalists have discovered signatures of chaos in a definitely quantum system. As an illustration of what can go wrong when quantum effects are forced into a linear interpretation, I examine Bell-type inequalities. In conventional derivations of such inequalities, classical systems are found to impose upper limits on the statistical correlations between, say, the properties of a pair of separated but entangled particles, whereas quantum systems allow greater correlations. Numerous experiments have upheld the quantum predictions (greater statistical correlations than allowed classically), which has led to inferences such as the instantaneous transmission of information between effectively infinitely separated particles - Einstein's 'spooky action-at-a-distance', incompatible with relativity. I argue that there is nothing wrong with the quantum mechanical side of such derivations (the usual point of attack by those attempting to debunk Bell-type arguments), but implicit in the derivations on the classical side is the assumption of independent, uncorrelated particles. As a result, one is comparing uncorrelated probabilities versus conditional probabilities rather than comparing classical versus quantum mechanics, making moot the experimental inferences. Further, nonlinear classical systems are known to exhibit correlations that can easily be as great as and overlap with quantum correlations - so-called nonextensive thermodynamics with its nonadditive entropy has verified this with numerous examples. Perhaps quantum mechanics does contain fundamental nonlinear elements. Nonlinear dynamics and chaos theory could

  1. Chaos and the quantum: how nonlinear effects can explain certain quantum paradoxes

    International Nuclear Information System (INIS)

    McHarris, Wm C

    2011-01-01

    In recent years we have suggested that many of the so-called paradoxes resulting from the Copenhagen interpretation of quantum mechanics could well have more logical parallels based in nonlinear dynamics and chaos theory. Perhaps quantum mechanics might not be strictly linear as has been commonly postulated, and indeed, during the past year experimentalists have discovered signatures of chaos in a definitely quantum system. As an illustration of what can go wrong when quantum effects are forced into a linear interpretation, I examine Bell-type inequalities. In conventional derivations of such inequalities, classical systems are found to impose upper limits on the statistical correlations between, say, the properties of a pair of separated but entangled particles, whereas quantum systems allow greater correlations. Numerous experiments have upheld the quantum predictions (greater statistical correlations than allowed classically), which has led to inferences such as the instantaneous transmission of information between effectively infinitely separated particles - Einstein's 'spooky action-at-a-distance', incompatible with relativity. I argue that there is nothing wrong with the quantum mechanical side of such derivations (the usual point of attack by those attempting to debunk Bell-type arguments), but implicit in the derivations on the classical side is the assumption of independent, uncorrelated particles. As a result, one is comparing uncorrelated probabilities versus conditional probabilities rather than comparing classical versus quantum mechanics, making moot the experimental inferences. Further, nonlinear classical systems are known to exhibit correlations that can easily be as great as and overlap with quantum correlations - so-called nonextensive thermodynamics with its nonadditive entropy has verified this with numerous examples. Perhaps quantum mechanics does contain fundamental nonlinear elements. Nonlinear dynamics and chaos theory could well provide a

  2. Depression of Nonlinearity in Decaying Isotropic MHD Turbulence

    International Nuclear Information System (INIS)

    Servidio, S.; Matthaeus, W. H.; Dmitruk, P.

    2008-01-01

    Spectral method simulations show that undriven magnetohydrodynamic turbulence spontaneously generates coherent spatial correlations of several types, associated with local Beltrami fields, directional alignment of velocity and magnetic fields, and antialignment of magnetic and fluid acceleration components. These correlations suppress nonlinearity to levels lower than what is obtained from Gaussian fields, and occur in spatial patches. We suggest that this rapid relaxation leads to non-Gaussian statistics and spatial intermittency

  3. Association between eating disorders and migraine may be explained by major depression.

    Science.gov (United States)

    Mustelin, Linda; Raevuori, Anu; Kaprio, Jaakko; Keski-Rahkonen, Anna

    2014-12-01

    The association between eating disorders and migraine remains unclear. We identified women with lifetime diagnoses of anorexia nervosa (AN) (N = 55) and bulimia nervosa (BN) (N = 60) and their co-twins from the FinnTwin16 cohort born in 1975-1979 (N = 2,825 women). Eating disorder and major depressive disorder (MDD) diagnoses were obtained from clinical interviews and data on migraine by self-report questionnaire. The women with eating disorders were compared with their unaffected co-twins and with unrelated women from the same birth cohorts. The prevalence of migraine was 12% in the general female population, but 22% for both AN and BN (odds ratio 2.0, p = .04). The prevalence of MDD was high in women with an eating disorder (42%). MDD was strongly associated with migraine (odds ratio 3.0, p eating disorders and migraine. The highest migraine prevalence (36%) was found in women with both an eating disorder and MDD. Pairwise twin analyses also supported the clustering of migraine, MDD and eating disorders. Women with a lifetime diagnosis of an eating disorder were twice as likely to report a history of migraine as unrelated women from the same cohort; this relationship was explained by comorbid MDD. © 2014 Wiley Periodicals, Inc.

  4. Memory loss after electroconvulsive treatment--may the sudden alleviation of depression-inducing memories explain patient despair?

    Science.gov (United States)

    Berg, John E

    2011-12-01

    Electroconvulsive treatment (ECT) has developed over 70 years to a modern, effective way of lifting depressive moods. Memory loss after electroconvulsive treatment is the only remaining relevant criticism of the treatment modality when considering the overall rate of remission from this treatment compared to all other treatment modalities. A depressive state impedes memory. After treatment memory improves on several qualities of cognition. However, comparing a person's memory ability from the months before depression started to the level after a course of ECT is never done, of obvious reasons. There are great clinical difficulties explaining who would develop memory problems, regardless of stimulation techniques, age or sex of the patient. The memory loss seen in some patients undergoing electroconvulsive treatment (ECT) is not explained by the treatment alone. After ECT unpleasant memories are disclosed rapidly and the patient may unconsciously try to defend herself by extending memory repression to other areas of memory. This may be unrelated to treatment modality, number of sessions or severity of depression. Psychological factors may partly explain why some patients unfold memory problems when the depression is rapidly lifted, rather than the treatment modality itself. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Explaining Macroeconomic and Term Structure Dynamics Jointly in a Non-linear DSGE Model

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller

    This paper shows how a standard DSGE model can be extended to reproduce the dynamics in the 10 year yield curve for the post-war US economy with a similar degree of precision as in reduced form term structure models. At the same time, we are able to reproduce the dynamics of four key macro...... variables almost perfectly. Our extension of a standard DSGE model is to introduce three non-stationary shocks which allow us to explain interest rates with medium and long maturities without distorting the dynamics of the macroeconomy....

  6. Does Powerlessness Explain the Relationship between Intimate Partner Violence and Depression?

    Science.gov (United States)

    Filson, Jennifer; Ulloa, Emilio; Runfola, Cristin; Hokoda, Audrey

    2010-01-01

    The current study aimed to test whether relationship power could act as a mediator of the relationship between intimate partner violence and depression. The proposed mediation model was based on the theory of gender and power and on previous research of intimate partner violence and depression. Survey results from a sample of 327 single…

  7. Explaining Intentions to Seek Help for Depressive Symptoms in the Context of Responsibility Message Framing.

    Science.gov (United States)

    Lueck, Jennifer; Yzer, Marco

    2018-08-01

    U.S. college students are disproportionally affected by depression but typically do not seek help. To advance understanding of the role of health messages in shaping college students' help-seeking intentions, we used a reasoned action approach to experimentally investigate help-seeking intentions for depressive symptoms. Due to negative interpretation biases among those who suffer from depression, scholars have previously warned against attempts to decrease feelings of responsibility for one's depression in health messages. We tested the determinants of help-seeking intentions as a function of exposure to depression help-seeking messages that differed in responsibility cues. Findings revealed that in our sample low responsibility health message framing did not affect determinants of help-seeking intentions. We identified instrumental attitude (β = .53) and descriptive norms (β = .24) as determinants of intentions to seek help (R 2  = .42) across message conditions and across levels of depression. These findings indicate potentially important targets for messages that seek to increase help-seeking among depressed college students.

  8. A longitudinal study to explain the pain-depression link in older adults with osteoarthritis.

    Science.gov (United States)

    Hawker, Gillian A; Gignac, Monique A M; Badley, Elizabeth; Davis, Aileen M; French, Melissa R; Li, Ye; Perruccio, Anthony V; Power, J Denise; Sale, Joanna; Lou, Wendy

    2011-10-01

    To evaluate whether osteoarthritis (OA) pain determines depressed mood, taking into consideration fatigue and disability and controlling for other factors. In a community cohort with hip/knee OA, telephone interviews assessed OA pain and disability (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]), fatigue (Multidimensional Fatigue Symptom Inventory), depressed mood (Center for Epidemiologic Studies Depression Scale), and covariates (demographics, self-rated health, comorbidity, pain coping, pain catastrophizing, and social support) at 3 time points over 2 years. Drawing on previous research, a path model was developed to test the interrelationships among the key concepts (pain, depression, fatigue, disability) over time, controlling for covariates. The baseline mean age was 75.4 years; 78.5% of the subjects were women, 37.2% were living alone, and 15.5% had ≥3 comorbid conditions. WOMAC scores indicated moderate OA symptoms and disability. From the final model with 529 subjects, adjusting for covariates, we found that current OA pain strongly predicted future fatigue and disability (both short and long term), that fatigue and disability in turn predicted future depressed mood, that depressed mood and fatigue were interrelated such that depressed mood exacerbated fatigue and vice versa, and that fatigue and disability, but not depressed mood, led to worsening of OA pain. Controlling for other factors, OA pain determined subsequent depressed mood through its effect on fatigue and disability. These effects led to worsening of pain and disability over time. These results support the need for improved pain management in OA to prevent or attenuate the downstream effects of pain on disability and mood. Copyright © 2011 by the American College of Rheumatology.

  9. Altered amygdalar resting-state connectivity in depression is explained by both genes and environment.

    Science.gov (United States)

    Córdova-Palomera, Aldo; Tornador, Cristian; Falcón, Carles; Bargalló, Nuria; Nenadic, Igor; Deco, Gustavo; Fañanás, Lourdes

    2015-10-01

    Recent findings indicate that alterations of the amygdalar resting-state fMRI connectivity play an important role in the etiology of depression. While both depression and resting-state brain activity are shaped by genes and environment, the relative contribution of genetic and environmental factors mediating the relationship between amygdalar resting-state connectivity and depression remain largely unexplored. Likewise, novel neuroimaging research indicates that different mathematical representations of resting-state fMRI activity patterns are able to embed distinct information relevant to brain health and disease. The present study analyzed the influence of genes and environment on amygdalar resting-state fMRI connectivity, in relation to depression risk. High-resolution resting-state fMRI scans were analyzed to estimate functional connectivity patterns in a sample of 48 twins (24 monozygotic pairs) informative for depressive psychopathology (6 concordant, 8 discordant and 10 healthy control pairs). A graph-theoretical framework was employed to construct brain networks using two methods: (i) the conventional approach of filtered BOLD fMRI time-series and (ii) analytic components of this fMRI activity. Results using both methods indicate that depression risk is increased by environmental factors altering amygdalar connectivity. When analyzing the analytic components of the BOLD fMRI time-series, genetic factors altering the amygdala neural activity at rest show an important contribution to depression risk. Overall, these findings show that both genes and environment modify different patterns the amygdala resting-state connectivity to increase depression risk. The genetic relationship between amygdalar connectivity and depression may be better elicited by examining analytic components of the brain resting-state BOLD fMRI signals. © 2015 Wiley Periodicals, Inc.

  10. Nonlinear Associations Between Co-Rumination and Both Social Support and Depression Symptoms.

    Science.gov (United States)

    Ames-Sikora, Alyssa M; Donohue, Meghan Rose; Tully, Erin C

    2017-08-18

    Co-ruminating about one's problems appears to involve both beneficial self-disclosure and harmful rumination, suggesting that moderate levels may be the most adaptive. This study used nonlinear regression to determine whether moderate levels of self-reported co-rumination in relationships with a sibling, parent, friend, and romantic partner are linked to the highest levels of self-perceived social support and lowest levels of self-reported depression symptoms in 175 emerging adults (77% female; M = 19.66 years). As expected, moderate co-rumination was associated with high social support across all four relationship types, but, somewhat unexpectedly, high levels of co-rumination were also associated with high social support. As predicted, moderate levels of co-rumination with friends and siblings were associated with low levels of depression. Contrary to hypotheses, high levels of co-rumination were associated with high depression within romantic relationships. Co-rumination with a parent did not have a linear or quadratic association with depression. These findings suggest that high co-ruminating in supportive relationships and to a lesser extent low co-ruminating in unsupportive relationships are maladaptive interpersonal processes but that co-rumination's relation to depression depends on the co-ruminating partner. Psychotherapies for depression may target these maladaptive processes by supporting clients' development of balanced self-focused negative talk.

  11. Adolescent stress and symptoms of anxiety and depression: Resilience explains and differentiates the relationships.

    Science.gov (United States)

    Anyan, Frederick; Hjemdal, Odin

    2016-10-01

    Some adolescents exhibit resilience even in the face of high levels of stress exposure. Despite this relationship, studies that investigate explanations for how resilience interacts with risk to produce particular outcomes and why this is so are lacking. The effect of resilience across the relationship between stress and symptoms of anxiety and stress and symptoms of depression was tested to provide explanations for how resilience interacts with stress and symptoms of anxiety, and depression. In a cross-sectional survey, 533 Ghanaian adolescents aged 13-17 years (M=15.25, SD=1.52), comprising 290 girls and 237 boys completed the Resilience Scale for Adolescents, Adolescent Stress Questionnaire, Spielberger State Anxiety Inventory, and Short Mood Feeling Questionnaire. Mediation and moderation analyses were conducted. The results indicated that resilience partially mediated the relationship between stress, and symptoms of anxiety, and depression. Effects of stress were negatively associated with resilience, and positively associated with symptoms of anxiety and depression. In a differential moderator effect, resilience moderated the relationship between stress and symptoms of depression but not stress and symptoms of anxiety. Although the findings in this study are novel, they do not answer questions about protective mechanisms or processes. Evidence that resilience did not have the same effect across stress, and symptoms of anxiety and depression may support resilience as a dynamic process model. Access to different levels of resilience shows that enhancing resilience while minimizing stress may improve psychiatric health in adolescents' general population. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. BODE index versus GOLD classification for explaining anxious and depressive symptoms in patients with COPD – a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Burghuber Otto

    2009-01-01

    Full Text Available Abstract Background Anxiety and depression are common and treatable risk factors for re-hospitalisation and death in patients with COPD. The degree of lung function impairment does not sufficiently explain anxiety and depression. The BODE index allows a functional classification of COPD beyond FEV1. The aim of this cross-sectional study was (1 to test whether the BODE index is superior to the GOLD classification for explaining anxious and depressive symptoms; and (2 to assess which components of the BODE index are associated with these psychological aspects of COPD. Methods COPD was classified according to the GOLD stages based on FEV1%predicted in 122 stable patients with COPD. An additional four stage classification was constructed based on the quartiles of the BODE index. The hospital anxiety and depression scale was used to assess anxious and depressive symptoms. Results The overall prevalence of anxious and depressive symptoms was 49% and 52%, respectively. The prevalence of anxious symptoms increased with increasing BODE stages but not with increasing GOLD stages. The prevalence of depressive symptoms increased with both increasing GOLD and BODE stages. The BODE index was superior to FEV1%predicted for explaining anxious and depressive symptoms. Anxious symptoms were explained by dyspnoea. Depressive symptoms were explained by both dyspnoea and reduced exercise capacity. Conclusion The BODE index is superior to the GOLD classification for explaining anxious and depressive symptoms in COPD patients. These psychological consequences of the disease may play a role in future classification systems of COPD.

  13. Assessment of linear and nonlinear/complex heartbeat dynamics in subclinical depression (dysphoria).

    Science.gov (United States)

    Greco, Alberto; Messerotti Benvenuti, Simone; Gentili, Claudio; Palomba, Daniela; Scilingo, Enzo Pasquale; Valenza, Gaetano

    2018-03-29

    Depression is one of the leading causes of disability worldwide. Most previous studies have focused on major depression, and studies on subclinical depression, such as those on so-called dysphoria, have been overlooked. Indeed, dysphoria is associated with a high prevalence of somatic disorders, and a reduction of quality of life and life expectancy. In current clinical practice, dysphoria is assessed using psychometric questionnaires and structured interviews only, without taking into account objective pathophysiological indices. To address this problem, in this study we investigated heartbeat linear and nonlinear dynamics to derive objective autonomic nervous system biomarkers of dysphoria. Sixty undergraduate students participated in the study: according to clinical evaluation, 24 of them were dysphoric. Extensive group-wise statistics was performed to characterize the pathological and control groups. Moreover, a recursive feature elimination algorithm based on a K-NN classifier was carried out for the automatic recognition of dysphoria at a single-subject level. The results showed that the most significant group-wise differences referred to increased heartbeat complexity (particularly for fractal dimension, sample entropy and recurrence plot analysis) with regards to the healthy controls, confirming dysfunctional nonlinear sympatho-vagal dynamics in mood disorders. Furthermore, a balanced accuracy of 79.17% was achieved in automatically distinguishing dysphoric patients from controls, with the most informative power attributed to nonlinear, spectral and polyspectral quantifiers of cardiovascular variability. This study experimentally supports the assessment of dysphoria as a defined clinical condition with specific characteristics which are different both from healthy, fully euthymic controls and from full-blown major depression.

  14. Co-occurring manic symptomatology as a dimension which may help explaining heterogeneity of depression

    NARCIS (Netherlands)

    Jabben, Nienke; Penninx, Brenda; Beekman, Aartjan T. F.; Smit, Johannes H.; Nolen, Willem A.

    Background: The dichotomous distinction between unipolar and bipolar disorders may be challenged by heterogeneity within diagnoses and overlap between different diagnoses. A broad mood disorder category in which patients differ as a result of variation along separate manic and depressive mood

  15. Intensity of positive and negative emotions : Explaining the association between personality and depressive symptoms

    NARCIS (Netherlands)

    Karreman, A.; van Assen, M.A.L.M.; Bekker, M.H.J.

    2013-01-01

    The aim was to examine to what extent emotional intensity accounted for associations between the Big Five personality dimensions and depressive symptoms. Study 1 tested the model cross-sectionally, using survey data of 266 Dutch social science students. Study 2 experimentally examined how

  16. Might depression, psychosocial adversity, and limited social assets explain vulnerability to and resistance against violent radicalisation?

    Directory of Open Access Journals (Sweden)

    Kamaldeep Bhui

    Full Text Available BACKGROUND: This study tests whether depression, psychosocial adversity, and limited social assets offer protection or suggest vulnerability to the process of radicalisation. METHODS: A population sample of 608 men and women of Pakistani or Bangladeshi origin, of Muslim heritage, and aged 18-45 were recruited by quota sampling. Radicalisation was measured by 16 questions asking about sympathies for violent protest and terrorism. Cluster analysis of the 16 items generated three groups: most sympathetic (or most vulnerable, most condemning (most resistant, and a large intermediary group that acted as a reference group. Associations were calculated with depression (PHQ9, anxiety (GAD7, poor health, and psychosocial adversity (adverse life events, perceived discrimination, unemployment. We also investigated protective factors such as the number social contacts, social capital (trust, satisfaction, feeling safe, political engagement and religiosity. RESULTS: Those showing the most sympathy for violent protest and terrorism were more likely to report depression (PHQ9 score of 5 or more; RR = 5.43, 1.35 to 21.84 and to report religion to be important (less often said religion was fairly rather than very important; RR = 0.08, 0.01 to 0.48. Resistance to radicalisation measured by condemnation of violent protest and terrorism was associated with larger number of social contacts (per contact: RR = 1.52, 1.26 to 1.83, less social capital (RR = 0.63, 0.50 to 0.80, unavailability for work due to housekeeping or disability (RR = 8.81, 1.06 to 37.46, and not being born in the UK (RR = 0.22, 0.08 to 0.65. CONCLUSIONS: Vulnerability to radicalisation is characterised by depression but resistance to radicalisation shows a different profile of health and psychosocial variables. The paradoxical role of social capital warrants further investigation.

  17. Might depression, psychosocial adversity, and limited social assets explain vulnerability to and resistance against violent radicalisation?

    Science.gov (United States)

    Bhui, Kamaldeep; Everitt, Brian; Jones, Edgar

    2014-01-01

    This study tests whether depression, psychosocial adversity, and limited social assets offer protection or suggest vulnerability to the process of radicalisation. A population sample of 608 men and women of Pakistani or Bangladeshi origin, of Muslim heritage, and aged 18-45 were recruited by quota sampling. Radicalisation was measured by 16 questions asking about sympathies for violent protest and terrorism. Cluster analysis of the 16 items generated three groups: most sympathetic (or most vulnerable), most condemning (most resistant), and a large intermediary group that acted as a reference group. Associations were calculated with depression (PHQ9), anxiety (GAD7), poor health, and psychosocial adversity (adverse life events, perceived discrimination, unemployment). We also investigated protective factors such as the number social contacts, social capital (trust, satisfaction, feeling safe), political engagement and religiosity. Those showing the most sympathy for violent protest and terrorism were more likely to report depression (PHQ9 score of 5 or more; RR = 5.43, 1.35 to 21.84) and to report religion to be important (less often said religion was fairly rather than very important; RR = 0.08, 0.01 to 0.48). Resistance to radicalisation measured by condemnation of violent protest and terrorism was associated with larger number of social contacts (per contact: RR = 1.52, 1.26 to 1.83), less social capital (RR = 0.63, 0.50 to 0.80), unavailability for work due to housekeeping or disability (RR = 8.81, 1.06 to 37.46), and not being born in the UK (RR = 0.22, 0.08 to 0.65). Vulnerability to radicalisation is characterised by depression but resistance to radicalisation shows a different profile of health and psychosocial variables. The paradoxical role of social capital warrants further investigation.

  18. Nonlinear modulation of interacting between COMT and depression on brain function.

    Science.gov (United States)

    Gong, L; He, C; Yin, Y; Ye, Q; Bai, F; Yuan, Y; Zhang, H; Lv, L; Zhang, H; Zhang, Z; Xie, C

    2017-09-01

    The catechol-O-methyltransferase (COMT) gene is related to dopamine degradation and has been suggested to be involved in the pathogenesis of major depressive disorder (MDD). However, how this gene affects brain function properties in MDD is still unclear. Fifty patients with MDD and 35 cognitively normal participants underwent a resting-state functional magnetic resonance imaging scan. A voxelwise and data-drive global functional connectivity density (gFCD) analysis was used to investigate the main effects and the interactions of disease states and COMT rs4680 gene polymorphism on brain function. We found significant group differences of the gFCD in bilateral fusiform area (FFA), post-central and pre-central cortex, left superior temporal gyrus (STG), rectal and superior temporal gyrus and right ventrolateral prefrontal cortex (vlPFC); abnormal gFCDs in left STG were positively correlated with severity of depression in MDD group. Significant disease×COMT interaction effects were found in the bilateral calcarine gyrus, right vlPFC, hippocampus and thalamus, and left SFG and FFA. Further post-hoc tests showed a nonlinear modulation effect of COMT on gFCD in the development of MDD. Interestingly, an inverted U-shaped modulation was found in the prefrontal cortex (control system) but U-shaped modulations were found in the hippocampus, thalamus and occipital cortex (processing system). Our study demonstrated nonlinear modulation of the interaction between COMT and depression on brain function. These findings expand our understanding of the COMT effect underlying the pathophysiology of MDD. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  19. Nonlinear analysis of EEGs of patients with major depression during different emotional states.

    Science.gov (United States)

    Akdemir Akar, Saime; Kara, Sadık; Agambayev, Sümeyra; Bilgiç, Vedat

    2015-12-01

    Although patients with major depressive disorder (MDD) have dysfunctions in cognitive behaviors and the regulation of emotions, the underlying brain dynamics of the pathophysiology are unclear. Therefore, nonlinear techniques can be used to understand the dynamic behavior of the EEG signals of MDD patients. To investigate and clarify the dynamics of MDD patients׳ brains during different emotional states, EEG recordings were analyzed using nonlinear techniques. The purpose of the present study was to assess whether there are different EEG complexities that discriminate between MDD patients and healthy controls during emotional processing. Therefore, nonlinear parameters, such as Katz fractal dimension (KFD), Higuchi fractal dimension (HFD), Shannon entropy (ShEn), Lempel-Ziv complexity (LZC) and Kolmogorov complexity (KC), were computed from the EEG signals of two groups under different experimental states: noise (negative emotional content) and music (positive emotional content) periods. First, higher complexity values were generated by MDD patients relative to controls. Significant differences were obtained in the frontal and parietal scalp locations using KFD (pemotional bias was demonstrated by their higher brain complexities during the noise period than the music stimulus. Additionally, we found that the KFD, HFD and LZC values were more sensitive in discriminating between patients and controls than the ShEn and KC measures, according to the results of ANOVA and ROC calculations. It can be concluded that the nonlinear analysis may be a useful and discriminative tool in investigating the neuro-dynamic properties of the brain in patients with MDD during emotional stimulation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Nonlinear Predictive Models for Multiple Mediation Analysis: With an Application to Explore Ethnic Disparities in Anxiety and Depression Among Cancer Survivors.

    Science.gov (United States)

    Yu, Qingzhao; Medeiros, Kaelen L; Wu, Xiaocheng; Jensen, Roxanne E

    2018-04-02

    Mediation analysis allows the examination of effects of a third variable (mediator/confounder) in the causal pathway between an exposure and an outcome. The general multiple mediation analysis method (MMA), proposed by Yu et al., improves traditional methods (e.g., estimation of natural and controlled direct effects) to enable consideration of multiple mediators/confounders simultaneously and the use of linear and nonlinear predictive models for estimating mediation/confounding effects. Previous studies find that compared with non-Hispanic cancer survivors, Hispanic survivors are more likely to endure anxiety and depression after cancer diagnoses. In this paper, we applied MMA on MY-Health study to identify mediators/confounders and quantify the indirect effect of each identified mediator/confounder in explaining ethnic disparities in anxiety and depression among cancer survivors who enrolled in the study. We considered a number of socio-demographic variables, tumor characteristics, and treatment factors as potential mediators/confounders and found that most of the ethnic differences in anxiety or depression between Hispanic and non-Hispanic white cancer survivors were explained by younger diagnosis age, lower education level, lower proportions of employment, less likely of being born in the USA, less insurance, and less social support among Hispanic patients.

  1. Can variation in hypothalamic-pituitary-adrenal (HPA-axis activity explain the relationship between depression and cognition in bipolar patients?

    Directory of Open Access Journals (Sweden)

    Marieke J van der Werf-Eldering

    Full Text Available Dysregulation of the hypothalamic-pituitary-adrenal (HPA axis is thought to be associated with more mood symptoms and worse cognitive functioning. This study examined whether variation in HPA axis activity underlies the association between mood symptoms and cognitive functioning.In 65 bipolar patients cognitive functioning was measured in domains of psychomotor speed, speed of information processing, attentional switching, verbal memory, visual memory, executive functioning and an overall mean score. Severity of depression was assessed by the Inventory of Depressive Symptomatology-self rating version. Saliva cortisol measurements were performed to calculate HPA axis indicators: cortisol awakening response, diurnal slope, the evening cortisol level and the cortisol suppression on the dexamethasone suppression test. Regression analyses of depressive symptoms and cognitive functioning on each HPA axis indicator were performed. In addition we calculated percentages explanation of the association between depressive symptoms and cognition by HPA axis indicators. Depressive symptoms were associated with dysfunction in psychomotor speed, attentional switching and the mean score, as well as with attenuation in diurnal slope value. No association was found between HPA axis activity and cognitive functioning and HPA axis activity did not explain the associations between depressive symptoms and cognition.As our study is the first one in this field specific for bipolar patients and changes in HPA-axis activity did not seem to explain the association between severity of depressive symptoms and cognitive functioning in bipolar patients, future studies are needed to evaluate other factors that might explain this relationship.

  2. Mania and depression explained

    African Journals Online (AJOL)

    are thought to play a role in neuro-developmental processes, lending further ... Because serotonin, noradrenaline and dopamine are strongly implicated in the .... Genome-wide association study reveals two new risk loci for bipolar disorder.

  3. Visuo-manual tracking: does intermittent control with aperiodic sampling explain linear power and non-linear remnant without sensorimotor noise?

    Science.gov (United States)

    Gollee, Henrik; Gawthrop, Peter J; Lakie, Martin; Loram, Ian D

    2017-11-01

    A human controlling an external system is described most easily and conventionally as linearly and continuously translating sensory input to motor output, with the inevitable output remnant, non-linearly related to the input, attributed to sensorimotor noise. Recent experiments show sustained manual tracking involves repeated refractoriness (insensitivity to sensory information for a certain duration), with the temporary 200-500 ms periods of irresponsiveness to sensory input making the control process intrinsically non-linear. This evidence calls for re-examination of the extent to which random sensorimotor noise is required to explain the non-linear remnant. This investigation of manual tracking shows how the full motor output (linear component and remnant) can be explained mechanistically by aperiodic sampling triggered by prediction error thresholds. Whereas broadband physiological noise is general to all processes, aperiodic sampling is associated with sensorimotor decision making within specific frontal, striatal and parietal networks; we conclude that manual tracking utilises such slow serial decision making pathways up to several times per second. The human operator is described adequately by linear translation of sensory input to motor output. Motor output also always includes a non-linear remnant resulting from random sensorimotor noise from multiple sources, and non-linear input transformations, for example thresholds or refractory periods. Recent evidence showed that manual tracking incurs substantial, serial, refractoriness (insensitivity to sensory information of 350 and 550 ms for 1st and 2nd order systems respectively). Our two questions are: (i) What are the comparative merits of explaining the non-linear remnant using noise or non-linear transformations? (ii) Can non-linear transformations represent serial motor decision making within the sensorimotor feedback loop intrinsic to tracking? Twelve participants (instructed to act in three prescribed

  4. Nonlinear digital signal processing in mental health: characterization of major depression using instantaneous entropy measures of heartbeat dynamics.

    Science.gov (United States)

    Valenza, Gaetano; Garcia, Ronald G; Citi, Luca; Scilingo, Enzo P; Tomaz, Carlos A; Barbieri, Riccardo

    2015-01-01

    Nonlinear digital signal processing methods that address system complexity have provided useful computational tools for helping in the diagnosis and treatment of a wide range of pathologies. More specifically, nonlinear measures have been successful in characterizing patients with mental disorders such as Major Depression (MD). In this study, we propose the use of instantaneous measures of entropy, namely the inhomogeneous point-process approximate entropy (ipApEn) and the inhomogeneous point-process sample entropy (ipSampEn), to describe a novel characterization of MD patients undergoing affective elicitation. Because these measures are built within a nonlinear point-process model, they allow for the assessment of complexity in cardiovascular dynamics at each moment in time. Heartbeat dynamics were characterized from 48 healthy controls and 48 patients with MD while emotionally elicited through either neutral or arousing audiovisual stimuli. Experimental results coming from the arousing tasks show that ipApEn measures are able to instantaneously track heartbeat complexity as well as discern between healthy subjects and MD patients. Conversely, standard heart rate variability (HRV) analysis performed in both time and frequency domains did not show any statistical significance. We conclude that measures of entropy based on nonlinear point-process models might contribute to devising useful computational tools for care in mental health.

  5. The Applicability of Cognitive Mediational and Moderational Models to Explain Children's Depression Inventory Factor Scores in Urban Youth

    Science.gov (United States)

    Reinemann, Dawn H. S.; Teeter Ellison, Phyllis A.

    2004-01-01

    This investigation examined whether cognition serves as a direct factor, mediates, or moderates the relationship between stressful life events and Children's Depression Inventory (CDI; Kovacs, 1992) factor scores in urban, ethnic minority youth. Ninety-eight middle school students completed measures of stressful life events, cognition (cognitive…

  6. Did technology shocks drive the great depression? Explaining cyclical productivity movements in US manufacturing, 1919-1939

    NARCIS (Netherlands)

    Inklaar, Robert; de Jong, Herman; Gouma, Reitze

    2011-01-01

    Technology shocks and declining productivity have been advanced as important factors driving the Great Depression in the United States, based on real business cycle theory. We estimate an improved measure of technology for interwar manufacturing, using data from the U.S. census reports. There is

  7. Anxiety and Depression during Transition from Hospital to Community in Older Adults: Concepts of a Study to Explain Late Age Onset Depression

    Directory of Open Access Journals (Sweden)

    Aislinn F. Lalor

    2015-06-01

    Full Text Available The transition between extended hospitalization and discharge home to community-living contexts for older adults is a critical time period. This transition can have an impact on the health outcomes of older adults such as increasing the risk for health outcomes like falls, functional decline and depression and anxiety. The aim of this work is to identify and understand why older adults experience symptoms of depression and anxiety post-discharge and what factors are associated with this. This is a mixed methods study of adults aged 65 years and over who experienced a period of hospitalization longer than two weeks and return to community-living post-discharge. Participants will complete a questionnaire at baseline and additional monthly follow-up questionnaires for six months. Anxiety and depression and their resulting behaviors are major public health concerns and are significant determinants of health and wellbeing among the ageing population. There is a critical need for research into the impact of an extended period of hospitalization on the health status of older adults post-discharge from hospital. This research will provide evidence that will inform interventions and services provided for older adults after they have been discharged home from hospital care.

  8. Depression

    Science.gov (United States)

    ... in the winter. Depression is one part of bipolar disorder. There are effective treatments for depression, including antidepressants, talk therapy, or both. NIH: National Institute of Mental Health

  9. Depression

    Science.gov (United States)

    ... reasons why a woman may have depression: Family history . Women with a family history of depression may be more at risk. But depression can also happen in women who don’t have a family history of depression. Brain changes. The brains of people ...

  10. An Underlying Common Factor, Influenced by Genetics and Unique Environment, Explains the Covariation Between Major Depressive Disorder, Generalized Anxiety Disorder, and Burnout: A Swedish Twin Study.

    Science.gov (United States)

    Mather, Lisa; Blom, Victoria; Bergström, Gunnar; Svedberg, Pia

    2016-12-01

    Depression and anxiety are highly comorbid due to shared genetic risk factors, but less is known about whether burnout shares these risk factors. We aimed to examine whether the covariation between major depressive disorder (MDD), generalized anxiety disorder (GAD), and burnout is explained by common genetic and/or environmental factors. This cross-sectional study included 25,378 Swedish twins responding to a survey in 2005-2006. Structural equation models were used to analyze whether the trait variances and covariances were due to additive genetics, non-additive genetics, shared environment, and unique environment. Univariate analyses tested sex limitation models and multivariate analysis tested Cholesky, independent pathway, and common pathway models. The phenotypic correlations were 0.71 (0.69-0.74) between MDD and GAD, 0.58 (0.56-0.60) between MDD and burnout, and 0.53 (0.50-0.56) between GAD and burnout. Heritabilities were 45% for MDD, 49% for GAD, and 38% for burnout; no statistically significant sex differences were found. A common pathway model was chosen as the final model. The common factor was influenced by genetics (58%) and unique environment (42%), and explained 77% of the variation in MDD, 69% in GAD, and 44% in burnout. GAD and burnout had additive genetic factors unique to the phenotypes (11% each), while MDD did not. Unique environment explained 23% of the variability in MDD, 20% in GAD, and 45% in burnout. In conclusion, the covariation was explained by an underlying common factor, largely influenced by genetics. Burnout was to a large degree influenced by unique environmental factors not shared with MDD and GAD.

  11. Depression

    DEFF Research Database (Denmark)

    Kessing, Lars Veddel; Bukh, Jens Drachmann

    2014-01-01

    The prevalence of depression is not clearly established, but estimated to 3-4% in a Danish questionnaire study. Lifetime's prevalences of 12-17% are reported in other community samples. In the current diagnostic system depression is defined categorically and operationally. It has been argued......, that these diagnostic criteria represent an oversimplification, which has blurred the concept of depression. We suggest a greater emphasis on the depressed mood as the core symptom of depression, which may increase the specificity of the diagnosis. Furthermore, basic principles for the treatment of depression...

  12. Depressants

    Science.gov (United States)

    ... For Teens / Depressants Print en español Depresores del sistema nervioso What They Are: Tranquilizers and other depressants ... of Use Notice of Nondiscrimination Visit the Nemours Web site. Note: All information on TeensHealth® is for ...

  13. Depression

    DEFF Research Database (Denmark)

    Cizza, G; Ravn, Pernille; Chrousos, G P

    2001-01-01

    Existing studies of the relationship between depression and osteoporosis have been heterogeneous in their design and use of diagnostic instruments for depression, which might have contributed to the different results on the comorbidity of these two conditions. Nevertheless, these studies reveal...... a strong association between depression and osteoporosis. Endocrine factors such as depression-induced hypersecretion of corticotropin-releasing hormone and hypercortisolism, hypogonadism, growth hormone deficiency and increased concentration of circulating interleukin 6, might play a crucial role...... in the bone loss observed in subjects suffering from major depression....

  14. Depression

    DEFF Research Database (Denmark)

    Pouwer, Frans

    2017-01-01

    There is ample evidence that depression is000  a common comorbid health issue in people with type 1 or type 2 diabetes. Reviews have also concluded that depression in diabetes is associated with higher HbA1c levels, less optimal self-care behaviours, lower quality of life, incident vascular...... complications and higher mortality rates. However, longitudinal studies into the course of depression in people with type 1 diabetes remain scarce. In this issue of Diabetologia, Kampling and colleagues (doi: 10.1007/s00125-016-4123-0 ) report the 5 year trajectories of depression in adults with newly diagnosed...... type 1 diabetes (mean age, 28 years). Their baseline results showed that shortly after the diagnosis of type 1 diabetes a major depressive episode was diagnosed in approximately 6% of participants, while 8% suffered from an anxiety disorder. The longitudinal depression data showed that, in a 5 year...

  15. Depression

    DEFF Research Database (Denmark)

    Johansen, Jon O. J.

    2013-01-01

    Nyhederne er fulde af historier om depression. Overskrifter som: ’Danskerne propper sig med lykkepiller’ eller ‘depression er stadigvæk tabu’ går tit igen i dagspressen. Men hvor er nuancerne, og hvorfor gider vi læse de samme historier igen og igen? Måske er det fordi, vores egne forestillinger er...

  16. Nonlinear Science

    CERN Document Server

    Yoshida, Zensho

    2010-01-01

    This book gives a general, basic understanding of the mathematical structure "nonlinearity" that lies in the depths of complex systems. Analyzing the heterogeneity that the prefix "non" represents with respect to notions such as the linear space, integrability and scale hierarchy, "nonlinear science" is explained as a challenge of deconstruction of the modern sciences. This book is not a technical guide to teach mathematical tools of nonlinear analysis, nor a zoology of so-called nonlinear phenomena. By critically analyzing the structure of linear theories, and cl

  17. A New Computational Model for Neuro-Glio-Vascular Coupling: Astrocyte Activation Can Explain Cerebral Blood Flow Nonlinear Response to Interictal Events.

    Directory of Open Access Journals (Sweden)

    Solenna Blanchard

    Full Text Available Developing a clear understanding of the relationship between cerebral blood flow (CBF response and neuronal activity is of significant importance because CBF increase is essential to the health of neurons, for instance through oxygen supply. This relationship can be investigated by analyzing multimodal (fMRI, PET, laser Doppler… recordings. However, the important number of intermediate (non-observable variables involved in the underlying neurovascular coupling makes the discovery of mechanisms all the more difficult from the sole multimodal data. We present a new computational model developed at the population scale (voxel with physiologically relevant but simple equations to facilitate the interpretation of regional multimodal recordings. This model links neuronal activity to regional CBF dynamics through neuro-glio-vascular coupling. This coupling involves a population of glial cells called astrocytes via their role in neurotransmitter (glutamate and GABA recycling and their impact on neighboring vessels. In epilepsy, neuronal networks generate epileptiform discharges, leading to variations in astrocytic and CBF dynamics. In this study, we took advantage of these large variations in neuronal activity magnitude to test the capacity of our model to reproduce experimental data. We compared simulations from our model with isolated epileptiform events, which were obtained in vivo by simultaneous local field potential and laser Doppler recordings in rats after local bicuculline injection. We showed a predominant neuronal contribution for low level discharges and a significant astrocytic contribution for higher level discharges. Besides, neuronal contribution to CBF was linear while astrocytic contribution was nonlinear. Results thus indicate that the relationship between neuronal activity and CBF magnitudes can be nonlinear for isolated events and that this nonlinearity is due to astrocytic activity, highlighting the importance of astrocytes in

  18. Milk fat depression in dairy ewes fed fish oil: Might differences in rumen biohydrogenation, fermentation, or bacterial community explain the individual variation?

    Science.gov (United States)

    Frutos, P; Toral, P G; Belenguer, A; Hervás, G

    2018-07-01

    Dairy ewes show large individual variation in the extent of diet-induced milk fat depression (MFD) but reasons behind this variability remain uncertain. Previous results offered no convincing support for these differences being related to relevant changes in the milk fatty acid (FA) profile, including potentially antilipogenic FA, or in the transcript abundance of candidate genes involved in mammary lipogenesis. Therefore, we hypothesized that alterations in the processes of rumen biohydrogenation and fermentation, as well as in the bacterial community structure, might account for individual variation in fish oil-induced MFD severity. To test this explanation, 15 ewes received a total mixed ration without lipid supplementation (control; n = 5) or supplemented with 20 g of fish oil/kg of dry matter [10 animals divided into those showing a strong (RESPON+; -25.4%; n = 5) or a mild (RESPON-; -7.7%; n = 5) decrease in milk fat concentration] for 5 wk. Rumen fermentation parameters, biohydrogenation metabolites, and bacterial structure and diversity were analyzed in rumen samples collected before and after treatments. Although the fish oil supplementation increased the concentration of demonstrated or putative antilipogenic FA (e.g., cis-9 16:1, cis-11 18:1, or trans-10,cis-12 CLA), surprisingly, none of them differed significantly in relation to the extent of MFD (i.e., between RESPON- and RESPON+), and this was the case only for a few minor FA (e.g., cis-6+7 16:1 or 17:0 anteiso). Changes in total volatile FA, acetate, and propionate concentrations were associated with MFD severity, with higher decreases in more susceptible animals. Individual responses were not related to shifts in rumen bacterial structure but some terminal restriction fragments compatible with Clostridiales, Ruminococcaceae, Lachnospiraceae, and Succiniclasticum showed greater abundances in RESPON-, whereas some others that may correspond to Prevotella, Mogibacterium, and Quinella-related spp. were

  19. Familial aggregation of suicide explained by cluster B traits: a three-group family study of suicide controlling for major depressive disorder.

    Science.gov (United States)

    McGirr, Alexander; Alda, Martin; Séguin, Monique; Cabot, Sophie; Lesage, Alain; Turecki, Gustavo

    2009-10-01

    There is substantial evidence suggesting that suicide aggregates in families. However, the extent of overlap between the liability to suicide and psychiatric disorders, particularly major depressive disorder, remains an important issue. Similarly, factors that account for the familial transmission of suicidal behavior remain unclear. Thus, through direct and blind assessment of first-degree relatives, the authors conducted a family study of suicide by examining three proband groups: probands who committed suicide in the context of major depressive disorder, living depressed probands with no history of suicidal behavior, and psychiatrically normal community comparison probands. Participants were 718 first-degree relatives from 120 families: 296 relatives of 51 depressed probands who committed suicide, 185 relatives of 34 nonsuicidal depressed probands, and 237 relatives of 35 community comparison subjects. Psychopathology, suicidal behavior, and behavioral measures were assessed via interviews. The relatives of probands who committed suicide had higher levels of suicidal behavior (10.8%) than the relatives of nonsuicidal depressed probands (6.5%) and community comparison probands (3.4%). Testing cluster B traits as intermediate phenotypes of suicide showed that the relatives of depressed probands who committed suicide had elevated levels of cluster B traits; familial predisposition to suicide was associated with increased levels of cluster B traits; cluster B traits demonstrated familial aggregation and were associated with suicide attempts among relatives; and cluster B traits mediated, at least in part, the relationship between familial predisposition and suicide attempts among relatives. Analyses were repeated for severity of attempts, where cluster B traits also met criteria for endophenotypes of suicide. Familial transmission of suicide and major depression, while partially overlapping, are distinct. Cluster B traits and impulsive-aggressive behavior represent

  20. Complexity explained

    CERN Document Server

    Erdi, Peter

    2008-01-01

    This book explains why complex systems research is important in understanding the structure, function and dynamics of complex natural and social phenomena. Readers will learn the basic concepts and methods of complex system research.

  1. GABAERGIC ALTERATIONS IN NEOCORTEX OF PATIENTS WITH PHARMACORESISTANT TEMPORAL LOBE EPILEPSY CAN EXPLAIN THE COMORBIDITY OF ANXIETY AND DEPRESSION: THE POTENTIAL IMPACT OF CLINICAL FACTORS

    Directory of Open Access Journals (Sweden)

    Luisa Lilia Rocha

    2015-01-01

    Full Text Available Temporal lobe epilepsy (TLE is a chronic neurodegenerative disease with a high prevalence of psychiatric disorders. Temporal neocortex contributes to either seizure propagation or generation in TLE, a situation that has been associated with alterations of the γ-aminobutyric acid (GABA system. On the other hand, an impaired neurotransmission mediated by GABA in temporal neocortex has also been involved with the pathophysiology of psychiatric disorders. In spite of these situations, the role of the necortical GABA system in the comorbidity of TLE and mood disorders has not been investigated. The present study was designed to identify alterations in the GABA system such as: binding to GABAA and GABAB receptors and benzodiazepine site, the tissue content of GABA and the expression of the mRNA encoding the α1-6, β1-3 and γ GABAA subunits, in the temporal neocortex of surgically treated patients with TLE with and without anxiety and/or depression. Neocortex of patients with TLE and comorbid anxiety and/or depression showed increased expression of the mRNA encoding the γ2-subunit, reduced GABAB-induced G protein activation in spite of elevated GABAB binding, and lower tissue content of GABA when compared to autopsy controls. Some of these changes significantly correlated with seizure frequency and duration of epilepsy. The results obtained suggest a dysfunction of the GABAergic neurotransmission in temporal neocortex of patients with TLE and comorbid anxiety and/or depression that could be also influenced by clinical factors such as seizure frequency and duration of illness.

  2. Increased 20-HETE synthesis explains reduced cerebral blood flow but not impaired neurovascular coupling after cortical spreading depression in rat cerebral cortex

    DEFF Research Database (Denmark)

    Fordsmann, Jonas Christoffer; ko, Rebecca; Choi, Hyun B

    2013-01-01

    Cortical spreading depression (CSD) is associated with release of arachidonic acid (AA), impaired neurovascular coupling, and reduced cerebral blood flow (CBF), caused by cortical vasoconstriction. We tested the hypothesis that the released AA is metabolized by the cytochrome P450 enzyme to produce...... neurovascular coupling after CSD. These findings suggest that CSD-induced increments in 20-HETE cause the reduction in CBF after CSD, and that the attenuation of stimulation-induced CBF responses after CSD has a different mechanism. We suggest that blockade of 20-HETE synthesis may be clinically relevant...

  3. SPSS explained

    CERN Document Server

    Hinton, Perry R; Brownlow, Charlotte

    2014-01-01

    SPSS Explained provides the student with all that they need to undertake statistical analysis using SPSS. It combines a step-by-step approach to each procedure with easy to follow screenshots at each stage of the process. A number of other helpful features are provided: regular advice boxes with tips specific to each test explanations divided into 'essential' and 'advanced' sections to suit readers at different levels frequently asked questions at the end of each chapter. The first edition of this popular book has been fully updated for IBM SPSS version 21 and also includes: chapters that expl

  4. Astronomy Explained

    Science.gov (United States)

    North, Gerald

    Every year large numbers of people take up the study of astronomy, mostly at amateur level. There are plenty of elementary books on the market, full of colourful photographs, but lacking in proper explanations of how and why things are as they are. Many people eventually wish to go beyond the 'coffee-table book' stage and study this fascinating subject in greater depth. This book is written for them. In addition, many people sit for public examinations in this subject each year and this book is also intended to be of use to them. All the topics from the GCSE syllabus are covered here, with sample questions at the end of each chapter. Astronomy Explained provides a comprehensive treatment of the subject in more depth than is usually found in elementary works, and will be of interest to both amateur astronomers and students of astronomy.

  5. WAP explained

    International Nuclear Information System (INIS)

    Kaiser, M.J.; Pulsipher, A.G.

    2004-01-01

    The Weatherization Assistance Program (WAP) is a federal block grant program administered by all 50 states and the District of Columbia through community action agencies, state energy offices, local government, and other nonprofit organizations to provide weatherization services to eligible households. The WAP was established in 1976 to increase the energy efficiency, reduce the energy expenditures, and improve the health and safety of low-income households, especially those households that are particularly vulnerable such as families with children, persons with disabilities, and the elderly. The manner in which WAP funds have been allocated to states, however, has been a contentious issue since the inception of the program. Southern states have argued that too much of the federal funding goes to cold-climate and rural states. Northern states disagree. In 1990, Congress amended the Energy Conservation and Production Act and required the Department of Energy to develop a new funding formula. The Department of Energy currently uses a three-factor formula developed in 1995 in conjunction with a two-factor formula developed in 1977 and a hold-harmless provision to allocate WAP funding. The purpose of this paper is to explain the WAP allocation mechanism and the assumptions associated with the 1977 and the 1995 funding formula. The factors that compose each funding formula are critically assessed and various implementation issues are reviewed, including the selection of the trigger point and program capacity levels. It is not possible to define the need for weatherization assistance objectively and in a unique manner, and this ambiguity is the main reason why the WAP allocation mechanism is expected to remain a lively topic of debate and contention

  6. Solitons and nonlinear waves in space plasmas

    International Nuclear Information System (INIS)

    Stasiewicz, K.

    2005-01-01

    Recent measurements made on the ESA/NASA Cluster mission to the Earth's magnetosphere have provided first detailed measurements of magnetosonic solitons in space. The solitons represent localized enhancements of the magnetic field by a factor of 2-10, or depressions down to 10% of the ambient field. The magnetic field signatures are associated with density depressions/enhancements A two-fluid model of nonlinear electron and ion inertial waves in anisotropic plasmas explains the main properties of these structures. It is shown that warm plasmas support four types of nonlinear waves, which correspond to four linear modes: Alfvenic, magnetosonic, sound, and electron inertial waves. Each of these nonlinear modes has slow and fast versions. It is shown by direct integration that the exponential growth rate of nonlinear modes is balanced by the ion and electron dispersion leading to solutions in the form of trains of solitons or cnoidal waves. By using a novel technique of phase portraits it is shown how the dispersive properties of electron and ion inertial waves change at the transition between warm and hot plasmas, and how trains of solitons ('' mirror modes '') are produced in a hot, anisotropic plasma. The applicability of the model is illustrated with data from Cluster spacecraft. (author)

  7. Possible impact of the CYP2D6*10 polymorphism on the nonlinear pharmacokinetic parameter estimates of paroxetine in Japanese patients with major depressive disorders

    Directory of Open Access Journals (Sweden)

    Saruwatari J

    2014-04-01

    Full Text Available Junji Saruwatari,1 Hiroo Nakashima,1 Shoko Tsuchimine,2 Miki Nishimura,1 Naoki Ogusu,1 Norio Yasui-Furukori21Division of Pharmacology and Therapeutics, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan; 2Department of Neuropsychiatry, Graduate School of Medicine, Hirosaki University, Hirosaki, JapanAbstract: It has been suggested that the reduced function allele with reduced cytochrome P450 (CYP 2D6 activity, CYP2D6*10, is associated with the interindividual differences in the plasma paroxetine concentrations, but there is no data presently available regarding the influence of the CYP2D6*10 polymorphism on the pharmacokinetic parameters, eg, Michaelis–Menten constant (Km and maximum velocity (Vmax, in Asian populations. The present study investigated the effects of the CYP2D6 polymorphisms, including CYP2D6*10, on the pharmacokinetic parameters of paroxetine in Japanese patients with major depressive disorders. This retrospective study included 15 Japanese patients with major depressive disorders (four males and eleven females who were treated with paroxetine. The CYP2D6*2, CYP2D6*4, CYP2D6*5, CYP2D6*10, CYP2D6*18, CYP2D6*39, and CYP2D6*41 polymorphisms were evaluated. A total of 56 blood samples were collected from the patients. The Km and Vmax values of paroxetine were estimated for each patient. The allele frequencies of CYP2D6*2, CYP2D6*4, CYP2D6*5, CYP2D6*10, CYP2D6*18, CYP2D6*39, and CYP2D6*41 were 6.7%, 0%, 10.0%, 56.7%, 0%, 26.7%, and 0%, respectively. The mean values of Km and Vmax were 50.5±68.4 ng/mL and 50.6±18.8 mg/day, respectively. Both the Km and Vmax values were significantly smaller in CYP2D6*10 allele carriers than in the noncarriers (24.2±18.3 ng/mL versus 122.5±106.3 ng/mL, P=0.008; 44.2±16.1 mg/day versus 68.3±15.0 mg/day, P=0.022, respectively. This is the first study to demonstrate that the CYP2D6*10 polymorphism could affect the nonlinear pharmacokinetic parameter estimates of

  8. Major depression

    Science.gov (United States)

    Depression - major; Depression - clinical; Clinical depression; Unipolar depression; Major depressive disorder ... providers do not know the exact causes of depression. It is believed that chemical changes in the ...

  9. Depression (Major Depressive Disorder)

    Science.gov (United States)

    ... generally miserable or unhappy without really knowing why. Depression symptoms in children and teens Common signs and ... in normal activities, and avoidance of social interaction. Depression symptoms in older adults Depression is not a ...

  10. Introduction to nonlinear acoustics

    Science.gov (United States)

    Bjørnø, Leif

    2010-01-01

    A brief review of the basic principles of fluid mechanics needed for development of linear and nonlinear ultrasonic concepts will be given. The fundamental equations of nonlinear ultrasonics will be derived and their physical properties explained. It will be shown how an originally monochromatic finite-amplitude ultrasonic wave, due to nonlinear effects, will distort during its propagation in time and space to form higher harmonics to its fundamental frequency. The concepts of shock formation will be presented. The material nonlinearity, described by the nonlinearity parameter B/A of the material, and the convective nonlinearity, described by the ultrasonic Mach Number, will be explained. Two procedures for determination of B/A will briefly be described and some B/A-values characterizing biological materials will be presented. Shock formation, described by use of the Goldberg Number,and Ultrasonic Saturation will be discussed.. An introduction to focused ultrasonic fields will be given and it will be shown how the ultrasonic intensity will vary axially and laterally in and near the focal region and how the field parameters of interest to biomedical applications may be described by use of the KZK-Model. Finally, an introduction will be given to the parametric acoustic array formed by mixing and interaction of two monochromatic, finite-amplitude ultrasonic waves in a liquid and the potentials of this mixing process in biomedical ultrasound will briefly be mentioned.

  11. Explaining Away Intuitions

    Directory of Open Access Journals (Sweden)

    Jonathan Ichikawa

    2009-12-01

    Full Text Available What is it to explain away an intuition? Philosophers regularly attempt to explain intuitions away, but it is often unclear what the success conditions for their project consist in. I attempt to articulate some of these conditions, taking philosophical case studies as guides, and arguing that many attempts to explain away intuitions underestimate the challenge the project of explaining away involves. I will conclude, therefore, that explaining away intuitions is a more difficult task than has sometimes been appreciated; I also suggest, however, that the importance of explaining away intuitions has often been exaggerated.

  12. Nonlinear optics

    International Nuclear Information System (INIS)

    Boyd, R.W.

    1992-01-01

    Nonlinear optics is the study of the interaction of intense laser light with matter. This book is a textbook on nonlinear optics at the level of a beginning graduate student. The intent of the book is to provide an introduction to the field of nonlinear optics that stresses fundamental concepts and that enables the student to go on to perform independent research in this field. This book covers the areas of nonlinear optics, quantum optics, quantum electronics, laser physics, electrooptics, and modern optics

  13. Nonlinear optics

    CERN Document Server

    Bloembergen, Nicolaas

    1996-01-01

    Nicolaas Bloembergen, recipient of the Nobel Prize for Physics (1981), wrote Nonlinear Optics in 1964, when the field of nonlinear optics was only three years old. The available literature has since grown by at least three orders of magnitude.The vitality of Nonlinear Optics is evident from the still-growing number of scientists and engineers engaged in the study of new nonlinear phenomena and in the development of new nonlinear devices in the field of opto-electronics. This monograph should be helpful in providing a historical introduction and a general background of basic ideas both for expe

  14. Nonlinearity management in higher dimensions

    International Nuclear Information System (INIS)

    Kevrekidis, P G; Pelinovsky, D E; Stefanov, A

    2006-01-01

    In the present paper, we revisit nonlinearity management of the time-periodic nonlinear Schroedinger equation and the related averaging procedure. By means of rigorous estimates, we show that the averaged nonlinear Schroedinger equation does not blow up in the higher dimensional case so long as the corresponding solution remains smooth. In particular, we show that the H 1 norm remains bounded, in contrast with the usual blow-up mechanism for the focusing Schroedinger equation. This conclusion agrees with earlier works in the case of strong nonlinearity management but contradicts those in the case of weak nonlinearity management. The apparent discrepancy is explained by the divergence of the averaging procedure in the limit of weak nonlinearity management

  15. Depression - resources

    Science.gov (United States)

    Resources - depression ... Depression is a medical condition. If you think you may be depressed, see a health care provider. ... following organizations are good sources of information on depression : American Psychological Association -- www.apa.org/topics/depression/ ...

  16. Nonlinear oscillations

    CERN Document Server

    Nayfeh, Ali Hasan

    1995-01-01

    Nonlinear Oscillations is a self-contained and thorough treatment of the vigorous research that has occurred in nonlinear mechanics since 1970. The book begins with fundamental concepts and techniques of analysis and progresses through recent developments and provides an overview that abstracts and introduces main nonlinear phenomena. It treats systems having a single degree of freedom, introducing basic concepts and analytical methods, and extends concepts and methods to systems having degrees of freedom. Most of this material cannot be found in any other text. Nonlinear Oscillations uses sim

  17. Plagiarism explainer for students

    OpenAIRE

    Barba, Lorena A.

    2016-01-01

    A slide deck to serve as an explainer of plagiarism in academic settings, with a personal viewpoint. For my students.Also on SpeakerDeck:https://speakerdeck.com/labarba/plagiarism-explainer-for-students(The slide viewer on SpeakerDeck is much nicer.)

  18. Depression (Major Depressive Disorder)

    Science.gov (United States)

    ... your mood. Chronic pain causes a number of problems that can lead to depression, such as trouble sleeping and stress. Disabling pain can cause low self-esteem due to work, legal or financial issues. Depression ...

  19. Nonlinear systems

    CERN Document Server

    Palmero, Faustino; Lemos, M; Sánchez-Rey, Bernardo; Casado-Pascual, Jesús

    2018-01-01

    This book presents an overview of the most recent advances in nonlinear science. It provides a unified view of nonlinear properties in many different systems and highlights many  new developments. While volume 1 concentrates on mathematical theory and computational techniques and challenges, which are essential for the study of nonlinear science, this second volume deals with nonlinear excitations in several fields. These excitations can be localized and transport energy and matter in the form of breathers, solitons, kinks or quodons with very different characteristics, which are discussed in the book. They can also transport electric charge, in which case they are known as polarobreathers or solectrons. Nonlinear excitations can influence function and structure in biology, as for example, protein folding. In crystals and other condensed matter, they can modify transport properties, reaction kinetics and interact with defects. There are also engineering applications in electric lattices, Josephson junction a...

  20. Nonlinear fibre optics overview

    DEFF Research Database (Denmark)

    Travers, J. C.; Frosz, Michael Henoch; Dudley, J. M.

    2010-01-01

    The optical fiber based supercontinuum source has recently become a significant scientific and commercial success, with applications ranging from frequency comb production to advanced medical imaging. This one-of-a-kind book explains the theory of fiber supercontinuum broadening, describes......, provides a background to the associated nonlinear optical processes, treats the generation mechanisms from continuous wave to femtosecond pulse pump regimes and highlights the diverse applications. A full discussion of numerical methods and comprehensive computer code are also provided, enabling readers...

  1. Nonlinear optics principles and applications

    CERN Document Server

    Li, Chunfei

    2017-01-01

    This book reflects the latest advances in nonlinear optics. Besides the simple, strict mathematical deduction, it also discusses the experimental verification and possible future applications, such as the all-optical switches. It consistently uses the practical unit system throughout. It employs simple physical images, such as "light waves" and "photons" to systematically explain the main principles of nonlinear optical effects. It uses the first-order nonlinear wave equation in frequency domain under the condition of “slowly varying amplitude approximation" and the classical model of the interaction between the light and electric dipole. At the same time, it also uses the rate equations based on the energy-level transition of particle systems excited by photons and the energy and momentum conservation principles to explain the nonlinear optical phenomenon. The book is intended for researchers, engineers and graduate students in the field of the optics, optoelectronics, fiber communication, information tech...

  2. Nonlinear optics

    CERN Document Server

    Boyd, Robert W

    2013-01-01

    Nonlinear Optics is an advanced textbook for courses dealing with nonlinear optics, quantum electronics, laser physics, contemporary and quantum optics, and electrooptics. Its pedagogical emphasis is on fundamentals rather than particular, transitory applications. As a result, this textbook will have lasting appeal to a wide audience of electrical engineering, physics, and optics students, as well as those in related fields such as materials science and chemistry.Key Features* The origin of optical nonlinearities, including dependence on the polarization of light* A detailed treatment of the q

  3. Multiorder nonlinear diffraction in frequency doubling processes

    DEFF Research Database (Denmark)

    Saltiel, Solomon M.; Neshev, Dragomir N.; Krolikowski, Wieslaw

    2009-01-01

    We analyze experimentally light scattering from 2 nonlinear gratings and observe two types of second-harmonic frequency-scattering processes. The first process is identified as Raman–Nath type nonlinear diffraction that is explained by applying only transverse phase-matching conditions. The angular...... position of this type of diffraction is defined by the ratio of the second-harmonic wavelength and the grating period. In contrast, the second type of nonlinear scattering process is explained by the longitudinal phase matching only, being insensitive to the nonlinear grating...

  4. Nonlinear systems

    National Research Council Canada - National Science Library

    Drazin, P. G

    1992-01-01

    This book is an introduction to the theories of bifurcation and chaos. It treats the solution of nonlinear equations, especially difference and ordinary differential equations, as a parameter varies...

  5. Nonlinear analysis

    CERN Document Server

    Gasinski, Leszek

    2005-01-01

    Hausdorff Measures and Capacity. Lebesgue-Bochner and Sobolev Spaces. Nonlinear Operators and Young Measures. Smooth and Nonsmooth Analysis and Variational Principles. Critical Point Theory. Eigenvalue Problems and Maximum Principles. Fixed Point Theory.

  6. Computer jargon explained

    CERN Document Server

    Enticknap, Nicholas

    2014-01-01

    Computer Jargon Explained is a feature in Computer Weekly publications that discusses 68 of the most commonly used technical computing terms. The book explains what the terms mean and why the terms are important to computer professionals. The text also discusses how the terms relate to the trends and developments that are driving the information technology industry. Computer jargon irritates non-computer people and in turn causes problems for computer people. The technology and the industry are changing so rapidly; it is very hard even for professionals to keep updated. Computer people do not

  7. The wireless internet explained

    CERN Document Server

    Rhoton, John

    2001-01-01

    The Wireless Internet Explained covers the full spectrum of wireless technologies from a wide range of vendors, including initiatives by Microsoft and Compaq. The Wireless Internet Explained takes a practical look at wireless technology. Rhoton explains the concepts behind the physics, and provides an overview that clarifies the convoluted set of standards heaped together under the umbrella of wireless. It then expands on these technical foundations to give a panorama of the increasingly crowded landscape of wireless product offerings. When it comes to actual implementation the book gives abundant down-to-earth advice on topics ranging from the selection and deployment of mobile devices to the extremely sensitive subject of security.Written by an expert on Internet messaging, the author of Digital Press''s successful Programmer''s Guide to Internet Mail and X.400 and SMTP: Battle of the E-mail Protocols, The Wireless Internet Explained describes and evaluates the current state of the fast-growing and crucial...

  8. Self-explaining roads

    NARCIS (Netherlands)

    Horst, A.R.A. van der; Kaptein, N.

    1999-01-01

    As a means to a sustainable safe traffic environment the concept of Self-Explaining Roads (SER) has been developed. The SER concept advocates a traffic environment that elicits safe driving behaviour simply by its design. In order to support safe driving behaviour and appropriate speed choice,

  9. Time series with tailored nonlinearities

    Science.gov (United States)

    Räth, C.; Laut, I.

    2015-10-01

    It is demonstrated how to generate time series with tailored nonlinearities by inducing well-defined constraints on the Fourier phases. Correlations between the phase information of adjacent phases and (static and dynamic) measures of nonlinearities are established and their origin is explained. By applying a set of simple constraints on the phases of an originally linear and uncorrelated Gaussian time series, the observed scaling behavior of the intensity distribution of empirical time series can be reproduced. The power law character of the intensity distributions being typical for, e.g., turbulence and financial data can thus be explained in terms of phase correlations.

  10. Nonlinear excitations in biomolecules

    International Nuclear Information System (INIS)

    Peyrard, M.

    1995-01-01

    The aim of the workshop entitled ''Nonlinear Excitations in Biomolecules'' is to attempt to bridge the gap between the physicists and biologists communities which is mainly due to language and cultural barriers. The progress of nonlinear science in the last few decades which have shown that the combination of nonlinearity, which characterize most biological phenomena, and cooperative effects in a system having a large number of degrees of freedom, can give rise to coherent excitations with remarkable properties. New concepts, such as solitons nd nonlinear energy localisation have become familiar to physicists and applied mathematicians. It is thus tempting to make an analogy between these coherent excitations and the exceptional stability of some biological processes, such as for instance DNA transcription, which require the coordination of many events in the ever changing environment of a cell. Physicists are now invoking nonlinear excitations to describe and explain many bio-molecular processes while biologists often doubt that the seemingly infinite variety of phenomena that they are attempting to classify can be reduced to such simple concepts. A large part of the meeting is devoted to tutorial lectures rather than to latest research results. The book provides a pedagogical introduction to the two topics forming the backbone of the meeting: the theory of nonlinear excitations and solitons, and their application in biology; and the structure and function of biomolecules, as well as energy and charge transport in biophysics. In order to emphasize the link between physics and biology, the volume is not divided along these two topics but according to biological subjects. Each chapter starts with a short introduction attempting to help the reader to find his way among the contributions and point out the connection between them. 23 lectures over the 32 presented have been selected and refers to quantum properties of macro-molecules. (J.S.)

  11. Nonlinear distortion in wireless systems modeling and simulation with Matlab

    CERN Document Server

    Gharaibeh, Khaled M

    2011-01-01

    This book covers the principles of modeling and simulation of nonlinear distortion in wireless communication systems with MATLAB simulations and techniques In this book, the author describes the principles of modeling and simulation of nonlinear distortion in single and multichannel wireless communication systems using both deterministic and stochastic signals. Models and simulation methods of nonlinear amplifiers explain in detail how to analyze and evaluate the performance of data communication links under nonlinear amplification. The book addresses the analysis of nonlinear systems

  12. Nonlinear optimization

    CERN Document Server

    Ruszczynski, Andrzej

    2011-01-01

    Optimization is one of the most important areas of modern applied mathematics, with applications in fields from engineering and economics to finance, statistics, management science, and medicine. While many books have addressed its various aspects, Nonlinear Optimization is the first comprehensive treatment that will allow graduate students and researchers to understand its modern ideas, principles, and methods within a reasonable time, but without sacrificing mathematical precision. Andrzej Ruszczynski, a leading expert in the optimization of nonlinear stochastic systems, integrates the theory and the methods of nonlinear optimization in a unified, clear, and mathematically rigorous fashion, with detailed and easy-to-follow proofs illustrated by numerous examples and figures. The book covers convex analysis, the theory of optimality conditions, duality theory, and numerical methods for solving unconstrained and constrained optimization problems. It addresses not only classical material but also modern top...

  13. MAGMADIM: Young Explainers Program

    International Nuclear Information System (INIS)

    Paltiel, Z.

    2005-01-01

    Full Text:Physics teachers and educators constantly face the problem of inspiring their students to major in physics. On the other hand, science museums are designed to provide a pleasant environment which will stimulate and encourage a science associated experience to the general public. Typically, there is no intention to teach science as such in science museums. One may, however, use the science museum to teach and inspire certain groups of students in a much deeper sense. In fact they may actually enthusiastically learn much of the school physics curriculum at the museum. This report discusses the Magmadim program through which 10th graders are trained to be young explainers at the Weizmann Institutes Clore Garden of Science. To this end they study the physics underlying its exhibits in an after-school course. The ultimate goal is for the 'magmadim' to become the best possible explainers and be able to face all sorts of museum visitors. Along with learning how to instruct visitors, they must learn the physics behind the exhibits to give a full explanation of the exhibit and be able to answer any question that may arise. Our 5 year experience with the program shows that its self-selected participants not only study a lot of science, but also like it and learn how to explain the content to other people. This program, along with similar programs at the Bloomfield Science Museum and the Madatzim (young physics tutors) program of Ort, help in promoting the interest in science in general and physics in particular among school students. Various ways to expand the programs will also be discussed

  14. Linear Algebra Thoroughly Explained

    CERN Document Server

    Vujičić, Milan

    2008-01-01

    Linear Algebra Thoroughly Explained provides a comprehensive introduction to the subject suitable for adoption as a self-contained text for courses at undergraduate and postgraduate level. The clear and comprehensive presentation of the basic theory is illustrated throughout with an abundance of worked examples. The book is written for teachers and students of linear algebra at all levels and across mathematics and the applied sciences, particularly physics and engineering. It will also be an invaluable addition to research libraries as a comprehensive resource book for the subject.

  15. Nonlinear Dynamics in Spear Wigglers

    International Nuclear Information System (INIS)

    2002-01-01

    BL11, the most recently installed wiggler in the SPEAR storage ring at SSRL, produces a large nonlinear perturbation of the electron beam dynamics, which was not directly evident in the integrated magnetic field measurements. Measurements of tune shifts with betatron oscillation amplitude and with closed orbit shifts were used to characterize the nonlinear fields of the SPEAR insertion devices (IDs). Because of the narrow pole width in BL11, the nonlinear fields seen along the wiggling electron trajectory are dramatically different than the flip coil measurements made along a straight line. This difference explains the tune shift measurements and the observed degradation in dynamic aperture. Corrector magnets to cancel the BL11 nonlinear fields are presently under construction

  16. Matlab for engineers explained

    CERN Document Server

    Gustafsson, Fredrik

    2003-01-01

    This book is written for students at bachelor and master programs and has four different purposes, which split the book into four parts: 1. To teach first or early year undergraduate engineering students basic knowledge in technical computations and programming using MATLAB. The first part starts from first principles and is therefore well suited both for readers with prior exposure to MATLAB but lacking a solid foundational knowledge of the capabilities of the system and readers not having any previous experience with MATLAB. The foundational knowledge gained from these interactive guided tours of the system will hopefully be sufficient for an effective utilization of MATLAB in the engineering profession, in education and in research. 2. To explain the foundations of more advanced use of MATLAB using the facilities added the last couple of years, such as extended data structures, object orientation and advanced graphics. 3. To give an introduction to the use of MATLAB in typical undergraduate courses in elec...

  17. Caregiver Depression

    Science.gov (United States)

    ... will not sell or share your name. Caregiver Depression Tweet Bookmark this page | Email | Print Many caregivers ... depression See your doctor Treatment Coping Symptoms of depression Caregiving is hard — and can lead to feelings ...

  18. Depression FAQs

    Science.gov (United States)

    Depression affects about 15 million American adults every year. Women are more likely to get depression than men. In general, about one out of every four women will get depression at some point in her life.

  19. Depression Screening

    Science.gov (United States)

    ... Depression Screening Substance Abuse Screening Alcohol Use Screening Depression Screening (PHQ-9) - Instructions The following questions are ... this tool, there is also text-only version . Depression Screening - Manual Instructions The following questions are a ...

  20. Nonlinear dynamics and numerical uncertainties in CFD

    Science.gov (United States)

    Yee, H. C.; Sweby, P. K.

    1996-01-01

    The application of nonlinear dynamics to improve the understanding of numerical uncertainties in computational fluid dynamics (CFD) is reviewed. Elementary examples in the use of dynamics to explain the nonlinear phenomena and spurious behavior that occur in numerics are given. The role of dynamics in the understanding of long time behavior of numerical integrations and the nonlinear stability, convergence, and reliability of using time-marching, approaches for obtaining steady-state numerical solutions in CFD is explained. The study is complemented with spurious behavior observed in CFD computations.

  1. Some Aspects of Nonlinear Dynamics and CFD

    Science.gov (United States)

    Yee, Helen C.; Merriam, Marshal (Technical Monitor)

    1996-01-01

    The application of nonlinear dynamics to improve the understanding of numerical uncertainties in computational fluid dynamics (CFD) is reviewed. Elementary examples in the use of dynamics to explain the nonlinear phenomena and spurious behavior that occur in numerics are given. The role of dynamics in the understanding of long time behavior of numerical integrations and the nonlinear stability, convergence, and reliability of using time-marching approaches for obtaining steady-state numerical solutions in CFD is explained. The study is complemented with examples of spurious behavior observed in CFD computations.

  2. The nonlinear universe chaos, emergence, life

    CERN Document Server

    Scott, A C

    2007-01-01

    Written in Alwyn Scott’s inimitable style – lucid and accessible – The Nonlinear Universe surveys and explores the explosion of activity in nonlinear science that began in the 1970s and 1980s and continues today. The book explains the wide-ranging implications of nonlinear phenomena for future developments in many areas of modern science, including mathematics, physics, engineering, chemistry, biology, and neuroscience. Arguably as important as quantum theory, modern nonlinear science – and an appreciation of its implications – is essential for understanding scientific developments of the twenty-first century.

  3. Nonlinear Elliptic Differential Equations with Multivalued Nonlinearities

    Indian Academy of Sciences (India)

    In this paper we study nonlinear elliptic boundary value problems with monotone and nonmonotone multivalued nonlinearities. First we consider the case of monotone nonlinearities. In the first result we assume that the multivalued nonlinearity is defined on all R R . Assuming the existence of an upper and of a lower ...

  4. Non-linear osmosis

    Science.gov (United States)

    Diamond, Jared M.

    1966-01-01

    1. The relation between osmotic gradient and rate of osmotic water flow has been measured in rabbit gall-bladder by a gravimetric procedure and by a rapid method based on streaming potentials. Streaming potentials were directly proportional to gravimetrically measured water fluxes. 2. As in many other tissues, water flow was found to vary with gradient in a markedly non-linear fashion. There was no consistent relation between the water permeability and either the direction or the rate of water flow. 3. Water flow in response to a given gradient decreased at higher osmolarities. The resistance to water flow increased linearly with osmolarity over the range 186-825 m-osM. 4. The resistance to water flow was the same when the gall-bladder separated any two bathing solutions with the same average osmolarity, regardless of the magnitude of the gradient. In other words, the rate of water flow is given by the expression (Om — Os)/[Ro′ + ½k′ (Om + Os)], where Ro′ and k′ are constants and Om and Os are the bathing solution osmolarities. 5. Of the theories advanced to explain non-linear osmosis in other tissues, flow-induced membrane deformations, unstirred layers, asymmetrical series-membrane effects, and non-osmotic effects of solutes could not explain the results. However, experimental measurements of water permeability as a function of osmolarity permitted quantitative reconstruction of the observed water flow—osmotic gradient curves. Hence non-linear osmosis in rabbit gall-bladder is due to a decrease in water permeability with increasing osmolarity. 6. The results suggest that aqueous channels in the cell membrane behave as osmometers, shrinking in concentrated solutions of impermeant molecules and thereby increasing membrane resistance to water flow. A mathematical formulation of such a membrane structure is offered. PMID:5945254

  5. Introduction to nonlinear finite element analysis

    CERN Document Server

    Kim, Nam-Ho

    2015-01-01

    This book introduces the key concepts of nonlinear finite element analysis procedures. The book explains the fundamental theories of the field and provides instructions on how to apply the concepts to solving practical engineering problems. Instead of covering many nonlinear problems, the book focuses on three representative problems: nonlinear elasticity, elastoplasticity, and contact problems. The book is written independent of any particular software, but tutorials and examples using four commercial programs are included as appendices: ANSYS, NASTRAN, ABAQUS, and MATLAB. In particular, the MATLAB program includes all source codes so that students can develop their own material models, or different algorithms. This book also: ·         Presents clear explanations of nonlinear finite element analysis for elasticity, elastoplasticity, and contact problems ·         Includes many informative examples of nonlinear analyses so that students can clearly understand the nonlinear theory ·    ...

  6. New methods of testing nonlinear hypothesis using iterative NLLS estimator

    Science.gov (United States)

    Mahaboob, B.; Venkateswarlu, B.; Mokeshrayalu, G.; Balasiddamuni, P.

    2017-11-01

    This research paper discusses the method of testing nonlinear hypothesis using iterative Nonlinear Least Squares (NLLS) estimator. Takeshi Amemiya [1] explained this method. However in the present research paper, a modified Wald test statistic due to Engle, Robert [6] is proposed to test the nonlinear hypothesis using iterative NLLS estimator. An alternative method for testing nonlinear hypothesis using iterative NLLS estimator based on nonlinear hypothesis using iterative NLLS estimator based on nonlinear studentized residuals has been proposed. In this research article an innovative method of testing nonlinear hypothesis using iterative restricted NLLS estimator is derived. Pesaran and Deaton [10] explained the methods of testing nonlinear hypothesis. This paper uses asymptotic properties of nonlinear least squares estimator proposed by Jenrich [8]. The main purpose of this paper is to provide very innovative methods of testing nonlinear hypothesis using iterative NLLS estimator, iterative NLLS estimator based on nonlinear studentized residuals and iterative restricted NLLS estimator. Eakambaram et al. [12] discussed least absolute deviation estimations versus nonlinear regression model with heteroscedastic errors and also they studied the problem of heteroscedasticity with reference to nonlinear regression models with suitable illustration. William Grene [13] examined the interaction effect in nonlinear models disused by Ai and Norton [14] and suggested ways to examine the effects that do not involve statistical testing. Peter [15] provided guidelines for identifying composite hypothesis and addressing the probability of false rejection for multiple hypotheses.

  7. Nonlinear Elasticity

    Science.gov (United States)

    Fu, Y. B.; Ogden, R. W.

    2001-05-01

    This collection of papers by leading researchers in the field of finite, nonlinear elasticity concerns itself with the behavior of objects that deform when external forces or temperature gradients are applied. This process is extremely important in many industrial settings, such as aerospace and rubber industries. This book covers the various aspects of the subject comprehensively with careful explanations of the basic theories and individual chapters each covering a different research direction. The authors discuss the use of symbolic manipulation software as well as computer algorithm issues. The emphasis is placed firmly on covering modern, recent developments, rather than the very theoretical approach often found. The book will be an excellent reference for both beginners and specialists in engineering, applied mathematics and physics.

  8. Nonlinear resonances

    CERN Document Server

    Rajasekar, Shanmuganathan

    2016-01-01

    This introductory text presents the basic aspects and most important features of various types of resonances and anti-resonances in dynamical systems. In particular, for each resonance, it covers the theoretical concepts, illustrates them with case studies, and reviews the available information on mechanisms, characterization, numerical simulations, experimental realizations, possible quantum analogues, applications and significant advances made over the years. Resonances are one of the most fundamental phenomena exhibited by nonlinear systems and refer to specific realizations of maximum response of a system due to the ability of that system to store and transfer energy received from an external forcing source. Resonances are of particular importance in physical, engineering and biological systems - they can prove to be advantageous in many applications, while leading to instability and even disasters in others. The book is self-contained, providing the details of mathematical derivations and techniques invo...

  9. Maternal Depression and Youth Internalizing and Externalizing Symptomatology: Severity and Chronicity of Past Maternal Depression and Current Maternal Depressive Symptoms

    Science.gov (United States)

    O’Connor, Erin E.; Langer, David A.; Tompson, Martha C.

    2017-01-01

    Maternal depression is a well-documented risk factor for youth depression, and taking into account its severity and chronicity may provide important insight into the degree of risk conferred. This study explored the degree to which the severity/chronicity of maternal depression history explained variance in youth internalizing and externalizing symptoms above and beyond current maternal depressive symptoms among 171 youth (58% male) ages 8 to 12 over a span of three years. Severity and chronicity of past maternal depression and current maternal depressive symptoms were examined as predictors of parent-reported youth internalizing and externalizing symptomatology, as well as youth self-reported depressive symptoms. Severity and chronicity of past maternal depression did not account for additional variance in youth internalizing and externalizing symptoms at Time 1 beyond what was accounted for by maternal depressive symptoms at Time 1. Longitudinal growth curve modeling indicated that prior severity/chronicity of maternal depression predicted levels of youth internalizing and externalizing symptoms at each time point when controlling for current maternal depressive symptoms at each time point. Chronicity of maternal depression, apart from severity, also predicted rate of change in youth externalizing symptoms over time. These findings highlight the importance of screening and assessing for current maternal depressive symptoms, as well as the nature of past depressive episodes. Possible mechanisms underlying the association between severity/chronicity of maternal depression and youth outcomes, such as residual effects from depressive history on mother–child interactions, are discussed. PMID:27401880

  10. Depression (PDQ)

    Science.gov (United States)

    ... Data Conducting Clinical Trials Statistical Tools and Data Terminology Resources NCI Data Catalog Cryo-EM NCI's Role ... that may also cause depression. There are many medical conditions that can cause depression. Medical conditions that ...

  11. Postpartum Depression

    Science.gov (United States)

    ... do not need treatment. The symptoms of postpartum depression last longer and are more severe. You may ... treatment right away, often in the hospital. Postpartum depression can begin anytime within the first year after ...

  12. Depression Treatment

    Science.gov (United States)

    ... 3286 After hours (404) 639-2888 Contact Media Depression Treatment Recommend on Facebook Tweet Share Compartir On ... How Do I Know if I Am Experiencing Depression? The following questions may help you determine if ...

  13. Teen Depression

    Science.gov (United States)

    What is depression in teens? Teen depression is a serious medical illness. It's more than just a feeling of being sad or "blue" for a few days. It is ... trouble focusing and have no motivation or energy. Depression can make you feel like it is hard ...

  14. Perspectives of nonlinear dynamics

    International Nuclear Information System (INIS)

    Jackson, E.A.

    1985-03-01

    Four lectures were given weekly in October and November, 1984, and some of the ideas presented here will be of use in the future. First, a brief survey of the historical development of nonlinear dynamics since about 1890 was given, and then, a few topics were discussed in detail. The objective was to introduce some of many concepts and methods which are presently used for describing nonlinear dynamics. The symbiotic relationship between sciences of all types and mathematics, two main categories of the models describing nature, the method for describing the dynamics of a system, the idea of control parameters and topological dimension, the asymptotic properties of dynamics, abstract dynamics, the concept of embedding, singular perturbation theory, strange attractor, Fermi-Pasta-Ulam phenomena, an example of computer heuristics, the idea of elementary catastrophe theory and so on were explained. The logistic map is the simplest introduction to complex dynamics. The complicated dynamics is referred to as strange attractors. Two-dimensional maps are the highest dimensional maps commonly studied. These were discussed in detail. (Kako, I.)

  15. Nonlinearities in Behavioral Macroeconomics.

    Science.gov (United States)

    Gomes, Orlando

    2017-07-01

    This article undertakes a journey across the literature on behavioral macroeconomics, with attention concentrated on the nonlinearities that the behavioral approach typically suggests or implies. The emphasis is placed on thinking the macro economy as a living organism, composed of many interacting parts, each one having a will of its own, which is in sharp contrast with the mechanism of the orthodox view (well represented by the neoclassical or new Keynesian dynamic stochastic general equilibrium - DSGE - model). The paper advocates that a thorough understanding of individual behavior in collective contexts is the only possible avenue to further explore macroeconomic phenomena and the often observed 'anomalies' that the benchmark DSGE macro framework is unable to explain or justify. After a reflection on the role of behavioral traits as a fundamental component of a new way of thinking the economy, the article proceeds with a debate on some of the most relevant frameworks in the literature that somehow link macro behavior and nonlinearities; covered subjects include macro models with disequilibrium rules, agent-based models that highlight interaction and complexity, evolutionary switching frameworks, and inattention based decision problems. These subjects have, as a fundamental point in common, the use of behavioral elements to transform existing interpretations of the economic reality, making it more evident how irregular fluctuations emerge and unfold on the aggregate.

  16. [Nonlinear magnetohydrodynamics

    International Nuclear Information System (INIS)

    1994-01-01

    Resistive MHD equilibrium, even for small resistivity, differs greatly from ideal equilibrium, as do the dynamical consequences of its instabilities. The requirement, imposed by Faraday's law, that time independent magnetic fields imply curl-free electric fields, greatly restricts the electric fields allowed inside a finite-resistivity plasma. If there is no flow and the implications of the Ohm's law are taken into account (and they need not be, for ideal equilibria), the electric field must equal the resistivity times the current density. The vanishing of the divergence of the current density then provides a partial differential equation which, together with boundary conditions, uniquely determines the scalar potential, the electric field, and the current density, for any given resistivity profile. The situation parallels closely that of driven shear flows in hydrodynamics, in that while dissipative steady states are somewhat more complex than ideal ones, there are vastly fewer of them to consider. Seen in this light, the vast majority of ideal MHD equilibria are just irrelevant, incapable of being set up in the first place. The steady state whose stability thresholds and nonlinear behavior needs to be investigated ceases to be an arbitrary ad hoc exercise dependent upon the whim of the investigator, but is determined by boundary conditions and choice of resistivity profile

  17. Explaining Physics – What Skills does a good Explainer Need?

    CERN Multimedia

    CERN. Geneva; Bartels, Hauke

    2018-01-01

    Explaining physics in a way that it is both scientifically correct and comprehensible is a highly demanding practice. But are explanations an effective way to teach physics? Under which circumstances should a physics teacher explain – and is there such a thing as a guideline for effective instructional explanations? Of course, explaining is more than just presenting content knowledge in clear language – but what more? In our talk, we want to discuss empirical studies on instructional explanations from science education and psychology to address these questions. Among other things, we will refer to results from a large study aiming to research whether teacher education contributes to the development of explaining skills. Besides, we will give insights into a project that seeks to measure explaining skills with an interactive online test instrument.

  18. Nonlinear beam mechanics

    NARCIS (Netherlands)

    Westra, H.J.R.

    2012-01-01

    In this Thesis, nonlinear dynamics and nonlinear interactions are studied from a micromechanical point of view. Single and doubly clamped beams are used as model systems where nonlinearity plays an important role. The nonlinearity also gives rise to rich dynamic behavior with phenomena like

  19. Derivation of an applied nonlinear Schroedinger equation

    Energy Technology Data Exchange (ETDEWEB)

    Pitts, Todd Alan [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Laine, Mark Richard [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Schwarz, Jens [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Rambo, Patrick K. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Karelitz, David B. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    We derive from first principles a mathematical physics model useful for understanding nonlinear optical propagation (including filamentation). All assumptions necessary for the development are clearly explained. We include the Kerr effect, Raman scattering, and ionization (as well as linear and nonlinear shock, diffraction and dispersion). We explain the phenomenological sub-models and each assumption required to arrive at a complete and consistent theoretical description. The development includes the relationship between shock and ionization and demonstrates why inclusion of Drude model impedance effects alters the nature of the shock operator. Unclassified Unlimited Release

  20. Male depression in females?

    Science.gov (United States)

    Möller-Leimkühler, Anne Maria; Yücel, Mete

    2010-02-01

    representative to the general population. Self-reports of the participants were not validated by a clinical evaluation. The results suggest that male depression might also be highly prevalent in females, at least in university students. This can be explained by a growing social acceptance of aggression in women, by a greater exposure to chronic stressors and by a more pronounced stress sensitivity. Particularly female students need special attention and support. Externalizing symptoms should be routinely assessed when diagnosing depression in men and women. 2009 Elsevier B.V. All rights reserved.

  1. Anxious? Depressed? You might be suffering from capitalism: Contradictory class locations and the prevalence of depression and anxiety in the United States

    Science.gov (United States)

    Prins, Seth J.; Bates, Lisa M.; Keyes, Katherine M.; Muntaner, Carles

    2015-01-01

    Despite a well-established social gradient for many mental disorders, evidence suggests that individuals near the middle of the social hierarchy suffer higher rates of depression and anxiety than those at the top or bottom. Although prevailing indicators of socioeconomic stratification (e.g., SES) cannot detect or easily explain such patterns, relational theories of social class, which emphasise political-economic processes and dimensions of power, might. We test whether the relational construct of contradictory class location, which embodies aspects of both ownership and labour, can explain this nonlinear pattern. Data on full-time workers from the National Epidemiologic Survey on Alcohol and Related Conditions (N=21,859) show that occupants of contradictory class locations have higher prevalence and odds of depression and anxiety than occupants of non-contradictory class locations. These findings suggest that the effects of class relations on depression and anxiety extend beyond those of SES, pointing to under-studied mechanisms in social epidemiology, e.g., domination and exploitation. PMID:26385581

  2. Anxious? Depressed? You might be suffering from capitalism: contradictory class locations and the prevalence of depression and anxiety in the USA.

    Science.gov (United States)

    Prins, Seth J; Bates, Lisa M; Keyes, Katherine M; Muntaner, Carles

    2015-11-01

    Despite a well-established social gradient for many mental disorders, there is evidence that individuals near the middle of the social hierarchy suffer higher rates of depression and anxiety than those at the top or bottom. Although prevailing indicators of socioeconomic status (SES) cannot detect or easily explain such patterns, relational theories of social class, which emphasise political-economic processes and dimensions of power, might. We test whether the relational construct of contradictory class location, which embodies aspects of both ownership and labour, can explain this nonlinear pattern. Data on full-time workers from the National Epidemiologic Survey on Alcohol and Related Conditions (n = 21859) show that occupants of contradictory class locations have higher prevalence and odds of depression and anxiety than occupants of non-contradictory class locations. These findings suggest that the effects of class relations on depression and anxiety extend beyond those of SES, pointing to under-studied mechanisms in social epidemiology, for example, domination and exploitation. © 2015 Foundation for the Sociology of Health & Illness.

  3. Your Radiologist Explains Nuclear Medicine

    Medline Plus

    Full Text Available ... Disorders Video: The Basketball Game: An MRI Story Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript Welcome to Radiology Info dot org Hello! I’m Dr. Ramji ...

  4. Your Radiologist Explains Nuclear Medicine

    Medline Plus

    Full Text Available ... by Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript Welcome to Radiology Info dot org Hello! ... d like to talk to you about nuclear medicine. Nuclear medicine offers the potential to identify disease ...

  5. Your Radiologist Explains Nuclear Medicine

    Medline Plus

    Full Text Available ... An MRI Story Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript ... by a special camera and computer to create images of the inside of your body. If you’ ...

  6. Your Radiologist Explains Nuclear Medicine

    Medline Plus

    Full Text Available ... Sponsored by Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript Welcome to Radiology Info dot org ... I’d like to talk to you about nuclear medicine. Nuclear medicine offers the potential to identify ...

  7. Explaining variation in nascent entrepreneurship

    NARCIS (Netherlands)

    A.J. van Stel (André); A.R.M. Wennekers (Sander); P. Reynolds (Paul); A.R. Thurik (Roy)

    2004-01-01

    textabstractThis paper aims at explaining cross-country variation in nascent entrepreneurship. Regression analysis is applied using various explanatory variables derived from three different approaches. We make use of the Global Entrepreneurship Monitor database, including nascent entrepreneurship

  8. Explaining nascent entrepreneurship across countries

    NARCIS (Netherlands)

    A.R. Thurik (Roy); A.J. van Stel (André); A.R.M. Wennekers (Sander); P. Reynolds (Paul)

    2003-01-01

    textabstractThis paper aims at explaining cross-country variation in nascent entrepreneurship. Regression analysis is applied using various explanatory variables derived from three different approaches. We make use of the Global Entrepreneurship Monitor database, including nascent entrepreneurship

  9. Percolation-enhanced nonlinear scattering from semicontinuous metal films

    Science.gov (United States)

    Breit, M.; von Plessen, G.; Feldmann, J.; Podolskiy, V. A.; Sarychev, A. K.; Shalaev, V. M.; Gresillon, S.; Rivoal, J. C.; Gadenne, P.

    2001-03-01

    Strongly enhanced second-harmonic generation (SHG), which is characterized by nearly isotropic distribution, is observed for gold-glass films near the percolation threshold. The diffuse-like SHG scattering, which can be thought of as nonlinear critical opalescence, is in sharp contrast with highly collimated linear reflection and transmission from these nanostructured semicontinuous metal films. Our observations, which can be explained by giant fluctuations of local nonlinear sources for SHG, verify recent predictions of percolation-enhanced nonlinear scattering.

  10. Depressive Disorders

    Science.gov (United States)

    Brown, Jacqueline A.; Russell, Samantha; Rasor, Kaitlin

    2017-01-01

    Depression is among the most common mental disorders in the United States. Its diagnosis is often related to impairment of functioning across several domains, including how an individual thinks, feels, and participates in daily activities. Although depression has a relatively high prevalence among adults, the rate is alarmingly higher among…

  11. Postpartum Depression

    Science.gov (United States)

    ... professionals for help. With support and treatment, new mothers with depression can go on to be healthy, happy parents. ... or two, talk to your doctor. A new mother who feels like giving up, who feels that life is not ... depression can last for several months or even longer ...

  12. Why is Past Depression the Best Predictor of Future Depression? Stress Generation as a Mechanism of Depression Continuity in Girls

    OpenAIRE

    Rudolph, Karen D.; Flynn, Megan; Abaied, Jamie; Groot, Alison; Thompson, Renee

    2009-01-01

    This study examined whether a transactional interpersonal life stress model helps to explain the continuity in depression over time in girls. Youth (86 girls, 81 boys; M age = 12.41, SD = 1.19) and their caregivers participated in a three-wave longitudinal study. Depression and episodic life stress were assessed with semi-structured interviews. Path analysis provided support for a transactional interpersonal life stress model in girls but not in boys, wherein depression predicted the generati...

  13. Alternative theories of the non-linear negative mass instability

    International Nuclear Information System (INIS)

    Channell, P.J.

    1974-01-01

    A theory non-linear negative mass instability is extended to include resistance. The basic assumption is explained physically and an alternative theory is offered. The two theories are compared computationally. 7 refs., 8 figs

  14. Nonlinear structures for extended Korteweg–de Vries equation in ...

    Indian Academy of Sciences (India)

    The presence of immobile nanodust grains changes the general properties of the ...... rational-type solutions, which may be helpful to explain the creation of very .... investigate the behaviour of nonlinear structures in the Earth's ionosphere ...

  15. Why Is Past Depression the Best Predictor of Future Depression? Stress Generation as a Mechanism of Depression Continuity in Girls

    Science.gov (United States)

    Rudolph, Karen D.; Flynn, Megan; Abaied, Jamie L.; Groot, Alison; Thompson, Renee

    2009-01-01

    This study examined whether a transactional interpersonal life stress model helps to explain the continuity in depression over time in girls. Youth (86 girls, 81 boys; M age = 12.41, SD = 1.19) and their caregivers participated in a three-wave longitudinal study. Depression and episodic life stress were assessed with semistructured interviews.…

  16. Correlations and Non-Linear Probability Models

    DEFF Research Database (Denmark)

    Breen, Richard; Holm, Anders; Karlson, Kristian Bernt

    2014-01-01

    the dependent variable of the latent variable model and its predictor variables. We show how this correlation can be derived from the parameters of non-linear probability models, develop tests for the statistical significance of the derived correlation, and illustrate its usefulness in two applications. Under......Although the parameters of logit and probit and other non-linear probability models are often explained and interpreted in relation to the regression coefficients of an underlying linear latent variable model, we argue that they may also be usefully interpreted in terms of the correlations between...... certain circumstances, which we explain, the derived correlation provides a way of overcoming the problems inherent in cross-sample comparisons of the parameters of non-linear probability models....

  17. Boundary induced nonlinearities at small Reynolds numbers

    NARCIS (Netherlands)

    Sbragaglia, M.; Sugiyama, K.

    2007-01-01

    We investigate the importance of boundary slip at finite Reynolds numbers for mixed boundary conditions. Nonlinear effects are induced by the non-homogeneity of the boundary condition and change the symmetry properties of the flow with an overall mean flow reduction. To explain the observed drag

  18. Nonlinear ordinary differential equations analytical approximation and numerical methods

    CERN Document Server

    Hermann, Martin

    2016-01-01

    The book discusses the solutions to nonlinear ordinary differential equations (ODEs) using analytical and numerical approximation methods. Recently, analytical approximation methods have been largely used in solving linear and nonlinear lower-order ODEs. It also discusses using these methods to solve some strong nonlinear ODEs. There are two chapters devoted to solving nonlinear ODEs using numerical methods, as in practice high-dimensional systems of nonlinear ODEs that cannot be solved by analytical approximate methods are common. Moreover, it studies analytical and numerical techniques for the treatment of parameter-depending ODEs. The book explains various methods for solving nonlinear-oscillator and structural-system problems, including the energy balance method, harmonic balance method, amplitude frequency formulation, variational iteration method, homotopy perturbation method, iteration perturbation method, homotopy analysis method, simple and multiple shooting method, and the nonlinear stabilized march...

  19. PSYCHOLOGICAL CORRELATES OF POSTPARTUM DEPRESSION

    Directory of Open Access Journals (Sweden)

    Anida Fazlagić

    2011-12-01

    Full Text Available Manual of Mental Disorders (DSM-IV, postpartum depression may include any nonpsychotic depressive disorder during the first four weeks of postpartum, according to research criteria during the first year after birth. The exact cause of postpartum depression is not yet known, and most researchers believe that postpartum depression is a bio-psycho-social problem. So far, the biological aspect of the disease is explained by changing the levels of estrogen and progesterone during pregnancy, and by decrease of hormone levels after birth. Psychological correlates are often associated with low selfesteem, pessimism as a personality trait, bad strategies of coping with stress, mood swings and emotional reactions. The social aspect of the disease is associated with the existential conditions of pregnant woman, support of partners and education level. This paper will include issues like hereditary causes and possible psychological factors of postpartum depression prevention. Nowadays, it is estimated that on average 15% of women, regardless of the pregnancy outcome, are suffering from postpartum depression. However, this information includes only those women who were diagnosed with postpartum depression and who themselves reported about it. Almost every woman receives basic care during pregnancy to prevent complications in the physiological level. This paper has shown possible psychological factors of postpartum depression prevention, the impact of optimism, self-esteem and coping skills.

  20. On Poisson Nonlinear Transformations

    Directory of Open Access Journals (Sweden)

    Nasir Ganikhodjaev

    2014-01-01

    Full Text Available We construct the family of Poisson nonlinear transformations defined on the countable sample space of nonnegative integers and investigate their trajectory behavior. We have proved that these nonlinear transformations are regular.

  1. Comparing coefficients of nested nonlinear probability models

    DEFF Research Database (Denmark)

    Kohler, Ulrich; Karlson, Kristian Bernt; Holm, Anders

    2011-01-01

    In a series of recent articles, Karlson, Holm and Breen have developed a method for comparing the estimated coeffcients of two nested nonlinear probability models. This article describes this method and the user-written program khb that implements the method. The KHB-method is a general decomposi......In a series of recent articles, Karlson, Holm and Breen have developed a method for comparing the estimated coeffcients of two nested nonlinear probability models. This article describes this method and the user-written program khb that implements the method. The KHB-method is a general...... decomposition method that is unaffected by the rescaling or attenuation bias that arise in cross-model comparisons in nonlinear models. It recovers the degree to which a control variable, Z, mediates or explains the relationship between X and a latent outcome variable, Y*, underlying the nonlinear probability...

  2. Nonlinear optical properties of ultrathin metal layers

    DEFF Research Database (Denmark)

    Lysenko, Oleg

    2016-01-01

    This thesis presents experimental and theoretical studies of nonlinear propagation of ultrashort long-range surface plasmon polaritons in gold strip waveguides. The strip plasmonic waveguides are fabricated in house, and contain a gold layer, adhesion layers, and silicon dioxide cladding. The opt......This thesis presents experimental and theoretical studies of nonlinear propagation of ultrashort long-range surface plasmon polaritons in gold strip waveguides. The strip plasmonic waveguides are fabricated in house, and contain a gold layer, adhesion layers, and silicon dioxide cladding......-order nonlinear susceptibility of the plasmonic mode in the gold strip waveguides significantly depends on the metal layer thickness and laser pulse duration. This dependence is explained in detail in terms of the free-electron temporal dynamics in gold. The third-order nonlinear susceptibility of the gold layer...

  3. Depressive realism and clinical depression.

    Science.gov (United States)

    Carson, Richard C; Hollon, Steven D; Shelton, Richard C

    2010-04-01

    Depressive realism suggests that depressed individuals make more accurate judgments of control than their nondepressed counterparts. However, most studies demonstrating this phenomenon were conducted in nonclinical samples. In this study, psychiatric patients who met criteria for major depressive disorder underestimated control in a contingent situation and were consistently more negative in their judgments than were nondepressed controls. Depressed patients were less likely than their nondepressed counterparts to overestimate control in a noncontingent situation, but largely because they perceived receiving less reinforcement. Depressed patients were no more likely to use the appropriate logical heuristic to generate their judgments of control than their nondepressed counterparts and each appeared to rely on different primitive heuristics. Depressed patients were consistently more negative than their nondepressed counterparts and when they did appear to be more "accurate" in their judgments of control (as in the noncontingent situation) it was largely because they applied the wrong heuristic to less accurate information. These findings do not support the notion of depressive realism and suggest that depressed patients distort their judgments in a characteristically negative fashion. 2009 Elsevier Ltd. All rights reserved.

  4. Depression in the Workplace

    Science.gov (United States)

    ... You are here Home » Depression In The Workplace Depression In The Workplace Clinical depression has become one ... will die by suicide vi . Employees' Attitudes Towards Depression Often times a depressed employee will not seek ...

  5. Genetics Home Reference: depression

    Science.gov (United States)

    ... Share: Email Facebook Twitter Home Health Conditions Depression Depression Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Depression (also known as major depression or major depressive ...

  6. Journalism and Explaining News Content

    NARCIS (Netherlands)

    Albæk, E.; Skovsgaard, M.; de Vreese, C.H.; Nussbaum, J.F.

    Three models are presented to explain variation in news content. In the first model the explanation is based on the individual journalist, in the second model on the professional journalist, and in the third model on the organized journalist. The individual journalist model focuses on how the

  7. Can Marxism Explain America's Racism?

    Science.gov (United States)

    Willhelm, Sidney M.

    1980-01-01

    The Marxist interpretation of the Black experience in America has always had difficulty explaining various noneconomic aspects of racism. A perspective is needed that can blend racism as a variable in relationship with economic variables. To reach this perspective, the labor process within capitalism must be more fully understood. (Author/GC)

  8. Does market competition explain fairness?

    Science.gov (United States)

    Descioli, Peter

    2013-02-01

    The target article by Baumard et al. uses their previous model of bargaining with outside options to explain fairness and other features of human sociality. This theory implies that fairness judgments are determined by supply and demand but humans often perceive prices (divisions of surplus) in competitive markets to be unfair.

  9. Advances in nonlinear optics

    CERN Document Server

    Chen, Xianfeng; Zeng, Heping; Guo, Qi; She, Weilong

    2015-01-01

    This book presents an overview of the state of the art of nonlinear optics from weak light nonlinear optics, ultrafast nonlinear optics to electro-optical theory and applications. Topics range from the fundamental studies of the interaction between matter and radiation to the development of devices, components, and systems of tremendous commercial interest for widespread applications in optical telecommunications, medicine, and biotechnology.

  10. Being alone and expectations lost: a critical realist study of maternal depression in South Western Sydney.

    Science.gov (United States)

    Eastwood, John G; Kemp, Lynn A; Jalaludin, Bin B

    2015-01-01

    The study reported here is part of a critical realist multilevel study. It seeks to identify and explain complex perinatal contextual social and psychosocial mechanisms that may influence the developmental origins of health and disease, with a focus on the role of postnatal depression. The aims of the greater study are to: (1) describe the phenomenon of postnatal depression in South Western Sydney; and (2) identify mechanisms that would add to our understanding of the psycho-social causes of maternal depression. This paper will move beyond our previous quantitative descriptions of individual-level predictors of depressive symptoms by seeking the views of local mothers and practitioners, to explain the mechanisms that might be involved. The study was set in South Western Sydney, New South Wales, Australia. An Explanatory Theory Building Method was used. The previously reported quantitative study was a non-linear principal component analysis and logistic regression study of 15,389 months delivering in 2002 and 2003. This intensive qualitative study used open coding of interviews, of seven practitioners and three naturally occurring mothers groups, to enable maximum emergence. The theoretical concepts identified were: attachment and nurturing, infant temperament, unplanned pregnancy and sole parenthood, support for mothers, access to services, stress, financial hardship, isolation and marginalisation, mothers' "loss of control" and "power", and expectations and dreams. Being alone and expectations lost emerged as possible triggers of stress and depression for mothers. These findings might also apply to others who have their dreams shattered during life's transitions. In these situations social and cultural context can either nurture and support or marginalise and isolate. The challenge for policy and practice is to support mothers and their partners during the transition to parenthood within a challenging social and material context.

  11. [Risk factors for post partum depression].

    Science.gov (United States)

    Dois, Angelina; Uribe, Claudia; Villarroel, Luis; Contreras, Aixa

    2012-06-01

    Postpartum depression (PPD) is a public health problem with high prevalence in Chile. Many factors are associated with PPD. To analyze the factors associated with the incidence of depressive symptoms (SD) in women with low obstetric risk. Cross-sectional analytical study on a sample of 105 postpartum women with low obstetric risk assessed by the Edinburgh Depression Scale at the eighth week postpartum. A 37% prevalence of depressive symptoms was found. Univariate analysis showed that the perception of family functioning, overcrowding and number of siblings, were significantly associated with postpartum depressive symptoms. A multiple regression model only accepted family functioning as a predictor of depression. Perception of family functioning was the only variable that explained in part the presence of depressive symptoms in women with low obstetric risk.

  12. Quantum Nonlinear Optics

    CERN Document Server

    Hanamura, Eiichi; Yamanaka, Akio

    2007-01-01

    This graduate-level textbook gives an introductory overview of the fundamentals of quantum nonlinear optics. Based on the quantum theory of radiation, Quantum Nonlinear Optics incorporates the exciting developments in novel nonlinear responses of materials (plus laser oscillation and superradiance) developed over the past decade. It deals with the organization of radiation field, interaction between electronic system and radiation field, statistics of light, mutual manipulation of light and matter, laser oscillation, dynamics of light, nonlinear optical response, and nonlinear spectroscopy, as well as ultrashort and ultrastrong laser pulse. Also considered are Q-switching, mode locking and pulse compression. Experimental and theoretical aspects are intertwined throughout.

  13. Nonlinear dynamics and complexity

    CERN Document Server

    Luo, Albert; Fu, Xilin

    2014-01-01

    This important collection presents recent advances in nonlinear dynamics including analytical solutions, chaos in Hamiltonian systems, time-delay, uncertainty, and bio-network dynamics. Nonlinear Dynamics and Complexity equips readers to appreciate this increasingly main-stream approach to understanding complex phenomena in nonlinear systems as they are examined in a broad array of disciplines. The book facilitates a better understanding of the mechanisms and phenomena in nonlinear dynamics and develops the corresponding mathematical theory to apply nonlinear design to practical engineering.

  14. Postpartum Depression

    DEFF Research Database (Denmark)

    Smith-Nielsen, Johanne

    Background: In three academic articles, this PhD thesis investigates maternal postpartum depression (PPD) as a risk factor for the infant-mother attachment and infant development. Previous studies have been contradictory with respect to the question of whether PPD can have long term effects...... on offspring. This may be due to not differing between when PPD is only occurring in the postpartum period and when effects are also due to ongoing or recurrent depression. However, it may also be due to viewing maternal depression as a unitary construct, and not considering underlying maternal psychological...... difficulties which may moderate potential adverse effects. The present thesis investigates two potential maternal moderators of risk:. Comorbid personality disorder and adult attachment insecurity. Moreover, the question of early environmental effects of PPD versus effects of later or ongoing depression...

  15. The Role of Marital Power in Depression and Marital Distress.

    Science.gov (United States)

    Halloran, Elizabeth C.

    1998-01-01

    Drawing on sex-role theory, the learned-helplessness model of depression, and a review of empirical research, this article explores inequity in marital power as a potential third variable that explains how depression and the quality of marriage are related. Aims to generate broad-minded thinking about how marital power, depression, and marital…

  16. Distributed nonlinear optical response

    DEFF Research Database (Denmark)

    Nikolov, Nikola Ivanov

    2005-01-01

    of bound states of out of phase bright solitons and dark solitons. Also, the newly introduced analogy between the nonlocal cubic nonlinear and the quadratic nonlinear media, presented in paper B and Chapter 3 is discussed. In particular it supplies intuitive physical meaning of the formation of solitons...... in quadratic nonlinear media. In the second part of the report (Chapter 4), the possibility to obtain light with ultrabroad spectrum due to the interplay of many nonlinear effects based on cubic nonlinearity is investigated thoroughly. The contribution of stimulated Raman scattering, a delayed nonlinear...... a modified nonlinear Schroedinger model equation. Chapter 4 and papers D and E are dedicated to this part of the research....

  17. Explaining Disparities in Unemployment Dynamics

    OpenAIRE

    Karanassou, Marika; Snower, Dennis J.

    1993-01-01

    This paper attempts to explain disparities among the unemployment experiences of different OECD countries in terms of the `fragility' of the short-run unemployment equilibrium (the impact of labour market shocks on the short-run unemployment rate) and the lag structure of the employment determination, wage setting, and labour force participation decisions. The effects of this lag structure on unemployment dynamics are captured through two general measures of `unemployment persistence' (occurr...

  18. Explaining the Gender Wealth Gap

    Science.gov (United States)

    Ruel, Erin; Hauser, Robert M.

    2013-01-01

    To assess and explain the United States’ gender wealth gap, we use the Wisconsin Longitudinal Study to examine wealth accumulated by a single cohort over 50 years by gender, by marital status, and limited to the respondents who are their family’s best financial reporters. We find large gender wealth gaps between currently married men and women, and never-married men and women. The never-married accumulate less wealth than the currently married, and there is a marital disruption cost to wealth accumulation. The status-attainment model shows the most power in explaining gender wealth gaps between these groups explaining about one-third to one-half of the gap, followed by the human-capital explanation. In other words, a lifetime of lower earnings for women translates into greatly reduced wealth accumulation. A gender wealth gap remains between married men and women after controlling for the full model that we speculate may be related to gender differences in investment strategies and selection effects. PMID:23264038

  19. The periodic structure of the natural record, and nonlinear dynamics.

    Science.gov (United States)

    Shaw, H.R.

    1987-01-01

    This paper addresses how nonlinear dynamics can contribute to interpretations of the geologic record and evolutionary processes. Background is given to explain why nonlinear concepts are important. A resume of personal research is offered to illustrate why I think nonlinear processes fit with observations on geological and cosmological time series data. The fabric of universal periodicity arrays generated by nonlinear processes is illustrated by means of a simple computer mode. I conclude with implications concerning patterns of evolution, stratigraphic boundary events, and close correlations of major geologically instantaneous events (such as impacts or massive volcanic episodes) with any sharply defined boundary in the geologic column. - from Author

  20. CORRELATION ANALYSIS BETWEEN DEPRESSIVE MANIFESTATIONS AND MORPHOLOGICAL LESION CHARACTERISTICS IN PATIENTS WITH STROKE

    Directory of Open Access Journals (Sweden)

    Stojanovic Zlatan

    2014-04-01

    Full Text Available Introduction: Knowledge of etiopathogenesis of post-stroke depressive phenomena contributes to early diagnostics which shortens recovery to a great extent and suits the social and professional rehabilitation of patients, if followed by proper psycho/pharmacotherapy. The aim of this work is to research dependence of depressive manifestations considering the size and anatomical localization of lesion. Subjects and Methods: The research included 118 patients with stroke. Lesion localization was defined on computerized axial tomography records, whereas the area and perimeter of lesion were measured by AutoCAD 2004 software. Examinations by means of Hamilton Rating Scale for Depression were carried out by the method of random selection 11–40 days after stroke. Correlation analysis was made by simple linear/nonlinear regression and Cox’s hazard regression model. Results: Negative correlation was observed between the intensity of depressive manifestations and the size of cerebrovascular lesion (Spearman’s r= – 0.263, P= 0.004. By means of Cox’s regression model we determined 4.389 times higher risk for depression occurrence in female patients (P< 0.001, as well as higher risk due to lobus limbicus structure damages (hazard ratio eb(HR = 2.661, P= 0.019. Conclusion: Lower intensity of depressive manifestations with larger cerebrovascular lesions, we have explained by activation of reparation mechanisms with energy savings and decrease (due to neurological deficits of afferent peripheral sensations which antecedent the occurrence of emotions (James-Lange peripheral theory of emotions.

  1. Different pathways explain alcohol related problems in female and male college students

    Science.gov (United States)

    Pedrelli, P.; Collado, A.; Shapero, B. G.; Brill, C.; MacPherson, L.

    2016-01-01

    Objectives Comprehensive models elucidating the intricate associations of depressive symptoms, coping motives, alcohol use, alcohol-related problems (ARP) and gender among young adults have been scarcely examined. This study investigated relationships among these variables and the effect of gender on these pathways. Methods College students (N = 163; 49.7% female) completed self-report measures on alcohol consumption, depressive symptoms, coping motives, and ARPs. Results Structural equation modeling showed that the association between depressive symptoms and ARPs was mediated by coping motives in both females and males. However, frequency of heavy alcohol use mediated the association between depressive symptoms and ARPs in females but not in males. Conclusions Different models explain the association between depressive symptoms and ARPs in male and female college students. Prevention programs aimed at reducing ARPs should focus on increasing alcohol screening among students with depressive symptoms, teaching coping skills, and emphasizing moderation in alcohol consumption. PMID:27219280

  2. Explaining the Evolution of Poverty

    DEFF Research Database (Denmark)

    Arndt, Channing; Hussain, Azhar; Jones, Edward Samuel

    2012-01-01

    We provide a comprehensive approach for analyzing the evolution of poverty using Mozambique as a case study. Bringing together data from disparate sources, we develop a novel “back-casting” framework that links a dynamic computable general equilibrium model to a micro-simulation poverty module....... This framework provides a new approach to explaining and decomposing the evolution of poverty, as well as to examining rigorously the coherence between poverty, economic growth, and inequality outcomes. Finally, various simple but useful and rarely-applied approaches to considering regional changes in poverty...

  3. Amplitude saturation of MEMS resonators explained by autoparametric resonance

    International Nuclear Information System (INIS)

    Van der Avoort, C; Bontemps, J J M; Steeneken, P G; Le Phan, K; Van Beek, J T M; Van der Hout, R; Hulshof, J; Fey, R H B

    2010-01-01

    This paper describes a phenomenon that limits the power handling of MEMS resonators. It is observed that above a certain driving level, the resonance amplitude becomes independent of the driving level. In contrast to previous studies of power handling of MEMS resonators, it is found that this amplitude saturation cannot be explained by nonlinear terms in the spring constant or electrostatic force. Instead we show that the amplitude in our experiments is limited by nonlinear terms in the equation of motion which couple the in-plane length-extensional resonance mode to one or more out-of-plane (OOP) bending modes. We present experimental evidence for the autoparametric excitation of these OOP modes using a vibrometer. The measurements are compared to a model that can be used to predict a power-handling limit for MEMS resonators

  4. Amplitude saturation of MEMS resonators explained by autoparametric resonance

    Energy Technology Data Exchange (ETDEWEB)

    Van der Avoort, C; Bontemps, J J M; Steeneken, P G; Le Phan, K; Van Beek, J T M [NXP Research, Eindhoven (Netherlands); Van der Hout, R; Hulshof, J [Department of Mathematics, VU University—Faculty of Sciences, De Boelelaan 1081a, 1081 HV Amsterdam (Netherlands); Fey, R H B, E-mail: cas.van.der.avoort@nxp.com [Department of Mechanical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven (Netherlands)

    2010-10-15

    This paper describes a phenomenon that limits the power handling of MEMS resonators. It is observed that above a certain driving level, the resonance amplitude becomes independent of the driving level. In contrast to previous studies of power handling of MEMS resonators, it is found that this amplitude saturation cannot be explained by nonlinear terms in the spring constant or electrostatic force. Instead we show that the amplitude in our experiments is limited by nonlinear terms in the equation of motion which couple the in-plane length-extensional resonance mode to one or more out-of-plane (OOP) bending modes. We present experimental evidence for the autoparametric excitation of these OOP modes using a vibrometer. The measurements are compared to a model that can be used to predict a power-handling limit for MEMS resonators.

  5. Depresion: Lo Que Toda Mujer Debe Saber (Depression: What Every Woman Should Know).

    Science.gov (United States)

    National Inst. of Mental Health (DHHS), Bethesda, MD.

    This publication, written in Spanish, explains why women are at greater risk for depression than men. Types of depressive illnesses are explained along with the symptoms. It states that some women are predisposed genetically to depression but biochemical, environmental, psychological, and social factors also often contribute to its occurrence.…

  6. Nonlinear Dirac Equations

    Directory of Open Access Journals (Sweden)

    Wei Khim Ng

    2009-02-01

    Full Text Available We construct nonlinear extensions of Dirac's relativistic electron equation that preserve its other desirable properties such as locality, separability, conservation of probability and Poincaré invariance. We determine the constraints that the nonlinear term must obey and classify the resultant non-polynomial nonlinearities in a double expansion in the degree of nonlinearity and number of derivatives. We give explicit examples of such nonlinear equations, studying their discrete symmetries and other properties. Motivated by some previously suggested applications we then consider nonlinear terms that simultaneously violate Lorentz covariance and again study various explicit examples. We contrast our equations and construction procedure with others in the literature and also show that our equations are not gauge equivalent to the linear Dirac equation. Finally we outline various physical applications for these equations.

  7. Nonlinear graphene plasmonics

    Science.gov (United States)

    Ooi, Kelvin J. A.; Tan, Dawn T. H.

    2017-10-01

    The rapid development of graphene has opened up exciting new fields in graphene plasmonics and nonlinear optics. Graphene's unique two-dimensional band structure provides extraordinary linear and nonlinear optical properties, which have led to extreme optical confinement in graphene plasmonics and ultrahigh nonlinear optical coefficients, respectively. The synergy between graphene's linear and nonlinear optical properties gave rise to nonlinear graphene plasmonics, which greatly augments graphene-based nonlinear device performance beyond a billion-fold. This nascent field of research will eventually find far-reaching revolutionary technological applications that require device miniaturization, low power consumption and a broad range of operating wavelengths approaching the far-infrared, such as optical computing, medical instrumentation and security applications.

  8. Stationary nonlinear Airy beams

    International Nuclear Information System (INIS)

    Lotti, A.; Faccio, D.; Couairon, A.; Papazoglou, D. G.; Panagiotopoulos, P.; Tzortzakis, S.; Abdollahpour, D.

    2011-01-01

    We demonstrate the existence of an additional class of stationary accelerating Airy wave forms that exist in the presence of third-order (Kerr) nonlinearity and nonlinear losses. Numerical simulations and experiments, in agreement with the analytical model, highlight how these stationary solutions sustain the nonlinear evolution of Airy beams. The generic nature of the Airy solution allows extension of these results to other settings, and a variety of applications are suggested.

  9. Generalized Nonlinear Yule Models

    OpenAIRE

    Lansky, Petr; Polito, Federico; Sacerdote, Laura

    2016-01-01

    With the aim of considering models with persistent memory we propose a fractional nonlinear modification of the classical Yule model often studied in the context of macrovolution. Here the model is analyzed and interpreted in the framework of the development of networks such as the World Wide Web. Nonlinearity is introduced by replacing the linear birth process governing the growth of the in-links of each specific webpage with a fractional nonlinear birth process with completely general birth...

  10. Nonlinear evolution equations

    CERN Document Server

    Uraltseva, N N

    1995-01-01

    This collection focuses on nonlinear problems in partial differential equations. Most of the papers are based on lectures presented at the seminar on partial differential equations and mathematical physics at St. Petersburg University. Among the topics explored are the existence and properties of solutions of various classes of nonlinear evolution equations, nonlinear imbedding theorems, bifurcations of solutions, and equations of mathematical physics (Navier-Stokes type equations and the nonlinear Schrödinger equation). The book will be useful to researchers and graduate students working in p

  11. Nonlinear Physics of Plasmas

    CERN Document Server

    Kono, Mitsuo

    2010-01-01

    A nonlinearity is one of the most important notions in modern physics. A plasma is rich in nonlinearities and provides a variety of behaviors inherent to instabilities, coherent wave structures and turbulence. The book covers the basic concepts and mathematical methods, necessary to comprehend nonlinear problems widely encountered in contemporary plasmas, but also in other fields of physics and current research on self-organized structures and magnetized plasma turbulence. The analyses make use of strongly nonlinear models solved by analytical techniques backed by extensive simulations and available experiments. The text is written for senior undergraduates, graduate students, lecturers and researchers in laboratory, space and fusion plasmas.

  12. Nonlinear optics at interfaces

    International Nuclear Information System (INIS)

    Chen, C.K.

    1980-12-01

    Two aspects of surface nonlinear optics are explored in this thesis. The first part is a theoretical and experimental study of nonlinear intraction of surface plasmons and bulk photons at metal-dielectric interfaces. The second part is a demonstration and study of surface enhanced second harmonic generation at rough metal surfaces. A general formulation for nonlinear interaction of surface plasmons at metal-dielectric interfaces is presented and applied to both second and third order nonlinear processes. Experimental results for coherent second and third harmonic generation by surface plasmons and surface coherent antiStokes Raman spectroscopy (CARS) are shown to be in good agreement with the theory

  13. Nonlinear drift tearing mode

    International Nuclear Information System (INIS)

    Zelenyj, L.M.; Kuznetsova, M.M.

    1989-01-01

    Nonlinear study of magnetic perturbation development under single-mode conditions in collision-free plasma in configurations with the magnetic field shear is investigated. Results are obtained with regard of transverse component of electrical field and its effect on ion dynamics within wide range of ion Larmor radius value and values of magnetic field shear. Increments of nonlinear drift tearing mode are obtained and it is shown that excitation drastic conditions of even linearly stable modes are possible. Mechanism of instability nonlinear stabilization is considered and the value of magnetic island at the saturation threshold is estimeted. Energy of nonlinear drift tearing mode is discussed

  14. It Takes Three: Selection, Influence, and De-Selection Processes of Depression in Adolescent Friendship Networks

    Science.gov (United States)

    Van Zalk, Maarten Herman Walter; Kerr, Margaret; Branje, Susan J. T.; Stattin, Hakan; Meeus, Wim H. J.

    2010-01-01

    The authors of this study tested a selection-influence-de-selection model of depression. This model explains friendship influence processes (i.e., friends' depressive symptoms increase adolescents' depressive symptoms) while controlling for two processes: friendship selection (i.e., selection of friends with similar levels of depressive symptoms)…

  15. Explaining the harmonic sequence paradox.

    Science.gov (United States)

    Schmidt, Ulrich; Zimper, Alexander

    2012-05-01

    According to the harmonic sequence paradox, an expected utility decision maker's willingness to pay for a gamble whose expected payoffs evolve according to the harmonic series is finite if and only if his marginal utility of additional income becomes zero for rather low payoff levels. Since the assumption of zero marginal utility is implausible for finite payoff levels, expected utility theory - as well as its standard generalizations such as cumulative prospect theory - are apparently unable to explain a finite willingness to pay. This paper presents first an experimental study of the harmonic sequence paradox. Additionally, it demonstrates that the theoretical argument of the harmonic sequence paradox only applies to time-patient decision makers, whereas the paradox is easily avoided if time-impatience is introduced. ©2011 The British Psychological Society.

  16. Polarization Nonlinear Optics of Quadratically Nonlinear Azopolymers

    International Nuclear Information System (INIS)

    Konorov, S.O.; Akimov, D.A.; Ivanov, A.A.; Petrov, A.N.; Alfimov, M.V.; Yakimanskii, A.V.; Smirnov, N.N.; Ivanova, V.N.; Kudryavtsev, V.V.; Podshivalov, A.A.; Sokolova, I.M.; Zheltikov, A.M.

    2005-01-01

    The polarization properties of second harmonic and sum-frequency signals generated by femtosecond laser pulses in films of polymers containing covalent groups of an azobenzothiazole chromophore polarized by an external electric field are investigated. It is shown that the methods of polarization nonlinear optics make it possible to determine the structure of oriented molecular dipoles and reveal important properties of the motion of collectivized πelectrons in organic molecules with strong optical nonlinearities. The polarization measurements show that the tensor of quadratic nonlinear optical susceptibility of chromophore fragments oriented by an external field in macromolecules of the noted azopolymers has a degenerate form. This is indicative of a predominantly one-dimensional character of motion of collectivized π electrons along an extended group of atoms in such molecules

  17. Depression and Multiple Sclerosis

    Science.gov (United States)

    ... Symptoms Depression Share this page Facebook Twitter Email Depression Depression Fatigue Walking (Gait) Difficulties Numbness or Tingling ... away from addictive substances such as alcohol. Clinical depression It’s important to distinguish between mild, everyday “blues” — ...

  18. Depression in Older Adults

    Science.gov (United States)

    ... here Home » Depression In Older Adults: More Facts Depression In Older Adults: More Facts Depression affects more ... combination of both. [8] Older Adult Attitudes Toward Depression: According to a Mental Health America survey [9] ...

  19. Older Adults and Depression

    Science.gov (United States)

    ... find more information? Reprints Share Older Adults and Depression Download PDF Download ePub Order a free hardcopy ... depression need treatment to feel better. Types of Depression There are several types of depression. The most ...

  20. Depression and Caregiving

    Science.gov (United States)

    ... FCA - A A + A You are here Home Depression and Caregiving Order this publication Printer-friendly version ... a more serious depression over time. Symptoms of Depression People experience depression in different ways. Some may ...

  1. Depression and Suicide Risk

    Science.gov (United States)

    ... due to another medical disorder Relationship Between Depression & Suicide: 1. Depression is the psychiatric diagnosis most commonly associated with ... of patients with treated depression eventually die by suicide. xiv 4. Depression is present in at least 50 percent of ...

  2. Effect of Anti-inflammatory Treatment on Depression, Depressive Symptoms, and Adverse Effects

    DEFF Research Database (Denmark)

    Köhler, Ole; Benros, Michael E; Nordentoft, Merete

    2014-01-01

    -controlled trials assessing the efficacy and adverse effects of pharmacologic anti-inflammatory treatment in adults with depressive symptoms, including those who fulfilled the criteria for depression. DATA EXTRACTION AND SYNTHESIS: Data were extracted by 2 independent reviewers. Pooled standard mean difference (SMD...... investigated cytokine inhibitors (n=2,004). The pooled effect estimate suggested that anti-inflammatory treatment reduced depressive symptoms (SMD, -0.34; 95% CI, -0.57 to -0.11; I2=90%) compared with placebo. This effect was observed in studies including patients with depression (SMD, -0.54; 95% CI, -1.......08 to -0.01; I2=68%) and depressive symptoms (SMD, -0.27; 95% CI, -0.53 to -0.01; I2=68%). The heterogeneity of the studies was not explained by differences in inclusion of clinical depression vs depressive symptoms or use of NSAIDs vs cytokine inhibitors. Subanalyses emphasized the antidepressant...

  3. Postpartum Depression

    Science.gov (United States)

    ... or guilty. These emotions can affect a woman’s self-esteem and how she deals with stress. Fatigue—Many ... FAQs Exercise After Pregnancy (FAQ131) Depression (FAQ106) Patient Education FAQs Resources & Publications Committee Opinions Practice Bulletins Patient ...

  4. Nonlinear (super)symmetries and amplitudes

    Energy Technology Data Exchange (ETDEWEB)

    Kallosh, Renata [Physics Department, Stanford University,382 Via Pueblo Mall, Stanford, CA 94305-4060 (United States)

    2017-03-07

    There is an increasing interest in nonlinear supersymmetries in cosmological model building. Independently, elegant expressions for the all-tree amplitudes in models with nonlinear symmetries, like D3 brane Dirac-Born-Infeld-Volkov-Akulov theory, were recently discovered. Using the generalized background field method we show how, in general, nonlinear symmetries of the action, bosonic and fermionic, constrain amplitudes beyond soft limits. The same identities control, for example, bosonic E{sub 7(7)} scalar sector symmetries as well as the fermionic goldstino symmetries. We present a universal derivation of the vanishing amplitudes in the single (bosonic or fermionic) soft limit. We explain why, universally, the double-soft limit probes the coset space algebra. We also provide identities describing the multiple-soft limit. We discuss loop corrections to N≥5 supergravity, to the D3 brane, and the UV completion of constrained multiplets in string theory.

  5. Nonlinear dynamics in Nuclotron

    International Nuclear Information System (INIS)

    Dinev, D.

    1997-01-01

    The paper represents an extensive study of the nonlinear beam dynamics in the Nuclotron. Chromatic effects, including the dependence of the betatron tunes on the amplitude, and chromatic perturbations have been investigated taking into account the measured field imperfections. Beam distortion, smear, dynamic aperture and nonlinear acceptance have been calculated for different particle energies and betatron tunes

  6. Nonlinear Optics and Applications

    Science.gov (United States)

    Abdeldayem, Hossin A. (Editor); Frazier, Donald O. (Editor)

    2007-01-01

    Nonlinear optics is the result of laser beam interaction with materials and started with the advent of lasers in the early 1960s. The field is growing daily and plays a major role in emerging photonic technology. Nonlinear optics play a major role in many of the optical applications such as optical signal processing, optical computers, ultrafast switches, ultra-short pulsed lasers, sensors, laser amplifiers, and many others. This special review volume on Nonlinear Optics and Applications is intended for those who want to be aware of the most recent technology. This book presents a survey of the recent advances of nonlinear optical applications. Emphasis will be on novel devices and materials, switching technology, optical computing, and important experimental results. Recent developments in topics which are of historical interest to researchers, and in the same time of potential use in the fields of all-optical communication and computing technologies, are also included. Additionally, a few new related topics which might provoke discussion are presented. The book includes chapters on nonlinear optics and applications; the nonlinear Schrodinger and associated equations that model spatio-temporal propagation; the supercontinuum light source; wideband ultrashort pulse fiber laser sources; lattice fabrication as well as their linear and nonlinear light guiding properties; the second-order EO effect (Pockels), the third-order (Kerr) and thermo-optical effects in optical waveguides and their applications in optical communication; and, the effect of magnetic field and its role in nonlinear optics, among other chapters.

  7. [Depressive realism: happiness or objectivity].

    Science.gov (United States)

    Birinci, Fatih; Dirik, Gülay

    2010-01-01

    Realism is described as objective evaluations and judgments about the world; however, some research indicates that judgments made by "normal" people include a self-favored, positive bias in the perception of reality. Additionally, some studies report that compared to normal people, such cognitive distortions are less likely among depressive people. These findings gave rise to the depressive realism hypothesis. While results of several studies verify the notion that depressive people evaluate reality more objectively, other studies fail to support this hypothesis. Several causes for these inconsistent findings have been proposed, which can be characterized under 3 headings. One proposed explanation suggests that what is accepted as "realistic" in these studies is not quite objective and is in fact ambiguous. According to another perspective, the term "depressive" used in these studies is inconsistent with the criteria of scientific diagnostic methods. Another suggests that the research results can only be obtained under the specific experimental conditions. General negativity and limited processing are popular approaches used for explaining the depressive realism hypothesis. Nowadays, the debate over this hypothesis continues. The present review focuses on frequently cited research related to depressive realism and discusses the findings.

  8. Nonlinear optical systems

    CERN Document Server

    Lugiato, Luigi; Brambilla, Massimo

    2015-01-01

    Guiding graduate students and researchers through the complex world of laser physics and nonlinear optics, this book provides an in-depth exploration of the dynamics of lasers and other relevant optical systems, under the umbrella of a unitary spatio-temporal vision. Adopting a balanced approach, the book covers traditional as well as special topics in laser physics, quantum electronics and nonlinear optics, treating them from the viewpoint of nonlinear dynamical systems. These include laser emission, frequency generation, solitons, optically bistable systems, pulsations and chaos and optical pattern formation. It also provides a coherent and up-to-date treatment of the hierarchy of nonlinear optical models and of the rich variety of phenomena they describe, helping readers to understand the limits of validity of each model and the connections among the phenomena. It is ideal for graduate students and researchers in nonlinear optics, quantum electronics, laser physics and photonics.

  9. Short-term depression and transient memory in sensory cortex.

    Science.gov (United States)

    Gillary, Grant; Heydt, Rüdiger von der; Niebur, Ernst

    2017-12-01

    Persistent neuronal activity is usually studied in the context of short-term memory localized in central cortical areas. Recent studies show that early sensory areas also can have persistent representations of stimuli which emerge quickly (over tens of milliseconds) and decay slowly (over seconds). Traditional positive feedback models cannot explain sensory persistence for at least two reasons: (i) They show attractor dynamics, with transient perturbations resulting in a quasi-permanent change of system state, whereas sensory systems return to the original state after a transient. (ii) As we show, those positive feedback models which decay to baseline lose their persistence when their recurrent connections are subject to short-term depression, a common property of excitatory connections in early sensory areas. Dual time constant network behavior has also been implemented by nonlinear afferents producing a large transient input followed by much smaller steady state input. We show that such networks require unphysiologically large onset transients to produce the rise and decay observed in sensory areas. Our study explores how memory and persistence can be implemented in another model class, derivative feedback networks. We show that these networks can operate with two vastly different time courses, changing their state quickly when new information is coming in but retaining it for a long time, and that these capabilities are robust to short-term depression. Specifically, derivative feedback networks with short-term depression that acts differentially on positive and negative feedback projections are capable of dynamically changing their time constant, thus allowing fast onset and slow decay of responses without requiring unrealistically large input transients.

  10. Depression: An Immuno-Inflammatory Cascade

    Directory of Open Access Journals (Sweden)

    Vivek Sharma

    2016-06-01

    Full Text Available Major depressive disorder also known as clinical depression, unipolar depression or depression is associated with significant morbidity, mortality, high suicidal tendencies and deaths. Preclinical and clinical studies suggest that psychiatric illnesses like MDD, are associated with inflammatory processes. While it is unlikely that major depressive disorder is a primary and lsquo;inflammatory' disorder, there is now evidence to suggest that inflammation play a subtle role in the pathophysiology of major depressive disorder. The inflammation in depression cascade pin points to the origin from immune hyperactivity and thus a new theory that explains role of immune system mediated inflammation has been accepted and researched upon. widely. This theory states that depression is accompanied by altered immune function and activation of the inflammatory response system. This theory is strengthened form the fact that the current therapeutic options which mainly target neurotransmitters, are not effective in many patients and these patients has been found to be associated with elevated levels of inflammatory mediators specifically cytokines. It is reported more recently that other risk factors for depression, including psychosocial stress, psychological trauma, sleep disturbance and pain, also increases inflammatory processes. Thus the intervention in the immune system originated from inflammatory cytokines seems a therapeutically viable option in the field of depression research. [Archives Medical Review Journal 2016; 25(2.000: 223-240

  11. Differentiating burnout from depression: personality matters!

    Directory of Open Access Journals (Sweden)

    Martin Christoph Melchers

    2015-08-01

    Full Text Available Stress related affective disorders have been identified as a core health problem of the 21st century. In the endeavor to identify vulnerability factors, personality has been discussed as a major factor explaining and predicting disorders like depression or burnout. An unsolved question is whether there are specific personality factors allowing differentiation of burnout from depression. The present study tested the relation between one of the most prominent, biological personality theories, Cloninger’s Temperament and Character Inventory (TCI, and common measures of burnout (Maslach Burnout Inventory General and depression (Beck Depression Inventory 2 in a sample of German employees (N=944 and a sample of inpatients (N = 425. Although the same personality traits (harm avoidance and self-directedness were predominantly associated with burnout and depression, there was a much stronger association to depression than to burnout in both samples. Besides, we observed specific associations between personality traits and subcomponents of burnout. Our results underline differences in the association of burnout vs. depression to personality, which may mirror differences in scope: While symptoms of depression affect all aspects of life, burnout is supposed to be specifically related to the workplace and its requirements. The much stronger association of personality to depression can be important to select appropriate therapy methods and to develop a more specified treatment for burnout in comparison to depression.

  12. Dosage-dependent non-linear effect of L-dopa on human motor cortex plasticity.

    Science.gov (United States)

    Monte-Silva, Katia; Liebetanz, David; Grundey, Jessica; Paulus, Walter; Nitsche, Michael A

    2010-09-15

    The neuromodulator dopamine affects learning and memory formation and their likely physiological correlates, long-term depression and potentiation, in animals and humans. It is known from animal experiments that dopamine exerts a dosage-dependent, inverted U-shaped effect on these functions. However, this has not been explored in humans so far. In order to reveal a non-linear dose-dependent effect of dopamine on cortical plasticity in humans, we explored the impact of 25, 100 and 200 mg of L-dopa on transcranial direct current (tDCS)-induced plasticity in twelve healthy human subjects. The primary motor cortex served as a model system, and plasticity was monitored by motor evoked potential amplitudes elicited by transcranial magnetic stimulation. As compared to placebo medication, low and high dosages of L-dopa abolished facilitatory as well as inhibitory plasticity, whereas the medium dosage prolonged inhibitory plasticity, and turned facilitatory plasticity into inhibition. Thus the results show clear non-linear, dosage-dependent effects of dopamine on both facilitatory and inhibitory plasticity, and support the assumption of the importance of a specific dosage of dopamine optimally suited to improve plasticity. This might be important for the therapeutic application of dopaminergic agents, especially for rehabilitative purposes, and explain some opposing results in former studies.

  13. General relativistic chaos and nonlinear dynamics

    International Nuclear Information System (INIS)

    Barrow, J.D.

    1982-01-01

    How new ideas in dynamical systems theory find application in the description of general relativistic systems is described. The concept of dynamical entropy is explained and the associated invariant evaluated for the Mixmaster cosmological model. The description of cosmological models as measure preserving dynamical systems leads to a number of interconnections with new ideas in non-linear dynamics. This may provide a new avenue of approach to ascertaining the nature of the general solution to Einstein's equations. (author)

  14. General relativistic chaos and nonlinear dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Barrow, J D [California Univ., Berkeley (USA). Dept. of Physics

    1982-06-01

    How new ideas in dynamical systems theory find application in the description of general relativistic systems is described. The concept of dynamical entropy is explained and the associated invariant evaluated for the Mixmaster cosmological model. The description of cosmological models as measure preserving dynamical systems leads to a number of interconnections with new ideas in non-linear dynamics. This may provide a new avenue of approach to ascertaining the nature of the general solution to Einstein's equations.

  15. Association between endothelial dysfunction and depression-like symptoms in chronic mild stress model of depression

    DEFF Research Database (Denmark)

    Bouzinova, Elena; Bødtkjer, Donna Marie Briggs; Kudryavtseva, Olga

    2014-01-01

    OBJECTIVE: Cardiovascular diseases have high comorbidity with major depression. Endothelial dysfunction may explain the adverse cardiovascular outcome in depression; therefore, we analyzed it in vitro. In the chronic mild stress model, some rats develop depression-like symptoms (including...... "anhedonia"), whereas others are stress resilient. METHODS: After 8 weeks of chronic mild stress, anhedonic rats reduced their sucrose intake by 55% (7%), whereas resilient rats did not. Acetylcholine-induced endothelium-dependent relaxation of norepinephrine-preconstricted mesenteric arteries was analyzed......-like response) was reduced in anhedonic rats (p depression-like symptoms are associated with reduced endothelium-dependent relaxation due to suppressed...

  16. Nonlinear photonic metasurfaces

    Science.gov (United States)

    Li, Guixin; Zhang, Shuang; Zentgraf, Thomas

    2017-03-01

    Compared with conventional optical elements, 2D photonic metasurfaces, consisting of arrays of antennas with subwavelength thickness (the 'meta-atoms'), enable the manipulation of light-matter interactions on more compact platforms. The use of metasurfaces with spatially varying arrangements of meta-atoms that have subwavelength lateral resolution allows control of the polarization, phase and amplitude of light. Many exotic phenomena have been successfully demonstrated in linear optics; however, to meet the growing demand for the integration of more functionalities into a single optoelectronic circuit, the tailorable nonlinear optical properties of metasurfaces will also need to be exploited. In this Review, we discuss the design of nonlinear photonic metasurfaces — in particular, the criteria for choosing the materials and symmetries of the meta-atoms — for the realization of nonlinear optical chirality, nonlinear geometric Berry phase and nonlinear wavefront engineering. Finally, we survey the application of nonlinear photonic metasurfaces in optical switching and modulation, and we conclude with an outlook on their use for terahertz nonlinear optics and quantum information processing.

  17. Nonlinear crack mechanics

    International Nuclear Information System (INIS)

    Khoroshun, L.P.

    1995-01-01

    The characteristic features of the deformation and failure of actual materials in the vicinity of a crack tip are due to their physical nonlinearity in the stress-concentration zone, which is a result of plasticity, microfailure, or a nonlinear dependence of the interatomic forces on the distance. Therefore, adequate models of the failure mechanics must be nonlinear, in principle, although linear failure mechanics is applicable if the zone of nonlinear deformation is small in comparison with the crack length. Models of crack mechanics are based on analytical solutions of the problem of the stress-strain state in the vicinity of the crack. On account of the complexity of the problem, nonlinear models are bason on approximate schematic solutions. In the Leonov-Panasyuk-Dugdale nonlinear model, one of the best known, the actual two-dimensional plastic zone (the nonlinearity zone) is replaced by a narrow one-dimensional zone, which is then modeled by extending the crack with a specified normal load equal to the yield point. The condition of finite stress is applied here, and hence the length of the plastic zone is determined. As a result of this approximation, the displacement in the plastic zone at the abscissa is nonzero

  18. Nonlinear Analysis of Renal Autoregulation Under Broadband Forcing Conditions

    DEFF Research Database (Denmark)

    Marmarelis, V Z; Chon, K H; Chen, Y M

    1994-01-01

    Linear analysis of renal blood flow fluctuations, induced experimentally in rats by broad-band (pseudorandom) arterial blood pressure forcing at various power levels, has been unable to explain fully the dynamics of renal autoregulation at low frequencies. This observation has suggested...... the possibility of nonlinear mechanisms subserving renal autoregulation at frequencies below 0.2 Hz. This paper presents results of 3rd-order Volterra-Wiener analysis that appear to explain adequately the nonlinearities in the pressure-flow relation below 0.2 Hz in rats. The contribution of the 3rd-order kernel...... in describing the dynamic pressure-flow relation is found to be important. Furthermore, the dependence of 1st-order kernel waveforms on the power level of broadband pressure forcing indicates the presence of nonlinear feedback (of sigmoid type) based on previously reported analysis of a class of nonlinear...

  19. Nonlinear analysis of dynamic signature

    Science.gov (United States)

    Rashidi, S.; Fallah, A.; Towhidkhah, F.

    2013-12-01

    Signature is a long trained motor skill resulting in well combination of segments like strokes and loops. It is a physical manifestation of complex motor processes. The problem, generally stated, is that how relative simplicity in behavior emerges from considerable complexity of perception-action system that produces behavior within an infinitely variable biomechanical and environmental context. To solve this problem, we present evidences which indicate that motor control dynamic in signing process is a chaotic process. This chaotic dynamic may explain a richer array of time series behavior in motor skill of signature. Nonlinear analysis is a powerful approach and suitable tool which seeks for characterizing dynamical systems through concepts such as fractal dimension and Lyapunov exponent. As a result, they can be analyzed in both horizontal and vertical for time series of position and velocity. We observed from the results that noninteger values for the correlation dimension indicates low dimensional deterministic dynamics. This result could be confirmed by using surrogate data tests. We have also used time series to calculate the largest Lyapunov exponent and obtain a positive value. These results constitute significant evidence that signature data are outcome of chaos in a nonlinear dynamical system of motor control.

  20. Nonlinear wave equations

    CERN Document Server

    Li, Tatsien

    2017-01-01

    This book focuses on nonlinear wave equations, which are of considerable significance from both physical and theoretical perspectives. It also presents complete results on the lower bound estimates of lifespan (including the global existence), which are established for classical solutions to the Cauchy problem of nonlinear wave equations with small initial data in all possible space dimensions and with all possible integer powers of nonlinear terms. Further, the book proposes the global iteration method, which offers a unified and straightforward approach for treating these kinds of problems. Purely based on the properties of solut ions to the corresponding linear problems, the method simply applies the contraction mapping principle.

  1. Rumination mediates the relationship between overgeneral autobiographical memory and depression in patients with major depressive disorder.

    Science.gov (United States)

    Liu, Yansong; Yu, Xinnian; Yang, Bixiu; Zhang, Fuquan; Zou, Wenhua; Na, Aiguo; Zhao, Xudong; Yin, Guangzhong

    2017-03-21

    Overgeneral autobiographical memory has been identified as a risk factor for the onset and maintenance of depression. However, little is known about the underlying mechanisms that might explain overgeneral autobiographical memory phenomenon in depression. The purpose of this study was to test the mediation effects of rumination on the relationship between overgeneral autobiographical memory and depressive symptoms. Specifically, the mediation effects of brooding and reflection subtypes of rumination were examined in patients with major depressive disorder. Eighty-seven patients with major depressive disorder completed the 17-item Hamilton Depression Rating Scale, Ruminative Response Scale, and Autobiographical Memory Test. Bootstrap mediation analysis for simple and multiple mediation models through the PROCESS macro was applied. Simple mediation analysis showed that rumination significantly mediated the relationship between overgeneral autobiographical memory and depression symptoms. Multiple mediation analyses showed that brooding, but not reflection, significantly mediated the relationship between overgeneral autobiographical memory and depression symptoms. Our results indicate that global rumination partly mediates the relationship between overgeneral autobiographical memory and depressive symptoms in patients with major depressive disorder. Furthermore, the present results suggest that the mediating role of rumination in the relationship between overgeneral autobiographical memory and depression is mainly due to the maladaptive brooding subtype of rumination.

  2. Nonlinear switching dynamics in a photonic-crystal nanocavity

    International Nuclear Information System (INIS)

    Yu, Yi; Palushani, Evarist; Heuck, Mikkel; Vukovic, Dragana; Peucheret, Christophe; Yvind, Kresten; Mork, Jesper

    2014-01-01

    We report the experimental observation of nonlinear switching dynamics in an InP photonic crystal nanocavity. Usually, the regime of relatively small cavity perturbations is explored, where the signal transmitted through the cavity follows the temporal variation of the cavity resonance. When the cavity is perturbed by strong pulses, we observe several nonlinear effects, i.e., saturation of the switching contrast, broadening of the switching window, and even initial reduction of the transmission. The effects are analyzed by comparison with nonlinear coupled mode theory and explained in terms of large dynamical variations of the cavity resonance in combination with nonlinear losses. The results provide insight into the nonlinear optical processes that govern the dynamics of nanocavities and are important for applications in optical signal processing, where one wants to optimize the switching contrast.

  3. Nonlinear switching dynamics in a photonic-crystal nanocavity

    DEFF Research Database (Denmark)

    Yu, Yi; Palushani, Evarist; Heuck, Mikkel

    2014-01-01

    We report the experimental observation of nonlinear switching dynamics in an InP photonic crystal nanocavity. Usually, the regime of relatively small cavity perturbations is explored, where the signal transmitted through the cavity follows the temporal variation of the cavity resonance. When...... of large dynamical variations of the cavity resonance in combination with nonlinear losses. The results provide insight into the nonlinear optical processes that govern the dynamics of nanocavities and are important for applications in optical signal processing, where one wants to optimize the switching...... the cavity is perturbed by strong pulses, we observe several nonlinear effects, i.e., saturation of the switching contrast, broadening of the switching window, and even initial reduction of the transmission. The effects are analyzed by comparison with nonlinear coupled mode theory and explained in terms...

  4. Photostable nonlinear optical polycarbonates

    NARCIS (Netherlands)

    Faccini, M.; Balakrishnan, M.; Diemeer, Mart; Torosantucci, Riccardo; Driessen, A.; Reinhoudt, David; Verboom, Willem

    2008-01-01

    Highly thermal and photostable nonlinear optical polymers were obtained by covalently incorporating the tricyanovinylidenediphenylaminobenzene (TCVDPA) chromophore to a polycarbonate backbone. NLO polycarbonates with different chromophore attachment modes and flexibilities were synthesized. In spite

  5. Nonlinear singular elliptic equations

    International Nuclear Information System (INIS)

    Dong Minh Duc.

    1988-09-01

    We improve the Poincare inequality, the Sobolev imbedding theorem and the Trudinger imbedding theorem and prove a Mountain pass theorem. Applying these results we study a nonlinear singular mixed boundary problem. (author). 22 refs

  6. Nonlinear Optical Terahertz Technology

    Data.gov (United States)

    National Aeronautics and Space Administration — We develop a new approach to generation of THz radiation. Our method relies on mixing two optical frequency beams in a nonlinear crystalline Whispering Gallery Mode...

  7. Nonlinear differential equations

    CERN Document Server

    Struble, Raimond A

    2017-01-01

    Detailed treatment covers existence and uniqueness of a solution of the initial value problem, properties of solutions, properties of linear systems, stability of nonlinear systems, and two-dimensional systems. 1962 edition.

  8. Terahertz semiconductor nonlinear optics

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias

    2013-01-01

    In this proceedings we describe our recent results on semiconductor nonlinear optics, investigated using single-cycle THz pulses. We demonstrate the nonlinear absorption and self-phase modulation of strong-field THz pulses in doped semiconductors, using n-GaAs as a model system. The THz...... nonlinearity in doped semiconductors originates from the near-instantaneous heating of free electrons in the ponderomotive potential created by electric field of the THz pulse, leading to ultrafast increase of electron effective mass by intervalley scattering. Modification of effective mass in turn leads...... to a decrease of plasma frequency in semiconductor and produces a substantial modification of THz-range material dielectric function, described by the Drude model. As a result, the nonlinearity of both absorption coefficient and refractive index of the semiconductor is observed. In particular we demonstrate...

  9. Ultrafast nonlinear optics

    CERN Document Server

    Leburn, Christopher; Reid, Derryck

    2013-01-01

    The field of ultrafast nonlinear optics is broad and multidisciplinary, and encompasses areas concerned with both the generation and measurement of ultrashort pulses of light, as well as those concerned with the applications of such pulses. Ultrashort pulses are extreme events – both in terms of their durations, and also the high peak powers which their short durations can facilitate. These extreme properties make them powerful experiment tools. On one hand, their ultrashort durations facilitate the probing and manipulation of matter on incredibly short timescales. On the other, their ultrashort durations can facilitate high peak powers which can drive highly nonlinear light-matter interaction processes. Ultrafast Nonlinear Optics covers a complete range of topics, both applied and fundamental in nature, within the area of ultrafast nonlinear optics. Chapters 1 to 4 are concerned with the generation and measurement of ultrashort pulses. Chapters 5 to 7 are concerned with fundamental applications of ultrasho...

  10. Nonlinear surface Alfven waves

    International Nuclear Information System (INIS)

    Cramer, N.F.

    1991-01-01

    The problem of nonlinear surface Alfven waves propagating on an interface between a plasma and a vacuum is discussed, with dispersion provided by the finite-frequency effect, i.e. the finite ratio of the frequency to the ion-cyclotron frequency. A set of simplified nonlinear wave equations is derived using the method of stretched co-ordinates, and another approach uses the generation of a second-harmonic wave and its interaction with the first harmonic to obtain a nonlinear dispersion relation. A nonlinear Schroedinger equation is then derived, and soliton solutions found that propagate as solitary pulses in directions close to parallel and antiparallel to the background magnetic field. (author)

  11. Nonlinear Structural Analysis

    Indian Academy of Sciences (India)

    The Structures Panel of the Aeronautics Research and Development Board of India ... A great variety of topics was covered, including themes such as nonlinear finite ... or shell structures, and three are on the composite form of construction, ...

  12. A nonlinear oscillatory problem

    International Nuclear Information System (INIS)

    Zhou Qingqing.

    1991-10-01

    We have studied the nonlinear oscillatory problem of orthotropic cylindrical shell, we have analyzed the character of the oscillatory system. The stable condition of the oscillatory system has been given. (author). 6 refs

  13. Degenerate nonlinear diffusion equations

    CERN Document Server

    Favini, Angelo

    2012-01-01

    The aim of these notes is to include in a uniform presentation style several topics related to the theory of degenerate nonlinear diffusion equations, treated in the mathematical framework of evolution equations with multivalued m-accretive operators in Hilbert spaces. The problems concern nonlinear parabolic equations involving two cases of degeneracy. More precisely, one case is due to the vanishing of the time derivative coefficient and the other is provided by the vanishing of the diffusion coefficient on subsets of positive measure of the domain. From the mathematical point of view the results presented in these notes can be considered as general results in the theory of degenerate nonlinear diffusion equations. However, this work does not seek to present an exhaustive study of degenerate diffusion equations, but rather to emphasize some rigorous and efficient techniques for approaching various problems involving degenerate nonlinear diffusion equations, such as well-posedness, periodic solutions, asympt...

  14. Introduction to nonlinear science

    CERN Document Server

    Nicolis, G

    1995-01-01

    One of the most unexpected results in science in recent years is that quite ordinary systems obeying simple laws can give rise to complex, nonlinear or chaotic, behavior. In this book, the author presents a unified treatment of the concepts and tools needed to analyze nonlinear phenomena and to outline some representative applications drawn from the physical, engineering, and biological sciences. Some of the interesting topics covered include: dynamical systems with a finite number of degrees of freedom, linear stability analysis of fixed points, nonlinear behavior of fixed points, bifurcation analysis, spatially distributed systems, broken symmetries, pattern formation, and chaotic dynamics. The author makes a special effort to provide a logical connection between ordinary dynamical systems and spatially extended systems, and to balance the emphasis on chaotic behavior and more classical nonlinear behavior. He also develops a statistical approach to complex systems and compares it to traditional deterministi...

  15. Helping your teen with depression

    Science.gov (United States)

    Teen depression - helping; Teen depression - talk therapy; Teen depression - medicine ... teen the most. The most effective treatments for depression are: Talk therapy Antidepressant medicines If your teen ...

  16. Attributional Style and Depression in Multiple Sclerosis

    Science.gov (United States)

    Arnett, Peter A.

    2013-01-01

    Several etiologic theories have been proposed to explain depression in the general population. Studying these models and modifying them for use in the multiple sclerosis (MS) population may allow us to better understand depression in MS. According to the reformulated learned helplessness (LH) theory, individuals who attribute negative events to internal, stable, and global causes are more vulnerable to depression. This study differentiated attributional style that was or was not related to MS in 52 patients with MS to test the LH theory in this population and to determine possible differences between illness-related and non-illness-related attributions. Patients were administered measures of attributional style, daily stressors, disability, and depressive symptoms. Participants were more likely to list non-MS-related than MS-related causes of negative events on the Attributional Style Questionnaire (ASQ), and more-disabled participants listed significantly more MS-related causes than did less-disabled individuals. Non-MS-related attributional style correlated with stress and depressive symptoms, but MS-related attributional style did not correlate with disability or depressive symptoms. Stress mediated the effect of non-MS-related attributional style on depressive symptoms. These results suggest that, although attributional style appears to be an important construct in MS, it does not seem to be related directly to depressive symptoms; rather, it is related to more perceived stress, which in turn is related to increased depressive symptoms. PMID:24453767

  17. Nonlinear Wave Propagation

    Science.gov (United States)

    2015-05-07

    associated with the lattice background; the nonlinearity is derived from the inclusion of cubic nonlinearity. Often the background potential is periodic...dispersion branch we can find discrete evolution equations for the envelope associated with the lattice NLS equation (1) by looking for solutions of...spatial operator in the above NLS equation can be elliptic, hyperbolic or parabolic . We remark that further reduction is possible by going into a moving

  18. Nonlinear dynamics and astrophysics

    International Nuclear Information System (INIS)

    Vallejo, J. C.; Sanjuan, M. A. F.

    2000-01-01

    Concepts and techniques from Nonlinear Dynamics, also known as Chaos Theory, have been applied successfully to several astrophysical fields such as orbital motion, time series analysis or galactic dynamics, providing answers to old questions but also opening a few new ones. Some of these topics are described in this review article, showing the basis of Nonlinear Dynamics, and how it is applied in Astrophysics. (Author)

  19. Relation between depression and sociodemographic factors

    Directory of Open Access Journals (Sweden)

    Akhtar-Danesh Noori

    2007-09-01

    Full Text Available Abstract Background Depression is one of the most common mental disorders in Western countries and is related to increased morbidity and mortality from medical conditions and decreased quality of life. The sociodemographic factors of age, gender, marital status, education, immigrant status, and income have consistently been identified as important factors in explaining the variability in depression prevalence rates. This study evaluates the relationship between depression and these sociodemographic factors in the province of Ontario in Canada using the Canadian Community Health Survey, Cycle 1.2 (CCHS-1.2 dataset. Methods The CCHS-1.2 survey classified depression into lifetime depression and 12-month depression. The data were collected based on unequal sampling probabilities to ensure adequate representation of young persons (15 to 24 and seniors (65 and over. The sampling weights were used to estimate the prevalence of depression in each subgroup of the population. The multiple logistic regression technique was used to estimate the odds ratio of depression for each sociodemographic factor. Results The odds ratio of depression for men compared with women is about 0.60. The lowest and highest rates of depression are seen among people living with their married partners and divorced individuals, respectively. Prevalence of depression among people who live with common-law partners is similar to rates of depression among separated and divorced individuals. The lowest and highest rates of depression based on the level of education is seen among individuals with less than secondary school and those with "other post-secondary" education, respectively. Prevalence of 12-month and lifetime depression among individuals who were born in Canada is higher compared to Canadian residents who immigrated to Canada irrespective of gender. There is an inverse relation between income and the prevalence of depression (p Conclusion The patterns uncovered in this

  20. Analytical Evaluation of the Nonlinear Vibration of Coupled Oscillator Systems

    DEFF Research Database (Denmark)

    Bayat, M.; Shahidi, M.; Barari, Amin

    2011-01-01

    approximations to the achieved nonlinear differential oscillation equations where the displacement of the two-mass system can be obtained directly from the linear second-order differential equation using the first order of the current approach. Compared with exact solutions, just one iteration leads us to high......We consider periodic solutions for nonlinear free vibration of conservative, coupled mass-spring systems with linear and nonlinear stiffnesses. Two practical cases of these systems are explained and introduced. An analytical technique called energy balance method (EBM) was applied to calculate...

  1. Pescara benchmarks: nonlinear identification

    Science.gov (United States)

    Gandino, E.; Garibaldi, L.; Marchesiello, S.

    2011-07-01

    Recent nonlinear methods are suitable for identifying large systems with lumped nonlinearities, but in practice most structural nonlinearities are distributed and an ideal nonlinear identification method should cater for them as well. In order to extend the current NSI method to be applied also on realistic large engineering structures, a modal counterpart of the method is proposed in this paper. The modal NSI technique is applied on one of the reinforced concrete beams that have been tested in Pescara, under the project titled "Monitoring and diagnostics of railway bridges by means of the analysis of the dynamic response due to train crossing", financed by Italian Ministry of Research. The beam showed a softening nonlinear behaviour, so that the nonlinearity concerning the first mode is characterized and its force contribution is quantified. Moreover, estimates for the modal parameters are obtained and the model is validated by comparing the measured and the reconstructed output. The identified estimates are also used to accurately predict the behaviour of the same beam, when subject to different initial conditions.

  2. Nonlinear Multiantenna Detection Methods

    Directory of Open Access Journals (Sweden)

    Chen Sheng

    2004-01-01

    Full Text Available A nonlinear detection technique designed for multiple-antenna assisted receivers employed in space-division multiple-access systems is investigated. We derive the optimal solution of the nonlinear spatial-processing assisted receiver for binary phase shift keying signalling, which we refer to as the Bayesian detector. It is shown that this optimal Bayesian receiver significantly outperforms the standard linear beamforming assisted receiver in terms of a reduced bit error rate, at the expense of an increased complexity, while the achievable system capacity is substantially enhanced with the advent of employing nonlinear detection. Specifically, when the spatial separation expressed in terms of the angle of arrival between the desired and interfering signals is below a certain threshold, a linear beamformer would fail to separate them, while a nonlinear detection assisted receiver is still capable of performing adequately. The adaptive implementation of the optimal Bayesian detector can be realized using a radial basis function network. Two techniques are presented for constructing block-data-based adaptive nonlinear multiple-antenna assisted receivers. One of them is based on the relevance vector machine invoked for classification, while the other on the orthogonal forward selection procedure combined with the Fisher ratio class-separability measure. A recursive sample-by-sample adaptation procedure is also proposed for training nonlinear detectors based on an amalgam of enhanced -means clustering techniques and the recursive least squares algorithm.

  3. Pescara benchmarks: nonlinear identification

    International Nuclear Information System (INIS)

    Gandino, E; Garibaldi, L; Marchesiello, S

    2011-01-01

    Recent nonlinear methods are suitable for identifying large systems with lumped nonlinearities, but in practice most structural nonlinearities are distributed and an ideal nonlinear identification method should cater for them as well. In order to extend the current NSI method to be applied also on realistic large engineering structures, a modal counterpart of the method is proposed in this paper. The modal NSI technique is applied on one of the reinforced concrete beams that have been tested in Pescara, under the project titled M onitoring and diagnostics of railway bridges by means of the analysis of the dynamic response due to train crossing , financed by Italian Ministry of Research. The beam showed a softening nonlinear behaviour, so that the nonlinearity concerning the first mode is characterized and its force contribution is quantified. Moreover, estimates for the modal parameters are obtained and the model is validated by comparing the measured and the reconstructed output. The identified estimates are also used to accurately predict the behaviour of the same beam, when subject to different initial conditions.

  4. Neglected children, shame-proneness, and depressive symptoms.

    Science.gov (United States)

    Bennett, David S; Sullivan, Margaret Wolan; Lewis, Michael

    2010-11-01

    Neglected children may be at increased risk for depressive symptoms. This study examines shame-proneness as an outcome of child neglect and as a potential explanatory variable in the relation between neglect and depressive symptoms. Participants were 111 children (52 with a Child Protective Services [CPS] allegation of neglect) seen at age 7. Neglected children reported more shame-proneness and more depressive symptoms than comparison children. Guilt-proneness, in contrast, was unrelated to neglect and depressive symptoms, indicating specificity for shame-proneness. The potential role of shame as a process variable that can help explain how some neglected children exhibit depressive symptoms is discussed.

  5. Gendered portraits of depression in Swedish newspapers.

    Science.gov (United States)

    Bengs, Carita; Johansson, Eva; Danielsson, Ulla; Lehti, Arja; Hammarström, Anne

    2008-07-01

    Mass media are influential mediators of information, knowledge, and narratives of health and illness. In this article, we report on an examination of personal accounts of illness as presented in three Swedish newspapers, focusing on the gendered representation of laypersons' experiences of depression. A database search identified all articles mentioning depression during the year 2002. Twenty six articles focusing on personal experiences of depression were then subjected to a qualitative content analysis. We identified four themes: displaying a successful facade, experiencing a cracking facade, losing and regaining control, and explaining the illness. We found both similarities and differences with regard to gendered experiences. The mediated accounts of depression both upheld and challenged traditional gender stereotypes. The women's stories were more detailed, relational, emotionally oriented, and embodied. The portrayal of men was less emotional and expressive, and described a more dramatic onset of depression, reflecting hegemonic patterns of masculinity.

  6. Nonlinear Coherent Structures, Microbursts and Turbulence

    Science.gov (United States)

    Lakhina, G. S.

    2015-12-01

    Nonlinear waves are found everywhere, in fluids, atmosphere, laboratory, space and astrophysical plasmas. The interplay of nonlinear effects, dispersion and dissipation in the medium can lead to a variety of nonlinear waves and turbulence. Two cases of coherent nonlinear waves: chorus and electrostatic solitary waves (ESWs) and their impact on modifying the plasma medium are discussed. Chorus is a right-hand, circularly-polarized electromagnetic plane wave. Dayside chorus is a bursty emission composed of rising frequency "elements" with duration of ~0.1 to 1.0 s. Each element is composed of coherent subelements with durations of ~1 to 100 ms or more. The cyclotron resonant interaction between energetic electrons and the coherent chorus waves is studied. An expression for the pitch angle transport due to this interaction is derived considering a Gaussian distribution for the time duration of the chorus elements. The rapid pitch scattering can provide an explanation for the ionospheric microbursts of ~0.1 to 0.5 s in bremsstrahlung x-rays formed by ~10-100 keV precipitating electrons. On the other hand, the ESWs are observed in the electric field component parallel to the background magnetic field, and are usually bipolar or tripolar. Generation of coherent ESWs has been explained in terms of nonlinear fluid models of ion- and electron-acoustic solitons and double layers (DLs) based on Sagdeev pseudopotential technique. Fast Fourier transform of electron- and ion-acoustic solitons/DLs produces broadband wave spectra which can explain the properties of the electrostatic turbulence observed in the magnetosheath and plasma sheet boundary layer, and in the solar wind, respectively.

  7. Fundamentals of nonlinear optical materials

    Indian Academy of Sciences (India)

    Nonlinear optics; nonlinear polarization; optical fiber communication; optical switch- ing. PACS Nos 42.65Tg; ... The importance of nonlinear optics is to understand the nonlinear behavior in the induced polarization and to ..... but much work in material development and characterization remains to be done. 16. Conclusion.

  8. Nonlinear Approaches in Engineering Applications

    CERN Document Server

    Jazar, Reza

    2012-01-01

    Nonlinear Approaches in Engineering Applications focuses on nonlinear phenomena that are common in the engineering field. The nonlinear approaches described in this book provide a sound theoretical base and practical tools to design and analyze engineering systems with high efficiency and accuracy and with less energy and downtime. Presented here are nonlinear approaches in areas such as dynamic systems, optimal control and approaches in nonlinear dynamics and acoustics. Coverage encompasses a wide range of applications and fields including mathematical modeling and nonlinear behavior as applied to microresonators, nanotechnologies, nonlinear behavior in soil erosion,nonlinear population dynamics, and optimization in reducing vibration and noise as well as vibration in triple-walled carbon nanotubes. This book also: Provides a complete introduction to nonlinear behavior of systems and the advantages of nonlinearity as a tool for solving engineering problems Includes applications and examples drawn from the el...

  9. Nonlinear electrokinetics at large voltages

    Energy Technology Data Exchange (ETDEWEB)

    Bazant, Martin Z [Department of Chemical Engineering and Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Sabri Kilic, Mustafa; Ajdari, Armand [Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Storey, Brian D [Franklin W Olin College of Engineering, Needham, MA 02492 (United States)], E-mail: bazant@mit.edu

    2009-07-15

    The classical theory of electrokinetic phenomena assumes a dilute solution of point-like ions in chemical equilibrium with a surface whose double-layer voltage is of order the thermal voltage, k{sub B}T/e=25 mV. In nonlinear 'induced-charge' electrokinetic phenomena, such as ac electro-osmosis, several volts {approx}100k{sub B}T/e are applied to the double layer, and the theory breaks down and cannot explain many observed features. We argue that, under such a large voltage, counterions 'condense' near the surface, even for dilute bulk solutions. Based on simple models, we predict that the double-layer capacitance decreases and the electro-osmotic mobility saturates at large voltages, due to steric repulsion and increased viscosity of the condensed layer, respectively. The former suffices to explain observed high-frequency flow reversal in ac electro-osmosis; the latter leads to a salt concentration dependence of induced-charge flows comparable to experiments, although a complete theory is still lacking.

  10. 50 years of nonlinear optics

    International Nuclear Information System (INIS)

    Shen Yuanrang

    2011-01-01

    This article presents a brief introduction to the birth and early investigations of nonlinear optics, such as second harmonic generation,sum and difference frequency generation, stimulated Raman scattering,and self-action of light etc. Several important research achievements and applications of nonlinear optics are presented as well, including nonlinear optical spectroscopy, phase conjugation and adaptive optics, coherent nonlinear optics, and high-order harmonic generation. In the end, current and future research topics in nonlinear optics are summarized. (authors)

  11. Personality, depressive symptoms during pregnancy and their influence on postnatal depression in Spanish pregnant Spanish women

    Directory of Open Access Journals (Sweden)

    Dolores Marín-Morales

    2014-10-01

    Full Text Available The aim of this study was to analyse the influence of personality factors and antenatal depressive symptomatology in postnatal depression. A prospective ex post facto design was carried out. The sample consisted of 116 women, recruited in their first trimester of pregnancy and followed up until four months postpartum. The measurement instruments used were the Edinburg Postnatal Depression Scale (EPDS to assess postpartum depression, the NEO-Five Factor Inventory (NEO-FFI to analyse personality traits and the depression subscale of the Symptoms Check List 90 (SCL-90-R to assess depressive symptomatology in the first half of pregnancy. Socio-demographic variables (age, parity, educational level, employment status, and planned pregnancy and clinical variables (neonatal Apgar score and mode of delivery were also taken into account. A positive correlation was found between postpartum depression and depressive symptomatology in the first trimester; however after the regression analysis neuroticism was the only factor that predicted postpartum depressive symptoms, explaining 24.8% of the variance. Neuroticism significantly influences psychological health during life events such as motherhood. Due to its stable condition, personality could be assessed from the beginning of pregnancy, contributing to the care of pregnant women with high scores in neuroticism, to prevent, detect and treat early postnatal depression.

  12. Postpartum Depression - Multiple Languages

    Science.gov (United States)

    ... Русский (Russian) Bilingual PDF Health Information Translations Postpartum Depression - English PDF Postpartum Depression - Русский (Russian) PDF Postpartum Depression - English MP3 ...

  13. Major Depression Among Adults

    Science.gov (United States)

    ... Depressive Episode Among Adolescents Data Sources Share Major Depression Definitions Major depression is one of the most ... Bethesda, MD 20892-9663 Follow Us Facebook Twitter YouTube Google Plus NIMH Newsletter NIMH RSS Feed NIMH ...

  14. Recognizing teen depression

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000648.htm Recognizing teen depression To use the sharing features on this page, ... life. Be Aware of the Risk for Teen Depression Your teen is more at risk for depression ...

  15. Sadness and Depression

    Science.gov (United States)

    ... Videos for Educators Search English Español Sadness and Depression KidsHealth / For Kids / Sadness and Depression Print en ... big difference in your life. When Sadness Is Depression When you're in a sad mood, it ...

  16. Postpartum Depression Facts

    Science.gov (United States)

    ... Where can I find more information? Share Postpartum Depression Facts Download PDF Download ePub Download Mobi Order ... for herself or her family. What is postpartum depression? Postpartum depression is a mood disorder that can ...

  17. Depression and College Students

    Science.gov (United States)

    ... depression and other mental health issues? Reference Share Depression and College Students Download PDF Download ePub Order ... Answers to college students’ frequently asked questions about depression Feeling moody, sad, or grouchy? Who doesn’t ...

  18. Nonlinear Recurrent Dynamics and Long-Term Nonstationarities in EEG Alpha Cortical Activity: Implications for Choosing Adequate Segment Length in Nonlinear EEG Analyses.

    Science.gov (United States)

    Cerquera, Alexander; Vollebregt, Madelon A; Arns, Martijn

    2018-03-01

    Nonlinear analysis of EEG recordings allows detection of characteristics that would probably be neglected by linear methods. This study aimed to determine a suitable epoch length for nonlinear analysis of EEG data based on its recurrence rate in EEG alpha activity (electrodes Fz, Oz, and Pz) from 28 healthy and 64 major depressive disorder subjects. Two nonlinear metrics, Lempel-Ziv complexity and scaling index, were applied in sliding windows of 20 seconds shifted every 1 second and in nonoverlapping windows of 1 minute. In addition, linear spectral analysis was carried out for comparison with the nonlinear results. The analysis with sliding windows showed that the cortical dynamics underlying alpha activity had a recurrence period of around 40 seconds in both groups. In the analysis with nonoverlapping windows, long-term nonstationarities entailed changes over time in the nonlinear dynamics that became significantly different between epochs across time, which was not detected with the linear spectral analysis. Findings suggest that epoch lengths shorter than 40 seconds neglect information in EEG nonlinear studies. In turn, linear analysis did not detect characteristics from long-term nonstationarities in EEG alpha waves of control subjects and patients with major depressive disorder patients. We recommend that application of nonlinear metrics in EEG time series, particularly of alpha activity, should be carried out with epochs around 60 seconds. In addition, this study aimed to demonstrate that long-term nonlinearities are inherent to the cortical brain dynamics regardless of the presence or absence of a mental disorder.

  19. Explaining Support Vector Machines: A Color Based Nomogram.

    Directory of Open Access Journals (Sweden)

    Vanya Van Belle

    Full Text Available Support vector machines (SVMs are very popular tools for classification, regression and other problems. Due to the large choice of kernels they can be applied with, a large variety of data can be analysed using these tools. Machine learning thanks its popularity to the good performance of the resulting models. However, interpreting the models is far from obvious, especially when non-linear kernels are used. Hence, the methods are used as black boxes. As a consequence, the use of SVMs is less supported in areas where interpretability is important and where people are held responsible for the decisions made by models.In this work, we investigate whether SVMs using linear, polynomial and RBF kernels can be explained such that interpretations for model-based decisions can be provided. We further indicate when SVMs can be explained and in which situations interpretation of SVMs is (hitherto not possible. Here, explainability is defined as the ability to produce the final decision based on a sum of contributions which depend on one single or at most two input variables.Our experiments on simulated and real-life data show that explainability of an SVM depends on the chosen parameter values (degree of polynomial kernel, width of RBF kernel and regularization constant. When several combinations of parameter values yield the same cross-validation performance, combinations with a lower polynomial degree or a larger kernel width have a higher chance of being explainable.This work summarizes SVM classifiers obtained with linear, polynomial and RBF kernels in a single plot. Linear and polynomial kernels up to the second degree are represented exactly. For other kernels an indication of the reliability of the approximation is presented. The complete methodology is available as an R package and two apps and a movie are provided to illustrate the possibilities offered by the method.

  20. Supporting people with diabetes related\\ud stress and depression

    OpenAIRE

    Gillibrand, Warren P.; Holdich, Phil

    2010-01-01

    Diabetes can have a significant detrimental impact on wellbeing and psychological functioning. Warren Gillibrand and Phil Holdich explain how practice nurses can help people with diabetes deal with stress or depressive illness

  1. Topics in nonlinear wave theory with applications

    International Nuclear Information System (INIS)

    Tracy, E.R.

    1984-01-01

    Selected topics in nonlinear wave theory are discussed, and applications to the study of modulational instabilities are presented. A historical survey is given of topics relating to solitons and modulational problems. A method is then presented for generating exact periodic and quasi-periodic solutions to several nonlinear wave equations, which have important physical applications. The method is then specialized for the purposes of studying the modulational instability of a plane wave solution of the nonlinear Schroedinger equation, an equation with general applicability in one-dimensional modulational problems. Some numerical results obtained in conjunction with the analytic study are presented. The analytic approach explains the recurrence phenomena seen in the numerical studies, and the numerical work of other authors. The method of solution (related to the inverse scattering method) is then analyzed within the context of Hamiltonian dynamics where it is shown that the method can be viewed as simply a pair of canonical transformations. The Abel Transformation, which appears here and in the work of other authors, is shown to be a special form of Liouville's transformation to action-angle variables. The construction of closed form solutions of these nonlinear wave equations, via the solution of Jacobi's inversion problem, is surveyed briefly

  2. Nonlinear wave collapse and strong turbulence

    International Nuclear Information System (INIS)

    Robinson, P.A.

    1997-01-01

    The theory and applications of wave self-focusing, collapse, and strongly nonlinear wave turbulence are reviewed. In the last decade, the theory of these phenomena and experimental realizations have progressed rapidly. Various nonlinear wave systems are discussed, but the simplest case of collapse and strong turbulence of Langmuir waves in an unmagnetized plasma is primarily used in explaining the theory and illustrating the main ideas. First, an overview of the basic physics of linear waves and nonlinear wave-wave interactions is given from an introductory perspective. Wave-wave processes are then considered in more detail. Next, an introductory overview of the physics of wave collapse and strong turbulence is provided, followed by a more detailed theoretical treatment. Later sections cover numerical simulations of Langmuir collapse and strong turbulence and experimental applications to space, ionospheric, and laboratory plasmas, including laser-plasma and beam-plasma interactions. Generalizations to self-focusing, collapse, and strong turbulence of waves in other systems are also discussed, including nonlinear optics, solid-state systems, magnetized auroral and astrophysical plasmas, and deep-water waves. The review ends with a summary of the main ideas of wave collapse and strong-turbulence theory, a collection of open questions in the field, and a brief discussion of possible future research directions. copyright 1997 The American Physical Society

  3. Nonlinear dynamics of structures

    CERN Document Server

    Oller, Sergio

    2014-01-01

    This book lays the foundation of knowledge that will allow a better understanding of nonlinear phenomena that occur in structural dynamics.   This work is intended for graduate engineering students who want to expand their knowledge on the dynamic behavior of structures, specifically in the nonlinear field, by presenting the basis of dynamic balance in non‐linear behavior structures due to the material and kinematics mechanical effects.   Particularly, this publication shows the solution of the equation of dynamic equilibrium for structure with nonlinear time‐independent materials (plasticity, damage and frequencies evolution), as well as those time dependent non‐linear behavior materials (viscoelasticity and viscoplasticity). The convergence conditions for the non‐linear dynamic structure solution  are studied, and the theoretical concepts and its programming algorithms are presented.  

  4. Nonlinear Dot Plots.

    Science.gov (United States)

    Rodrigues, Nils; Weiskopf, Daniel

    2018-01-01

    Conventional dot plots use a constant dot size and are typically applied to show the frequency distribution of small data sets. Unfortunately, they are not designed for a high dynamic range of frequencies. We address this problem by introducing nonlinear dot plots. Adopting the idea of nonlinear scaling from logarithmic bar charts, our plots allow for dots of varying size so that columns with a large number of samples are reduced in height. For the construction of these diagrams, we introduce an efficient two-way sweep algorithm that leads to a dense and symmetrical layout. We compensate aliasing artifacts at high dot densities by a specifically designed low-pass filtering method. Examples of nonlinear dot plots are compared to conventional dot plots as well as linear and logarithmic histograms. Finally, we include feedback from an expert review.

  5. Multidimensional nonlinear descriptive analysis

    CERN Document Server

    Nishisato, Shizuhiko

    2006-01-01

    Quantification of categorical, or non-numerical, data is a problem that scientists face across a wide range of disciplines. Exploring data analysis in various areas of research, such as the social sciences and biology, Multidimensional Nonlinear Descriptive Analysis presents methods for analyzing categorical data that are not necessarily sampled randomly from a normal population and often involve nonlinear relations. This reference not only provides an overview of multidimensional nonlinear descriptive analysis (MUNDA) of discrete data, it also offers new results in a variety of fields. The first part of the book covers conceptual and technical preliminaries needed to understand the data analysis in subsequent chapters. The next two parts contain applications of MUNDA to diverse data types, with each chapter devoted to one type of categorical data, a brief historical comment, and basic skills peculiar to the data types. The final part examines several problems and then concludes with suggestions for futu...

  6. Nonlinear Source Emulator

    DEFF Research Database (Denmark)

    Nguyen-Duy, Khiem

    of a proposed NSE system with high dynamic performance. The goal of the work is to achieve a state-of-the art transient time of 10 µs. In order to produce the arbitrary nonlinear curve, the exponential function of a typical diode is used, but the diode can be replaced by other nonlinear curve reference...... of conductive common-mode current produced by the high rate of change of voltage over time (high dv/dt) at the NSE output. v/xvii The contributions of the thesis are based on the development of both units: the low Cio isolated power supply and the high dynamic performance NSE. Both units are investigated......-of-the-art dynamic performance among devices of the same kind. It also offers a complete solution for simulation of nonlinear source systems of different sizes, both in terrestrial and non-terrestrial applications. Key words: Current transformers, dc-dc power converters, hysteresis, parasitic capacitance, system...

  7. Physical (in)activity and depression in older people

    NARCIS (Netherlands)

    Wassink-Vossen, S.; Collard, R.M.; Oude Voshaar, R.C.; Comijs, H.C.; de Vocht, H.M.; Naarding, P.

    2014-01-01

    Background Knowledge about characteristics explaining low level of physical activity in late-life depression is needed to develop specific interventions aimed at improving physical health in depressed people above the age of 60. Methods This cross-sectional study used data from the Netherlands Study

  8. Nonlinear elastic waves in materials

    CERN Document Server

    Rushchitsky, Jeremiah J

    2014-01-01

    The main goal of the book is a coherent treatment of the theory of propagation in materials of nonlinearly elastic waves of displacements, which corresponds to one modern line of development of the nonlinear theory of elastic waves. The book is divided on five basic parts: the necessary information on waves and materials; the necessary information on nonlinear theory of elasticity and elastic materials; analysis of one-dimensional nonlinear elastic waves of displacement – longitudinal, vertically and horizontally polarized transverse plane nonlinear elastic waves of displacement; analysis of one-dimensional nonlinear elastic waves of displacement – cylindrical and torsional nonlinear elastic waves of displacement; analysis of two-dimensional nonlinear elastic waves of displacement – Rayleigh and Love nonlinear elastic surface waves. The book is addressed first of all to people working in solid mechanics – from the students at an advanced undergraduate and graduate level to the scientists, professional...

  9. Oscillations in nonlinear systems

    CERN Document Server

    Hale, Jack K

    2015-01-01

    By focusing on ordinary differential equations that contain a small parameter, this concise graduate-level introduction to the theory of nonlinear oscillations provides a unified approach to obtaining periodic solutions to nonautonomous and autonomous differential equations. It also indicates key relationships with other related procedures and probes the consequences of the methods of averaging and integral manifolds.Part I of the text features introductory material, including discussions of matrices, linear systems of differential equations, and stability of solutions of nonlinear systems. Pa

  10. Nonlinearity in nanomechanical cantilevers

    DEFF Research Database (Denmark)

    Villanueva Torrijo, Luis Guillermo; Karabalin, R. B.; Matheny, M. H.

    2013-01-01

    Euler-Bernoulli beam theory is widely used to successfully predict the linear dynamics of micro-and nanocantilever beams. However, its capacity to characterize the nonlinear dynamics of these devices has not yet been rigorously assessed, despite its use in nanoelectromechanical systems developmen....... These findings underscore the delicate balance between inertial and geometric nonlinear effects in the fundamental mode, and strongly motivate further work to develop theories beyond the Euler-Bernoulli approximation. DOI: 10.1103/PhysRevB.87.024304...

  11. Coupled nonlinear oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, J; Scott, A C

    1983-01-01

    Topics discussed include transitions in weakly coupled nonlinear oscillators, singularly perturbed delay-differential equations, and chaos in simple laser systems. Papers are presented on truncated Navier-Stokes equations in a two-dimensional torus, on frequency locking in Josephson point contacts, and on soliton excitations in Josephson tunnel junctions. Attention is also given to the nonlinear coupling of radiation pulses to absorbing anharmonic molecular media, to aspects of interrupted coarse-graining in stimulated excitation, and to a statistical analysis of long-term dynamic irregularity in an exactly soluble quantum mechanical model.

  12. Engineered nonlinear lattices

    DEFF Research Database (Denmark)

    Clausen, Carl A. Balslev; Christiansen, Peter Leth; Torner, L.

    1999-01-01

    We show that with the quasi-phase-matching technique it is possible to fabricate stripes of nonlinearity that trap and guide light like waveguides. We investigate an array of such stripes and find that when the stripes are sufficiently narrow, the beam dynamics is governed by a quadratic nonlinear...... discrete equation. The proposed structure therefore provides an experimental setting for exploring discrete effects in a controlled manner. In particular, we show propagation of breathers that are eventually trapped by discreteness. When the stripes are wide the beams evolve in a structure we term...

  13. Nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind

    2012-01-01

    Since the 4e appeared, a fast evolution of the field has occurred. The 5e of this classic work provides an up-to-date account of the nonlinear phenomena occurring inside optical fibers, the basis of all our telecommunications infastructure as well as being used in the medical field. Reflecting the big developments in research, this new edition includes major new content: slow light effects, which offers a reduction in noise and power consumption and more ordered network traffic-stimulated Brillouin scattering; vectorial treatment of highly nonlinear fibers; and a brand new chapter o

  14. Cumulative Effect of Depression on Dementia Risk

    Directory of Open Access Journals (Sweden)

    J. Olazarán

    2013-01-01

    Full Text Available Objective. To analyze a potential cumulative effect of life-time depression on dementia and Alzheimer’s disease (AD, with control of vascular factors (VFs. Methods. This study was a subanalysis of the Neurological Disorders in Central Spain (NEDICES study. Past and present depression, VFs, dementia status, and dementia due to AD were documented at study inception. Dementia status was also documented after three years. Four groups were created according to baseline data: never depression (nD, past depression (pD, present depression (prD, and present and past depression (prpD. Logistic regression was used. Results. Data of 1,807 subjects were investigated at baseline (mean age 74.3, 59.3% women, and 1,376 (81.6% subjects were evaluated after three years. The prevalence of dementia at baseline was 6.7%, and dementia incidence was 6.3%. An effect of depression was observed on dementia prevalence (OR [CI 95%] 1.84 [1.01–3.35] for prD and 2.73 [1.08–6.87] for prpD, and on dementia due to AD (OR 1.98 [0.98–3.99] for prD and OR 3.98 [1.48–10.71] for prpD (fully adjusted models, nD as reference. Depression did not influence dementia incidence. Conclusions. Present depression and, particularly, present and past depression are associated with dementia at old age. Multiple mechanisms, including toxic effect of depression on hippocampal neurons, plausibly explain these associations.

  15. The Effects of a Problem Solving-Based Intervention on Depressive Symptoms and HIV Medication Adherence Are Independent

    NARCIS (Netherlands)

    Gross, Robert; Bellamy, Scarlett L.; Chapman, Jennifer; Han, Xiaoyan; O'Duor, Jacqueline; Strom, Brian L.; Houts, Peter S.; Palmer, Steven C.; Coyne, James C.

    2014-01-01

    Depression and depressive symptoms predict poor adherence to medical therapy, but the association is complex, nonspecific, and difficult to interpret. Understanding this association may help to identify the mechanism explaining the results of interventions that improve both medical therapy adherence

  16. BOOK REVIEW: Nonlinear Magnetohydrodynamics

    Science.gov (United States)

    Shafranov, V.

    1998-08-01

    Nonlinear magnetohydrodynamics by Dieter Biskamp is a thorough introduction to the physics of the most impressive non-linear phenomena that occur in conducting magnetoplasmas. The basic systems, in which non-trivial dynamic processes are observed, accompanied by changes of geometry of the magnetic field and the effects of energy transformation (magnetic energy into kinetic energy or the opposite effect in magnetic dynamos), are the plasma magnetic confinement systems for nuclear fusion and space plasmas, mainly the solar plasma. A significant number of the examples of the dynamic processes considered are taken from laboratory plasmas, for which an experimental check of the theory is possible. Therefore, though the book is intended for researchers and students interested in both laboratory, including nuclear fusion, and astrophysical plasmas, it is most probably closer to the first category of reader. In the Introduction the author notes that unlike the hydrodynamics of non-conducting fluids, where the phenomena caused by rapid fluid motions are the most interesting, for plasmas in a strong magnetic field the quasi-static configurations inside which the local dynamic processes occur are often the most important. Therefore, the reader will also find in this book rather traditional material on the theory of plasma equilibrium and stability in magnetic fields. In addition, it is notable that, as opposed to a linear theory, the non-linear theory, as a rule, cannot give quite definite explanations or predictions of phenomena, and consequently there are in the book many results obtained by consideration of numerical models with the use of supercomputers. The treatment of non-linear dynamics is preceded by Chapters 2 to 4, in which the basics of MHD theory are presented with an emphasis on the role of integral invariants of the magnetic helicity type, a derivation of the reduced MHD equations is given, together with examples of the exact solutions of the equilibrium

  17. Do Parental Stressors and Avoidance Coping Mediate between Parental Depression and Offspring Depression? A 23-Year Follow-Up

    Science.gov (United States)

    Timko, Christine; Cronkite, Ruth C.; Moos, Rudolf H.

    2010-01-01

    We examined whether parents' stressors and avoidance coping when offspring were children helped to explain associations between parent depression at baseline and offspring's avoidance coping and depression in adulthood. Self-report data were collected at baseline and 1 year from parents (N = 326) and at 23 years from adult offspring (N = 326).…

  18. Depression, anxiety, and somatic symptoms in older cancer patients: a comparison across age groups.

    Science.gov (United States)

    Cohen, Miri

    2014-02-01

    Previous studies have reported that older cancer patients experience lower psychological distress than younger patients, but most prior studies do not differentiate between age groups within the 'older' category. The aim of this study was to assess the intensity of the symptoms of depression, anxiety, and somatic symptoms among different age groups of older cancer patients. Participants were composed of 321 cancer patients 60 years and older, who were divided into three age groups: 60-69, 70-79, and 80+ years. The participants answered the Brief Symptom Inventory-18, which included subscales for depression, anxiety, and somatic symptoms and the cancer-related problem list, in addition to providing personal and cancer-related details. Depressive, anxiety, and somatic symptoms and cancer-related problems were lowest in the 70-79 years age group and highest in the 80+ years age group. Comparisons between pairs of groups showed significant differences between each of the groups in Brief Symptom Inventory total scores and between the 80+ years age group and the other two groups in regard to depressive symptoms and cancer-related problems. Differences, related to anxiety and somatic symptoms, were significant for the 70-79 year olds, in comparison with the youngest and oldest groups. Intensity of symptoms was explained by older age, higher number of cancer-related problems, female gender, and lower income. Nonlinear relations exist between age and psychological symptoms, which is in line with the postponement of age-related health and functional decline in the modern era. These results suggest that the study of psychological reactions to cancer should examine differences between age groups among older cancer patients. Copyright © 2013 John Wiley & Sons, Ltd.

  19. Explanation of the Inverse Doppler Effect Observed in Nonlinear Transmission Lines

    International Nuclear Information System (INIS)

    Kozyrev, Alexander B.; Weide, Daniel W. van der

    2005-01-01

    The theory of the inverse Doppler effect recently observed in magnetic nonlinear transmission lines is developed. We explain the crucial role of the backward spatial harmonic in the occurrence of an inverse Doppler effect and draw analogies of the magnetic nonlinear transmission line to the backward wave oscillator

  20. Nonlinear silicon photonics

    Science.gov (United States)

    Tsia, Kevin K.; Jalali, Bahram

    2010-05-01

    An intriguing optical property of silicon is that it exhibits a large third-order optical nonlinearity, with orders-ofmagnitude larger than that of silica glass in the telecommunication band. This allows efficient nonlinear optical interaction at relatively low power levels in a small footprint. Indeed, we have witnessed a stunning progress in harnessing the Raman and Kerr effects in silicon as the mechanisms for enabling chip-scale optical amplification, lasing, and wavelength conversion - functions that until recently were perceived to be beyond the reach of silicon. With all the continuous efforts developing novel techniques, nonlinear silicon photonics is expected to be able to reach even beyond the prior achievements. Instead of providing a comprehensive overview of this field, this manuscript highlights a number of new branches of nonlinear silicon photonics, which have not been fully recognized in the past. In particular, they are two-photon photovoltaic effect, mid-wave infrared (MWIR) silicon photonics, broadband Raman effects, inverse Raman scattering, and periodically-poled silicon (PePSi). These novel effects and techniques could create a new paradigm for silicon photonics and extend its utility beyond the traditionally anticipated applications.

  1. Nonlinear Regression with R

    CERN Document Server

    Ritz, Christian; Parmigiani, Giovanni

    2009-01-01

    R is a rapidly evolving lingua franca of graphical display and statistical analysis of experiments from the applied sciences. This book provides a coherent treatment of nonlinear regression with R by means of examples from a diversity of applied sciences such as biology, chemistry, engineering, medicine and toxicology.

  2. Nonlinear silicon photonics

    Science.gov (United States)

    Borghi, M.; Castellan, C.; Signorini, S.; Trenti, A.; Pavesi, L.

    2017-09-01

    Silicon photonics is a technology based on fabricating integrated optical circuits by using the same paradigms as the dominant electronics industry. After twenty years of fervid development, silicon photonics is entering the market with low cost, high performance and mass-manufacturable optical devices. Until now, most silicon photonic devices have been based on linear optical effects, despite the many phenomenologies associated with nonlinear optics in both bulk materials and integrated waveguides. Silicon and silicon-based materials have strong optical nonlinearities which are enhanced in integrated devices by the small cross-section of the high-index contrast silicon waveguides or photonic crystals. Here the photons are made to strongly interact with the medium where they propagate. This is the central argument of nonlinear silicon photonics. It is the aim of this review to describe the state-of-the-art in the field. Starting from the basic nonlinearities in a silicon waveguide or in optical resonator geometries, many phenomena and applications are described—including frequency generation, frequency conversion, frequency-comb generation, supercontinuum generation, soliton formation, temporal imaging and time lensing, Raman lasing, and comb spectroscopy. Emerging quantum photonics applications, such as entangled photon sources, heralded single-photon sources and integrated quantum photonic circuits are also addressed at the end of this review.

  3. Generalized Nonlinear Yule Models

    Science.gov (United States)

    Lansky, Petr; Polito, Federico; Sacerdote, Laura

    2016-11-01

    With the aim of considering models related to random graphs growth exhibiting persistent memory, we propose a fractional nonlinear modification of the classical Yule model often studied in the context of macroevolution. Here the model is analyzed and interpreted in the framework of the development of networks such as the World Wide Web. Nonlinearity is introduced by replacing the linear birth process governing the growth of the in-links of each specific webpage with a fractional nonlinear birth process with completely general birth rates. Among the main results we derive the explicit distribution of the number of in-links of a webpage chosen uniformly at random recognizing the contribution to the asymptotics and the finite time correction. The mean value of the latter distribution is also calculated explicitly in the most general case. Furthermore, in order to show the usefulness of our results, we particularize them in the case of specific birth rates giving rise to a saturating behaviour, a property that is often observed in nature. The further specialization to the non-fractional case allows us to extend the Yule model accounting for a nonlinear growth.

  4. Intramolecular and nonlinear dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Davis, M.J. [Argonne National Laboratory, IL (United States)

    1993-12-01

    Research in this program focuses on three interconnected areas. The first involves the study of intramolecular dynamics, particularly of highly excited systems. The second area involves the use of nonlinear dynamics as a tool for the study of molecular dynamics and complex kinetics. The third area is the study of the classical/quantum correspondence for highly excited systems, particularly systems exhibiting classical chaos.

  5. Balancing for nonlinear systems

    NARCIS (Netherlands)

    Scherpen, J.M.A.

    1993-01-01

    We present a method of balancing for nonlinear systems which is an extension of balancing for linear systems in the sense that it is based on the input and output energy of a system. It is a local result, but gives 'broader' results than we obtain by just linearizing the system. Furthermore, the

  6. Depression After Heart Attack

    Science.gov (United States)

    ... Can Be Done to Reduce the Impact of Depression on My Mental and Physical Health? There is some good news here. Depression is ... Can Be Done to Reduce the Impact of Depression on My Mental and Physical Health? What Can I Do About the Depression I’ ...

  7. Learning Disability and Depression in Young Adulthood

    Science.gov (United States)

    MacInnes, Maryhelen; Broman, Clifford L.

    2013-01-01

    It is well established that children and adolescents with learning disabilities are more likely to experience depressed mood than are their peers. Many scholars explain this relationship as resulting from low self-esteem, stress, or social isolation. However, little work has explored whether this relationship continues to exist into young…

  8. A study of depression among Alexandria preparatory school adolescents.

    Science.gov (United States)

    Abou Nazel, M W; Fahmy, S I; Younis, I A; Seif el-Din, A G; Abdel Fatah, M; Mokhtar, S; Ayoub, A I

    1991-01-01

    Using a constructed Arabic version of Children Depression Inventory (CDI), screening of a stratified random sample of 1% (1561) of Alexandria Preparatory school adolescents was carried out. The prevalence of depressive scorers was 10.25% of total sample. A sub-sample of depressed scorers (111 pupils) were compared with controls (non-depressed scorers) matched on age and sex to study a variety of personal, familial, medical and scholastic ecological variables. Pupils neuroticism scorers were most predictive of depressive scorers where they explained 59.79% of the variance. Other ecological factors including peer and sibling relationships, introversive and lie scale scorers and scholastic performance explained an additional 14.87% of the variance. Using Beck Depression Inventory (BDI) and Mother-Father relationship check list, a sub-sample of depressed pupils' mothers were compared with controls of non-depressed pupils' mothers (42 mothers for each). Results indicated a strong positive correlation between pupils, CDI scores and their mothers BDI scores. On the other hand poor mother-father relationship was significantly associated with depressive scores of pupils. Findings, pointed to the need for reconsideration of school mental health program, since the presented medical and social services to depressed pupils were very poor.

  9. Neuroticism, Life Events and Negative Thoughts in the Development of Depression in Adolescent Girls

    Science.gov (United States)

    Kercher, Amy J.; Rapee, Ronald M.; Schniering, Carolyn A.

    2009-01-01

    Theories of depression suggest that cognitive and environmental factors may explain the relationship between personality and depression. This study tested such a model in early adolescence, incorporating neuroticism, stress-generation and negative automatic thoughts in the development of depressive symptoms. Participants (896 girls, mean age 12.3…

  10. Is It More Than the Blues? Children Can Suffer from Depression, Too.

    Science.gov (United States)

    Tuscano, Antoinette

    2000-01-01

    Explains that children be depressed, though they may express it very differently than adults, noting symptoms to watch for; causes of depression; when to seek help; what to do if a child appears depressed; how to talk to a child about what is wrong; and the importance of finding expert help. Sidebars present resources and tips on finding a…

  11. Non-linear excitation of gravitational radiation antennae

    International Nuclear Information System (INIS)

    Blair, D.G.

    1982-01-01

    A mechanism of non-linear excitation is proposed to explain observed excess noise in gravitational radiation antennae, driven by low frequency vibration. The mechanism is analogous to the excitation of a violin string by low frequency bowing. Numerical estimates for Weber bars suspended by cables are in good agreement with observations. (Auth.)

  12. Nonlinear analysis of a cross-coupled quadrature harmonic oscillator

    DEFF Research Database (Denmark)

    Djurhuus, Torsten; Krozer, Viktor; Vidkjær, Jens

    2005-01-01

    The dynamic equations governing the cross-coupled quadrature harmonic oscillator are derived assuming quasi-sinusoidal operation. This allows for an investigation of the previously reported tradeoff between close-to-carrier phase noise and quadrature precision. The results explain how nonlinearity...

  13. Depression associated with dementia.

    Science.gov (United States)

    Gutzmann, H; Qazi, A

    2015-06-01

    Depression and cognitive disorders, including dementia and mild cognitive impairment, are common disorders in old age. Depression is frequent in dementia, causing distress, reducing the quality of life, exacerbating cognitive and functional impairment and increasing caregiver stress. Even mild levels of depression can significantly add to the functional impairment of dementia patients and the severity of psychopathological and neurological impairments increases with increasing severity of depression. Depressive symptoms may be both a risk factor for, as well as a prodrome of dementia. Major depressive syndrome of Alzheimer's disease may be among the most common mood disorders of older adults. Treating depression is therefore a key clinical priority to improve the quality of life both of people with dementia as well as their carergivers. Nonpharmacological approaches and watchful waiting should be attempted first in patients who present with mild to moderate depression and dementia. In cases of severe depression or depression not able to be managed through nonpharmacological means, antidepressant therapy should be considered.

  14. Identification of nonlinear anelastic models

    International Nuclear Information System (INIS)

    Draganescu, G E; Bereteu, L; Ercuta, A

    2008-01-01

    A useful nonlinear identification technique applied to the anelastic and rheologic models is presented in this paper. First introduced by Feldman, the method is based on the Hilbert transform, and is currently used for identification of the nonlinear vibrations

  15. Nonlinear chaos control and synchronization

    NARCIS (Netherlands)

    Huijberts, H.J.C.; Nijmeijer, H.; Schöll, E.; Schuster, H.G.

    2007-01-01

    This chapter contains sections titled: Introduction Nonlinear Geometric Control Some Differential Geometric Concepts Nonlinear Controllability Chaos Control Through Feedback Linearization Chaos Control Through Input-Output Linearization Lyapunov Design Lyapunov Stability and Lyapunov's First Method

  16. Nonlinearity and disorder: Classification and stability of nonlinear impurity modes

    DEFF Research Database (Denmark)

    Sukhorukov, Andrey A.; Kivshar, Yuri S.; Bang, Ole

    2001-01-01

    We study the effects produced by competition of two physical mechanisms of energy localization in inhomogeneous nonlinear systems. As an example, we analyze spatially localized modes supported by a nonlinear impurity in the generalized nonlinear Schrödinger equation and describe three types of no...... the case of a power-law nonlinearity in detail. We discuss several scenarios of the instability-induced dynamics of the nonlinear impurity modes, including the mode decay or switching to a new stable state, and collapse at the impurity site....

  17. Nonlinear FMR spectra in yttrium iron garnet

    Directory of Open Access Journals (Sweden)

    Yu.M. Bunkov, P.M. Vetoshko, I.G. Motygullin, T.R. Safin, M.S. Tagirov, N.A. Tukmakova

    2015-12-01

    Full Text Available Results of demagnetizing effect studies in yttrium iron garnet Y3Fe5O12 thin films are reported. Experiments were performed on X-Band of electron paramagnetic resonance spectrometer at room temperature. The ferromagnetic resonance (FMR spectra were obtained for one-layer single crystal YIG films for different values of the applied microwave power. Nonlinear FMR spectra transformation by the microwave power increasing in various directions of magnetic field sweep was observed. It is explained by the influence of the demagnetization action of nonequilibrium magnons.

  18. Non-Linear Dynamics of Saturn's Rings

    Science.gov (United States)

    Esposito, L. W.

    2016-12-01

    Non-linear processes can explain why Saturn's rings are so active and dynamic. Ring systems differ from simple linear systems in two significant ways: 1. They are systems of granular material: where particle-to-particle collisions dominate; thus a kinetic, not a fluid description needed. Stresses are strikingly inhomogeneous and fluctuations are large compared to equilibrium. 2. They are strongly forced by resonances: which drive a non-linear response, that push the system across thresholds that lead to persistent states. Some of this non-linearity is captured in a simple Predator-Prey Model: Periodic forcing from the moon causes streamline crowding; This damps the relative velocity. About a quarter phase later, the aggregates stir the system to higher relative velocity and the limit cycle repeats each orbit, with relative velocity ranging from nearly zero to a multiple of the orbit average. Summary of Halo Results: A predator-prey model for ring dynamics produces transient structures like `straw' that can explain the halo morphology and spectroscopy: Cyclic velocity changes cause perturbed regions to reach higher collision speeds at some orbital phases, which preferentially removes small regolith particles; surrounding particles diffuse back too slowly to erase the effect: this gives the halo morphology; this requires energetic collisions (v ≈ 10m/sec, with throw distances about 200km, implying objects of scale R ≈ 20km).Transform to Duffing Eqn : With the coordinate transformation, z = M2/3, the Predator-Prey equations can be combined to form a single second-order differential equation with harmonic resonance forcing.Ring dynamics and history implications: Moon-triggered clumping explains both small and large particles at resonances. We calculate the stationary size distribution using a cell-to-cell mapping procedure that converts the phase-plane trajectories to a Markov chain. Approximating it as an asymmetric random walk with reflecting boundaries

  19. Terahertz Nonlinear Optics in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias C.

    2013-01-01

    We demonstrate the nonlinear optical effects – selfphase modulation and saturable absorption of a single-cycle THz pulse in a semiconductor. Resulting from THz-induced modulation of Drude plasma, these nonlinear optical effects, in particular, lead to self-shortening and nonlinear spectral...... breathing of a single-cycle THz pulse in a semiconductor....

  20. FRF decoupling of nonlinear systems

    Science.gov (United States)

    Kalaycıoğlu, Taner; Özgüven, H. Nevzat

    2018-03-01

    Structural decoupling problem, i.e. predicting dynamic behavior of a particular substructure from the knowledge of the dynamics of the coupled structure and the other substructure, has been well investigated for three decades and led to several decoupling methods. In spite of the inherent nonlinearities in a structural system in various forms such as clearances, friction and nonlinear stiffness, all decoupling studies are for linear systems. In this study, decoupling problem for nonlinear systems is addressed for the first time. A method, named as FRF Decoupling Method for Nonlinear Systems (FDM-NS), is proposed for calculating FRFs of a substructure decoupled from a coupled nonlinear structure where nonlinearity can be modeled as a single nonlinear element. Depending on where nonlinear element is, i.e., either in the known or unknown subsystem, or at the connection point, the formulation differs. The method requires relative displacement information between two end points of the nonlinear element, in addition to point and transfer FRFs at some points of the known subsystem. However, it is not necessary to excite the system from the unknown subsystem even when the nonlinear element is in that subsystem. The validation of FDM-NS is demonstrated with two different case studies using nonlinear lumped parameter systems. Finally, a nonlinear experimental test structure is used in order to show the real-life application and accuracy of FDM-NS.

  1. Rogue waves in nonlinear science

    International Nuclear Information System (INIS)

    Yan Zhenya

    2012-01-01

    Rogue waves, as a special type of solitary waves, play an important role in nonlinear optics, Bose-Einstein condensates, ocean, atmosphere, and even finance. In this report, we mainly review on the history of the rogue wave phenomenon and recent development of rogue wave solutions in some nonlinear physical models arising in the fields of nonlinear science.

  2. H∞ Balancing for Nonlinear Systems

    NARCIS (Netherlands)

    Scherpen, Jacquelien M.A.

    1996-01-01

    In previously obtained balancing methods for nonlinear systems a past and a future energy function are used to bring the nonlinear system in balanced form. By considering a different pair of past and future energy functions that are related to the H∞ control problem for nonlinear systems we define

  3. Effectiveness of Pranayama on Depression in Elderly

    Directory of Open Access Journals (Sweden)

    Kannan K

    2015-01-01

    Full Text Available The knowledge of Pranayama in elderly is very important in day to day life. In case of mental health problem like depression, the availability of the source of Complementary and Alternative Medicine (CAM like Pranayama helps to decrease depression. The aim of the review is to discuss the articles pertaining to pranayama on depression in elderly including both quantitative and qualitative studies published and unpublished and to review the related studies and other articles regarding effectiveness of pranayama on depression in elderly. The review was based on the studies conducted globally. Systematic searches were conducted on a range of databases, citations were sought from relevant reviews and several websites were also included in the search, including those of MIND and the Mental Health Foundation. MEDline, EMBASE, and PsycINFO were searched for studies published from 2000 January to December 2013. Five independent reviewers assessed the eligibility of each report based on predefined inclusion criteria (study design and measure of depression. Individual effect sizes were standardized. Results of 87 abstracts reviewed, 7 results were not Randomized Controlled Trial (RCT, 36 Studies were excluded due to their intervention and other problems, 25 Studies were excluded due to their outcomes, 2 dissertations was excluded, 17 Full Text articles were assessed for eligibility, Exclusion of study reports through full text screening n=8 duplicated: editorial review article: 3 Did not meet inclusion criteria: 4 Incomplete information: 9 studies met inclusion criteria and were included for final review. Heterogeneity between studies was not explained by age or sex, but could be partly explained by the types of depression and assessments. Collaborative care interventions are more effective for depression in older people than usual care and are also of high value. Pranayama are effective component with depression.

  4. Depressive symptoms in institutionalized older adults

    Directory of Open Access Journals (Sweden)

    Lívia Maria Santiago

    2014-04-01

    Full Text Available OBJECTIVE To estimate the prevalence of depressive symptoms among institutionalized elderly individuals and to analyze factors associated with this condition. METHODS This was a cross-sectional study involving 462 individuals aged 60 or older, residents in long stay institutions in four Brazilian municipalities. The dependent variable was assessed using the 15-item Geriatric Depression Scale. Poisson’s regression was used to evaluate associations with co-variables. We investigated which variables were most relevant in terms of presence of depressive symptoms within the studied context through factor analysis. RESULTS Prevalence of depressive symptoms was 48.7%. The variables associated with depressive symptoms were: regular/bad/very bad self-rated health; comorbidities; hospitalizations; and lack of friends in the institution. Five components accounted for 49.2% of total variance of the sample: functioning, social support, sensory deficiency, institutionalization and health conditions. In the factor analysis, functionality and social support were the components which explained a large part of observed variance. CONCLUSIONS A high prevalence of depressive symptoms, with significant variation in distribution, was observed. Such results emphasize the importance of health conditions and functioning for institutionalized older individuals developing depression. They also point to the importance of providing opportunities for interaction among institutionalized individuals.

  5. Topics in fluctuating nonlinear hydrodynamics

    International Nuclear Information System (INIS)

    Milner, S.T.

    1986-01-01

    Models of fluctuating nonlinear hydrodynamics have enjoyed much success in explaining the effect of long-wavelength fluctuations in diverse hydrodynamic systems. This thesis explores two such problems; in both, the body of hydrodynamic assumptions powerfully constrains the predictions of a well-posed theory. The effects of layer fluctuations in smectic-A liquid crystals are first examined. The static theory (introduced by Grinstein and Pelcovits) is reviewed. Ward identities, resulting from the arbitrariness of the layering direction, are derived and exploited. The static results motivate an examination of dynamic fluctuation effects. A new sound-damping experiment is proposed that would probe singular dependence of viscosities on applied stress. A theory of Procaccia and Gitterman that reaction rates of chemically reacting binary mixtures are drastically reduced near their thermodynamic critical points is analyzed. Hydrodynamic arguments and Van Hove theory are applied, concluding that the PG idea is drastically slowed, and spatially varying composition fluctuations are at best slowed down over a narrow range of wavenumbers

  6. Negative cognitive style and cortisol recovery accentuate the relationship between life stress and depressive symptoms.

    Science.gov (United States)

    Quinn, Meghan E; Grant, Kathryn E; Adam, Emma K

    2018-03-01

    When exposed to stressful life events, a significant number of adolescents will experience depressive symptoms. One model of depression suggests that individuals with a negative cognitive style are most vulnerable to depression following life stress. Alternatively, altered activation of the hypothalamic-pituitary-adrenal axis may explain vulnerability to depression following life stress. Each of these models plausibly explains the emergence of depressive symptoms during adolescence and have been investigated largely independently. The current study recruited a sample of urban adolescents (N = 179) to evaluate whether cortisol response to a laboratory stress induction and negative cognitive style are related and whether they independently interact with exposure to stressful life events to predict symptoms of depression. Negative cognitive style was not associated with cortisol response to the laboratory stressor. Rather, negative cognitive style and cortisol recovery independently interacted with stressful life events to predict current symptoms of depression. Results support a heterogeneous etiology of depression.

  7. Nonlinear differential equations

    Energy Technology Data Exchange (ETDEWEB)

    Dresner, L.

    1988-01-01

    This report is the text of a graduate course on nonlinear differential equations given by the author at the University of Wisconsin-Madison during the summer of 1987. The topics covered are: direction fields of first-order differential equations; the Lie (group) theory of ordinary differential equations; similarity solutions of second-order partial differential equations; maximum principles and differential inequalities; monotone operators and iteration; complementary variational principles; and stability of numerical methods. The report should be of interest to graduate students, faculty, and practicing scientists and engineers. No prior knowledge is required beyond a good working knowledge of the calculus. The emphasis is on practical results. Most of the illustrative examples are taken from the fields of nonlinear diffusion, heat and mass transfer, applied superconductivity, and helium cryogenics.

  8. Nonlinear (Anharmonic Casimir Oscillator

    Directory of Open Access Journals (Sweden)

    Habibollah Razmi

    2011-01-01

    Full Text Available We want to study the dynamics of a simple linear harmonic micro spring which is under the influence of the quantum Casimir force/pressure and thus behaves as a (an nonlinear (anharmonic Casimir oscillator. Generally, the equation of motion of this nonlinear micromechanical Casimir oscillator has no exact solvable (analytical solution and the turning point(s of the system has (have no fixed position(s; however, for particular values of the stiffness of the micro spring and at appropriately well-chosen distance scales and conditions, there is (are approximately sinusoidal solution(s for the problem (the variable turning points are collected in a very small interval of positions. This, as a simple and elementary plan, may be useful in controlling the Casimir stiction problem in micromechanical devices.

  9. Limits to Nonlinear Inversion

    DEFF Research Database (Denmark)

    Mosegaard, Klaus

    2012-01-01

    For non-linear inverse problems, the mathematical structure of the mapping from model parameters to data is usually unknown or partly unknown. Absence of information about the mathematical structure of this function prevents us from presenting an analytical solution, so our solution depends on our......-heuristics are inefficient for large-scale, non-linear inverse problems, and that the 'no-free-lunch' theorem holds. We discuss typical objections to the relevance of this theorem. A consequence of the no-free-lunch theorem is that algorithms adapted to the mathematical structure of the problem perform more efficiently than...... pure meta-heuristics. We study problem-adapted inversion algorithms that exploit the knowledge of the smoothness of the misfit function of the problem. Optimal sampling strategies exist for such problems, but many of these problems remain hard. © 2012 Springer-Verlag....

  10. Nonlinear Photonics 2014: introduction.

    Science.gov (United States)

    Akhmediev, N; Kartashov, Yaroslav

    2015-01-12

    International Conference "Nonlinear Photonics-2014" took place in Barcelona, Spain on July 27-31, 2014. It was a part of the "Advanced Photonics Congress" which is becoming a traditional notable event in the world of photonics. The current focus issue of Optics Express contains contributions from the participants of the Conference and the Congress. The articles in this focus issue by no means represent the total number of the congress contributions (around 400). However, it demonstrates wide range of topics covered at the event. The next conference of this series is to be held in 2016 in Australia, which is the home of many researchers working in the field of photonics in general and nonlinear photonics in particular.

  11. Nonlinear data assimilation

    CERN Document Server

    Van Leeuwen, Peter Jan; Reich, Sebastian

    2015-01-01

    This book contains two review articles on nonlinear data assimilation that deal with closely related topics but were written and can be read independently. Both contributions focus on so-called particle filters. The first contribution by Jan van Leeuwen focuses on the potential of proposal densities. It discusses the issues with present-day particle filters and explorers new ideas for proposal densities to solve them, converging to particle filters that work well in systems of any dimension, closing the contribution with a high-dimensional example. The second contribution by Cheng and Reich discusses a unified framework for ensemble-transform particle filters. This allows one to bridge successful ensemble Kalman filters with fully nonlinear particle filters, and allows a proper introduction of localization in particle filters, which has been lacking up to now.

  12. Essentials of nonlinear optics

    CERN Document Server

    Murti, Y V G S

    2014-01-01

    Current literature on Nonlinear Optics varies widely in terms of content, style, and coverage of specific topics, relative emphasis of areas and the depth of treatment. While most of these books are excellent resources for the researchers, there is a strong need for books appropriate for presenting the subject at the undergraduate or postgraduate levels in Universities. The need for such a book to serve as a textbook at the level of the bachelors and masters courses was felt by the authors while teaching courses on nonlinear optics to students of both science and engineering during the past two decades. This book has emerged from an attempt to address the requirement of presenting the subject at college level. A one-semester course covering the essentials can effectively be designed based on this.

  13. Nonlinear differential equations

    International Nuclear Information System (INIS)

    Dresner, L.

    1988-01-01

    This report is the text of a graduate course on nonlinear differential equations given by the author at the University of Wisconsin-Madison during the summer of 1987. The topics covered are: direction fields of first-order differential equations; the Lie (group) theory of ordinary differential equations; similarity solutions of second-order partial differential equations; maximum principles and differential inequalities; monotone operators and iteration; complementary variational principles; and stability of numerical methods. The report should be of interest to graduate students, faculty, and practicing scientists and engineers. No prior knowledge is required beyond a good working knowledge of the calculus. The emphasis is on practical results. Most of the illustrative examples are taken from the fields of nonlinear diffusion, heat and mass transfer, applied superconductivity, and helium cryogenics

  14. The forced nonlinear Schroedinger equation

    International Nuclear Information System (INIS)

    Kaup, D.J.; Hansen, P.J.

    1985-01-01

    The nonlinear Schroedinger equation describes the behaviour of a radio frequency wave in the ionosphere near the reflexion point where nonlinear processes are important. A simple model of this phenomenon leads to the forced nonlinear Schroedinger equation in terms of a nonlinear boundary value problem. A WKB analysis of the time evolution equations for the nonlinear Schroedinger equation in the inverse scattering transform formalism gives a crude order of magnitude estimation of the qualitative behaviour of the solutions. This estimation is compared with the numerical solutions. (D.Gy.)

  15. Nonlinear electrodynamics and cosmology

    International Nuclear Information System (INIS)

    Breton, Nora

    2010-01-01

    Nonlinear electrodynamics (NLED) generalizes Maxwell's theory for strong fields. When coupled to general relativity NLED presents interesting features like the non-vanishing of the trace of the energy-momentum tensor that leads to the possibility of violation of some energy conditions and of acting as a repulsive contribution in the Raychaudhuri equation. This theory is worth to study in cosmological and astrophysical situations characterized by strong electromagnetic and gravitational fields.

  16. Damped nonlinear Schrodinger equation

    International Nuclear Information System (INIS)

    Nicholson, D.R.; Goldman, M.V.

    1976-01-01

    High frequency electrostatic plasma oscillations described by the nonlinear Schrodinger equation in the presence of damping, collisional or Landau, are considered. At early times, Landau damping of an initial soliton profile results in a broader, but smaller amplitude soliton, while collisional damping reduces the soliton size everywhere; soliton speeds at early times are unchanged by either kind of damping. For collisional damping, soliton speeds are unchanged for all time

  17. Breastfeeding and postpartum depression: state of the art review

    Directory of Open Access Journals (Sweden)

    Bárbara Figueiredo

    2013-07-01

    Conclusions: Studies demonstrate that breastfeeding can protect mothers from postpartum depression, and are starting to clarify which biological and psychological processes may explain this protection. However, there are still equivocal results in the literature that may be explained by the methodological limitations presented by some studies.

  18. Nonlinearity without superluminality

    International Nuclear Information System (INIS)

    Kent, Adrian

    2005-01-01

    Quantum theory is compatible with special relativity. In particular, though measurements on entangled systems are correlated in a way that cannot be reproduced by local hidden variables, they cannot be used for superluminal signaling. As Czachor, Gisin, and Polchinski pointed out, this is not generally true of general nonlinear modifications of the Schroedinger equation. Excluding superluminal signaling has thus been taken to rule out most nonlinear versions of quantum theory. The no-superluminal-signaling constraint has also been used for alternative derivations of the optimal fidelities attainable for imperfect quantum cloning and other operations. These results apply to theories satisfying the rule that their predictions for widely separated and slowly moving entangled systems can be approximated by nonrelativistic equations of motion with respect to a preferred time coordinate. This paper describes a natural way in which this rule might fail to hold. In particular, it is shown that quantum readout devices which display the values of localized pure states need not allow superluminal signaling, provided that the devices display the values of the states of entangled subsystems as defined in a nonstandard, although natural, way. It follows that any locally defined nonlinear evolution of pure states can be made consistent with Minkowski causality

  19. Nonlinear dynamics approach of modeling the bifurcation for aircraft wing flutter in transonic speed

    DEFF Research Database (Denmark)

    Matsushita, Hiroshi; Miyata, T.; Christiansen, Lasse Engbo

    2002-01-01

    The procedure of obtaining the two-degrees-of-freedom, finite dimensional. nonlinear mathematical model. which models the nonlinear features of aircraft flutter in transonic speed is reported. The model enables to explain every feature of the transonic flutter data of the wind tunnel tests...... conducted at National Aerospace Laboratory in Japan for a high aspect ratio wing. It explains the nonlinear features of the transonic flutter such as the subcritical Hopf bifurcation of a limit cycle oscillation (LCO), a saddle-node bifurcation, and an unstable limit cycle as well as a normal (linear...

  20. Prevalence of depression and depressive symptoms among outpatients: a systematic review and meta-analysis.

    Science.gov (United States)

    Wang, Jinghui; Wu, Xiaohang; Lai, Weiyi; Long, Erping; Zhang, Xiayin; Li, Wangting; Zhu, Yi; Chen, Chuan; Zhong, Xiaojian; Liu, Zhenzhen; Wang, Dongni; Lin, Haotian

    2017-08-23

    symptoms in different specialties varied from 17.0% to 53.0%. The prevalence of depression and depressive symptoms was higher among outpatients in developing countries than in outpatients from developed countries. Moreover, the prevalence of depression and depressive symptoms in outpatients slightly decreased from 1996 to 2010. Regarding screening instruments, the Beck Depression Inventory led to a higher estimate of the prevalence of depression and depressive symptoms (1316/4702, 36.0%, 95% CI 29.0% to 44.0%, I 2 =94.8%) than the Hospital Anxiety and Depression Scale (1003/2025, 22.0%, 95% CI 12.0% to 35.0%, I 2 =96.6%). Our study provides evidence that a significant proportion of outpatients experience depression or depressive symptoms, highlighting the importance of developing effective management strategies for the early identification and treatment of these conditions among outpatients in clinical practice. The substantial heterogeneity between studies was not fully explained by the variables examined. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  1. Topology Explains Why Automobile Sunshades Fold Oddly

    Science.gov (United States)

    Feist, Curtis; Naimi, Ramin

    2009-01-01

    Automobile sunshades always fold into an "odd" number of loops. The explanation why involves elementary topology (braid theory and linking number, both explained in detail here with definitions and examples), and an elementary fact from algebra about symmetric group.

  2. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Disorders Video: The Basketball Game: An MRI Story Radiology and You Sponsored by Image/Video Gallery Your ... Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot org Hello, I’m Dr. Elliot ...

  3. Explorers Presentation: Explaining the Tides to Children

    OpenAIRE

    Institute, Marine

    2015-01-01

    Explaining the tides to children Presentation includes information about: Orbits of the Earth, Moon and Sun; Moon phases and the lunar cycle; Gravity; Gravity and the tide; Types of tides; The tides and me!; Tide tables; Extra insight

  4. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... An MRI Story Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography ( ... posted: How to Obtain and Share Your Medical Images Movement Disorders Video: The Basketball Game: An MRI ...

  5. A model to explain human voice production

    Science.gov (United States)

    Vilas Bôas, C. S. N.; Gobara, S. T.

    2018-05-01

    This article presents a device constructed with low-cost material to demonstrate and explain voice production. It also provides a contextualized, interdisciplinary approach to introduce the study of sound waves.

  6. Using Expectancy Theory to Explain Performance Appraisal ...

    African Journals Online (AJOL)

    pc

    2018-03-05

    Mar 5, 2018 ... appraisal conducting style, the relation between the performance appraisal system and task ... the article first explains the theory model which is based expectancy theory. II. ... which in return lead to rewards. According to [12],.

  7. A population-based study of anxiety as a precursor for depression in childhood and adolescence

    OpenAIRE

    van den Bree Marianne BM; Rice Frances; Thapar Anita

    2004-01-01

    Background Anxiety and depression co-occur in children and adolescents with anxiety commonly preceding depression. Although there is some evidence to suggest that the association between early anxiety and later depression is explained by a shared genetic aetiology, the contribution of environmental factors is less well examined and it is unknown whether anxiety itself is a phenotypic risk factor for later depression. These explanations of the association between early anxiety and later depre...

  8. A population-based study of anxiety as a precursor for depression in childhood and adolescence.

    OpenAIRE

    Rice, F.; van den Bree, M. B. M.; Thapar, A.

    2004-01-01

    Background: Anxiety and depression co-occur in children and adolescents with anxiety commonly preceding depression. Although there is some evidence to suggest that the association between early anxiety and later depression is explained by a shared genetic aetiology, the contribution of environmental factors is less well examined and it is unknown whether anxiety itself is a phenotypic risk factor for later depression. These explanations of the association between early anxiety and later depre...

  9. Diagnosing and treating depression in epilepsy.

    Science.gov (United States)

    Elger, Christian E; Johnston, Samantha A; Hoppe, Christian

    2017-01-01

    At least one third of patients with active epilepsy suffer from significant impairment of their emotional well-being. A targeted examination for possible depression (irrespective of any social, financial or personal burdens) can identify patients who may benefit from medical attention and therapeutic support. Reliable screening instruments such as the Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) are suitable for the timely identification of patients needing help. Neurologists should be capable of managing mild to moderate comorbid depression but referral to mental health specialists is mandatory in severe and difficult-to-treat depression, or if the patient is acutely suicidal. In terms of the therapeutic approach, it is essential first to optimize seizure control and minimize unwanted antiepileptic drug-related side effects. Psychotherapy for depression in epilepsy (including online self-treatment programs) is underutilized although it has proven effective in ten well-controlled trials. In contrast, the effectiveness of antidepressant drugs for depression in epilepsy is unknown. However, if modern antidepressants are used (e.g. SSRI, SNRI, NaSSA), concerns about an aggravation of seizures and or problematic interactions with antiepileptic drugs seem unwarranted. Epilepsy-related stress ("burden of epilepsy") explains depression in many patients but acute and temporary seizure-related states of depression or suicidality have also been reported. Limbic encephalitits may cause isolated mood alteration without any recognizable psychoetiological background indicating a possible role of neuroinflammation. This review will argue that, overall, a bio-psycho-social model best captures the currently available evidence relating to the etiology and treatment of depression as a comorbidity of epilepsy. Copyright © 2016 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  10. In Systemic Sclerosis, Anxiety and Depression Assessed by Hospital Anxiety Depression Scale Are Independently Associated with Disability and Psychological Factors

    Directory of Open Access Journals (Sweden)

    Angela Del Rosso

    2013-01-01

    Full Text Available Background. Anxious and depressive symptoms are frequent in Systemic Sclerosis (SSc. Our objective is to assess their prevalence and association with district and global disability and psychological variables. Methods. 119 SSc patients were assessed by Hospital Anxiety Depression Scale (HADS. Clinical depression and anxiety were defined for HADS score cutoff ≥8. Patients were assessed for psychological symptoms (RSES, COPE-NIV, hand (HAMIS, CHFDS, fist closure, and hand opening and face disability (MHISS, mouth opening, global disability, and fatigue (HAQ, FACIT. Results. Both depression and anxiety in SSc are 36%. Depressive patients with comorbid anxiety have higher HADS-D score than patients with depression only (. HADS-A and -D are positively correlated with global disability, hands and mouth disability, fatigue, self-esteem and avoidance coping strategy, and, only HADS-A, also with social support (. By multiple regression, HADS-D is independently associated with FACIT-F (, RSES (, and MHISS total score (, together explaining 50% of variance. HADS-A is independently associated with RSES (, COPE-NIV SA (, COPE-NIV SS (, FACIT-F (, and MHISS mouth opening (, explaining 41% of variance. Conclusions. In SSc depression and anxiety correlate to local and global disabilities and psychological characteristics. Depressive patients with comorbid anxiety have higher level of depressive symptoms.

  11. An enstrophy-based linear and nonlinear receptivity theory

    Science.gov (United States)

    Sengupta, Aditi; Suman, V. K.; Sengupta, Tapan K.; Bhaumik, Swagata

    2018-05-01

    In the present research, a new theory of instability based on enstrophy is presented for incompressible flows. Explaining instability through enstrophy is counter-intuitive, as it has been usually associated with dissipation for the Navier-Stokes equation (NSE). This developed theory is valid for both linear and nonlinear stages of disturbance growth. A previously developed nonlinear theory of incompressible flow instability based on total mechanical energy described in the work of Sengupta et al. ["Vortex-induced instability of an incompressible wall-bounded shear layer," J. Fluid Mech. 493, 277-286 (2003)] is used to compare with the present enstrophy based theory. The developed equations for disturbance enstrophy and disturbance mechanical energy are derived from NSE without any simplifying assumptions, as compared to other classical linear/nonlinear theories. The theory is tested for bypass transition caused by free stream convecting vortex over a zero pressure gradient boundary layer. We explain the creation of smaller scales in the flow by a cascade of enstrophy, which creates rotationality, in general inhomogeneous flows. Linear and nonlinear versions of the theory help explain the vortex-induced instability problem under consideration.

  12. Nonlinear robust hierarchical control for nonlinear uncertain systems

    Directory of Open Access Journals (Sweden)

    Leonessa Alexander

    1999-01-01

    Full Text Available A nonlinear robust control-system design framework predicated on a hierarchical switching controller architecture parameterized over a set of moving nominal system equilibria is developed. Specifically, using equilibria-dependent Lyapunov functions, a hierarchical nonlinear robust control strategy is developed that robustly stabilizes a given nonlinear system over a prescribed range of system uncertainty by robustly stabilizing a collection of nonlinear controlled uncertain subsystems. The robust switching nonlinear controller architecture is designed based on a generalized (lower semicontinuous Lyapunov function obtained by minimizing a potential function over a given switching set induced by the parameterized nominal system equilibria. The proposed framework robustly stabilizes a compact positively invariant set of a given nonlinear uncertain dynamical system with structured parametric uncertainty. Finally, the efficacy of the proposed approach is demonstrated on a jet engine propulsion control problem with uncertain pressure-flow map data.

  13. Behandlingsresistent depression kan behandles

    DEFF Research Database (Denmark)

    Vinberg, Maj; Levinsen, Mette Frandsen; Kessing, Lars Vedel

    2011-01-01

    Depression is considered resistant when two treatment attempts with antidepressants from different classes fail to produce significant clinical improvement. In cases of treatment-resistant depression, it is recommended to reevaluate the diagnosis, clarify comorbidity, substance abuse and lack of ...

  14. Learning about depression

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000325.htm Learning about depression To use the sharing features on this page, ... trigger or reason. What are the Signs of Depression? You may notice some or all of the ...

  15. Signs of Depression

    Science.gov (United States)

    Everyone has down days and times when they feel sad. But depression is more than feeling sad or having a bad day. You may have depression if you feel sad every day (or most days) for at least two weeks.

  16. Men and Depression

    Science.gov (United States)

    ... crisis? For More Information Reprints Share Men and Depression Download PDF Download ePub Order a free hardcopy ... affects a large number of men. What is depression? Everyone feels sad or irritable and has trouble ...

  17. Heart disease and depression

    Science.gov (United States)

    ... gov/ency/patientinstructions/000790.htm Heart disease and depression To use the sharing features on this page, ... a heart attack or heart surgery Signs of Depression It is pretty common to feel down or ...

  18. Depression - stopping your medicines

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000570.htm Depression - stopping your medicines To use the sharing features ... prescription medicines you may take to help with depression, anxiety, or pain. Like any medicine, there are ...

  19. Depression Disturbs Germany

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The suicide of Robert Enke,the goalkeeper of the Germany national football team who had battled depression for years,stunned the country and cast depression into the national spotlight as a disturbing disease.

  20. Personality and Depression: Explanatory Models and Review of the Evidence

    Science.gov (United States)

    Klein, Daniel N.; Kotov, Roman; Bufferd, Sara J.

    2012-01-01

    Understanding the association between personality and depression has implications for elucidating etiology and comorbidity, identifying at-risk individuals, and tailoring treatment. We discuss seven major models that have been proposed to explain the relation between personality and depression, and we review key methodological issues, including study design, the heterogeneity of mood disorders, and the assessment of personality. We then selectively review the extensive empirical literature on the role of personality traits in depression in adults and children. Current evidence suggests that depression is linked to traits such as neuroticism/negative emotionality, extraversion/positive emotionality, and conscientiousness. Moreover, personality characteristics appear to contribute to the onset and course of depression through a variety of pathways. Implications for prevention and prediction of treatment response are discussed, as well as specific considerations to guide future research on the relation between personality and depression. PMID:21166535

  1. Discrete nonlinear Schrodinger equations with arbitrarily high-order nonlinearities

    DEFF Research Database (Denmark)

    Khare, A.; Rasmussen, Kim Ø; Salerno, M.

    2006-01-01

    -Ladik equation. As a common property, these equations possess three kinds of exact analytical stationary solutions for which the Peierls-Nabarro barrier is zero. Several properties of these solutions, including stability, discrete breathers, and moving solutions, are investigated.......A class of discrete nonlinear Schrodinger equations with arbitrarily high-order nonlinearities is introduced. These equations are derived from the same Hamiltonian using different Poisson brackets and include as particular cases the saturable discrete nonlinear Schrodinger equation and the Ablowitz...

  2. Nonlinear simulation of electromagnetic current diffusive interchange mode turbulence

    International Nuclear Information System (INIS)

    Yagi, M.; Itoh, S.I.; Fukuyama, A.

    1998-01-01

    The anomalous transport in toroidal plasmas has been investigated extensively. It is pointed out that the nonlinear instability is important in driving the microturbulence[1], i.e., the self-sustained plasma turbulence. This concept is explained as follows; when the electron motion along the magnetic field line is resisted by the background turbulence, it gives rise to the effective resistivity and enhances the level of the turbulence. The nonlinear simulation of the electrostatic current diffusive interchange mode (CDIM) in the two dimensional sheared slab geometry has been performed as an example. The occurrence of the nonlinear instability and the self-sustainment of the plasma turbulence were confirmed by this simulation[2]. On the other hand, the electromagnetic turbulence is sustained in the high pressure limit. The possibility of the self-organization with more variety has been pointed out[3]. It is important to study the electromagnetic turbulence based on the nonlinear simulation. In this paper, the model equation for the electrostatic CDIM turbulence[2] is extended for both electrostatic and electromagnetic turbulence. (1) Not only E x B convective nonlinearity but also the electromagnetic nonlinearity which is related to the parallel flow are incorporated into the model equation. (2) The electron and ion pressure evolution equations are solved separately, making it possible to distinguish the electron and ion thermal diffusivities. The two dimensional nonlinear simulation of the electromagnetic CDIM is performed based on the extended fluid model. This paper is organized as follows. The model equation is explained in section II. The result of simulation is shown in section III. The conclusion and discussion are given in section IV. (author)

  3. Preventing Depression in Adults With Subthreshold Depression

    DEFF Research Database (Denmark)

    Buntrock, Claudia; Berking, Matthias; Smit, Filip

    2017-01-01

    -based guided self-help intervention (ie, cognitive-behavioral therapy and problem-solving therapy assisted by supervised graduate students or health care professionals) in addition to usual care or to usual care supplemented with Web-based psycho-education (enhanced usual care). Depression-free years (DFYs......BACKGROUND: Psychological interventions for the prevention of depression might be a cost-effective way to reduce the burden associated with depressive disorders. OBJECTIVE: To evaluate the cost-effectiveness of a Web-based guided self-help intervention to prevent major depressive disorder (MDD......) in people with subthreshold depression (sD). METHODS: A pragmatic randomized controlled trial was conducted with follow-up at 12 months. Participants were recruited from the general population via a large statutory health insurance company and an open access website. Participants were randomized to a Web...

  4. Huntingtin gene repeat size variations affect risk of lifetime depression.

    Science.gov (United States)

    Gardiner, Sarah L; van Belzen, Martine J; Boogaard, Merel W; van Roon-Mom, Willeke M C; Rozing, Maarten P; van Hemert, Albert M; Smit, Johannes H; Beekman, Aartjan T F; van Grootheest, Gerard; Schoevers, Robert A; Oude Voshaar, Richard C; Roos, Raymund A C; Comijs, Hannie C; Penninx, Brenda W J H; van der Mast, Roos C; Aziz, N Ahmad

    2017-12-11

    Huntington disease (HD) is a severe neuropsychiatric disorder caused by a cytosine-adenine-guanine (CAG) repeat expansion in the HTT gene. Although HD is frequently complicated by depression, it is still unknown to what extent common HTT CAG repeat size variations in the normal range could affect depression risk in the general population. Using binary logistic regression, we assessed the association between HTT CAG repeat size and depression risk in two well-characterized Dutch cohorts─the Netherlands Study of Depression and Anxiety and the Netherlands Study of Depression in Older Persons─including 2165 depressed and 1058 non-depressed persons. In both cohorts, separately as well as combined, there was a significant non-linear association between the risk of lifetime depression and HTT CAG repeat size in which both relatively short and relatively large alleles were associated with an increased risk of depression (β = -0.292 and β = 0.006 for the linear and the quadratic term, respectively; both P < 0.01 after adjustment for the effects of sex, age, and education level). The odds of lifetime depression were lowest in persons with a HTT CAG repeat size of 21 (odds ratio: 0.71, 95% confidence interval: 0.52 to 0.98) compared to the average odds in the total cohort. In conclusion, lifetime depression risk was higher with both relatively short and relatively large HTT CAG repeat sizes in the normal range. Our study provides important proof-of-principle that repeat polymorphisms can act as hitherto unappreciated but complex genetic modifiers of depression.

  5. Method of treating depression

    Science.gov (United States)

    Henn, Fritz [East Patchogue, NY

    2012-01-24

    Methods for treatment of depression-related mood disorders in mammals, particularly humans are disclosed. The methods of the invention include administration of compounds capable of enhancing glutamate transporter activity in the brain of mammals suffering from depression. ATP-sensitive K.sup.+ channel openers and .beta.-lactam antibiotics are used to enhance glutamate transport and to treat depression-related mood disorders and depressive symptoms.

  6. Lifetime socio-economic position and depression

    DEFF Research Database (Denmark)

    Osler, Merete; Bruunsgaard, Helle; Mortensen, Erik Lykke

    2015-01-01

    biomarkers explained any associations. Methods: A cohort of 2482 Danish men born in 1953 with information from birth, and conscript board examinations was followed-up with assessment of depressive mood and blood sampling in 2010. Simple and multiple linear regression were used to investigate associations....... These covariables were also associated with depressive mood and when they were included into the regression model together with life time SEP, the β-estimates for the latter attenuated, when smoking, alcohol and BMI were entered, while the inclusion of cognitive function and the inflammatory biomarkers had limited...

  7. Nonlinear diffusion equations

    CERN Document Server

    Wu Zhuo Qun; Li Hui Lai; Zhao Jun Ning

    2001-01-01

    Nonlinear diffusion equations, an important class of parabolic equations, come from a variety of diffusion phenomena which appear widely in nature. They are suggested as mathematical models of physical problems in many fields, such as filtration, phase transition, biochemistry and dynamics of biological groups. In many cases, the equations possess degeneracy or singularity. The appearance of degeneracy or singularity makes the study more involved and challenging. Many new ideas and methods have been developed to overcome the special difficulties caused by the degeneracy and singularity, which

  8. Methods of nonlinear analysis

    CERN Document Server

    Bellman, Richard Ernest

    1970-01-01

    In this book, we study theoretical and practical aspects of computing methods for mathematical modelling of nonlinear systems. A number of computing techniques are considered, such as methods of operator approximation with any given accuracy; operator interpolation techniques including a non-Lagrange interpolation; methods of system representation subject to constraints associated with concepts of causality, memory and stationarity; methods of system representation with an accuracy that is the best within a given class of models; methods of covariance matrix estimation;methods for low-rank mat

  9. Nonlinear optimal control theory

    CERN Document Server

    Berkovitz, Leonard David

    2012-01-01

    Nonlinear Optimal Control Theory presents a deep, wide-ranging introduction to the mathematical theory of the optimal control of processes governed by ordinary differential equations and certain types of differential equations with memory. Many examples illustrate the mathematical issues that need to be addressed when using optimal control techniques in diverse areas. Drawing on classroom-tested material from Purdue University and North Carolina State University, the book gives a unified account of bounded state problems governed by ordinary, integrodifferential, and delay systems. It also dis

  10. Topics in Nonlinear Dynamics

    DEFF Research Database (Denmark)

    Mosekilde, Erik

    Through a significant number of detailed and realistic examples this book illustrates how the insights gained over the past couple of decades in the fields of nonlinear dynamics and chaos theory can be applied in practice. Aomng the topics considered are microbiological reaction systems, ecological...... food-web systems, nephron pressure and flow regulation, pulsatile secretion of hormones, thermostatically controlled radiator systems, post-stall maneuvering of aircrafts, transfer electron devices for microwave generation, economic long waves, human decision making behavior, and pattern formation...... in chemical reaction-diffusion systems....

  11. Nonlinear dynamics in psychology

    Directory of Open Access Journals (Sweden)

    Stephen J. Guastello

    2001-01-01

    Full Text Available This article provides a survey of the applications of nonlinear dynamical systems theory to substantive problems encountered in the full scope of psychological science. Applications are organized into three topical areas – cognitive science, social and organizational psychology, and personality and clinical psychology. Both theoretical and empirical studies are considered with an emphasis on works that capture the broadest scope of issues that are of substantive interest to psychological theory. A budding literature on the implications of NDS principles in professional practice is reported also.

  12. Nonlinear Hamiltonian systems

    DEFF Research Database (Denmark)

    Jørgensen, Michael Finn

    1995-01-01

    It is generally very difficult to solve nonlinear systems, and such systems often possess chaotic solutions. In the rare event that a system is completely solvable, it is said to integrable. Such systems never have chaotic solutions. Using the Inverse Scattering Transform Method (ISTM) two...... particular configurations of the Discrete Self-Trapping (DST) system are shown to be completely solvable. One of these systems includes the Toda lattice in a certain limit. An explicit integration is carried through for this Near-Toda lattice. The Near-Toda lattice is then generalized to include singular...

  13. Nonlinear surface electromagnetic phenomena

    CERN Document Server

    Ponath, H-E

    1991-01-01

    In recent years the physics of electromagnetic surface phenomena has developed rapidly, evolving into technologies for communications and industry, such as fiber and integrated optics. The variety of phenomena based on electromagnetism at surfaces is rich and this book was written with the aim of summarizing the available knowledge in selected areas of the field. The book contains reviews written by solid state and optical physicists on the nonlinear interaction of electromagnetic waves at and with surfaces and films. Both the physical phenomena and some potential applications are

  14. Oscillators from nonlinear realizations

    Science.gov (United States)

    Kozyrev, N.; Krivonos, S.

    2018-02-01

    We construct the systems of the harmonic and Pais-Uhlenbeck oscillators, which are invariant with respect to arbitrary noncompact Lie algebras. The equations of motion of these systems can be obtained with the help of the formalism of nonlinear realizations. We prove that it is always possible to choose time and the fields within this formalism in such a way that the equations of motion become linear and, therefore, reduce to ones of ordinary harmonic and Pais-Uhlenbeck oscillators. The first-order actions, that produce these equations, can also be provided. As particular examples of this construction, we discuss the so(2, 3) and G 2(2) algebras.

  15. Therapeutics of postpartum depression.

    Science.gov (United States)

    Thomson, Michael; Sharma, Verinder

    2017-05-01

    Postpartum depression is a prevalent disorder affecting many women of reproductive age. Despite increasing public awareness, it is frequently underdiagnosed and undertreated leading to significant maternal morbidity and adverse child outcomes. When identified, postpartum depression is usually treated as major depressive disorder. Many studies have identified the postpartum as a period of high risk for first presentations and relapses of bipolar disorder. Areas covered: This article reviews the acute and prophylactic treatment of postpartum major depressive disorder, bipolar depression and major depressive disorder with mixed features. The safety of antidepressant and mood stabilizing medications in pregnancy and breastfeeding will also be reviewed. Expert commentary: Differentiating postpartum major depressive disorder and postpartum bipolar depression can be difficult given their clinical similarities but accurate identification is vital for initiating proper treatment. Antidepressants are the mainstay of drug treatment for postpartum major depressive disorder, yet randomized controlled trials have shown conflicting results. A paucity of evidence exists for the effectiveness of antidepressant prophylaxis in the prevention of recurrences of major depressive disorder. Mood stabilizing medications reduce the risk of postpartum bipolar depression relapse but no randomized controlled trials have examined their use in the acute or prophylactic treatment of postpartum bipolar depression.

  16. Measuring psychotic depression

    DEFF Research Database (Denmark)

    Østergaard, Søren Dinesen; Meyers, B S; Flint, A J

    Psychotic depression (PD) is a highly debilitating condition, which needs intensive monitoring. However, there is no established rating scale for evaluating the severity of PD. The aim of this analysis was to assess the psychometric properties of established depression rating scales and a number...... of new composite rating scales, covering both depressive and psychotic symptoms, in relation to PD....

  17. Depression (For Parents)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Depression KidsHealth / For Parents / Depression What's in this article? ... Ways to Help Print en español Depresión About Depression It's normal for kids to feel sad, down, ...

  18. Handling Depression | Smokefree 60+

    Science.gov (United States)

    Everyone feels blue now and then. It's a part of life. But if your feelings last more than few days and interfere with your normal daily activities, you may be suffering from depression. On this page: Symptoms of depression Who gets depressed and why?

  19. Depression (For Teens)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Depression KidsHealth / For Teens / Depression What's in this article? ... Yourself Print en español Depresión Regular Sadness vs. Depression It's natural to feel sad, down, or discouraged ...

  20. Linear and nonlinear subspace analysis of hand movements during grasping.

    Science.gov (United States)

    Cui, Phil Hengjun; Visell, Yon

    2014-01-01

    This study investigated nonlinear patterns of coordination, or synergies, underlying whole-hand grasping kinematics. Prior research has shed considerable light on roles played by such coordinated degrees-of-freedom (DOF), illuminating how motor control is facilitated by structural and functional specializations in the brain, peripheral nervous system, and musculoskeletal system. However, existing analyses suppose that the patterns of coordination can be captured by means of linear analyses, as linear combinations of nominally independent DOF. In contrast, hand kinematics is itself highly nonlinear in nature. To address this discrepancy, we sought to to determine whether nonlinear synergies might serve to more accurately and efficiently explain human grasping kinematics than is possible with linear analyses. We analyzed motion capture data acquired from the hands of individuals as they grasped an array of common objects, using four of the most widely used linear and nonlinear dimensionality reduction algorithms. We compared the results using a recently developed algorithm-agnostic quality measure, which enabled us to assess the quality of the dimensional reductions that resulted by assessing the extent to which local neighborhood information in the data was preserved. Although qualitative inspection of this data suggested that nonlinear correlations between kinematic variables were present, we found that linear modeling, in the form of Principle Components Analysis, could perform better than any of the nonlinear techniques we applied.

  1. Global Analysis of Nonlinear Dynamics

    CERN Document Server

    Luo, Albert

    2012-01-01

    Global Analysis of Nonlinear Dynamics collects chapters on recent developments in global analysis of non-linear dynamical systems with a particular emphasis on cell mapping methods developed by Professor C.S. Hsu of the University of California, Berkeley. This collection of contributions prepared by a diverse group of internationally recognized researchers is intended to stimulate interests in global analysis of complex and high-dimensional nonlinear dynamical systems, whose global properties are largely unexplored at this time. This book also: Presents recent developments in global analysis of non-linear dynamical systems Provides in-depth considerations and extensions of cell mapping methods Adopts an inclusive style accessible to non-specialists and graduate students Global Analysis of Nonlinear Dynamics is an ideal reference for the community of nonlinear dynamics in different disciplines including engineering, applied mathematics, meteorology, life science, computational science, and medicine.  

  2. Collapse of nonlinear Langmuir waves

    International Nuclear Information System (INIS)

    Malkin, V.M.

    1986-01-01

    The dispersion of sufficiently intensive Langmuir waves is determined by intrinsic (electron) nonlinearity. During Langmuir collapse the wave energy density required for the appearance of electron nonlinearity is attained, generally speaking, prior to the development of dissipative processes. Up to now, the effect of electron nonlinearity on the collapse dynamics and spectrum of strong Langmuir turbulence ( which may be very appreciable ) has not been studied extensively because of the difficulty of describing nonlinear Langmuir waves. In the present paper the positive determinacy of the electron nonlinear hamiltonian is proven, the increment of modulation instability of a nonlinear Langmuir wave cluster localized in a cavity is calculated, and the universal law of their collapse is found

  3. Why might poor sleep quality lead to depression? A role for emotion regulation.

    Science.gov (United States)

    O'Leary, Kimberly; Bylsma, Lauren M; Rottenberg, Jonathan

    2017-12-01

    Disordered sleep is strongly linked to future depression, but the reasons for this link are not well understood. This study tested one possibility - that poorer sleep impairs emotion regulation (ER), which over time leads to increased depressive symptoms. Our sample contained individuals with a wide range of depression symptoms (current depression, N = 54, remitted depression, N = 36, and healthy control, N = 53), who were followed clinically over six months and reassessed for changes in depressive symptom levels. As predicted, maladaptive ER mediated both cross-sectional and prospective relationships between poor sleep quality and depression symptoms. In contrast, an alternative mediator, physical activity levels, did not mediate the link between sleep quality and depression symptoms. Maladaptive ER may help explain why sleep difficulties contribute to depression symptoms; implications for interventions are discussed.

  4. Nonlinear optical properties of colloidal silver nanoparticles produced by laser ablation in liquids

    International Nuclear Information System (INIS)

    Karavanskii, V A; Krasovskii, V I; Ivanchenko, P V; Simakin, Aleksandr V

    2004-01-01

    The optical and nonlinear optical properties of colloidal solutions of silver obtained by laser ablation in water and ethanol are studied. It is shown that freshly prepared colloids experience a full or partial sedimentation by changing their nonlinear optical properties. Aqueous colloids undergo a partial sedimentation and their nonlinear optical absorption changes to nonlinear optical transmission. The obtained results are interpreted using the Drude model for metal particles taking the particle size into account and can be explained by the sedimentation of larger silver particles accompanied by the formation of a stable colloid containing silver nanoparticles with a tentatively silver oxide shell. The characteristic size of particles forming such a stable colloid is determined and its optical nonlinearity is estimated. (nonlinear optical phenomena)

  5. Depression following a spinal cord injury.

    Science.gov (United States)

    Boekamp, J R; Overholser, J C; Schubert, D S

    1996-01-01

    Depression is a common problem following a spinal cord injury (SCI) and can greatly interfere with the rehabilitation process because of reduced energy, negative expectations, and social withdrawal. Understanding various factors which influence a vulnerability to depression may improve the diagnosis and treatment of depressive disorders and can improve rehabilitation outcome. A thorough literature search was conducted using Medline, PsychLit, Pyschinfo, and Social Science Citation Index to identify relevant articles published between 1967 and 1995. A diathesis-stress model is proposed to explain the increased risk of depressive symptoms after a SCI. Biological changes associated with SCI and pre-existing cognitive biases may influence the individual's vulnerability to stressful life events following the injury. The nature and frequency of stressful life events following the injury can tax the individual's coping resources. Furthermore, the perceived quality of social support and the severity of conflict within the family can influence the individual's adaptation. Social support and recent stressors should be assessed to identify patients at high risk for depression. Patients are less likely to become depressed if their independence is fostered and they are encouraged to develop new sources of self-esteem. Relatives can be counseled to help maintain supportive relationships within the family.

  6. Unmasking materialistic depression as a mental health problem: its effect on depression and materialism in an African-United States undergraduate sample.

    Science.gov (United States)

    Azibo, Daudi Ajani ya

    2013-09-05

    Misdiagnosis of African-U.S. persons is argued to be a built-in characteristic of Western-based assessment requiring augmentation with culture-focused input where possible. Regarding depression, materialistic depression is explained as an African-centered African-U.S. culture-focused construct of masked depression. Materialistic depression symptomatology is presented. Materialism orientation is postulated to necessarily be associated with materialistic depression. 144 undergraduates, 37 male (25.7%) and 107 female (74.3%), average age of 21 completed the Zung Self-rating Depression Scale, the depression subscale of the Symptom Checklist 90-R, the materialism subscale of the Cultural Misorientation Scale, and the Materialistic Depression Quiz. Contrasting high versus lower scoring MDQ groups on both depression scores produced reliable t-tests (pMaterialistic Depression Quiz, high scorers versus medium and low scorers had greater depression scores on two depression measures and greater materialism scores. Materialistic depression appears a masked form of depression not to be overlooked. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Applications of nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind

    2008-01-01

    * The only book describing applications of nonlinear fiber optics * Two new chapters on the latest developments: highly nonlinear fibers and quantum applications* Coverage of biomedical applications* Problems provided at the end of each chapterThe development of new highly nonlinear fibers - referred to as microstructured fibers, holey fibers and photonic crystal fibers - is the next generation technology for all-optical signal processing and biomedical applications. This new edition has been thoroughly updated to incorporate these key technology developments.The bo

  8. Recent topics in nonlinear PDE

    International Nuclear Information System (INIS)

    Mimura, Masayasu; Nishida, Takaaki

    1984-01-01

    The meeting on the subject of nonlinear partial differential equations was held at Hiroshima University in February, 1983. Leading and active mathematicians were invited to talk on their current research interests in nonlinear pdes occuring in the areas of fluid dynamics, free boundary problems, population dynamics and mathematical physics. This volume contains the theory of nonlinear pdes and the related topics which have been recently developed in Japan. (Auth.)

  9. Testing the Temporal Relationship Between Maternal and Adolescent Depressive and Anxiety Symptoms in a Community Sample

    Science.gov (United States)

    Brown, Ruth C.; Clark, Shaunna L.; Dahne, Jennifer; Stratton, Kelcey J.; MacPherson, Laura; Lejuez, C. W.; Amstadter, Ananda B.

    2014-01-01

    Objective Transactional models have been used to explain the relationship between maternal depression and child behavioral problems; however, few studies have examined transactional models for maternal depression and adolescent depression and anxiety. Method Using an autoregressive cross-lagged analysis, we examined the longitudinal association between maternal and adolescent depression to determine the extent to which maternal depression influences adolescent depression and anxiety, and vice versa, over the course of a four-year period. Participants were a community sample of 277 mother-adolescent dyads with offspring aged 10–14 at the first year used in the analyses (43.7% female; 35% African American, 2.9% Hispanic/Latino). Depressive symptoms were assessed using maternal self-report (Center for Epidemiological Studies-Depression Scale [CESD]; Radloff, 1977), and adolescent depression and anxiety were assessed by self-report (Revised Child Anxiety and Depression Scale [RCADS]; Chorpita, Yim, Moffitt, Umemoto, & Francis, 2000). Results The final model, χ2 (14) = 23.74, p= .05; TLI= .97; CFI= .98; RMSEA= .05, indicated that maternal depression was significantly associated with adolescent depression two years later. Interestingly, adolescent depression did not significantly predict maternal depression, and the association between maternal and adolescent depression was not moderated by gender, age, or ethnicity. The association between maternal depression and adolescent anxiety was weaker than that observed for adolescent depression. Conclusions Results suggest that the transaction model of maternal depression may not extend to adolescent depression and anxiety. Furthermore, maternal depression can have an enduring effect on adolescent depression and continued research and clinical monitoring over extended periods of time is warranted. PMID:24702257

  10. Ship-induced solitary Riemann waves of depression in Venice Lagoon

    International Nuclear Information System (INIS)

    Parnell, Kevin E.; Soomere, Tarmo; Zaggia, Luca; Rodin, Artem; Lorenzetti, Giuliano; Rapaglia, John; Scarpa, Gian Marco

    2015-01-01

    We demonstrate that ships of moderate size, sailing at low depth Froude numbers (0.37–0.5) in a navigation channel surrounded by shallow banks, produce depressions with depths up to 2.5 m. These depressions (Bernoulli wakes) propagate as long-living strongly nonlinear solitary Riemann waves of depression substantial distances into Venice Lagoon. They gradually become strongly asymmetric with the rear of the depression becoming extremely steep, similar to a bore. As they are dynamically similar, air pressure fluctuations moving over variable-depth coastal areas could generate meteorological tsunamis with a leading depression wave followed by a devastating bore-like feature. - Highlights: • Unprecedently deep long-living ship-induced waves of depression detected. • Such waves are generated in channels with side banks under low Froude numbers. • The propagation of these waves is replicated using Riemann waves. • Long-living waves of depression form bore-like features at rear slope

  11. Ship-induced solitary Riemann waves of depression in Venice Lagoon

    Energy Technology Data Exchange (ETDEWEB)

    Parnell, Kevin E. [College of Marine and Environmental Sciences and Centre for Tropical Environmental and Sustainability Sciences, James Cook University, Queensland 4811 (Australia); Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn (Estonia); Soomere, Tarmo, E-mail: soomere@cs.ioc.ee [Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn (Estonia); Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn (Estonia); Zaggia, Luca [Institute of Marine Sciences, National Research Council, Castello 2737/F, 30122 Venice (Italy); Rodin, Artem [Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn (Estonia); Lorenzetti, Giuliano [Institute of Marine Sciences, National Research Council, Castello 2737/F, 30122 Venice (Italy); Rapaglia, John [Sacred Heart University Department of Biology, 5151 Park Avenue, Fairfield, CT 06825 (United States); Scarpa, Gian Marco [Università Ca' Foscari, Dorsoduro 3246, 30123 Venice (Italy)

    2015-03-06

    We demonstrate that ships of moderate size, sailing at low depth Froude numbers (0.37–0.5) in a navigation channel surrounded by shallow banks, produce depressions with depths up to 2.5 m. These depressions (Bernoulli wakes) propagate as long-living strongly nonlinear solitary Riemann waves of depression substantial distances into Venice Lagoon. They gradually become strongly asymmetric with the rear of the depression becoming extremely steep, similar to a bore. As they are dynamically similar, air pressure fluctuations moving over variable-depth coastal areas could generate meteorological tsunamis with a leading depression wave followed by a devastating bore-like feature. - Highlights: • Unprecedently deep long-living ship-induced waves of depression detected. • Such waves are generated in channels with side banks under low Froude numbers. • The propagation of these waves is replicated using Riemann waves. • Long-living waves of depression form bore-like features at rear slope.

  12. Childhood abuse and late-life depression: Mediating effects of psychosocial factors for early- and late-onset depression.

    Science.gov (United States)

    Wielaard, Ilse; Hoyer, Mathijs; Rhebergen, Didi; Stek, Max L; Comijs, Hannie C

    2018-03-01

    Childhood abuse makes people vulnerable to developing depression, even in late life. Psychosocial factors that are common in late life, such as loneliness or lack of a partner, may explain this association. Our aim was to investigate whether the association between childhood abuse and depression in older adults can be explained by psychosocial factors. Cross-sectional data were derived from the Netherlands Study of Depression in Older Persons (aged 60-93), including 132 without lifetime depression, 242 persons with an early-onset depression (Childhood abuse (yes/no) and a frequency-based childhood abuse index were included. Multinomial regression and multivariable mediation analyses were used to examine the association between childhood abuse and the onset of depression, and the influence of loneliness, social network, and partner status. Multinomial regression analyses showed a significant association between childhood abuse and the childhood abuse index with early- and late-onset depression. Multivariable mediation analyses showed that the association between childhood abuse and early-onset depression was partly mediated by social network size and loneliness. This was particularly present for emotional neglect and psychological abuse, but not for physical and sexual abuse. No psychosocial mediators were found for the association between childhood abuse and late-onset depression. A smaller social network and feelings of loneliness mediate the association between childhood abuse and early-onset depression in older adults. Our findings show the importance of detecting childhood abuse as well as the age at depression onset and mapping of relevant psychosocial factors in the treatment of late-life depression. Copyright © 2018 John Wiley & Sons, Ltd.

  13. Nonlinear Waves in Complex Systems

    DEFF Research Database (Denmark)

    2007-01-01

    The study of nonlinear waves has exploded due to the combination of analysis and computations, since the discovery of the famous recurrence phenomenon on a chain of nonlinearly coupled oscillators by Fermi-Pasta-Ulam fifty years ago. More than the discovery of new integrable equations, it is the ......The study of nonlinear waves has exploded due to the combination of analysis and computations, since the discovery of the famous recurrence phenomenon on a chain of nonlinearly coupled oscillators by Fermi-Pasta-Ulam fifty years ago. More than the discovery of new integrable equations...

  14. Problems in nonlinear resistive MHD

    International Nuclear Information System (INIS)

    Turnbull, A.D.; Strait, E.J.; La Haye, R.J.; Chu, M.S.; Miller, R.L.

    1998-01-01

    Two experimentally relevant problems can relatively easily be tackled by nonlinear MHD codes. Both problems require plasma rotation in addition to the nonlinear mode coupling and full geometry already incorporated into the codes, but no additional physics seems to be crucial. These problems discussed here are: (1) nonlinear coupling and interaction of multiple MHD modes near the B limit and (2) nonlinear coupling of the m/n = 1/1 sawtooth mode with higher n gongs and development of seed islands outside q = 1

  15. Prosocial Behavior and Depression: a Case for Developmental Gender Differences.

    Science.gov (United States)

    Alarcón, Gabriela; Forbes, Erika E

    2017-06-01

    Prosocial behavior and depression are related constructs that both increase during adolescence and display gender-specific effects. The current review surveys literature examining the association between depressive symptoms and prosociality, measured with behavioral economic paradigms, across development and proposes a theoretical model explaining a mechanism through which adolescent girls have higher risk for depression than boys. Relative to healthy controls, prosocial behavior is reduced in adults with major depressive disorder (MDD) but may be increased in adolescents with MDD. The relationship between non-clinical levels of depressive symptoms and prosocial behavior remains to be studied experimentally; however, self-reported prosocial behavior is negatively associated with depressive symptoms in non-clinical adolescents, which may suggest a shift in the relation of prosocial behavior and depressive symptoms across the non-clinical (i.e., negative) to clinical range (i.e., positive). The effect of gender on these developmental and clinical status shifts has not been studied but could have important implications for understanding the emergence of higher rates of depression in girls than boys during adolescence. We propose that girls are at heightened risk for depression due to higher social-evaluative concern and other-oriented prosocial motivation that emphasize the needs of others over the self, leading to more altruistic prosocial behavior (despite personal cost) and a higher burden that enables depressive symptoms.

  16. Ethnic Variation in the Cross-sectional Association between Domains of Depressive Symptoms and Clinical Depression

    Directory of Open Access Journals (Sweden)

    Shervin eAssari

    2016-04-01

    Full Text Available BackgroundThe degree by which depressive symptoms and clinical depression reflect each other may vary across populations. The present study compared Blacks and Whites for the magnitude of the cross-sectional associations between various domains of depressive symptoms and endorsement of clinical disorders of depression. MethodsData came from the National Survey of American Life (NSAL, 2001–2003. We included 3,570 Black (African Americans, and 891 Non-Hispanic Whites. Predictors were positive affect, negative affect, and interpersonal problems measured using the 12-item Center for Epidemiologic Studies Depression Scale (CES-D. Outcomes were lifetime MDD, lifetime MDE, 12 month MDE, 30 days MDE, and 30 days MDDH based on the Composite International Diagnostic Interview (CIDI. Logistic regression models were applied in the pooled sample, as well as Blacks and Whites.ResultsRegarding CES-D, Blacks had lower total scores, positive affect, negative affect, and interpersonal problems compared to Whites (p < 0.05 for all comparisons. Blacks also had lower odds of meeting criteria for lifetime MDD and MDE, 12 month MDE, and 30 days MDE and MDDH (p < 0.05 for all comparisons. For most depressive diagnoses, ethnicity showed a positive and significant interaction with the negative affect and interpersonal domains, suggesting stronger associations for Blacks compared to Whites. CES-D total and CES-D positive affect did not interact with ethnicity on CIDI based diagnoses.ConclusionStronger associations between multiple domains of depressive symptoms and clinical MDD may be due to higher severity of depression among Blacks, when they endorse the disorder. This finding may explain some of previously observed ethnic differences in social, psychological, and medical correlates of depressive symptoms and clinical depression in the general population as well as clinical settings.

  17. Nonlinear calculations for bump Cepheids

    International Nuclear Information System (INIS)

    Hodson, S.W.; Cox, A.N.

    1979-01-01

    Hydrodynamic calculations to find strictly periodic solutions for the fundamental mode pulsations of 7 M/sub sun/ models were made using the von Sengbusch--Stellingwerf relaxation method. The models have a helium enrichment in the surface convection zones to Y = 0.78, which from the linear theory period ratio π 2 /π 0 and the Simon and Schmidt resonance hypothesis, should give the observed Hertzsprung progression of light and velocity curve bump phase with period. These surface helium enhanced models show the proper nonlinear bump phase behavior without resort to any mass loss before or during the blue loop phases of yellow giant evolution. At 6000 K and the evolution theory luminosity of 4744 L/sub sun/ for 7 M/sub sun/, that is, at a fundamental mode period of 8.5 day, the velocity curve bump is well after the maximum expansion velocity. At 5400 K and at the same luminosity (period of 12.5 days), there is a bump on the velocity curve well before maximum expansion velocity time. The latter case seems to exhibit the Christy echos but not the former. The echo interpretation may not be appropriate for these masses which are larger than the anomalous masses used by Christy, Stobie, and Adams. Resonance of the fundamental and second overtone modes should not necessarily show echos of surface disturbances from the center. The conclusion is that helium enrichment in the surface convection zones can adequately explain observations of bump Cepheids at evolution theory masses. 12 references

  18. Do changes in connectivity explain desertification?

    Science.gov (United States)

    Desertification, broad-scale land degradation in drylands, is a major environmental hazard facing inhabitants of the world’s deserts as well as an important component of global change. There is no unifying framework that simply and effectively explains different forms of desertification. Here we arg...

  19. Can the inherence heuristic explain vitalistic reasoning?

    Science.gov (United States)

    Bastian, Brock

    2014-10-01

    Inherence is an important component of psychological essentialism. By drawing on vitalism as a way in which to explain this link, however, the authors appear to conflate causal explanations based on fixed features with those based on general causal forces. The disjuncture between these two types of explanatory principles highlights potential new avenues for the inherence heuristic.

  20. Explaining probalistic risk assessment in common language

    International Nuclear Information System (INIS)

    Wong, J.W.

    1994-01-01

    Probabilistic human health risk assessment is explained in ordinary language using a hypothetical example and the ingestion equation from EPA's Risk Assessment Guidance for Superfund. A section on understanding probabilities and probability distributions used in a Monte Carlo simulation is included as well as an appendix showing the computer run and the technical assumptions behind it

  1. Explaining Violence in Sierra Leone's Civil War

    African Journals Online (AJOL)

    Explaining the violence of civil war is never a simple task for the scholar. In the case of the Sierra Leone, paradoxically, the task has in some ways been rendered more difficult by the sheer variety of compelling scholarship on the question. This paper seeks to identify the most useful of the explanations offered thus far, and ...

  2. Measuring and explaining house price developments

    NARCIS (Netherlands)

    De Vries, P.

    2010-01-01

    This study discusses ways of measuring and explaining the development of house prices. The goal of the research underpinning this dissertation was to develop a methodological framework for studying these developments. This framework relates, first, to correcting for changes in the composition of

  3. Adaptive hatching hypotheses do not explain asynchronous ...

    African Journals Online (AJOL)

    At the core of the suite of adaptive hatching hypotheses advanced to explain asynchronous hatching in birds is the assumption that if food is not limited then all the hatchlings will develop normally to adulthood. In this study Brown-headed Parrot Poicephalus cryptoxanthus chicks were hand fed and weighed on a daily basis.

  4. Explaining convergence of oecd welfare states

    DEFF Research Database (Denmark)

    Schmitt, C.; Starke, Peter

    2011-01-01

    of conditional convergence helps to both better describe and explain the phenomenon. By applying error correction models, we examine conditional convergence of various types of social expenditure in 21 OECD countries between 1980 and 2005. Our empirical findings go beyond the existing literature in two respects...

  5. Explaining the VET Applied Research Developmental Framework

    Science.gov (United States)

    Simon, Linda; Beddie, Francesca M.

    2017-01-01

    This document explains the VET Applied Research Developmental Framework, created as part of a project that explored how the vocational education and training (VET) sector could broaden its engagement in Australia's research and development (R&D) and innovation systems. Achieving this engagement will rely significantly on building the…

  6. Explaining Teachers' Use of Textbooks

    Science.gov (United States)

    Reichenberg, Monica

    2016-01-01

    In educational systems without comprehensive systems for regulating textbooks, teachers can exert considerable influence on the use of textbooks. However, existing research has not yet identified the mechanisms of this use. Accordingly, the aim of this article is to examine and explain teachers' strategic use of textbooks. I administered a…

  7. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot ... I’d like to talk with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA ...

  8. Nonlinear Response of Strong Nonlinear System Arisen in Polymer Cushion

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2013-01-01

    Full Text Available A dynamic model is proposed for a polymer foam-based nonlinear cushioning system. An accurate analytical solution for the nonlinear free vibration of the system is derived by applying He's variational iteration method, and conditions for resonance are obtained, which should be avoided in the cushioning design.

  9. Depression in Hemodialysis Patients

    Directory of Open Access Journals (Sweden)

    Badema Čengić

    2010-04-01

    Full Text Available Depression is the most frequent psychological complication of haemodialysis (HD patients (pts and has been associated with impaired Quality of Life (QoL. The aim of our study was to investigate the prevalence of depression in HD pts in relation to sociodemographic factors and the relationship between depression and QoL.200 pts from Clinic for haemodialysis in Sarajevo, B&H were participating in the study. Mean age was S7,26±13,78 years and mean HD duration was 64’26±58,18 months. From the test material we applied BDI and SF-36.51% of our pts have shown depression (BDI>11 in various degrees (30%-mild depression, 8,5%-moderate depression and 12,5%-severe depression. As we could expect, the most emphasized symptoms of depression were somatic symptoms. 55,5% of pts have shown QoL lower then average. Sociodemographic data such as gender, marital status and HD duration did not influence significantly on pt’s QoL and occurrence of depression (p>0,05. As the age of the pts increased, level of depression increased too and QoL significantly decreased (p<0,05. Employed pts have shown significantly better QoL and lower level of depression in relation to unemployed pts (p<0,05. As the educational level of pts increased, QoL increased too and level of depression significantly decreased (p<0,05. Pts in 1st HD shift were significantly more depressed and have significantly worse mental health in compare to pts in 3rd HD shift (p<0,05. Our results showed a high prevalence of depressive symptoms among the study group that was linked to trend of poor QoL.

  10. Nonlinear aspects of structural fatigue damage assessment and accumulation

    International Nuclear Information System (INIS)

    Leis, B.N.

    1977-01-01

    The present paper reviews a recently developed concept for structural fatigue analysis which is capable of accounting for nonlinearities in both the above noted transformations. It is shown that, for cases where the local stressing and straining is proportional, the multiplicity of initiation sites and mechanisms observed to dominate structural fatigue resistance can be explained in terms of these additional nonlinearities. The ability of current concepts for structural fatigue analysis which account for nonlinear action to handle situaions where nonproportional stressing occurs in fatigue critical locations is next examined. Limitations in the assumptions made in fatigue analysis are shown to essentially preclude the application of present technology to that class of problems. A new approach whereby the present fatigue analysis procedures based on a deformation-type plasticity analysis can be extended to handle the nonproportional cycling by their application on a 'memory event' by 'memory event' basis is postulated and discussed in the context of a simple component

  11. Perspectives on Nonlinear Filtering

    KAUST Repository

    Law, Kody

    2015-01-01

    The solution to the problem of nonlinear filtering may be given either as an estimate of the signal (and ideally some measure of concentration), or as a full posterior distribution. Similarly, one may evaluate the fidelity of the filter either by its ability to track the signal or its proximity to the posterior filtering distribution. Hence, the field enjoys a lively symbiosis between probability and control theory, and there are plenty of applications which benefit from algorithmic advances, from signal processing, to econometrics, to large-scale ocean, atmosphere, and climate modeling. This talk will survey some recent theoretical results involving accurate signal tracking with noise-free (degenerate) dynamics in high-dimensions (infinite, in principle, but say d between 103 and 108 , depending on the size of your application and your computer), and high-fidelity approximations of the filtering distribution in low dimensions (say d between 1 and several 10s).

  12. Nonlinear Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Hansen, Kim Per

    2004-01-01

    Despite the general recession in the global economy and the collapse of the optical telecommunication market, research within specialty fibers is thriving. This is, more than anything else, due to the technology transition from standard all-glass fibers to photonic crystal fibers, which, instead....... The freedom to design the dispersion profile of the fibers is much larger and it is possible to create fibers, which support only a single spatial mode, regardless of wavelength. In comparison, the standard dispersion-shifted fibers are limited by a much lower index-contrast between the core and the cladding...... in 1996, and are today on their way to become the dominating technology within the specialty fiber field. Whether they will replace the standard fiber in the more traditional areas like telecommunication transmission, is not yet clear, but the nonlinear photonic crystal fibers are here to stay....

  13. Nonlinear estimation and classification

    CERN Document Server

    Hansen, Mark; Holmes, Christopher; Mallick, Bani; Yu, Bin

    2003-01-01

    Researchers in many disciplines face the formidable task of analyzing massive amounts of high-dimensional and highly-structured data This is due in part to recent advances in data collection and computing technologies As a result, fundamental statistical research is being undertaken in a variety of different fields Driven by the complexity of these new problems, and fueled by the explosion of available computer power, highly adaptive, non-linear procedures are now essential components of modern "data analysis," a term that we liberally interpret to include speech and pattern recognition, classification, data compression and signal processing The development of new, flexible methods combines advances from many sources, including approximation theory, numerical analysis, machine learning, signal processing and statistics The proposed workshop intends to bring together eminent experts from these fields in order to exchange ideas and forge directions for the future

  14. Nonlinear Water Waves

    CERN Document Server

    2016-01-01

    This volume brings together four lecture courses on modern aspects of water waves. The intention, through the lectures, is to present quite a range of mathematical ideas, primarily to show what is possible and what, currently, is of particular interest. Water waves of large amplitude can only be fully understood in terms of nonlinear effects, linear theory being not adequate for their description. Taking advantage of insights from physical observation, experimental evidence and numerical simulations, classical and modern mathematical approaches can be used to gain insight into their dynamics. The book presents several avenues and offers a wide range of material of current interest. Due to the interdisciplinary nature of the subject, the book should be of interest to mathematicians (pure and applied), physicists and engineers. The lectures provide a useful source for those who want to begin to investigate how mathematics can be used to improve our understanding of water wave phenomena. In addition, some of the...

  15. Perspectives on Nonlinear Filtering

    KAUST Repository

    Law, Kody

    2015-01-07

    The solution to the problem of nonlinear filtering may be given either as an estimate of the signal (and ideally some measure of concentration), or as a full posterior distribution. Similarly, one may evaluate the fidelity of the filter either by its ability to track the signal or its proximity to the posterior filtering distribution. Hence, the field enjoys a lively symbiosis between probability and control theory, and there are plenty of applications which benefit from algorithmic advances, from signal processing, to econometrics, to large-scale ocean, atmosphere, and climate modeling. This talk will survey some recent theoretical results involving accurate signal tracking with noise-free (degenerate) dynamics in high-dimensions (infinite, in principle, but say d between 103 and 108 , depending on the size of your application and your computer), and high-fidelity approximations of the filtering distribution in low dimensions (say d between 1 and several 10s).

  16. Analysis, control and optimal operations in hybrid power systems advanced techniques and applications for linear and nonlinear systems

    CERN Document Server

    Bizon, Nicu; Mahdavi Tabatabaei, Naser

    2014-01-01

    This book explains and analyzes the dynamic performance of linear and nonlinear systems, particularly for Power Systems including Hybrid Power Sources. Offers a detailed description of system stability using state space energy conservation principle, and more.

  17. Wave transmission in nonlinear lattices

    International Nuclear Information System (INIS)

    Hennig, D.; Tsironis, G.P.

    1999-01-01

    The interplay of nonlinearity with lattice discreteness leads to phenomena and propagation properties quite distinct from those appearing in continuous nonlinear systems. For a large variety of condensed matter and optics applications the continuous wave approximation is not appropriate. In the present review we discuss wave transmission properties in one dimensional nonlinear lattices. Our paradigmatic equations are discrete nonlinear Schroedinger equations and their study is done through a dynamical systems approach. We focus on stationary wave properties and utilize well known results from the theory of dynamical systems to investigate various aspects of wave transmission and wave localization. We analyze in detail the more general dynamical system corresponding to the equation that interpolates between the non-integrable discrete nonlinear Schroedinger equation and the integrable Albowitz-Ladik equation. We utilize this analysis in a nonlinear Kronig-Penney model and investigate transmission and band modification properties. We discuss the modifications that are effected through an electric field and the nonlinear Wannier-Stark localization effects that are induced. Several applications are described, such as polarons in one dimensional lattices, semiconductor superlattices and one dimensional nonlinear photonic band gap systems. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  18. Solving Nonlinear Coupled Differential Equations

    Science.gov (United States)

    Mitchell, L.; David, J.

    1986-01-01

    Harmonic balance method developed to obtain approximate steady-state solutions for nonlinear coupled ordinary differential equations. Method usable with transfer matrices commonly used to analyze shaft systems. Solution to nonlinear equation, with periodic forcing function represented as sum of series similar to Fourier series but with form of terms suggested by equation itself.

  19. Nonlinear Elasticity of Doped Semiconductors

    Science.gov (United States)

    2017-02-01

    AFRL-RY-WP-TR-2016-0206 NONLINEAR ELASTICITY OF DOPED SEMICONDUCTORS Mark Dykman and Kirill Moskovtsev Michigan State University...2016 4. TITLE AND SUBTITLE NONLINEAR ELASTICITY OF DOPED SEMICONDUCTORS 5a. CONTRACT NUMBER FA8650-16-1-7600 5b. GRANT NUMBER 5c. PROGRAM...vibration amplitude. 15. SUBJECT TERMS semiconductors , microresonators, microelectromechanical 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  20. Nonlinear evolution of MHD instabilities

    International Nuclear Information System (INIS)

    Bateman, G.; Hicks, H.R.; Wooten, J.W.; Dory, R.A.

    1975-01-01

    A 3-D nonlinear MHD computer code was used to study the time evolution of internal instabilities. Velocity vortex cells are observed to persist into the nonlinear evolution. Pressure and density profiles convect around these cells for a weak localized instability, or convect into the wall for a strong instability. (U.S.)

  1. Nonlinear theory of elastic shells

    International Nuclear Information System (INIS)

    Costa Junior, J.A.

    1979-08-01

    Nonlinear theory of elastic shells is developed which incorporates both geometric and physical nonlinearities and which does not make use of the well known Love-Kirchhoff hypothesis. The resulting equations are formulated in tensorial notation and are reduced to the ones of common use when simplifying assumptions encountered in the especific litterature are taken. (Author) [pt

  2. Balancing for Unstable Nonlinear Systems

    NARCIS (Netherlands)

    Scherpen, J.M.A.

    1993-01-01

    A previously obtained method of balancing for stable nonlinear systems is extended to unstable nonlinear systems. The similarity invariants obtained by the concept of LQG balancing for an unstable linear system can also be obtained by considering a past and future energy function of the system. By

  3. Causal Inference and Explaining Away in a Spiking Network

    Science.gov (United States)

    Moreno-Bote, Rubén; Drugowitsch, Jan

    2015-01-01

    While the brain uses spiking neurons for communication, theoretical research on brain computations has mostly focused on non-spiking networks. The nature of spike-based algorithms that achieve complex computations, such as object probabilistic inference, is largely unknown. Here we demonstrate that a family of high-dimensional quadratic optimization problems with non-negativity constraints can be solved exactly and efficiently by a network of spiking neurons. The network naturally imposes the non-negativity of causal contributions that is fundamental to causal inference, and uses simple operations, such as linear synapses with realistic time constants, and neural spike generation and reset non-linearities. The network infers the set of most likely causes from an observation using explaining away, which is dynamically implemented by spike-based, tuned inhibition. The algorithm performs remarkably well even when the network intrinsically generates variable spike trains, the timing of spikes is scrambled by external sources of noise, or the network is mistuned. This type of network might underlie tasks such as odor identification and classification. PMID:26621426

  4. Factors Influencing Depression and Anxiety among Black Sexual Minority Men

    Directory of Open Access Journals (Sweden)

    Louis F. Graham

    2011-01-01

    Full Text Available The primary aim of this study was to examine the relationships between depression and anxiety, and ethnic and sexual identity development, and discrimination and harassment (DH among Black sexual minority men. Additional aims were to determine whether an interaction effect existed between ethnic and sexual identity and whether coping skills level moderated these relationships. Using an observational cross-sectional design, 54 participants recruited through snowball sampling completed self-administered online surveys. Stepwise multiple regression analysis was used. Sixty-four percent of the variance in depression scores and 53% of the variance in anxiety scores were explained by DH and internalized homonegativity together. Thirty percent of the sample had scale scores indicating likelihood of depression and anxiety. Experience of DH and internalized homonegativity explained a large portion of the variability in depression and anxiety among Black sexual minority men. The study showed high prevalence of mental distress among this sample.

  5. Nonlinear hyperbolic waves in multidimensions

    CERN Document Server

    Prasad, Phoolan

    2001-01-01

    The propagation of curved, nonlinear wavefronts and shock fronts are very complex phenomena. Since the 1993 publication of his work Propagation of a Curved Shock and Nonlinear Ray Theory, author Phoolan Prasad and his research group have made significant advances in the underlying theory of these phenomena. This volume presents their results and provides a self-contained account and gradual development of mathematical methods for studying successive positions of these fronts.Nonlinear Hyperbolic Waves in Multidimensions includes all introductory material on nonlinear hyperbolic waves and the theory of shock waves. The author derives the ray theory for a nonlinear wavefront, discusses kink phenomena, and develops a new theory for plane and curved shock propagation. He also derives a full set of conservation laws for a front propagating in two space dimensions, and uses these laws to obtain successive positions of a front with kinks. The treatment includes examples of the theory applied to converging wavefronts...

  6. Cubication of conservative nonlinear oscillators

    International Nuclear Information System (INIS)

    Belendez, Augusto; Alvarez, Mariela L; Fernandez, Elena; Pascual, Inmaculada

    2009-01-01

    A cubication procedure of the nonlinear differential equation for conservative nonlinear oscillators is analysed and discussed. This scheme is based on the Chebyshev series expansion of the restoring force, and this allows us to approximate the original nonlinear differential equation by a Duffing equation in which the coefficients for the linear and cubic terms depend on the initial amplitude, A, while in a Taylor expansion of the restoring force these coefficients are independent of A. The replacement of the original nonlinear equation by an approximate Duffing equation allows us to obtain an approximate frequency-amplitude relation as a function of the complete elliptic integral of the first kind. Some conservative nonlinear oscillators are analysed to illustrate the usefulness and effectiveness of this scheme.

  7. Explaining money creation by commercial banks

    DEFF Research Database (Denmark)

    Ravn, Ib

    2015-01-01

    Educators and economists concerned with monetary reform face the extraordinary challenge of explaining to the public and its elected representatives not only what a reformed system would look like, but also how the current system works. Centrally, the point that in a modern economy money is largely...... created by commercial banks, as explained by the Bank of England recently (McLeay, Radia & Thomas, 2014b), is often met with incredulity: “What do you mean, created?” This paper introduces five easy-to-grasp analogies that educators and reformers may use to convey key money-creation concepts to a lay...... audience. The analogies offered include (1) money as patches in an expandable patchwork quilt that covers a nation’s real assets, (2) the money supply as water in a bathtub with a faucet and a drain, (3) money understood as debt in a model economy run by schoolchildren, (4) the misleading concept of a bank...

  8. HIV As Trojan Exosome: Immunological Paradox Explained?

    Science.gov (United States)

    Hildreth, James E K

    2017-01-01

    The HIV pandemic is still a major global challenge, despite the widespread availability of antiretroviral drugs. An effective vaccine would be the ideal approach to bringing the pandemic to an end. However, developing an effective HIV vaccine has proven to be an elusive goal. Three major human HIV vaccine trials revealed a strong trend toward greater risk of infection among vaccine recipients versus controls. A similar observation was made in a macaque SIV vaccine study. The mechanism explaining this phenomenon is not known. Here, a model is presented that may explain the troubling results of vaccine studies and an immunological paradox of HIV pathogenesis: preferential infection of HIV-specific T cells. The central hypothesis of this perspective is that as "Trojan exosomes" HIV particles can directly activate HIV-specific T cells enhancing their susceptibility to infection. Understanding the biology of HIV as an exosome may provide insights that enable novel approaches to vaccine development.

  9. Children's Theories and the Drive to Explain

    Science.gov (United States)

    Schwitzgebel, Eric

    Debate has been growing in developmental psychology over how much the cognitive development of children is like theory change in science. Useful debate on this topic requires a clear understanding of what it would be for a child to have a theory. I argue that existing accounts of theories within philosophy of science and developmental psychology either are less precise than is ideal for the task or cannot capture everyday theorizing of the sort that children, if they theorize, must do. I then propose an account of theories that ties theories and explanation very closely together, treating theories primarily as products of a drive to explain. I clarify some of the positions people have taken regarding the theory theory of development, and I conclude by proposing that psychologists interested in the ''theory theory'' look for patterns of affect and arousal in development that would accompany the existence of a drive to explain.

  10. Explaining the Allocation of Regional Structural Funds

    DEFF Research Database (Denmark)

    Charron, Nicholas

    2016-01-01

    What regional factors can explain the heterogeneity in Structural Funds distribution to European Union regions? Past studies have shown that aside from the level of economic development and rates of unemployment, other political, and economic factors systematically explain why certain European...... Union regions receive greater funding than others, in particular where there is room for bargaining. In this article, a novel theory is posited which argues that the determination of Structural Funds is based on an interaction between a region’s formal institutions (the level of a regional autonomy......) and informal institutions (its level of quality of government). In cases of low regional autonomy, member states and European Union level actors prefer to allocate greater levels of Funds to regions with lower quality of government in order to increase cohesion. Yet in cases of high regional autonomy, risks...

  11. Social processes explaining the benefits of Al-Anon participation.

    Science.gov (United States)

    Timko, Christine; Halvorson, Max; Kong, Calvin; Moos, Rudolf H

    2015-12-01

    This study examined social processes of support, goal direction, provision of role models, and involvement in rewarding activities to explain benefits of participating in Al-Anon, a 12-step mutual-help program for people concerned about another person's substance use. Newcomers to Al-Anon were studied at baseline and 6 months later, at which time they were identified as having either sustained attendance or dropped out. Among both newcomers and established Al-Anon members ("old-timers"), we also used number of Al-Anon meetings attended during follow-up to indicate extent of participation. Social processes significantly mediated newcomers' sustained attendance status versus dropped out and outcomes of Al-Anon in the areas of life context (e.g., better quality of life, better able to handle problems due to the drinker), improved positive symptoms (e.g., higher self-esteem, more hopeful), and decreased negative symptoms (e.g., less abuse, less depressed). Social processes also significantly mediated newcomers' number of meetings attended and outcomes. However, among old-timers, Al-Anon attendance was not associated with outcomes, so the potential mediating role of social processes could not be examined, but social processes were associated with outcomes. Findings add to the growing body of work identifying mechanisms by which 12-step groups are effective, by showing that bonding, goal direction, and access to peers in recovery and rewarding pursuits help to explain associations between sustained Al-Anon participation among newcomers and improvements on key concerns of Al-Anon attendees. Al-Anon is free of charge and widely available, making it a potentially cost-effective public health resource for help alleviating negative consequences of concern about another's addiction. (c) 2016 APA, all rights reserved).

  12. IEE wiring regulations explained and illustrated

    CERN Document Server

    Scaddan, Brian

    2013-01-01

    The IEE Wiring Regulations Explained and Illustrated, Second Edition discusses the recommendations of the IEE Regulations for the Electrical Equipment of Buildings for the safe selection or erection of wiring installations. The book emphasizes earthing, bonding, protection, and circuit design of electrical wirings. The text reviews the fundamental requirements for safety, earthing systems, the earth fault loop impedance, and supplementary bonding. The book also describes the different types of protection, such as protection against mechanical damage, overcurrent, under voltage (which prevents

  13. A More Practical Method for Explaining Equilibrium

    OpenAIRE

    Yi-Jang Yu

    2014-01-01

    The aim of this study is to suggest a more practical method for explaining market equilibrium in a two-dimensional risk-return world. Its main difference from textbook contents is to define, in both qualitative and quantitative ways, the environment or the system factor and treat it as an endogenous variable. Once the two-dimensional framework that is capable of managing uncertainty and environmental relationship can be reasonably established, a greater number of economic issues can be effect...

  14. "Explaining the Gender Wage Gap in Georgia"

    OpenAIRE

    Tamar Khitarishvili

    2009-01-01

    This paper evaluates gender wage differentials in Georgia between 2000 and 2004. Using ordinary least squares, we find that the gender wage gap in Georgia is substantially higher than in other transition countries. Correcting for sample selection bias using the Heckman approach further increases the gender wage gap. The Blinder Oaxaca decomposition results suggest that most of the wage gap remains unexplained. The explained portion of the gap is almost entirely attributed to industrial variab...

  15. Explaining seeing? Disentangling qualia from perceptual organization.

    Science.gov (United States)

    Ibáñez, Agustin; Bekinschtein, Tristan

    2010-09-01

    Abstract Visual perception and integration seem to play an essential role in our conscious phenomenology. Relatively local neural processing of reentrant nature may explain several visual integration processes (feature binding or figure-ground segregation, object recognition, inference, competition), even without attention or cognitive control. Based on the above statements, should the neural signatures of visual integration (via reentrant process) be non-reportable phenomenological qualia? We argue that qualia are not required to understand this perceptual organization.

  16. PREFACE Integrability and nonlinear phenomena Integrability and nonlinear phenomena

    Science.gov (United States)

    Gómez-Ullate, David; Lombardo, Sara; Mañas, Manuel; Mazzocco, Marta; Nijhoff, Frank; Sommacal, Matteo

    2010-10-01

    Back in 1967, Clifford Gardner, John Greene, Martin Kruskal and Robert Miura published a seminal paper in Physical Review Letters which was to become a cornerstone in the theory of integrable systems. In 2006, the authors of this paper received the AMS Steele Prize. In this award the AMS pointed out that `In applications of mathematics, solitons and their descendants (kinks, anti-kinks, instantons, and breathers) have entered and changed such diverse fields as nonlinear optics, plasma physics, and ocean, atmospheric, and planetary sciences. Nonlinearity has undergone a revolution: from a nuisance to be eliminated, to a new tool to be exploited.' From this discovery the modern theory of integrability bloomed, leading scientists to a deep understanding of many nonlinear phenomena which is by no means reachable by perturbation methods or other previous tools from linear theories. Nonlinear phenomena appear everywhere in nature, their description and understanding is therefore of great interest both from the theoretical and applicative point of view. If a nonlinear phenomenon can be represented by an integrable system then we have at our disposal a variety of tools to achieve a better mathematical description of the phenomenon. This special issue is largely dedicated to investigations of nonlinear phenomena which are related to the concept of integrability, either involving integrable systems themselves or because they use techniques from the theory of integrability. The idea of this special issue originated during the 18th edition of the Nonlinear Evolution Equations and Dynamical Systems (NEEDS) workshop, held at Isola Rossa, Sardinia, Italy, 16-23 May 2009 (http://needs-conferences.net/2009/). The issue benefits from the occasion offered by the meeting, in particular by its mini-workshops programme, and contains invited review papers and contributed papers. It is worth pointing out that there was an open call for papers and all contributions were peer reviewed

  17. Comparison of depression symptoms between primary depression and secondary-to-schizophrenia depression.

    Science.gov (United States)

    Rahim, Twana; Rashid, Roshe

    2017-11-01

    This study exclusively aimed to clinically assess which symptom pattern discriminates primary depression from depression-secondary to-schizophrenia. A total of 98 patients with primary depression and 71 patients with secondary-to-schizophrenia depression were assessed for identifying the clinical phenomena of depression. Diagnosis of schizophrenia was confirmed by Mini International Neuropsychiatric Interview. Each participant was, however, assessed by Patient Health Questionnaire-9 as well as Calgary Depression Scale for Schizophrenia (CDSS) for possible concurrent depressive symptoms. Depressed mood, loss of interest, reduced energy and pathological guilt were more common in primary depression, whereas sleep disturbance and guilty ideas of reference were more amounting towards the diagnosis of depression secondary-to-schizophrenia. It is clinically hard to differentiate primary from secondary-to-schizophrenia depression, especially in the absence of obvious psychotic symptoms. However, the classical symptoms of depression like subjective depressed mood, anhedonia, reduced energy and pathological guilt are more prominent in the primary depression.

  18. Big Five personality characteristics are associated with depression subtypes and symptom dimensions of depression in older adults.

    Science.gov (United States)

    Koorevaar, A M L; Hegeman, J M; Lamers, F; Dhondt, A D F; van der Mast, R C; Stek, M L; Comijs, H C

    2017-12-01

    This study examined the associations of personality characteristics with both subtypes and symptom dimensions of depression in older adults. Three hundred and seventy-eight depressed older adults participated in the Netherlands Study of Depression in Older Persons. Personality characteristics were assessed by the NEO-Five Factor Inventory. Subtypes and symptom dimensions of depression were determined using the Composite International Diagnostic Interview and the Inventory of Depressive Symptomatology (IDS). Multinomial logistic regression analyses were performed to examine the associations between personality and atypical, melancholic, and unspecified subtypes of major depression. Linear regression analyses examined the associations between personality and the IDS mood, somatic, and motivation symptom dimensions. The analyses were adjusted for confounders and additionally adjusted for depression severity. Neuroticism, Extraversion, Conscientiousness, and Agreeableness were associated with specified (atypical or melancholic) major depression compared with unspecified major depression in the bivariate analyses but lost their significance after adjustments for functional limitations and severity of depression. Neuroticism was positively associated with the IDS mood and motivation symptom dimensions, also in the adjusted models. Further, Extraversion and Agreeableness were negatively associated with the IDS mood symptom dimension, and Extraversion and Conscientiousness were negatively associated with the IDS motivation symptom dimension. None was associated with the IDS somatic symptom dimension. This study demonstrated the association of personality characteristics with mood and motivational symptoms of late-life depression. The lacking ability of personality to differentiate between melancholic and atypical depression seems to be largely explained by severity of depressive symptoms. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  19. Nonlinear Ritz approximation for Fredholm functionals

    Directory of Open Access Journals (Sweden)

    Mudhir A. Abdul Hussain

    2015-11-01

    Full Text Available In this article we use the modify Lyapunov-Schmidt reduction to find nonlinear Ritz approximation for a Fredholm functional. This functional corresponds to a nonlinear Fredholm operator defined by a nonlinear fourth-order differential equation.

  20. Breatherlike impurity modes in discrete nonlinear lattices

    DEFF Research Database (Denmark)

    Hennig, D.; Rasmussen, Kim; Tsironis, G. P.

    1995-01-01

    We investigate the properties of a disordered generalized discrete nonlinear Schrodinger equation, containing both diagonal and nondiagonal nonlinear terms. The equation models a Linear host lattice doped with nonlinear impurities. We find different types of impurity states that form itinerant...

  1. Depression, diet and exercise.

    Science.gov (United States)

    Jacka, Felice N; Berk, Michael

    2013-09-16

    Unhealthy lifestyle behaviour is driving an increase in the burden of chronic non-communicable diseases worldwide. Recent evidence suggests that poor diet and a lack of exercise contribute to the genesis and course of depression. While studies examining dietary improvement as a treatment strategy in depression are lacking, epidemiological evidence clearly points to diet quality being of importance to the risk of depression. Exercise has been shown to be an effective treatment strategy for depression, but this is not reflected in treatment guidelines, and increased physical activity is not routinely encouraged when managing depression in clinical practice. Recommendations regarding dietary improvement, increases in physical activity and smoking cessation should be routinely given to patients with depression. Specialised and detailed advice may not be necessary. Recommendations should focus on following national guidelines for healthy eating and physical activity.

  2. Standardization of depression measurement

    DEFF Research Database (Denmark)

    Wahl, Inka; Löwe, Bernd; Bjørner, Jakob

    2014-01-01

    OBJECTIVES: To provide a standardized metric for the assessment of depression severity to enable comparability among results of established depression measures. STUDY DESIGN AND SETTING: A common metric for 11 depression questionnaires was developed applying item response theory (IRT) methods. Data...... of 33,844 adults were used for secondary analysis including routine assessments of 23,817 in- and outpatients with mental and/or medical conditions (46% with depressive disorders) and a general population sample of 10,027 randomly selected participants from three representative German household surveys....... RESULTS: A standardized metric for depression severity was defined by 143 items, and scores were normed to a general population mean of 50 (standard deviation = 10) for easy interpretability. It covers the entire range of depression severity assessed by established instruments. The metric allows...

  3. Male depression and suicide.

    Science.gov (United States)

    Wålinder, J; Rutzt, W

    2001-03-01

    Based on the experiences of the Gotland Study that education of general practitioners about depressive illness resulted in a statistically significant reduction in the number of female suicides, leaving the rate of male suicides almost unaffected, we propose the concept of a male depressive syndrome. This syndrome comprises a low stress tolerance, an acting-out behavior, a low impulse control, substance abuse and a hereditary loading of depressive illness, alcoholism and suicide. This notion is supported by data from The Amish study as well as the concept of van Praag of a stress-precipitated, cortisol-induced, serotonin-related and anxiety-driven depressive illness most often seen in males. In order to identify depressed males, the Gotland Male Depression Scale has been developed. Some preliminary data using the scale in a group of alcohol-dependant patients are presented.

  4. What is depression?

    DEFF Research Database (Denmark)

    Davidsen, Annette Sofie; Fosgerau, Christina Fogtmann

    2014-01-01

    of depression is insufficient and a collaborative care (CC) model between general practice and psychiatry has been proposed to overcome this. However, for successful implementation, a CC model demands shared agreement about the concept of depression and the diagnostic process in the two sectors. We aimed......The diagnosis of depression is defined by psychiatrists, and guidelines for treatment of patients with depression are created in psychiatry. However, most patients with depression are treated exclusively in general practice. Psychiatrists point out that general practitioners' (GPs') treatment...... to explore how depression is understood by GPs and clinical psychiatrists. We carried out qualitative in-depth interviews with 11 psychiatrists and 12 GPs. Analysis was made by Interpretative Phenomenological Analysis. We found that the two groups of physicians differed considerably in their views...

  5. Nonlinear periodic space-charge waves in plasma

    International Nuclear Information System (INIS)

    Kovalev, V. A.

    2009-01-01

    A solution is obtained in the form of coupled nonlinear periodic space-charge waves propagating in a magnetoactive plasma. The wave spectrum in the vicinity of the critical point, where the number of harmonics increases substantially, is found to fall with harmonic number as ∝ s -1/3 . Periodic space-charge waves are invoked to explain the zebra pattern in the radio emission from solar flares.

  6. Nonlinear propagation of Alfven waves in cometary plasmas

    International Nuclear Information System (INIS)

    Lakhina, G.S.; Shukla, P.K.

    1987-07-01

    Large amplitude Alfven waves propagating along the guide magnetic field in a three-component plasma are shown to be modulationally unstable due to their nonlinear interaction with nonresonant electrostatic density fluctuations. A new class of subsonic Alfven soliton solutions are found to exist in the three-component plasma. The Alfven solitons can be relevant in explaining the properties of hydromagnetic turbulence near the comets. (author). 15 refs

  7. A population-based study of anxiety as a precursor for depression in childhood and adolescence

    Directory of Open Access Journals (Sweden)

    van den Bree Marianne BM

    2004-12-01

    Full Text Available Background Anxiety and depression co-occur in children and adolescents with anxiety commonly preceding depression. Although there is some evidence to suggest that the association between early anxiety and later depression is explained by a shared genetic aetiology, the contribution of environmental factors is less well examined and it is unknown whether anxiety itself is a phenotypic risk factor for later depression. These explanations of the association between early anxiety and later depression were evaluated. Methods Anxiety and depressive symptoms were assessed longitudinally in a U.K. population-based sample of 676 twins aged 5–17 at baseline. At baseline, anxiety and depression were assessed by parental questionnaire. Depression was assessed three years later by parental and adolescent questionnaire. Results Shared genetic effects between early anxiety and later depression were found. A model of a phenotypic risk effect from early anxiety on later depression provided a poor fit to the data. However, there were significant genetic effects specific to later depression, showing that early anxiety and later depression do not index entirely the same genetic risk. Conclusions Anxiety and depression are associated over time because they share a partly common genetic aetiology rather than because the anxiety phenotype leads to later depression.

  8. A population-based study of anxiety as a precursor for depression in childhood and adolescence.

    Science.gov (United States)

    Rice, Frances; van den Bree, Marianne B M; Thapar, Anita

    2004-12-13

    Anxiety and depression co-occur in children and adolescents with anxiety commonly preceding depression. Although there is some evidence to suggest that the association between early anxiety and later depression is explained by a shared genetic aetiology, the contribution of environmental factors is less well examined and it is unknown whether anxiety itself is a phenotypic risk factor for later depression. These explanations of the association between early anxiety and later depression were evaluated. Anxiety and depressive symptoms were assessed longitudinally in a U.K. population-based sample of 676 twins aged 5-17 at baseline. At baseline, anxiety and depression were assessed by parental questionnaire. Depression was assessed three years later by parental and adolescent questionnaire. Shared genetic effects between early anxiety and later depression were found. A model of a phenotypic risk effect from early anxiety on later depression provided a poor fit to the data. However, there were significant genetic effects specific to later depression, showing that early anxiety and later depression do not index entirely the same genetic risk. Anxiety and depression are associated over time because they share a partly common genetic aetiology rather than because the anxiety phenotype leads to later depression.

  9. Immune and hormonal activity in adults suffering from depression

    Directory of Open Access Journals (Sweden)

    S.O.V. Nunes

    2002-05-01

    Full Text Available An association between depression and altered immune and hormonal systems has been suggested by the results of many studies. In the present study we carried out immune and hormonal measurements in 40 non-medicated, ambulatory adult patients with depression determined by CID-10 criteria and compared with 34 healthy nondepressed subjects. The severity of the condition was determined with the Hamilton Depression Rating Scale. Of 40 depressed patients, 31 had very severe and 9 severe or moderate depression, 29 (72.5% were females and 11 (27.5% were males (2.6:1 ratio. The results revealed a significant reduction of albumin and elevation of alpha-1, alpha-2 and ß-globulins, and soluble IL-2 receptor in patients with depression compared to the values obtained for nondepressed subjects (P<0.05. The decrease lymphocyte proliferation in response to a mitogen was significantly lower in severely or moderately depressed patients when compared to control (P<0.05. These data confirm the immunological disturbance of acute phase proteins and cellular immune response in patients with depression. Other results may be explained by a variety of interacting factors such as number of patients, age, sex, and the nature, severity and/or duration of depression. Thus, the data obtained should be interpreted with caution and the precise clinical relevance of these findings requires further investigation.

  10. Does the General Strain Theory Explain Gambling and Substance Use?

    Science.gov (United States)

    Greco, Romy; Curci, Antonietta

    2017-09-01

    General Strain Theory (GST: Agnew Criminology 30:47-87, 1992) posits that deviant behaviour results from adaptation to strain and the consequent negative emotions. Empirical research on GST has mainly focused on aggressive behaviours, while only few research studies have considered alternative manifestations of deviance, like substance use and gambling. The aim of the present study is to test the ability of GST to explain gambling behaviours and substance use. Also, the role of family in promoting the adoption of gambling and substance use as coping strategies was verified. Data from 266 families with in mean 8 observations for each group were collected. The multilevel nature of the data was verified before appropriate model construction. The clustered nature of gambling data was analysed by a two-level Hierarchical Linear Model while substance use was analysed by Multivariate Linear Model. Results confirmed the effect of strain on gambling and substance use while the positive effect of depressive emotions on these behaviours was not supported. Also, the impact of family on the individual tendency to engage in addictive behaviours was confirmed only for gambling.

  11. Spatial solitons in nonlinear photonic crystals

    DEFF Research Database (Denmark)

    Corney, Joel Frederick; Bang, Ole

    2000-01-01

    We study solitons in one-dimensional quadratic nonlinear photonic crystals with periodic linear and nonlinear susceptibilities. We show that such crystals support stable bright and dark solitons, even when the effective quadratic nonlinearity is zero.......We study solitons in one-dimensional quadratic nonlinear photonic crystals with periodic linear and nonlinear susceptibilities. We show that such crystals support stable bright and dark solitons, even when the effective quadratic nonlinearity is zero....

  12. Interwar Deflation and Depression

    OpenAIRE

    Dorval, Bill; Smith, Gregor W.

    2013-01-01

    Interwar macroeconomic history is a natural place to look for evidence on the correlations between (a) deflation and depression and (b) unexpected deflation and depression. We apply time-series methods to measure unexpected deflation or inflation for 26 countries from 1922 to 1939. The results suggest much variation across countries in the degree to which the ongoing deflation of the 1930s was unexpected. There is a significant, positive correlation between deflation and depression for the en...

  13. Depression in Old Age

    OpenAIRE

    MAŠTEROVÁ, Monika

    2008-01-01

    This thesis is theoretical and it engage in problems of the depression, in particular depression in old age. It divide in four chapters. In first chapter mentioned a characteristic deppresion. Here is a description, what is the depression and that exit some questionnaires, what make find, whether is a man it distress. Further here is mentioned it occurrence, history, mythes, causes, symptoms, types, treatment and consequences. In second chapter talk about age and growing old and their concomi...

  14. Nedley Depression Hit Hypothesis

    OpenAIRE

    Nedley, Neil; Ramirez, Francisco E.

    2014-01-01

    Depression is often diagnosed using the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5) criteria. We propose how certain lifestyle choices and non-modifiable factors can predict the development of depression. We identified 10 cause categories (hits or ?blows? to the brain) and theorize that four or more active hits could trigger a depression episode. Methods. A sample of 4271 participants from our community-based program (70% female; ages 17-94 years) was assessed ...

  15. Raised by Depressed Parents: Is it an Environmental Risk?

    Science.gov (United States)

    Natsuaki, Misaki N.; Shaw, Daniel S.; Neiderhiser, Jenae M.; Ganiban, M. Jody; Gordon, T. Harold; Reiss, David; Leve, Leslie D.

    2014-01-01

    The mechanisms explaining how parental depression compromises healthy child development are complex and multifaceted, with genetic and environmental pathways intertwined. Reexamination of whether and how maternal and paternal depression serve as environmental risk factors is important because such an investigation can be helpful to identify modifiable mechanisms that are accessible to interventions. We review studies that have employed designs that isolate the effects of the environment from genetic influences, including adoption studies and children of twins studies. Findings indicate that maternal depression is an environmental risk factor for the emotional, behavioral, and neurobiological development of children. Although more studies are needed, preliminary findings suggest that paternal depression appears to be a weaker environmental risk as compared to maternal depression, at least during infancy and toddlerhood. Implications for theory and future research are discussed. PMID:24817170

  16. Experiences of depression

    DEFF Research Database (Denmark)

    Rønberg, Mette

    In this thesis, I examine the complex experiences of what we call depression in everyday life, the multifaceted and ambiguous experiences of getting a depression diagnosis, and the in-depth processes involved in learning to live under the description of depression. The thesis is based......-and-for-all-dealt-with matters but rather messy and complicated processes, that involve several actors and multiple relations to the diagnosis. The thesis furthermore challenges the dominant diagnostic understanding depression as a neurobiological, and individual disorder in present-day diagnostic cultures, by arguing...

  17. Linear instability and nonlinear motion of rotating plasma

    International Nuclear Information System (INIS)

    Liu, J.

    1985-01-01

    Two coupled nonlinear equations describing the flute dynamics of the magnetically confined low-β collisionless rotating plasma are derived. The linear instability and nonlinear dynamics of the rotating column are analyzed theoretically. In the linear stability analysis, a new sufficient condition of stability is obtained. From the exact solution of eigenvalue equation for Gaussian density profile and uniform rotation of the plasma, the stability of the system strongly depends on the direction of plasma rotation, FLR effect and the location of the conducting wall. An analytic expression showing the finite wall effect on different normal modes is obtained and it explains the different behavior of (1,0) normal mode from other modes. The sheared rotation driven instability is investigated by using three model equilibrium profiles, and the analytic expressions of eigenvalues which includes the wall effect are obtained. The analogy between shear rotation driven instability and the instability driven by sheared plane parallel flow in the inviscid fluid is analyzed. Applying the linear analysis to the central cell of tandem mirror system, the trapped particle instability with only passing electronics is analyzed. For uniform rotation and Gaussian density profile, an analytic expression that determines the stability boundary is found. The nonlinear analysis shows that the nonlinear equations have a solitary vortex solution which is very similar to the vortex solution of nonlinear Rossby wave equation

  18. Nonlinear transport processes in tokamak plasmas. I. The collisional regimes

    International Nuclear Information System (INIS)

    Sonnino, Giorgio; Peeters, Philippe

    2008-01-01

    An application of the thermodynamic field theory (TFT) to transport processes in L-mode tokamak plasmas is presented. The nonlinear corrections to the linear ('Onsager') transport coefficients in the collisional regimes are derived. A quite encouraging result is the appearance of an asymmetry between the Pfirsch-Schlueter (P-S) ion and electron transport coefficients: the latter presents a nonlinear correction, which is absent for the ions, and makes the radial electron coefficients much larger than the former. Explicit calculations and comparisons between the neoclassical results and the TFT predictions for Joint European Torus (JET) plasmas are also reported. It is found that the nonlinear electron P-S transport coefficients exceed the values provided by neoclassical theory by a factor that may be of the order 10 2 . The nonlinear classical coefficients exceed the neoclassical ones by a factor that may be of order 2. For JET, the discrepancy between experimental and theoretical results for the electron losses is therefore significantly reduced by a factor 10 2 when the nonlinear contributions are duly taken into account but, there is still a factor of 10 2 to be explained. This is most likely due to turbulence. The expressions of the ion transport coefficients, determined by the neoclassical theory in these two regimes, remain unaltered. The low-collisional regimes, i.e., the plateau and the banana regimes, are analyzed in the second part of this work

  19. Stability, Nonlinearity and Reliability of Electrostatically Actuated MEMS Devices

    Directory of Open Access Journals (Sweden)

    Di Chen

    2007-05-01

    Full Text Available Electrostatic micro-electro-mechanical system (MEMS is a special branch with a wide range of applications in sensing and actuating devices in MEMS. This paper provides a survey and analysis of the electrostatic force of importance in MEMS, its physical model, scaling effect, stability, nonlinearity and reliability in detail. It is necessary to understand the effects of electrostatic forces in MEMS and then many phenomena of practical importance, such as pull-in instability and the effects of effective stiffness, dielectric charging, stress gradient, temperature on the pull-in voltage, nonlinear dynamic effects and reliability due to electrostatic forces occurred in MEMS can be explained scientifically, and consequently the great potential of MEMS technology could be explored effectively and utilized optimally. A simplified parallel-plate capacitor model is proposed to investigate the resonance response, inherent nonlinearity, stiffness softened effect and coupled nonlinear effect of the typical electrostatically actuated MEMS devices. Many failure modes and mechanisms and various methods and techniques, including materials selection, reasonable design and extending the controllable travel range used to analyze and reduce the failures are discussed in the electrostatically actuated MEMS devices. Numerical simulations and discussions indicate that the effects of instability, nonlinear characteristics and reliability subjected to electrostatic forces cannot be ignored and are in need of further investigation.

  20. LDRD report nonlinear model reduction

    Energy Technology Data Exchange (ETDEWEB)

    Segalman, D.; Heinstein, M.

    1997-09-01

    The very general problem of model reduction of nonlinear systems was made tractable by focusing on the very large subclass consisting of linear subsystems connected by nonlinear interfaces. Such problems constitute a large part of the nonlinear structural problems encountered in addressing the Sandia missions. A synthesis approach to this class of problems was developed consisting of: detailed modeling of the interface mechanics; collapsing the interface simulation results into simple nonlinear interface models; constructing system models by assembling model approximations of the linear subsystems and the nonlinear interface models. These system models, though nonlinear, would have very few degrees of freedom. A paradigm problem, that of machine tool vibration, was selected for application of the reduction approach outlined above. Research results achieved along the way as well as the overall modeling of a specific machine tool have been very encouraging. In order to confirm the interface models resulting from simulation, it was necessary to develop techniques to deduce interface mechanics from experimental data collected from the overall nonlinear structure. A program to develop such techniques was also pursued with good success.

  1. Sensitivity and Nonlinearity of Thermoacoustic Oscillations

    Science.gov (United States)

    Juniper, Matthew P.; Sujith, R. I.

    2018-01-01

    Nine decades of rocket engine and gas turbine development have shown that thermoacoustic oscillations are difficult to predict but can usually be eliminated with relatively small ad hoc design changes. These changes can, however, be ruinously expensive to devise. This review explains why linear and nonlinear thermoacoustic behavior is so sensitive to parameters such as operating point, fuel composition, and injector geometry. It shows how nonperiodic behavior arises in experiments and simulations and discusses how fluctuations in thermoacoustic systems with turbulent reacting flow, which are usually filtered or averaged out as noise, can reveal useful information. Finally, it proposes tools to exploit this sensitivity in the future: adjoint-based sensitivity analysis to optimize passive control designs and complex systems theory to warn of impending thermoacoustic oscillations and to identify the most sensitive elements of a thermoacoustic system.

  2. Nonlinear dynamics of the relativistic standard map

    International Nuclear Information System (INIS)

    Nomura, Y.; Ichikawa, Y.H.; Horton, W.

    1991-04-01

    Heating and acceleration of charged particles by RF fields have been extensively investigated by the standard map. The question arises as to how the relativistic effects change the nonlinear dynamical behavior described by the classical standard map. The relativistic standard map is a two parameter (K, Β = ω/kc) family of dynamical systems reducing to the standard map when Β → 0. For Β ≠ 0 the relativistic mass increase suppresses the onset of stochasticity. It shown that the speed of light limits the rate of advance of the phase in the relativistic standard map and introduces KAM surfaces persisting in the high momentum region. An intricate structure of mixing in the higher order periodic orbits and chaotic orbits is analyzed using the symmetry properties of the relativistic standard map. The interchange of the stability of the periodic orbits in the relativistic standard map is also observed and is explained by the local linear stability of the orbits. 12 refs., 16 figs

  3. Depression and inflammation in rheumatic diseases

    Directory of Open Access Journals (Sweden)

    Aleksandra Buras

    2016-03-01

    Full Text Available It is known that the prevalence of depression in rheumatologic patients is higher than in the general population. Socioeconomic factors are not a sufficient explanation of mood disorder in these patients. Symptoms reported by patients with chronic inflammatory diseases resemble changes defined as “sickness behavior”. Mood disorders among somatic patients could be explained by disturbances of the immune system according to the monoaminergic theory of depression. Inflammatory factors such as IL-1 (interleukin-1, IL-2 (interleukin-2, IL-6 (interleukin-6, TNF-α (tumor necrosis factor α, and IFN-γ (interferon-γ act within the CNS (central nervous system. They get through from peripheral tissues as well as being synthesized de novo by neurons. This cytokine activity correlates positively with depression intensity as well as with genetic polymorphism of the serotonin (5-HT transporter. The theory of glucocorticoid resistance-mediated depression (limbic-hypothalamic-pituitary-adrenal [LHPA] axis is also connected with gained proinflammatory cytokines activity. It might assume the form of a vicious circle. Depressed mood is probably linked with depression in immune-mediated diseases. An elevated level of proinflammatory cytokines is able to activate IDO (indoleamine 2,3-dioxygenase – an enzyme catabolizing tryptophan (5-HT precursor. Those reactions probably play the main role at the biochemical level. IDO metabolites extensively disturb neurotransmission. 3-Hydroxykynurenine (3OH-KYN, quinolinic acid (Quin and kynurenic acid (KYNA are neurotoxic by releasing oxidative stress mediators. Moreover, they activate MAO (monoamine oxidase, which degrades neurotransmitters responsible for stable mood. Bidirectional communication between the neuroendocrine and immune systems is significant for depression treatment, as well as CNS protection against incremental neurodegeneration among seemingly diverse diseases.

  4. Depression and inflammation in rheumatic diseases

    Directory of Open Access Journals (Sweden)

    Aleksandra Buras

    2016-03-01

    Full Text Available It is known that the prevalence of depression in rheumatologic patients is higher than in the general population. Socioeconomic factors are not a sufficient explanation of mood disorder in these patients. Symptoms reported by patients with chronic inflammatory diseases resemble changes defined as “sickness behavior”. Mood disorders among somatic patients could be explained by disturbances of the immune system according to the monoaminergic theory of depression. Inflammatory factors such as IL-1 (interleukin-1, IL-2 (interleukin-2, IL-6 (interleukin-6, TNF-α (tumor necrosis factor α, and IFN-γ (interferon-γ act within the CNS (central nervous system. They get through from peripheral tissues as well as being synthesized de novo by neurons. This cytokine activity correlates positively with depression intensity as well as with genetic polymorphism of the serotonin (5-HT transporter. The theory of glucocorticoid resistance-mediated depression (limbic-hypothalamic-pituitary-adrenal [LHPA] axis is also connected with gained proinflammatory cytokines activity. It might assume the form of a vicious circle. Depressed mood is probably linked with depression in immune-mediated diseases. An elevated level of proinflammatory cytokines is able to activate IDO (indoleamine 2,3-dioxygenase – an enzyme catabolizing tryptophan (5-HT precursor. Those reactions probably play the main role at the biochemical level. IDO metabolites extensively disturb neurotransmission. 3-Hydroxykynurenine (3OH-KYN, quinolinic acid (Quin and kynurenic acid (KYNA are neurotoxic by releasing oxidative stress mediators. Moreover, they activate MAO (monoamine oxidase, which degrades neurotransmitters responsible for stable mood. Bidirectional communication between the neuroendocrine and immune systems is significant for depression treatment, as well as CNS protection against incremental neurodegenerationamong seemingly diverse diseases.

  5. Nonlinear time heteronymous damping in nonlinear parametric planetary systems

    Czech Academy of Sciences Publication Activity Database

    Hortel, Milan; Škuderová, Alena

    2014-01-01

    Roč. 225, č. 7 (2014), s. 2059-2073 ISSN 0001-5970 Institutional support: RVO:61388998 Keywords : nonlinear dynamics * planetary systems * heteronymous damping Subject RIV: JT - Propulsion, Motors ; Fuels Impact factor: 1.465, year: 2014

  6. Nonlinear dynamic processes in modified ionospheric plasma

    Science.gov (United States)

    Kochetov, A.; Terina, G.

    Presented work is a contribution to the experimental and theoretical study of nonlinear effects arising on ionospheric plasma under the action of powerful radio emission (G.I. Terina, J. Atm. Terr. Phys., 1995, v.57, p.273; A.V. Kochetov et. al., Advances in Space Research, 2002, in press). The experimental results were obtained by the method of sounding of artificially disturbed ionosphere by short radio pulses. The amplitude and phase characteristics of scattered signal as of "caviton" type (CS) (analogy of narrow-band component of stimulation electromagnetic emission (SEE)) as the main signal (MS) of probing transmitter are considered. The theoretical model is based on numerical solution of driven nonlinear Shrödinger equation (NSE) in inhomogeneous plasma. The simulation allows us to study a self-consistent spatial-temporal dynamics of field and plasma. The observed evolution of phase characteristics of MS and CS qualitatively correspond to the results of numerical simulation and demonstrate the penetration processes of powerful electromagnetic wave in supercritical (in linear approach) plasma regions. The modeling results explain also the periodic generation of CS, the travel CS maximum down to density gradient, the aftereffect of CS. The obtained results show the excitation of strong turbulence and allow us to interpret CS, NC and so far inexplicable phenomena as "spikes" too. The work was supported in part by Russian Foundation for Basic Research (grants Nos. 99-02-16642, 99-02- 16399).

  7. Nonlinear price impact from linear models

    Science.gov (United States)

    Patzelt, Felix; Bouchaud, Jean-Philippe

    2017-12-01

    The impact of trades on asset prices is a crucial aspect of market dynamics for academics, regulators, and practitioners alike. Recently, universal and highly nonlinear master curves were observed for price impacts aggregated on all intra-day scales (Patzelt and Bouchaud 2017 arXiv:1706.04163). Here we investigate how well these curves, their scaling, and the underlying return dynamics are captured by linear ‘propagator’ models. We find that the classification of trades as price-changing versus non-price-changing can explain the price impact nonlinearities and short-term return dynamics to a very high degree. The explanatory power provided by the change indicator in addition to the order sign history increases with increasing tick size. To obtain these results, several long-standing technical issues for model calibration and testing are addressed. We present new spectral estimators for two- and three-point cross-correlations, removing the need for previously used approximations. We also show when calibration is unbiased and how to accurately reveal previously overlooked biases. Therefore, our results contribute significantly to understanding both recent empirical results and the properties of a popular class of impact models.

  8. Explaining variation in Down's syndrome screening uptake

    DEFF Research Database (Denmark)

    Crombag, Neeltje M T H; Vellinga, Ynke E; Kluijfhout, Sandra A

    2014-01-01

    ), in an attempt to explain the observed variation in national uptake rates. METHODS: We used a mixed methods approach with an embedded design: a) documentary analysis and b) expert stakeholder analysis. National central statistical offices and legal documents were studied first to gain insight in demographic....... RESULTS: There were many similarities in the demographics, healthcare systems, government abortion legislation and Down's syndrome screening policy across the studied countries. However, the additional cost for Down's syndrome screening over and above standard antenatal care in the Netherlands...

  9. SOME THEORETICAL MODELS EXPLAINING ADVERTISING EFFECTS

    Directory of Open Access Journals (Sweden)

    Vasilica Magdalena SOMEŞFĂLEAN

    2014-06-01

    Full Text Available Persuade clients is still the main focus of the companies, using a set of methods and techniques designed to influence their behavior, in order to obtain better results (profits over a longer period of time. Since the late nineteenth - early twentieth century, the american E.St.Elmo Lewis, considered a pioneer in advertising and sales, developed the first theory, AIDA model, later used by marketers and advertisers to develop a marketing communications strategy. Later studies have developed other models that are the main subject of this research, which explains how and why persuasive communication works, to understand why some approaches are effective and others are not.

  10. Weaker dental enamel explains dental decay.

    Science.gov (United States)

    Vieira, Alexandre R; Gibson, Carolyn W; Deeley, Kathleen; Xue, Hui; Li, Yong

    2015-01-01

    Dental caries continues to be the most prevalent bacteria-mediated non-contagious disease of humankind. Dental professionals assert the disease can be explained by poor oral hygiene and a diet rich in sugars but this does not account for caries free individuals exposed to the same risk factors. In order to test the hypothesis that amount of amelogenin during enamel development can influence caries susceptibility, we generated multiple strains of mice with varying levels of available amelogenin during dental development. Mechanical tests showed that dental enamel developed with less amelogenin is "weaker" while the dental enamel of animals over-expressing amelogenin appears to be more resistant to acid dissolution.

  11. Design with Nonlinear Constraints

    KAUST Repository

    Tang, Chengcheng

    2015-12-10

    Most modern industrial and architectural designs need to satisfy the requirements of their targeted performance and respect the limitations of available fabrication technologies. At the same time, they should reflect the artistic considerations and personal taste of the designers, which cannot be simply formulated as optimization goals with single best solutions. This thesis aims at a general, flexible yet e cient computational framework for interactive creation, exploration and discovery of serviceable, constructible, and stylish designs. By formulating nonlinear engineering considerations as linear or quadratic expressions by introducing auxiliary variables, the constrained space could be e ciently accessed by the proposed algorithm Guided Projection, with the guidance of aesthetic formulations. The approach is introduced through applications in different scenarios, its effectiveness is demonstrated by examples that were difficult or even impossible to be computationally designed before. The first application is the design of meshes under both geometric and static constraints, including self-supporting polyhedral meshes that are not height fields. Then, with a formulation bridging mesh based and spline based representations, the application is extended to developable surfaces including origami with curved creases. Finally, general approaches to extend hard constraints and soft energies are discussed, followed by a concluding remark outlooking possible future studies.

  12. Nonlinear functional analysis

    CERN Document Server

    Deimling, Klaus

    1985-01-01

    topics. However, only a modest preliminary knowledge is needed. In the first chapter, where we introduce an important topological concept, the so-called topological degree for continuous maps from subsets ofRn into Rn, you need not know anything about functional analysis. Starting with Chapter 2, where infinite dimensions first appear, one should be familiar with the essential step of consider­ ing a sequence or a function of some sort as a point in the corresponding vector space of all such sequences or functions, whenever this abstraction is worthwhile. One should also work out the things which are proved in § 7 and accept certain basic principles of linear functional analysis quoted there for easier references, until they are applied in later chapters. In other words, even the 'completely linear' sections which we have included for your convenience serve only as a vehicle for progress in nonlinearity. Another point that makes the text introductory is the use of an essentially uniform mathematical languag...

  13. Scalable Nonlinear Compact Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Debojyoti [Argonne National Lab. (ANL), Argonne, IL (United States); Constantinescu, Emil M. [Univ. of Chicago, IL (United States); Brown, Jed [Univ. of Colorado, Boulder, CO (United States)

    2014-04-01

    In this work, we focus on compact schemes resulting in tridiagonal systems of equations, specifically the fifth-order CRWENO scheme. We propose a scalable implementation of the nonlinear compact schemes by implementing a parallel tridiagonal solver based on the partitioning/substructuring approach. We use an iterative solver for the reduced system of equations; however, we solve this system to machine zero accuracy to ensure that no parallelization errors are introduced. It is possible to achieve machine-zero convergence with few iterations because of the diagonal dominance of the system. The number of iterations is specified a priori instead of a norm-based exit criterion, and collective communications are avoided. The overall algorithm thus involves only point-to-point communication between neighboring processors. Our implementation of the tridiagonal solver differs from and avoids the drawbacks of past efforts in the following ways: it introduces no parallelization-related approximations (multiprocessor solutions are exactly identical to uniprocessor ones), it involves minimal communication, the mathematical complexity is similar to that of the Thomas algorithm on a single processor, and it does not require any communication and computation scheduling.

  14. Acoustic-gravity nonlinear structures

    Directory of Open Access Journals (Sweden)

    D. Jovanović

    2002-01-01

    Full Text Available A catalogue of nonlinear vortex structures associated with acoustic-gravity perturbations in the Earth's atmosphere is presented. Besides the previously known Kelvin-Stewart cat's eyes, dipolar and tripolar structures, new solutions having the form of a row of counter-rotating vortices, and several weakly two-dimensional vortex chains are given. The existence conditions for these nonlinear structures are discussed with respect to the presence of inhomogeneities of the shear flows. The mode-coupling mechanism for the nonlinear generation of shear flows in the presence of linearly unstable acoustic-gravity waves, possibly also leading to intermittency and chaos, is presented.

  15. Nonlinear Dynamic Phenomena in Mechanics

    CERN Document Server

    Warminski, Jerzy; Cartmell, Matthew P

    2012-01-01

    Nonlinear phenomena should play a crucial role in the design and control of engineering systems and structures as they can drastically change the prevailing dynamical responses. This book covers theoretical and applications-based problems of nonlinear dynamics concerned with both discrete and continuous systems of interest in civil and mechanical engineering. They include pendulum-like systems, slender footbridges, shape memory alloys, sagged elastic cables and non-smooth problems. Pendulums can be used as a dynamic absorber mounted in high buildings, bridges or chimneys. Geometrical nonlinear

  16. Non-linear optical materials

    CERN Document Server

    Saravanan, R

    2018-01-01

    Non-linear optical materials have widespread and promising applications, but the efforts to understand the local structure, electron density distribution and bonding is still lacking. The present work explores the structural details, the electron density distribution and the local bond length distribution of some non-linear optical materials. It also gives estimation of the optical band gap, the particle size, crystallite size, and the elemental composition from UV-Visible analysis, SEM, XRD and EDS of some non-linear optical materials respectively.

  17. Nonlinear modulation of ionization waves

    International Nuclear Information System (INIS)

    Bekki, Naoaki

    1981-01-01

    In order to investigate the nonlinear characteristics of ionization waves (moving-striations) in the positive column of glow discharge, a nonlinear modulation of ionization waves in the region of the Pupp critical current is analysed by means of the reductive perturbation method. The modulation of ionization waves is described by a nonlinear Schroedinger type equation. The coefficients of the equation are evaluated using the data of the low pressure Argon-discharge, and the simple solutions (plane wave and envelope soliton type solutions) are presented. Under a certain condition an envelope soliton is propagated through the positive column. (author)

  18. Acculturation, Gender, Depression, and Cigarette Smoking Among U.S. Hispanic Youth: The Mediating Role of Perceived Discrimination

    OpenAIRE

    Lorenzo-Blanco, Elma I.; Unger, Jennifer B.; Ritt-Olson, Anamara; Soto, Daniel; Baezconde-Garbanati, Lourdes

    2011-01-01

    Hispanic youth are at risk for experiencing depressive symptoms and smoking cigarettes, and risk for depressive symptoms and cigarette use increase as Hispanic youth acculturate to U.S. culture. The mechanism by which acculturation leads to symptoms of depression and cigarette smoking is not well understood. The present study examined whether perceived discrimination explained the associations of acculturation with depressive symptoms and cigarette smoking among 1,124 Hispanic youth (54% fema...

  19. Single-shot measurement of nonlinear absorption and nonlinear refraction.

    Science.gov (United States)

    Jayabalan, J; Singh, Asha; Oak, Shrikant M

    2006-06-01

    A single-shot method for measurement of nonlinear optical absorption and refraction is described and analyzed. A spatial intensity variation of an elliptical Gaussian beam in conjugation with an array detector is the key element of this method. The advantages of this single-shot technique were demonstrated by measuring the two-photon absorption and free-carrier absorption in GaAs as well as the nonlinear refractive index of CS2 using a modified optical Kerr setup.

  20. Nonlinear dynamics of thin current sheets

    International Nuclear Information System (INIS)

    Daughton, William

    2002-01-01

    Observations indicate that the current sheet in the Earth's geomagnetic tail may compress to a thickness comparable to an ion gyro-radius prior to substorm onset. In recent years, there has been considerable controversy regarding the kinetic stability of these thin structures. In particular, the growth rate of the kink instability and its relevance to magnetotail dynamics is still being debated. In this work, a series of fully kinetic particle-in-cell simulations are performed for a thin Harris sheet. The ion to electron mass ratio is varied between m i /m e =4→400 and careful comparisons are made with a formally exact approach to the linear Vlasov theory. At low mass ratio m i /m e <64, the simulations are in excellent agreement with the linear theory, but at high mass ratio the kink instability is observed to grow more rapidly in the kinetic simulations than predicted by theory. The resolution to this apparent discrepancy involves the lower hybrid instability which is active on the edge of the sheet and rapidly produces nonlinear modifications to the initial equilibrium. The nature of this nonlinear deformation is characterized and a simple model is proposed to explain the physics. After the growth and saturation of the lower hybrid fluctuations, the deformed current sheet is similar in structure to a Harris equilibrium with an additional background population. This may explain the large growth rate of the kink instability at later times, since this type of modification to the Harris sheet has been shown to greatly enhance the growth rate of the kink mode

  1. HPA-axis stress reactivity in youth depression: evidence of impaired regulatory processes in depressed boys.

    Science.gov (United States)

    Lopez-Duran, Nestor L; McGinnis, Ellen; Kuhlman, Kate; Geiss, Elisa; Vargas, Ivan; Mayer, Stefanie

    2015-01-01

    Given the link between youth depression and stress exposure, efforts to identify related biomarkers have involved examinations of stress regulation systems, including the hypothalamic-pituitary-adrenal (HPA) axis. Despite these vast efforts, the underlying mechanisms at play, as well as factors that may explain heterogeneity of past findings, are not well understood. In this study, we simultaneously examined separate components of the HPA-axis response (e.g. activation intensity, peak levels, recovery) to the Socially Evaluated Cold-Pressor Test in a targeted sample of 115 youth (age 9-16), recruited to overrepresent youth with elevated symptoms of depression. Among youth who displayed a cortisol response to the task, depression symptoms were associated with higher peak responses but not greater rate of activation or recovery in boys only. Among those who did not respond to the task, depression symptoms were associated with greater cortisol levels throughout the visit in boys and girls. Results suggest that depression symptoms are associated with a more prolonged activation of the axis and impaired recovery to psychosocial stressors primarily in boys. We discussed two potential mechanistic explanations of the link between depression symptoms and the duration of activation: (1) inhibitory shift (i.e. point at which the ratio of inhibitory and excitatory input into the axis shifts from greater excitatory to greater inhibitory input) or (2) inhibitory threshold (i.e. level of cortisol exposure required to activate the axis' feedback inhibition system).

  2. [Primary headache and depression].

    Science.gov (United States)

    Gesztelyi, Gyöngyi

    2004-11-28

    Primary headaches--mainly tension-type headache and migraine--affect a significant portion of the population. Depression is also highly prevalent. The co-existence of a primary headache and depression in the same patient therefore might be a coincidence due to the high prevalence of these conditions, but there might be a causal relationship between them, or headaches and depression might have a common background. This review of the literature summarizes the features of the relationship between primary headaches and depression. Depression is more prevalent in headache patients than in the headache-free population. Prospective epidemiological studies suggest a common genetic, biochemical or environmental background behind primary headaches and depression. This theory is supported by the role of the same neurotransmitter systems (mostly serotonin and dopamine) in headaches as well as in depression. Comorbid depression is associated with female gender, higher age, and higher frequency of headaches. Most depression inventories--questionnaires used to screen for the severity of depressive symptoms--contain transdiagnostic items, therefore their use in their original form is limited in organic diseases: due to the somatic items they might overestimate the severity of depression. When examining a headache patient special attention should be paid to the recognition of comorbid depression. The diagnosis of suspected mood disorder could be supported by using simple screening methods, such as the original or the abbreviated versions of standard depression inventories, but the final diagnosis of major depression needs psychiatric evaluation. Quality of life of the headache patient is affected not only by the characteristics of pain (frequency, duration, severity) but also by the disability caused by headache and the associating mood disorder. Recognizing coexisting mood disorder and disability helps to make the best treatment choice for the acute and preventive treatment of

  3. Nutritional Aspects of Depression

    Directory of Open Access Journals (Sweden)

    Undine E. Lang

    2015-09-01

    Full Text Available Several nutrition, food and dietary compounds have been suggested to be involved in the onset and maintenance of depressive disorders and in the severity of depressive symptoms. Nutritional compounds might modulate depression associated biomarkers and parallel the development of depression, obesity and diabetes. In this context, recent studies revealed new mediators of both energy homeostasis and mood changes (i.e. IGF-1, NPY, BDNF, ghrelin, leptin, CCK, GLP-1, AGE, glucose metabolism and microbiota acting in gut brain circuits. In this context several healthy foods such as olive oil, fish, fruits, vegetables, nuts, legumes, poultry, dairy and unprocessed meat have been inversely associated with depression risk and even have been postulated to improve depressive symptoms. In contrast, unhealthy western dietary patterns including the consumption of sweetened beverage, refined food, fried food, processed meat, refined grain, and high fat diary, biscuits, snacking and pastries have been shown to be associated with an increased risk of depression in longitudinal studies. However, it is always difficult to conclude a real prospective causal relationship from these mostly retrospective studies as depressed individuals might also change their eating habits secondarily to their depression. Additionally specific selected nutritional compounds, e.g. calcium, chromium, folate, PUFAs, vitamin D, B12, zinc, magnesium and D-serine have been postulated to be used as ad-on strategies in antidepressant treatment. In this context, dietary and lifestyle interventions may be a desirable, effective, pragmatical and non-stigmatizing prevention and treatment strategy for depression. At last, several medications (pioglitazone, metformin, exenatide, atorvastatin, gram-negative antibiotics, which have traditionally been used to treat metabolic disorders showed a certain potential to treat depression in first randomized controlled clinical trials.

  4. Nutritional aspects of depression.

    Science.gov (United States)

    Lang, Undine E; Beglinger, Christoph; Schweinfurth, Nina; Walter, Marc; Borgwardt, Stefan

    2015-01-01

    Several nutrition, food and dietary compounds have been suggested to be involved in the onset and maintenance of depressive disorders and in the severity of depressive symptoms. Nutritional compounds might modulate depression associated biomarkers and parallel the development of depression, obesity and diabetes. In this context, recent studies revealed new mediators of both energy homeostasis and mood changes (i.e. IGF-1, NPY, BDNF, ghrelin, leptin, CCK, GLP-1, AGE, glucose metabolism and microbiota) acting in gut brain circuits. In this context several healthy foods such as olive oil, fish, fruits, vegetables, nuts, legumes, poultry, dairy and unprocessed meat have been inversely associated with depression risk and even have been postulated to improve depressive symptoms. In contrast, unhealthy western dietary patterns including the consumption of sweetened beverage, refined food, fried food, processed meat, refined grain, and high fat diary, biscuits, snacking and pastries have been shown to be associated with an increased risk of depression in longitudinal studies. However, it is always difficult to conclude a real prospective causal relationship from these mostly retrospective studies as depressed individuals might also change their eating habits secondarily to their depression. Additionally specific selected nutritional compounds, e.g. calcium, chromium, folate, PUFAs, vitamin D, B12, zinc, magnesium and D-serine have been postulated to be used as ad-on strategies in antidepressant treatment. In this context, dietary and lifestyle interventions may be a desirable, effective, pragmatical and non-stigmatizing prevention and treatment strategy for depression. At last, several medications (pioglitazone, metformin, exenatide, atorvastatin, gram-negative antibiotics), which have traditionally been used to treat metabolic disorders showed a certain potential to treat depression in first randomized controlled clinical trials. © 2015 The Author(s) Published by S

  5. EXPLAINING THE ASSOCIATION BETWEEN INCARCERATION AND DIVORCE*

    Science.gov (United States)

    Siennick, Sonja E.; Stewart, Eric A.; Staff, Jeremy

    2014-01-01

    Recent studies have suggested that incarceration dramatically increases the odds of divorce, but we know little about the mechanisms that explain the association. This study uses prospective longitudinal data from a subset of married young adults in the National Longitudinal Study of Adolescent Health (N = 1,919) to examine whether incarceration is associated with divorce indirectly via low marital love, economic strain, relationship violence, and extramarital sex. The findings confirmed that incarcerations occurring during, but not before, a marriage were associated with an increased hazard of divorce. Incarcerations occurring during marriage also were associated with less marital love, more relationship violence, more economic strain, and greater odds of extramarital sex. Above-average levels of economic strain were visible among respondents observed preincarceration, but only respondents observed postincarceration showed less marital love, more relationship violence, and higher odds of extramarital sex than did respondents who were not incarcerated during marriage. These relationship problems explained approximately 40 percent of the association between incarceration and marital dissolution. These findings are consistent with theoretical predictions that a spouse’s incarceration alters the rewards and costs of the marriage and the relative attractiveness of alternative partners. PMID:25598544

  6. Important variables in explaining real-time peak price in the independent power market of Ontario

    International Nuclear Information System (INIS)

    Rueda, I.E.A.; Marathe, A.

    2005-01-01

    This paper uses support vector machines (SVM) based learning algorithm to select important variables that help explain the real-time peak electricity price in the Ontario market. The Ontario market was opened to competition only in May 2002. Due to the limited number of observations available, finding a set of variables that can explain the independent power market of Ontario (IMO) real-time peak price is a significant challenge for the traders and analysts. The kernel regressions of the explanatory variables on the IMO real-time average peak price show that non-linear dependencies exist between the explanatory variables and the IMO price. This non-linear relationship combined with the low variable-observation ratio rule out conventional statistical analysis. Hence, we use an alternative machine learning technique to find the important explanatory variables for the IMO real-time average peak price. SVM sensitivity analysis based results find that the IMO's predispatch average peak price, the actual import peak volume, the peak load of the Ontario market and the net available supply after accounting for load (energy excess) are some of the most important variables in explaining the real-time average peak price in the Ontario electricity market. (author)

  7. Activities on Facebook reveal the depressive state of users.

    Science.gov (United States)

    Park, Sungkyu; Lee, Sang Won; Kwak, Jinah; Cha, Meeyoung; Jeong, Bumseok

    2013-10-01

    As online social media have become prominent, much effort has been spent on identifying users with depressive symptoms in order to aim at early diagnosis, treatment, and even prevention by using various online social media. In this paper, we focused on Facebook to discern any correlations between the platform's features and users' depressive symptoms. This work may be helpful in trying to reach and detect large numbers of depressed individuals more easily. Our goal was to develop a Web application and identify depressive symptom-related features from users of Facebook, a popular social networking platform. 55 Facebook users (male=40, female=15, mean age 24.43, SD 3.90) were recruited through advertisement fliers distributed to students in a large university in Korea. Using EmotionDiary, the Facebook application we developed, we evaluated depressive symptoms using the Center for Epidemiological Studies-Depression (CES-D) scale. We also provided tips and facts about depression to participants and measured their responses using EmotionDiary. To identify the Facebook features related to depression, correlation analyses were performed between CES-D and participants' responses to tips and facts or Facebook social features. Last, we interviewed depressed participants (CES-D≥25) to assess their depressive symptoms by a psychiatrist. Facebook activities had predictive power in distinguishing depressed and nondepressed individuals. Participants' response to tips and facts, which can be explained by the number of app tips viewed and app points, had a positive correlation (P=.04 for both cases), whereas the number of friends and location tags had a negative correlation with the CES-D scale (P=.08 and P=.045 respectively). Furthermore, in finding group differences in Facebook social activities, app tips viewed and app points resulted in significant differences (P=.01 and P=.03 respectively) between probably depressed and nondepressed individuals. Our results using Emotion

  8. Symptoms and Treatment of Depression

    Medline Plus

    Full Text Available ... few days. It is a serious illness that affects many people. Symptoms can vary, but many depressed ... suffer from depression trying to learn why it affects some people but not others. Treatments for depression ...

  9. Symptoms and Treatment of Depression

    Medline Plus

    Full Text Available ... 3 items) Institute Announcements (24 items) Symptoms and Treatment of Depression February 1, 2010 People with depression ... why it affects some people but not others. Treatments for depression do work. One type of effective ...

  10. Evaluation of self-esteem and depression symptoms in depressed and nondepressed subjects treated with onabotulinumtoxinA for glabellar lines.

    Science.gov (United States)

    Hexsel, Doris; Brum, Cristiano; Siega, Carolina; Schilling-Souza, Juliana; Dal'Forno, Taciana; Heckmann, Marc; Rodrigues, Ticiana C

    2013-07-01

    Botulinum toxin type A (BoNT-A) injection has become the most popular cosmetic nonsurgical procedure, and it has been suggested that BoNT-A injections may improve emotional states when frown lines are treated. To evaluate symptoms of depression and self-esteem before and after onabotulinumtoxinA (ONA) injections in the glabella in subjects with and without depression. Twenty-five subjects with depression were allocated into one group and 25 subjects without depression were matched to those according to demographic characteristics. The Beck Depression Inventory (BDI) and Rosenberg Self-Esteem Scale (RSES) were used to assess depression symptoms and self-esteem, respectively. Patients were assessed up to 12 weeks after the intervention. Patients with depression had significant improvement in depression symptoms after ONA injections. The maximum effect occurred within the first 8 weeks after treatment. A significant reduction from baseline in BDI score and significant improvement in self-esteem were also observed in patients with depression. This research presents new data regarding BoNT-A as a potential treatment to improve depression symptoms in patients with Major Depressive Disorder. Self-esteem scores alone cannot explain the improvement in depression symptoms. © 2013 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

  11. Ultra-fast dynamics in the nonlinear optical response of silver nanoprism ordered arrays.

    Science.gov (United States)

    Sánchez-Esquivel, Héctor; Raygoza-Sanchez, Karen Y; Rangel-Rojo, Raúl; Kalinic, Boris; Michieli, Niccolò; Cesca, Tiziana; Mattei, Giovanni

    2018-03-15

    In this work we present the study of the ultra-fast dynamics of the nonlinear optical response of a honeycomb array of silver triangular nanoprisms, performed using a femtosecond pulsed laser tuned with the dipolar surface plasmon resonance of the nanoarray. Nonlinear absorption and refraction, and their time-dependence, were explored using the z-scan and time-resolved excite-probe techniques. Nonlinear absorption is shown to change sign with the input irradiance and the behavior was explained on the basis of a three-level model. The response time was determined to be in the picosecond regime. A technique based on a variable frequency chopper was also used in order to discriminate the thermal and electronic contributions to the nonlinearity, which were found to have opposite signs. All these findings propel the investigated nanoprism arrays as good candidates for applications in advanced ultra-fast nonlinear nanophotonic devices.

  12. Explaining Sad People's Memory Advantage for Faces.

    Science.gov (United States)

    Hills, Peter J; Marquardt, Zoe; Young, Isabel; Goodenough, Imogen

    2017-01-01

    Sad people recognize faces more accurately than happy people (Hills et al., 2011). We devised four hypotheses for this finding that are tested between in the current study. The four hypotheses are: (1) sad people engage in more expert processing associated with face processing; (2) sad people are motivated to be more accurate than happy people in an attempt to repair their mood; (3) sad people have a defocused attentional strategy that allows more information about a face to be encoded; and (4) sad people scan more of the face than happy people leading to more facial features to be encoded. In Experiment 1, we found that dysphoria (sad mood often associated with depression) was not correlated with the face-inversion effect (a measure of expert processing) nor with response times but was correlated with defocused attention and recognition accuracy. Experiment 2 established that dysphoric participants detected changes made to more facial features than happy participants. In Experiment 3, using eye-tracking we found that sad-induced participants sampled more of the face whilst avoiding the eyes. Experiment 4 showed that sad-induced people demonstrated a smaller own-ethnicity bias. These results indicate that sad people show different attentional allocation to faces than happy and neutral people.

  13. Device Applications of Nonlinear Dynamics

    CERN Document Server

    Baglio, Salvatore

    2006-01-01

    This edited book is devoted specifically to the applications of complex nonlinear dynamic phenomena to real systems and device applications. While in the past decades there has been significant progress in the theory of nonlinear phenomena under an assortment of system boundary conditions and preparations, there exist comparatively few devices that actually take this rich behavior into account. "Device Applications of Nonlinear Dynamics" applies and exploits this knowledge to make devices which operate more efficiently and cheaply, while affording the promise of much better performance. Given the current explosion of ideas in areas as diverse as molecular motors, nonlinear filtering theory, noise-enhanced propagation, stochastic resonance and networked systems, the time is right to integrate the progress of complex systems research into real devices.

  14. Nonlinear programming analysis and methods

    CERN Document Server

    Avriel, Mordecai

    2012-01-01

    This text provides an excellent bridge between principal theories and concepts and their practical implementation. Topics include convex programming, duality, generalized convexity, analysis of selected nonlinear programs, techniques for numerical solutions, and unconstrained optimization methods.

  15. q-Deformed nonlinear maps

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 64; Issue 3 ... Keywords. Nonlinear dynamics; logistic map; -deformation; Tsallis statistics. ... As a specific example, a -deformation procedure is applied to the logistic map. Compared ...

  16. Born-Infeld Nonlinear Electrodynamics

    International Nuclear Information System (INIS)

    Bialynicki-Birula, I.

    1999-01-01

    This is only a summary of a lecture delivered at the Infeld Centennial Meeting. In the lecture the history of the Born-Infeld nonlinear electrodynamics was presented and some general features of the theory were discussed. (author)

  17. Nonlinear compression of optical solitons

    Indian Academy of Sciences (India)

    linear pulse propagation is the nonlinear Schrödinger (NLS) equation [1]. There are ... Optical pulse compression finds important applications in optical fibres. The pulse com ..... to thank CSIR, New Delhi for financial support in the form of SRF.

  18. Nonlinear transformations of random processes

    CERN Document Server

    Deutsch, Ralph

    2017-01-01

    This concise treatment of nonlinear noise techniques encountered in system applications is suitable for advanced undergraduates and graduate students. It is also a valuable reference for systems analysts and communication engineers. 1962 edition.

  19. Extreme Nonlinear Optics An Introduction

    CERN Document Server

    Wegener, Martin

    2005-01-01

    Following the birth of the laser in 1960, the field of "nonlinear optics" rapidly emerged. Today, laser intensities and pulse durations are readily available, for which the concepts and approximations of traditional nonlinear optics no longer apply. In this regime of "extreme nonlinear optics," a large variety of novel and unusual effects arise, for example frequency doubling in inversion symmetric materials or high-harmonic generation in gases, which can lead to attosecond electromagnetic pulses or pulse trains. Other examples of "extreme nonlinear optics" cover diverse areas such as solid-state physics, atomic physics, relativistic free electrons in a vacuum and even the vacuum itself. This book starts with an introduction to the field based primarily on extensions of two famous textbook examples, namely the Lorentz oscillator model and the Drude model. Here the level of sophistication should be accessible to any undergraduate physics student. Many graphical illustrations and examples are given. The followi...

  20. Nonlinear dynamics: Challenges and perspectives

    Indian Academy of Sciences (India)

    fields such as economics, social dynamics and so on [6–10]. These nonlinear ..... developing all-optical computers in homogeneous bulk media such as pho- ... suggestions have been given to develop effective chaos-based cryptographic.

  1. The Depression Coping Questionnaire.

    Science.gov (United States)

    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,…

  2. Postpartum Depression: An Overview.

    Science.gov (United States)

    Albright, Angela

    1993-01-01

    Occurring in about 12 percent of postpartum women, postpartum depression has been focus of considerable research. Variables that have been correlated with postpartum depression range from biological causes, to lack of social support, to relationship with husband, to attributional styles, to psychodynamic explanations. There is need for more…

  3. Testosterone and Depression

    Directory of Open Access Journals (Sweden)

    Şükrü Kartalcı

    2010-12-01

    Full Text Available Androgens have various effects on human body and mood. Testosterone, a hormone mainly secreted from testes and adrenals, is one of the most potent androgens. Multiple studies have found that testosterone plays a role in regulating sexual activity, libido, social behaviors, aggression, cognitive functions, sleep control and well-being in men and women. Testosterone deficiency in hypogonadic or elderly men leads to neuropsychiatric problems, such as fatigue, loss of libido, irritability, insomnia and depressive mood. Testosterone replacement therapy consistently reverses these sequel in men. On the other hand, hyperandrogenic states in women are related to aggression and antisocial behavior, which might lead to depressive mood. Low testosterone levels may also result in depression among oophorectomized women. Because of such effects, a relationship between testosterone and depression has long been an issue of speculation, but yet very few studies have addressed this relation. Along with clinical studies, experimental and epidemiological studies show that testosterone is related to depression in men and women. But studies of testosterone concentrations in depression have yielded inconsistent results reporting low as well as high testosterone levels associated with depression. In this article, the physiological and psychological effects of testosterone and evidence regarding its relationship to depressive disorders and possible gender differences have been reviewed.

  4. Depression in nursing homes.

    Science.gov (United States)

    Snowdon, John

    2010-11-01

    Although studies have shown the prevalence of depression in nursing homes to be high, under-recognition of depression in these facilities is widespread. Use of screening tests to enhance detection of depressive symptoms has been recommended. This paper aims to provoke discussion about optimal management of depression in nursing homes. The utility of the Cornell Scale for Depression in Dementia (CSDD) is considered. CSDD data relating to residents assessed in 2008-2009 were collected from three Sydney nursing homes. CSDD scores were available from 162 residents, though raters stated they were unable to score participants on at least one item in 47 cases. Scores of 13 or more were recorded for 23% of residents in these facilities, but in most of these cases little was documented in case files to show that the results had been discussed by staff, or that they led to interventions, or that follow-up testing was arranged. Results of CSDD testing should prompt care staff (including doctors) to consider causation of depression in cases where residents are identified as possibly depressed. In particular, there needs to be discussion of how to help residents to cope with disability, losses, and feelings of powerlessness. Research is needed, examining factors that might predict response to antidepressants, and what else helps. Accreditation of nursing homes could be made to depend partly on evidence that staff regularly search for, and (if found) ensure appropriate responses to, depression.

  5. Sleep deprivation and depression

    NARCIS (Netherlands)

    Elsenga, Simon

    1992-01-01

    The association between depression and sleep disturbances is perhaps as old as makind. In view of the longstanding experience with this association it is amazing that only some 20 years ago, a few depressed patients attracted attention to the fact that Total Sleep Deprivation (TSD) had

  6. A study of remitted and treatment-resistant depression using MMPI and including pessimism and optimism scales.

    Science.gov (United States)

    Suzuki, Masatoshi; Takahashi, Michio; Muneoka, Katsumasa; Sato, Koichi; Hashimoto, Kenji; Shirayama, Yukihiko

    2014-01-01

    The psychological aspects of treatment-resistant and remitted depression are not well documented. We administered the Minnesota Multiphasic Personality Inventory (MMPI) to patients with treatment-resistant depression (n = 34), remitted depression (n = 25), acute depression (n = 21), and healthy controls (n = 64). Pessimism and optimism were also evaluated by MMPI. ANOVA and post-hoc tests demonstrated that patients with treatment-resistant and acute depression showed similarly high scores for frequent scale (F), hypochondriasis, depression, conversion hysteria, psychopathic device, paranoia, psychasthenia and schizophrenia on the MMPI compared with normal controls. Patients with treatment-resistant depression, but not acute depression registered high on the scale for cannot say answer. Using Student's t-test, patients with remitted depression registered higher on depression and social introversion scales, compared with normal controls. For pessimism and optimism, patients with treatment-resistant depression demonstrated similar changes to acutely depressed patients. Remitted depression patients showed lower optimism than normal controls by Student's t-test, even though these patients were deemed recovered from depression using HAM-D. The patients with remitted depression and treatment-resistant depression showed subtle alterations on the MMPI, which may explain the hidden psychological features in these cohorts.

  7. A study of remitted and treatment-resistant depression using MMPI and including pessimism and optimism scales.

    Directory of Open Access Journals (Sweden)

    Masatoshi Suzuki

    Full Text Available The psychological aspects of treatment-resistant and remitted depression are not well documented.We administered the Minnesota Multiphasic Personality Inventory (MMPI to patients with treatment-resistant depression (n = 34, remitted depression (n = 25, acute depression (n = 21, and healthy controls (n = 64. Pessimism and optimism were also evaluated by MMPI.ANOVA and post-hoc tests demonstrated that patients with treatment-resistant and acute depression showed similarly high scores for frequent scale (F, hypochondriasis, depression, conversion hysteria, psychopathic device, paranoia, psychasthenia and schizophrenia on the MMPI compared with normal controls. Patients with treatment-resistant depression, but not acute depression registered high on the scale for cannot say answer. Using Student's t-test, patients with remitted depression registered higher on depression and social introversion scales, compared with normal controls. For pessimism and optimism, patients with treatment-resistant depression demonstrated similar changes to acutely depressed patients. Remitted depression patients showed lower optimism than normal controls by Student's t-test, even though these patients were deemed recovered from depression using HAM-D.The patients with remitted depression and treatment-resistant depression showed subtle alterations on the MMPI, which may explain the hidden psychological features in these cohorts.

  8. A Study of Remitted and Treatment-Resistant Depression Using MMPI and Including Pessimism and Optimism Scales

    Science.gov (United States)

    Suzuki, Masatoshi; Takahashi, Michio; Muneoka, Katsumasa; Sato, Koichi; Hashimoto, Kenji; Shirayama, Yukihiko

    2014-01-01

    Background The psychological aspects of treatment-resistant and remitted depression are not well documented. Methods We administered the Minnesota Multiphasic Personality Inventory (MMPI) to patients with treatment-resistant depression (n = 34), remitted depression (n = 25), acute depression (n = 21), and healthy controls (n = 64). Pessimism and optimism were also evaluated by MMPI. Results ANOVA and post-hoc tests demonstrated that patients with treatment-resistant and acute depression showed similarly high scores for frequent scale (F), hypochondriasis, depression, conversion hysteria, psychopathic device, paranoia, psychasthenia and schizophrenia on the MMPI compared with normal controls. Patients with treatment-resistant depression, but not acute depression registered high on the scale for cannot say answer. Using Student's t-test, patients with remitted depression registered higher on depression and social introversion scales, compared with normal controls. For pessimism and optimism, patients with treatment-resistant depression demonstrated similar changes to acutely depressed patients. Remitted depression patients showed lower optimism than normal controls by Student's t-test, even though these patients were deemed recovered from depression using HAM-D. Conclusions The patients with remitted depression and treatment-resistant depression showed subtle alterations on the MMPI, which may explain the hidden psychological features in these cohorts. PMID:25279466

  9. Nonlinear Optics: Principles and Applications

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Tidemand-Lichtenberg, Peter

    of applications, Nonlinear Optics: Principles and Applications effectively bridges physics and mathematics with relevant applied material for real-world use. The book progresses naturally from fundamental aspects to illustrative examples, and presents a strong theoretical foundation that equips the reader...... and matter, this text focuses on the physical understanding of nonlinear optics, and explores optical material response functions in the time and frequency domain....

  10. Dynamics of nonlinear feedback control

    OpenAIRE

    Snippe, H.P.; Hateren, J.H. van

    2007-01-01

    Feedback control in neural systems is ubiquitous. Here we study the mathematics of nonlinear feedback control. We compare models in which the input is multiplied by a dynamic gain (multiplicative control) with models in which the input is divided by a dynamic attenuation (divisive control). The gain signal (resp. the attenuation signal) is obtained through a concatenation of an instantaneous nonlinearity and a linear low-pass filter operating on the output of the feedback loop. For input step...

  11. On nonlinear periodic drift waves

    International Nuclear Information System (INIS)

    Kauschke, U.; Schlueter, H.

    1990-09-01

    Nonlinear periodic drift waves are investigated on the basis of a simple perturbation scheme for both the amplitude and inverse frequency. The coefficients for the generation of the forced harmonics are derived, a nonlinear dispersion relation is suggested and a criterion for the onset of the modulational instability is obtained. The results are compared with the ones obtained with the help of a standard KBM-treatment. Moreover cnoidal drift waves are suggested and compared to an experimental observation. (orig.)

  12. Competitive nonlinear pricing and bundling

    OpenAIRE

    Armstrong, Mark; Vickers, John

    2006-01-01

    We examine the impact of multiproduct nonlinear pricing on profit, consumer surplus and welfare in a duopoly. When consumers buy all their products from one firm (the one-stop shopping model), nonlinear pricing leads to higher profit and welfare, but often lower consumer surplus, than linear pricing. By contrast, in a unit-demand model where consumers may buy one product from one firm and another product from another firm, bundling generally acts to reduce profit and welfare and to boost cons...

  13. Optical polarization based logic functions (XOR or XNOR) with nonlinear Gallium nitride nanoslab.

    Science.gov (United States)

    Bovino, F A; Larciprete, M C; Giardina, M; Belardini, A; Centini, M; Sibilia, C; Bertolotti, M; Passaseo, A; Tasco, V

    2009-10-26

    We present a scheme of XOR/XNOR logic gate, based on non phase-matched noncollinear second harmonic generation from a medium of suitable crystalline symmetry, Gallium nitride. The polarization of the noncollinear generated beam is a function of the polarization of both pump beams, thus we experimentally investigated all possible polarization combinations, evidencing that only some of them are allowed and that the nonlinear interaction of optical signals behaves as a polarization based XOR. The experimental results show the peculiarity of the nonlinear optical response associated with noncollinear excitation, and are explained using the expression for the effective second order optical nonlinearity in noncollinear scheme.

  14. Inverse scattering solution of non-linear evolution equations in one space dimension: an introduction

    International Nuclear Information System (INIS)

    Alvarez-Estrada, R.F.

    1979-01-01

    A comprehensive review of the inverse scattering solution of certain non-linear evolution equations of physical interest in one space dimension is presented. We explain in some detail the interrelated techniques which allow to linearize exactly the following equations: (1) the Korteweg and de Vries equation; (2) the non-linear Schrodinger equation; (3) the modified Korteweg and de Vries equation; (4) the Sine-Gordon equation. We concentrate in discussing the pairs of linear operators which accomplish such an exact linearization and the solution of the associated initial value problem. The application of the method to other non-linear evolution equations is reviewed very briefly

  15. Experimental observation of percolation-enhanced nonlinear light scattering from semicontinuous metal films

    Science.gov (United States)

    Breit, M.; Podolskiy, V. A.; Grésillon, S.; von Plessen, G.; Feldmann, J.; Rivoal, J. C.; Gadenne, P.; Sarychev, Andrey K.; Shalaev, Vladimir M.

    2001-09-01

    Strongly enhanced second-harmonic generation (SHG), which is characterized by a nearly isotropic intensity distribution, is observed for gold-glass films near the percolation threshold. The diffuselike SHG scattering, which can be thought of as nonlinear critical opalescence, is in sharp contrast with highly collimated linear reflection and transmission from these nanostructured semicontinuous metal films. Our observations, which can be explained by giant fluctuations of local nonlinear sources for SHG due to plasmon localization, verify recent predictions of percolation-enhanced nonlinear scattering.

  16. Management of recurrent depression.

    Science.gov (United States)

    Howell, Cate; Marshall, Charlotte; Opolski, Melissa; Newbury, Wendy

    2008-09-01

    Depression is a potentially recurring or chronic disorder. The provision of evidence based treatment and effective practice organisation is central to chronic disease management, and these principles can be applied to managing depression. This article outlines the principles of chronic disease management, including the use of management plans and a team care approach, and their application to the management of depression. Treatment approaches that systematically assist patients in managing their chronic disease are more effective than those based on acute care. Depression treatment guidelines are available, as well as primary care initiatives which facilitate comprehensive and long term mental health care, including relapse prevention strategies. A number of risk factors for depression relapse have been identified, and research has recommended that novel intensive relapse prevention programs need to be developed.

  17. Measuring psychotic depression

    DEFF Research Database (Denmark)

    Østergaard, S D; Meyers, B S; Flint, A J

    2014-01-01

    OBJECTIVE: Psychotic depression (PD) is a highly debilitating condition, which needs intensive monitoring. However, there is no established rating scale for evaluating the severity of PD. The aim of this analysis was to assess the psychometric properties of established depression rating scales...... and a number of new composite rating scales, covering both depressive and psychotic symptoms, in relation to PD. METHOD: The psychometric properties of the rating scales were evaluated based on data from the Study of Pharmacotherapy of Psychotic Depression. RESULTS: A rating scale consisting of the 6-item......'s correlation coefficient between change in HAMD-BPRS11 and Clinical Global Impression - Improvement (CGI-I) scores = -0.74--0.78) and unidimensionality (Loevinger's coefficient of homogeneity = 0.41) in the evaluation of PD. The HAM-D6 fulfilled the same criteria, whereas the full 17-item Hamilton Depression...

  18. Depression following myocardial infarction

    DEFF Research Database (Denmark)

    Larsen, Karen Kjær

    2013-01-01

    whether the mental burden of MI is so heavy that it increases the risk of suicide. Although post-MI depression is common and burdensome, the condition remains under-recognised and under-treated. The development of new strategies to improve the quality of care for people with post-MI depression requires...... between post-MI depression and new cardiovascular events or death, taking potential mediators into account (Paper III); 4. To examine the association between MI and suicide (Paper IV). Two different study designs were employed: a population-based cohort study using data obtained from registers......Myocardial infarction (MI) is a severe life event that is accompanied by an increased risk of depression. Mounting evidence suggests that post-MI depression is associated with adverse outcomes, but the underlying mechanisms of this association remain unclear, and no previous studies have examined...

  19. Nonlinear optics principles and applications

    CERN Document Server

    Rottwitt, Karsten

    2014-01-01

    IntroductionReview of linear opticsInduced polarizationHarmonic oscillator modelLocal field correctionsEstimated nonlinear responseSummaryTime-domain material responseThe polarization time-response functionThe Born-Oppenheimer approximationRaman scattering response function of silicaSummaryMaterial response in the frequency domain, susceptibility tensorsThe susceptibility tensorThe induced polarization in the frequency domainSum of monochromatic fieldsThe prefactor to the induced polarizationThird-order polarization in the Born-Oppenheimer approximation in the frequency domainKramers-Kronig relationsSummarySymmetries in nonlinear opticsSpatial symmetriesSecond-order materialsThird-order nonlinear materialsCyclic coordinate-systemContracted notation for second-order susceptibility tensorsSummaryThe nonlinear wave equationMono and quasi-monochromatic beamsPlane waves - the transverse problemWaveguidesVectorial approachNonlinear birefringenceSummarySecond-order nonlinear effectsGeneral theoryCoupled wave theoryP...

  20. Modeling nonlinearities in MEMS oscillators.

    Science.gov (United States)

    Agrawal, Deepak K; Woodhouse, Jim; Seshia, Ashwin A

    2013-08-01

    We present a mathematical model of a microelectromechanical system (MEMS) oscillator that integrates the nonlinearities of the MEMS resonator and the oscillator circuitry in a single numerical modeling environment. This is achieved by transforming the conventional nonlinear mechanical model into the electrical domain while simultaneously considering the prominent nonlinearities of the resonator. The proposed nonlinear electrical model is validated by comparing the simulated amplitude-frequency response with measurements on an open-loop electrically addressed flexural silicon MEMS resonator driven to large motional amplitudes. Next, the essential nonlinearities in the oscillator circuit are investigated and a mathematical model of a MEMS oscillator is proposed that integrates the nonlinearities of the resonator. The concept is illustrated for MEMS transimpedance-amplifier- based square-wave and sine-wave oscillators. Closed-form expressions of steady-state output power and output frequency are derived for both oscillator models and compared with experimental and simulation results, with a good match in the predicted trends in all three cases.

  1. Personality Modulates the Efficacy of Treatment in Patients With Major Depressive Disorder

    NARCIS (Netherlands)

    Wardenaar, Klaas J.; Conradi, Henk Jan; Bos, Elisabeth H.; de Jonge, Peter

    OBJECTIVE: Effects of depression treatment are obscured by heterogeneity among patients. Personality types could be one source of heterogeneity that explains variability in treatment response. Clinically meaningful variations in personality patterns could be captured with data-driven subgroups. The

  2. Explaining the democratic anchorage of governance networks

    DEFF Research Database (Denmark)

    Skelcher, Chris; Klijn, Erik-Hans; Kübler, Daniel

    2011-01-01

    Advances in understanding the democratic anchorage of governance networks require carefully designed and contextually grounded empirical analysis that take into account contextual factors. The article uses a conjectural framework to study the impact of the national democratic milieu...... on the relationship between network governance and representative institutions in four European countries: the United Kingdom, Switzerland, the Netherlands, and Denmark. The article shows that the distinction between majoritarian and consensus democracy as well as the varying strength of voluntary associations...... are important contextual factors that help explain cross-national differences in the relationship between governance networks and representative institutions. We conclude that a context of weak associationalism in majoritarian democracies facilitates the instrumentalization of networks by government actors...

  3. Explaining CMS lepton excesses with supersymmetry

    CERN Multimedia

    CERN. Geneva; Prof. Allanach, Benjamin

    2014-01-01

    1) Kostas Theofilatos will give an introduction to CMS result 2) Ben Allanach: Several CMS analyses involving di-leptons have recently reported small 2.4-2.8 sigma local excesses: nothing to get too excited about, but worth keeping an eye on nonetheless. In particular, a search in the $lljj p_T$(miss) channel, a search for $W_R$ in the $lljj$ channel and a di-leptoquark search in the $lljj$ channel and $ljj p_T$(miss) channel have all yielded small excesses. We interpret the first excess in the MSSM, showing that the interpretation is viable in terms of other constraints, despite only having squark masses of around 1 TeV. We can explain the last three excesses with a single R-parity violating coupling that predicts a non-zero contribution to the neutrinoless double beta decay rate.

  4. Explaining the moral of the story.

    Science.gov (United States)

    Walker, Caren M; Lombrozo, Tania

    2017-10-01

    Although storybooks are often used as pedagogical tools for conveying moral lessons to children, the ability to spontaneously extract "the moral" of a story develops relatively late. Instead, children tend to represent stories at a concrete level - one that highlights surface features and understates more abstract themes. Here we examine the role of explanation in 5- and 6-year-old children's developing ability to learn the moral of a story. Two experiments demonstrate that, relative to a control condition, prompts to explain aspects of a story facilitate children's ability to override salient surface features, abstract the underlying moral, and generalize that moral to novel contexts. In some cases, generating an explanation is more effective than being explicitly told the moral of the story, as in a more traditional pedagogical exchange. These findings have implications for moral comprehension, the role of explanation in learning, and the development of abstract reasoning in early childhood. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Explaining NDVI trends in northern Burkina Faso

    DEFF Research Database (Denmark)

    Rasmussen, Kjeld; Fensholt, Rasmus; Fog, Bjarne

    2014-01-01

    by a distinct spatial pattern and strongly dominated by negative trends in Normalized Difference Vegetation Index (NDVI). The aim of the paper is to explain this distinct pattern. When studied over the period 2000–2012, using NDVI data from the MODIS sensor the spatial pattern of NDVI trends indicates that non......-climatic factors are involved. By relating NDVI trends to landscape elements and land use change we demonstrate that NDVI trends in the north-western parts of the study area are mostly related to landscape elements, while this is not the case in the south-eastern parts, where rapidly changing land use, including....... expansion of irrigation, plays a major role. It is inferred that a process of increased redistribution of fine soil material, water and vegetation from plateaus and slopes to valleys, possibly related to higher grazing pressure, may provide an explanation of the observed pattern of NDVI trends. Further work...

  6. Can molecular cell biology explain chromosome motions?

    Directory of Open Access Journals (Sweden)

    Gagliardi L

    2011-05-01

    Full Text Available Abstract Background Mitotic chromosome motions have recently been correlated with electrostatic forces, but a lingering "molecular cell biology" paradigm persists, proposing binding and release proteins or molecular geometries for force generation. Results Pole-facing kinetochore plates manifest positive charges and interact with negatively charged microtubule ends providing the motive force for poleward chromosome motions by classical electrostatics. This conceptual scheme explains dynamic tracking/coupling of kinetochores to microtubules and the simultaneous depolymerization of kinetochore microtubules as poleward force is generated. Conclusion We question here why cells would prefer complex molecular mechanisms to move chromosomes when direct electrostatic interactions between known bound charge distributions can accomplish the same task much more simply.

  7. Explaining fast radio bursts through Dicke's superradiance

    Science.gov (United States)

    Houde, Martin; Mathews, Abhilash; Rajabi, Fereshteh

    2018-03-01

    Fast radio bursts (FRBs), characterized by strong bursts of radiation intensity at radio wavelengths lasting on the order of a millisecond, have yet to be firmly associated with a family, or families, of astronomical sources. It follows that despite the large number of proposed models, no well-defined physical process has been identified to explain this phenomenon. In this paper, we demonstrate how Dicke's superradiance, for which evidence has recently been found in the interstellar medium, can account for the characteristics associated with FRBs. Our analysis and modelling of previously detected FRBs suggest they could originate from regions in many ways similar to those known to harbour masers or megamasers, and result from the coherent radiation emanating from populations of molecules associated with large-scale entangled quantum mechanical states. We estimate this entanglement to involve as many as ˜1030 to ˜1032 molecules over distances spanning 100-1000 au.

  8. Explaining mutualism variation: a new evolutionary paradox?

    Science.gov (United States)

    Heath, Katy D; Stinchcombe, John R

    2014-02-01

    The paradox of mutualism is typically framed as the persistence of interspecific cooperation, despite the potential advantages of cheating. Thus, mutualism research has tended to focus on stabilizing mechanisms that prevent the invasion of low-quality partners. These mechanisms alone cannot explain the persistence of variation for partner quality observed in nature, leaving a large gap in our understanding of how mutualisms evolve. Studying partner quality variation is necessary for applying genetically explicit models to predict evolution in natural populations, a necessary step for understanding the origins of mutualisms as well as their ongoing dynamics. An evolutionary genetic approach, which is focused on naturally occurring mutualist variation, can potentially synthesize the currently disconnected fields of mutualism evolution and coevolutionary genetics. We outline explanations for the maintenance of genetic variation for mutualism and suggest approaches necessary to address them. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  9. Explaining excess morbidity amongst homeless shelter users

    DEFF Research Database (Denmark)

    Benjaminsen, Lars; Birkelund, Jesper Fels

    2018-01-01

    AIMS: This article analyses excess morbidity amongst homeless shelter users compared to the general Danish population. The study provides an extensive control for confounding and investigates to what extent excess morbidity is explained by homelessness or other risk factors. METHODS: Data set...... includes administrative micro-data for 4,068,926 Danes who were 23 years or older on 1 January 2007. Nationwide data on shelter use identified 14,730 individuals as shelter users from 2002 to 2006. Somatic diseases were measured from 2007 to 2011 through diagnosis data from hospital discharges. The risk...... of somatic diseases amongst shelter users was analysed through a multivariate model that decomposed the total effect into a direct effect and indirect effects mediated by other risk factors. RESULTS: The excess morbidity associated with shelter use is substantially lower than in studies that did not include...

  10. Attributional Style and Depression in Multiple Sclerosis: The Learned Helplessness Model

    OpenAIRE

    Vargas, Gray A.; Arnett, Peter A.

    2013-01-01

    Several etiologic theories have been proposed to explain depression in the general population. Studying these models and modifying them for use in the multiple sclerosis (MS) population may allow us to better understand depression in MS. According to the reformulated learned helplessness (LH) theory, individuals who attribute negative events to internal, stable, and global causes are more vulnerable to depression. This study differentiated attributional style that was or was not related to MS...

  11. Nonlinear transport of dynamic system phase space

    International Nuclear Information System (INIS)

    Xie Xi; Xia Jiawen

    1993-01-01

    The inverse transform of any order solution of the differential equation of general nonlinear dynamic systems is derived, realizing theoretically the nonlinear transport for the phase space of nonlinear dynamic systems. The result is applicable to general nonlinear dynamic systems, with the transport of accelerator beam phase space as a typical example

  12. A reliable treatment for nonlinear Schroedinger equations

    International Nuclear Information System (INIS)

    Khani, F.; Hamedi-Nezhad, S.; Molabahrami, A.

    2007-01-01

    Exp-function method is used to find a unified solution of nonlinear wave equation. Nonlinear Schroedinger equations with cubic and power law nonlinearity are selected to illustrate the effectiveness and simplicity of the method. It is shown that the Exp-function method, with the help of symbolic computation, provides a powerful mathematical tool for solving nonlinear equation

  13. [Programmes against depression].

    Science.gov (United States)

    Taleb, M; Rouillon, F; Hegerl, U; Hamdani, N; Gorwood, Ph

    2006-01-01

    Depressive disorders represent a major public health concern, regarding their high frequency and their important cost. Depression impair the quality of life more than any other disease, sometimes leading to suicidal ideas or behavior. Indeed, 50% of patients with severe major depression commit suicide. Numerous studies showed that depressive disorders are frequently not recognised, and regularly untreated. In France, where at least 3 millions of inhabitants are concerned, 38% of depressed patients are not using any health system. When they are asking for care, the majority of depressed patients visit their general practitioner (51%), whereas less than 10% visit a psychiatrist. Even when the diagnostic is correct, the treatment prescribed is not systematically relevant. The treatment is, for example, frequently proposed for a too short period, and sometimes the prescribed product does not have proven antidepressive efficacy. Furthermore, as incorrect informations are frequently given to patients, and as there is a general biased judgement about psychotropic drugs in the general population, the compliance is usually poor for antidepressive treatment. Therefore, only a small minority of depressed patients benefits from an adequate care. Public health information methodological asserts. To improve this situation, delivering simple and clear-cut recommendations cannot be considered as sufficiently effective, and public health interventions are required. Different programs improving the recognition of depressive disorders have already been tested in some countries with encouraging results. These programs are based on information campaigns given to the public, and the training of general practitioners about the management of depressive disorders. The "Defeat Depression" campaign in Great-Britain and the "National Depression Screening Day" in the United-States of America may represent informative examples. Restricting these programs to general practitioners only is

  14. Detecting depression among adolescents in Santiago, Chile: sex differences.

    Science.gov (United States)

    Araya, Ricardo; Montero-Marin, Jesus; Barroilhet, Sergio; Fritsch, Rosemarie; Gaete, Jorge; Montgomery, Alan

    2013-04-23

    Depression among adolescents is common but most cases go undetected. Brief questionnaires offer an opportunity to identify probable cases but properly validated cut-off points are often unavailable, especially in non-western countries. Sex differences in the prevalence of depression become marked in adolescence and this needs to be accounted when establishing cut-off points. This study involved adolescents attending secondary state schools in Santiago, Chile. We compared the self-reported Beck Depression Inventory-II with a psychiatric interview to ascertain diagnosis. General psychometric features were estimated before establishing the criterion validity of the BDI-II. The BDI-II showed good psychometric properties with good internal consistency, a clear unidimensional factorial structure, and good capacity to discriminate between cases and non-cases of depression. Optimal cut-off points to establish caseness for depression were much higher for girls than boys. Sex discrepancies were primarily explained by differences in scores among those with depression rather than among those without depression. It is essential to validate scales with the populations intended to be used with. Sex differences are often ignored when applying cut-off points, leading to substantial misclassification. Early detection of depression is essential if we think that early intervention is a clinically important goal.

  15. Dimensions of Oppositional Defiant Disorder as Predictors of Depression and Conduct Disorder in Preadolescent Girls

    OpenAIRE

    Burke, Jeffrey D.; Hipwell, Alison E.; Loeber, Rolf

    2010-01-01

    Objectives: To examine whether Oppositional Defiant Disorder (ODD) rather than CD may explain the comorbidity between behavioral disorders and depression; to test whether distinct affective and behavioral dimensions can be discerned within the symptoms of ODD; and to determine if an affective dimension of ODD symptoms is specifically predictive of later depression.

  16. Associations of Child Sexual and Physical Abuse with Obesity and Depression in Middle-Aged Women

    Science.gov (United States)

    Rohde, Paul; Ichikawa, Laura; Simon, Gregory E.; Ludman, Evette J.; Linde, Jennifer A.; Jeffery, Robert W.; Operskalski, Belinda H.

    2008-01-01

    Objective: Examine whether (1) childhood maltreatment is associated with subsequent obesity and depression in middle-age; (2) maltreatment explains the associations between obesity and depression; and (3) binge eating or body dissatisfaction mediate associations between childhood maltreatment and subsequent obesity. Methods: Data were obtained…

  17. Stress and Emotional Reactivity as Explanations for Gender Differences in Adolescents' Depressive Symptoms

    Science.gov (United States)

    Charbonneau, Anna M.; Mezulis, Amy H.; Hyde, Janet Shibley

    2009-01-01

    In this longitudinal study, we examined whether certain types of stressful events and how individuals respond to these events would explain gender differences in depressive symptoms among adolescents. We hypothesized that certain stressful events would mediate the relationship between gender and depressive symptoms. We also hypothesized that…

  18. BDNF serum levels are not related to cognitive functioning in older depressed patients and controls

    NARCIS (Netherlands)

    Dols, A.; Thesing, C.; Bouckaert, F.; Oude Voshaar, R.C.; Comijs, H.C.; Stek, M.L.

    2015-01-01

    Background: Depression and cognitive decline are highly prevalent in older persons and both are associated with low serum brain derived neurotrophic factor (BDNF). Mutual pathways of depression and cognitive decline in older persons may explain the overlap in symptoms and low serum BDNF. We

  19. BDNF serum levels are not related to cognitive functioning in older depressed patients and controls

    NARCIS (Netherlands)

    Dols, Annemiek; Thesing, Carisha S.; Bouckaert, Filip; Oude Voshaar, Richard; Comijs, Hannie C.; Stek, M. L.

    Background: Depression and cognitive decline are highly prevalent in older persons and both are associated with low serum brain derived neurotrophic factor (BDNF). Mutual pathways of depression and cognitive decline in older persons may explain the overlap in symptoms and low serum BDNF. We

  20. Identification of Nonlinear Dynamic Systems Possessing Some Non-linearities

    Directory of Open Access Journals (Sweden)

    Y. N. Pavlov

    2015-01-01

    Full Text Available The subject of this work is the problem of identification of nonlinear dynamic systems based on the experimental data obtained by applying test signals to the system. The goal is to determinate coefficients of differential equations of systems by experimental frequency hodographs and separate similar, but different, in essence, forces: dissipative forces with the square of the first derivative in the motion equations and dissipative force from the action of dry friction. There was a proposal to use the harmonic linearization method to approximate each of the nonlinearity of "quadratic friction" and "dry friction" by linear friction with the appropriate harmonic linearization coefficient.Assume that a frequency transfer function of the identified system has a known form. Assume as well that there are disturbances while obtaining frequency characteristics of the realworld system. As a result, the points of experimentally obtained hodograph move randomly. Searching for solution of the identification problem was in the hodograph class, specified by the system model, which has the form of the frequency transfer function the same as the form of the frequency transfer function of the system identified. Minimizing a proximity criterion (measure of the experimentally obtained system hodograph and the system hodograph model for all the experimental points described and previously published by one of the authors allowed searching for the unknown coefficients of the frequenc ransfer function of the system model. The paper shows the possibility to identify a nonlinear dynamic system with multiple nonlinearities, obtained on the experimental samples of the frequency system hodograph. The proposed algorithm allows to select the nonlinearity of the type "quadratic friction" and "dry friction", i.e. also in the case where the nonlinearity is dependent on the same dynamic parameter, in particular, on the derivative of the system output value. For the dynamic