WorldWideScience

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 MAP Training. However, only in women did 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 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

  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. 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…

  6. Can Reporting Heterogeneity Explain Differences in Depressive Symptoms across Europe?

    Science.gov (United States)

    Kok, Renske; Avendano, Mauricio; d'Uva, Teresa Bago; Mackenbach, Johan

    2012-01-01

    Depression is one of the leading causes of disability in the developed world. Previous studies have shown varying depression prevalence rates between European countries, and also within countries, between socioeconomic groups. However, it is unclear whether these differences reflect true variations in prevalence or whether they are attributable to…

  7. Is the link between depressed mood and heart rate variability explained by disinhibited eating and diet?

    Science.gov (United States)

    Young, Hayley A; Cousins, Alecia L; Watkins, Heather T; Benton, David

    2017-02-01

    Consistently it has been reported that a depressed mood and low heart rate variability (HRV) are linked. However, studies have not considered that the association might be explained by dietary behaviour. The resting inter-beat interval data of 266 adults (Study 1: 156 (51M), Study 2: 112 (38M)) were recorded for six minutes and quantified using linear (HF power: 0.15-0.4Hz) and nonlinear indices (Sample entropy). Participants also completed the Profile of Mood States and the Three Factor Eating questionnaires. The Alternative Healthy Eating Index was used to quantify diet quality. In study 1 mood was associated with HRV; an effect partially mediated by diet. Study 2 replicated the finding: disinhibited eating (the tendency to lose control over one's eating) and diet sequentially mediated the association between mood and HRV. Diet plays a role in the link between mood and HRV and studies should consider the influence of this factor. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Psychophysiological biomarkers explaining the association between depression and prognosis in coronary artery patients

    DEFF Research Database (Denmark)

    de Jonge, Peter; Rosmalen, Judith G M; Kema, Ido P

    2010-01-01

    This paper aims to provide an overview of the current state of affairs on psychophysiological factors that may explain the link between depression and adverse outcome in coronary artery disease (CAD) patients. Factors discussed include heart rate variability, inflammation, platelet function......, hypothalamus-pituitary-adrenal axis activity, serotonin metabolism and polyunsaturated fatty acids. Evidence suggests the involvement of each of these factors in both depression and CAD, together contributing to the prospective association between depression and cardiac outcome. Unfortunately, the involvement...... of above factors has been evaluated mostly in isolation, despite their functional interrelations and associations with behavioral factors. Moreover, there may be specific relations between individual symptoms of depression and certain psychophysiological mechanisms, rather than with general depression...

  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. 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.

  11. Loneliness and HIV-related stigma explain depression among older HIV-positive adults

    Science.gov (United States)

    Grov, Christian; Golub, Sarit A.; Parsons, Jeffrey T.; Brennan, Mark; Karpiak, Stephen E.

    2010-01-01

    Advances in the treatment of HIV have resulted in a large growing population of older adults with HIV. These aging adults face added social, psychological, and physical challenges associated with the aging process. Correlations between depression, loneliness, health, and HIV/AIDS-related stigma have been studied, but there is little evaluation of these associations among HIV-positive adults over the age of 50. Data for these analyses were taken from the Research on Older Adults with HIV (ROAH) study of 914 New York City-based HIV-positive men and women over the age of 50. In total, 39.1% of participants exhibited symptoms of major depression (CES-D ≥ 23). Multivariate modeling successfully explained 42% of the variance in depression which was significantly related to increased HIV-associated stigma, increased loneliness, decreased cognitive functioning, reduced levels of energy, and being younger. These data underscore the need for service providers and researchers to assert more aggressive and innovative efforts to resolve both psychosocial and physical health issues that characterize the graying of the AIDS epidemic in the United States. Data suggest that focusing efforts to reduce HIV-related stigma and loneliness may have lasting effects in reducing major depressive symptoms and improving perceived health. PMID:20401765

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

    Science.gov (United States)

    McHarris, Wm C.

    2011-07-01

    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

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. Psychophysiological biomarkers explaining the association between depression and prognosis in coronary artery patients : A critical review of the literature

    NARCIS (Netherlands)

    de Jonge, Peter; Rosmalen, Judith G. M.; Kema, Ido P.; Doornbos, Bennard; van Melle, Joost P.; Pouwer, Francois; Kupper, Nina

    This paper aims to provide an overview of the current state of affairs on psychophysiological factors that may explain the link between depression and adverse outcome in coronary artery disease (CAD) patients. Factors discussed include heart rate variability, inflammation, platelet function,

  18. 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…

  19. Do depressive symptoms explain associations between binge eating symptoms and later psychosocial adjustment in young adulthood?

    Science.gov (United States)

    Mason, Tyler B; Heron, Kristin E

    2016-12-01

    Prospective associations between binge eating symptoms (i.e., objective overeating [OOE] and loss of control [LOC] eating) and psychosocial functioning during emerging adulthood were examined using data from the Longitudinal Study of Adolescent to Adult Health. We examined associations between OOE and LOC eating and psychosocial functioning variables with and without adjusting for concurrent depressive symptoms. Analyses revealed that OOE at Wave 3 (ages 18-28) was associated with depressive symptoms, social isolation, weight perception, and perceived attractiveness seven years later at Wave 4 (ages 25-35) and LOC eating at Wave 3 was associated with later depressive symptoms, suicidal thoughts, weight perception, social isolation, number of close friends, and sleep difficulty. Analyses adjusted for depressive symptoms at Wave 3 revealed that OOE at Wave 3 was associated with social isolation and perceived attractiveness at Wave 4 and LOC eating at Wave 3 was associated with later depressive symptoms, isolation, number of close friends, and sleep difficulty. Results show that binge eating symptoms are prospectively associated with psychosocial impairment during emerging adulthood even after controlling for depressive symptoms. Rather than simply screening for depressive symptoms, results highlight the utility of screening for binge eating symptoms as these symptoms are independently associated with psychosocial impairment in emerging adults. Published by Elsevier Ltd.

  20. 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.

  1. Association between depressive symptoms and metabolic syndrome is not explained by antidepressant medication: results from the PPP-Botnia Study.

    Science.gov (United States)

    Pyykkönen, Antti-Jussi; Räikkönen, Katri; Tuomi, Tiinamaija; Eriksson, Johan G; Groop, Leif; Isomaa, Bo

    2012-05-01

    To study whether the frequently reported association between depressive symptoms and the metabolic syndrome (MetS) and its individual components are secondary to the use of antidepressant medication and to established diabetes or cardiovascular diseases (CVD). A population-based, random sample of 4,967 women and men aged 18-75 years. MetS was defined according to the new, harmonized criteria. Glucose tolerance was assessed by oral glucose tolerance test (OGTT). CVD, depressive symptoms, and use of antidepressant medication were self-reported. The odds for having the MetS increased over 10%for each standard deviation increase in depressive symptoms. Users of antidepressant medication had more than 50% increased odds for having the MetS. Depressive symptoms were also associated with higher glucose response during the OGTT, higher serum triglyceride and lower HDL-cholesterol concentrations, and higher waist circumference, while use of antidepressant medication was associated with higher triglycerides, waist circumference, and systolic blood pressure. The associations of depressive symptoms were not secondary to use of antidepressant medication and were not explained by established diabetes or CVD. Depressive symptoms, the MetS, and the individual components of MetS are related. These associations are not driven by use of antidepressant medication, established diabetes, or CVD.

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 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 (pcomplexities were observed only in the controls when they were subjected to music compared to the resting baseline state in the frontal (pcomplexities when they were exposed to noise stimulus than did the controls׳ brains. Moreover, MDD patients׳ negative emotional 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

  7. Mania and depression explained

    African Journals Online (AJOL)

    ):11-8. 16. Houenou J, Frommberger J, Carde S, Glasbrenner M, Diener C, Leboyer M, et al. Neuroimaging-based markers of bipolar disorder: evidence from two meta-analyses. Journal of Affective Disorders 2011;132(3):344-55. 17. Konradi ...

  8. 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

  9. 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...... power density of power converters. Nonlinearities in piezoelectric transformers occur when the power density is increased enough. The simple linear equations are not valid at this point and more complex theory of electro elasticity must be applied. In This work a simplified thermo-electric model...

  10. Context counts: solitary drinking explains the association between depressive symptoms and alcohol-related problems in undergraduates.

    Science.gov (United States)

    Keough, Matthew T; O'Connor, Roisin M; Sherry, Simon B; Stewart, Sherry H

    2015-03-01

    According to theory, depressed individuals self-medicate their negative affect with alcohol. Due to isolation and interpersonal difficulties, undergraduates with elevated depressive symptoms may do much of their drinking alone and/or in intimate contexts (e.g., with family or romantic partners) rather than at normative social events (e.g., parties). Evidence suggests drinking in these contexts leads to heavy use and alcohol-related problems. Accordingly, context may be an explanatory mechanism linking depressive symptoms to problematic drinking. This pathway remains understudied in the literature. Our study aimed to examine solitary and intimate drinking as distinct mediators of the depression-problematic drinking association. We hypothesized that depressive symptoms would be positively associated with solitary and intimate drinking which in turn would be associated with elevated alcohol use and related problems. Undergraduates (N=295; 72% women) completed online self-reports. Consistent with hypotheses, path analyses supported depressive symptoms as a positive predictor of solitary drinking, which in turn was a positive predictor of alcohol-related problems, but not of alcohol use. Counter to hypotheses, depressive symptoms were unrelated to intimate drinking. Interestingly, depressive symptoms were negatively associated with drinking at parties, which in turn led to reduced risk for elevated alcohol use and related problems. Our results shed new light on the depression pathway to problematic drinking in undergraduates by considering the role of drinking context. Our findings suggest undergraduates with elevated depressive symptoms are at risk for potentially problematic drinking because they are drinking alone. Solitary drinking represents a malleable target for clinical interventions aimed at reducing risky depression-related alcohol use. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. 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

  12. 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.

  13. 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.

  14. Depression

    DEFF Research Database (Denmark)

    Kessing, Lars Veddel; Bukh, Jens Otto Drachmann

    2014-01-01

    , 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......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...

  15. 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...

  16. The retrograde P-wave theory: explaining ST segment depression in supraventricular tachycardia by retrograde AV node conduction.

    Science.gov (United States)

    Rivera, Santiago; De La Paz Ricapito, Maria; Conde, Diego; Verdu, Mariano Badra; Roux, Jean François; Paredes, Félix Ayala

    2014-09-01

    Pseudo ischemic ST segment changes during supraventricular tachycardia (SVT) are not yet fully understood. Our aim was to determine whether venticulo-atrial (VA) conduction during SVT may be a possible mechanism for ST depression (STd) in SVT. Patients undergoing SVT ablation (2010-2012) were analyzed (n = 72).Typical atrioventricular node reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) were included. Those with STd were compared to those without STd. VA interval length, tachycardia cycle length (TCL), and retrograde P-wave activation during SVT were assessed. Retrograde P waves arriving simultaneously with the ST segment (PWST) during SVT were considered, whenever an atrial electrogram (measured from the high right atrium) was "on time" with the ST segment. Patients with STd during SVT presented longer VA intervals than those without STd (VA 100 ± 37 ms vs VA 69 ± 22 ms; P = 0.006). No differences in TCL were observed (TCL 333 ± 35 ms vs TCL 360 ± 22 ms; P = 0.1). PWST was observed in 38.5% of patients with AVNRT and STd versus 0% in those without STd. The TCL was similar in both groups (355 ± 25 ms vs 334 ± 18 ms; P = 0.1). In patients with AVRT and STd, PWST was present in 81% of cases versus 0% in those without STd. The TCL was also similar (330 ± 29 ms vs 346 ± 17 ms; P = 0.1). STd during SVT is observed at long VA intervals when the retrograde P wave matches the ST segment, without dependence on the TCL. This suggests that STd is not necessarily rate dependent but a result of a fusion between the ST segment and the P wave. ©2014 Wiley Periodicals, Inc.

  17. Depressants

    Science.gov (United States)

    ... system. Doctors use them to treat things like insomnia or anxiety . But if depressant drugs (like sedatives, tranquilizers, or barbiturates) are abused, they can cause addiction , serious injury, or death. Depressants are usually ...

  18. 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...

  19. Depression

    Science.gov (United States)

    ... and insomnia References American Psychiatric Association. Depressive disorders. Diagnostic and Statistical Manual of Mental Disorders . 5th ed. Arlington, VA: American Psychiatric Publishing; 2013: ...

  20. 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...

  1. 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...

  2. 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

  3. Depression

    Science.gov (United States)

    ... don't have the right balance of chemicals. Hormonal factors – Menstrual cycle changes, pregnancy, miscarriage, postpartum period, perimenopause, and menopause may all cause a woman to develop depression. ...

  4. “I Didn’t Know What Was Wrong:” How People With Undiagnosed Depression Recognize, Name and Explain Their Distress

    Science.gov (United States)

    Duberstein, Paul R.; Feldman, Mitchell D.; Rochlen, Aaron B.; Bell, Robert A.; Kravitz, Richard L.; Cipri, Camille; Becker, Jennifer D.; Bamonti, Patricia M.; Paterniti, Debora A.

    2010-01-01

    BACKGROUND Diagnostic and treatment delay in depression are due to physician and patient factors. Patients vary in awareness of their depressive symptoms and ability to bring depression-related concerns to medical attention. OBJECTIVE To inform interventions to improve recognition and management of depression in primary care by understanding patients’ inner experiences prior to and during the process of seeking treatment. DESIGN Focus groups, analyzed qualitatively. PARTICIPANTS One hundred and sixteen adults (79% response) with personal or vicarious history of depression in Rochester NY, Austin TX and Sacramento CA. Neighborhood recruitment strategies achieved sociodemographic diversity. APPROACH Open-ended questions developed by a multidisciplinary team and refined in three pilot focus groups explored participants’ “lived experiences” of depression, depression-related beliefs, influences of significant others, and facilitators and barriers to care-seeking. Then, 12 focus groups stratified by gender and income were conducted, audio-recorded, and analyzed qualitatively using coding/editing methods. MAIN RESULTS Participants described three stages leading to engaging in care for depression — “knowing” (recognizing that something was wrong), “naming” (finding words to describe their distress) and “explaining” (seeking meaningful attributions). “Knowing” is influenced by patient personality and social attitudes. “Naming” is affected by incongruity between the personal experience of depression and its narrow clinical conceptualizations, colloquial use of the word depression, and stigma. “Explaining” is influenced by the media, socialization processes and social relations. Physical/medical explanations can appear to facilitate care-seeking, but may also have detrimental consequences. Other explanations (characterological, situational) are common, and can serve to either enhance or reduce blame of oneself or others. CONCLUSIONS To

  5. How can we explain the frontal presentation of insular lobe epilepsy? The impact of non-linear analysis of insular seizures.

    Science.gov (United States)

    Hagiwara, Koichi; Jung, Julien; Bouet, Romain; Abdallah, Chifaou; Guénot, Marc; Garcia-Larrea, Luis; Mauguière, François; Rheims, Sylvain; Isnard, Jean

    2017-05-01

    For a decade it has been known that the insular lobe epilepsy can mimic frontal lobe epilepsy. We aimed to clarify the pattern of functional coupling occurring during the frontal presentation. We analyzed five insular lobe epilepsy patients. Frontal semiology was predominant for three of them, whereas insular semiology was predominant for the two others. We applied the non-linear regression analysis to stereoelectroencephalography-recorded seizures. A directed functional coupling index was calculated during clonic discharge periods that were accompanied either with frontal or insular semiology. We found significant functional coupling between the insula and mesial frontal/cingulate regions, with the former being a leader region for seizures propagation. Extra-insular regions showed significantly less or even no coupling with the mesial hemispheric regions. The three patients with frontal semiology showed strong couplings with the mesial frontal as well as cingulate regions, including the medial orbitofrontal cortex, pre-SMA/SMA, and the anterior to posterior cingulate. The two patients with the insular semiology only showed couplings between the insula and cingulate regions. The frontal semiology was expressed by strong functional couplings between the insula and mesial frontal regions. The insular origin of seizure should be considered in cryptogenic mesial frontal epilepsies. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  6. Depression

    DEFF Research Database (Denmark)

    Eriksen, Stine Aistrup

    2017-01-01

    Use of antidepressants is associated with an increased risk of fractures, and may be a result of both negative effects on the skeleton as well as increased risk of falling; however, the specific mechanisms are not yet known. Vitamin D play important roles for bone and muscle, and has previously...... shown positive effects in lowering the risk of osteoporosis and risk of falling. In addition, vitamin D may improve mental health, and deficiency of vitamin D is a common condition among patients suffering from depression. This thesis investigates bone and factors related to fall risk (including muscle...

  7. 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

  8. 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.

  9. Multiple aberrations in shared inflammatory and oxidative & nitrosative stress (IO&NS) pathways explain the co-association of depression and cardiovascular disorder (CVD), and the increased risk for CVD and due mortality in depressed patients.

    Science.gov (United States)

    Maes, Michael; Ruckoanich, Piyanuj; Chang, Young Seun; Mahanonda, Nithi; Berk, Michael

    2011-04-29

    There is evidence that there is a bidirectional relationship between major depression and cardiovascular disorder (CVD): depressed patients are a population at risk for increased cardiac morbidity and mortality, and depression is more frequent in patients who suffer from CVD. There is also evidence that inflammatory and oxidative and nitrosative stress (IO&NS) pathways underpin the common pathophysiology of both CVD and major depression. Activation of these pathways may increase risk for both disorders and contribute to shared risk. The shared IO&NS pathways that may contribute to CVD and depression comprise the following: increased levels of pro-inflammatory cytokines, like interleukin-1β (IL-1β), IL-2, IL-6, IL-8, IL-12, tumor necrosis factor-α, and interferon-γ; T cell activation; increased acute phase proteins, like C-reactive protein, haptoglobin, fibrinogen and α1-antitrypsin; complement factors; increased LPS load through bacterial translocation and subsequent gut-derived inflammation; induction of indoleamine 2,3-dioxygenase with increased levels of tryptophan catabolites; decreased levels of antioxidants, like coenzyme Q10, zinc, vitamin E, glutathione and glutathione peroxidase; increased O&NS characterized by oxidative damage to low density lipoprotein (LDL) and phospholipid inositol, increased malondialdehyde, and damage to DNA and mitochondria; increased nitrosative stress; and decreased ω3 polyunsaturated fatty acids (PUFAs). The complex interplay between the abovementioned IO&NS pathways in depression results in pro-atherogenic effects and should be regarded as a risk factor to future clinical CVD and due mortality. We suggest that major depression should be added as a risk factor to the Charlson "comorbidity" index. It is advised that patients with (sub)chronic or recurrent major depression should routinely be assessed by serology tests to predict if they have an increased risk to cardiovascular disorders. Copyright © 2010 Elsevier Inc. All

  10. 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...

  11. 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

  12. 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.

  13. 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

  14. 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

  15. Non-linear oscillations

    CERN Document Server

    Hagedorn, Peter

    1982-01-01

    Thoroughly revised and updated, the second edition of this concise text provides an engineer's view of non-linear oscillations, explaining the most important phenomena and solution methods. Non-linear descriptions are important because under certain conditions there occur large deviations from the behaviors predicted by linear differential equations. In some cases, completely new phenomena arise that are not possible in purely linear systems. The theory of non-linear oscillations thus has important applications in classical mechanics, electronics, communications, biology, and many other branches of science. In addition to many other changes, this edition has a new section on bifurcation theory, including Hopf's theorem.

  16. 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

  17. 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

  18. 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

  19. Nonlinear analysis

    National Research Council Canada - National Science Library

    Rassias, Themistocles M

    1987-01-01

    ... known that nonlinear partial differential equations can not be treated in the same systematic way as linear ones and this volume provides, among other things, proofs of existence and uniqueness theorems for nonlinear differential equations of a global nature. However, the basic techniques which have proven to be efficient in dealing with li...

  20. 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...

  1. 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.)

  2. 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...

  3. 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

  4. 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/ ...

  5. Nonlinear reconstruction

    Science.gov (United States)

    Zhu, Hong-Ming; Yu, Yu; Pen, Ue-Li; Chen, Xuelei; Yu, Hao-Ran

    2017-12-01

    We present a direct approach to nonparametrically reconstruct the linear density field from an observed nonlinear map. We solve for the unique displacement potential consistent with the nonlinear density and positive definite coordinate transformation using a multigrid algorithm. We show that we recover the linear initial conditions up to the nonlinear scale (rδrδL>0.5 for k ≲1 h /Mpc ) with minimal computational cost. This reconstruction approach generalizes the linear displacement theory to fully nonlinear fields, potentially substantially expanding the baryon acoustic oscillations and redshift space distortions information content of dense large scale structure surveys, including for example SDSS main sample and 21 cm intensity mapping initiatives.

  6. 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.

  7. 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...

  8. Practical Nonlinearities

    Science.gov (United States)

    2016-07-01

    architectures , practical nonlinearities, nonlinear dynamics 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT: SAR 8. NUMBER OF PAGES...performers from Mesodynamic Architectures (MESO) and uPNT all to include devices in these runs. This cost-sharing was planned, and is necessary for...contributions to the performance of MEMS gyroscopes. In particular, we have demonstrated for the first time that Parametric Amplification can improve the

  9. 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 ...

  10. Reporting explained variance

    Science.gov (United States)

    Good, Ron; Fletcher, Harold J.

    The importance of reporting explained variance (sometimes referred to as magnitude of effects) in ANOVA designs is discussed in this paper. Explained variance is an estimate of the strength of the relationship between treatment (or other factors such as sex, grade level, etc.) and dependent variables of interest to the researcher(s). Three methods that can be used to obtain estimates of explained variance in ANOVA designs are described and applied to 16 studies that were reported in recent volumes of this journal. The results show that, while in most studies the treatment accounts for a relatively small proportion of the variance in dependent variable scores., in., some studies the magnitude of the treatment effect is respectable. The authors recommend that researchers in science education report explained variance in addition to the commonly reported tests of significance, since the latter are inadequate as the sole basis for making decisions about the practical importance of factors of interest to science education researchers.

  11. 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.

  12. 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

  13. Postpartum Depression

    Science.gov (United States)

    ... Patients Search FAQs Postpartum Depression Page Navigation ▼ ACOG Pregnancy Book Postpartum Depression Patient Education FAQs Postpartum Depression Patient Education Pamphlets - Spanish Postpartum ...

  14. 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...

  15. 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

  16. 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...

  17. A perspective on nonlinear dynamics

    Indian Academy of Sciences (India)

    of material stress is explained in terms of a dynamical model. Other talks at the conference dealt with the transition to turbulence in pipe flow (Eckhardt) .... ECG or EEG signals, and subsequent analysis through techniques developed for nonlinear dynamical systems has been useful and instructive, especially with respect.

  18. Nonlinearity, Conservation Law and Shocks

    Indian Academy of Sciences (India)

    the Mathematics. Olympiad in India. Phoolan Prasad. We present in two parts, a mathematical theory of conservation laws using the language of physics. In Part I we explain the concept of a special type of nonlinearity which appears in an important class of evolutionary processes governed by hyperbolic partial differential.

  19. Correlations and Non-Linear Probability Models

    DEFF Research Database (Denmark)

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

    2014-01-01

    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 betwee...... 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....

  20. Pathways from education to depression.

    Science.gov (United States)

    Lee, Jinkook

    2011-06-01

    We examine educational gradients in depression and identify underlying mechanisms of how education might affect depression. We use a nationally representative sample of community-residing adults aged 45 and older from the 2006 Korean Longitudinal Study of Aging, which collected information about depressive symptoms and education. Using tobit regression, we estimate the effect of education on depression and examine what can explain the education gradients by controlling for proxy variables of different pathways linking education to depression. We found cognitive ability, economic resources, social status, social network, and health behavior explain all of the education gradients. Education affects depression through different underlying mechanisms, and the single most important pathway is through developing cognitive ability. Through these pathways, educational attainment influences not only depression for an individual but also for one's spouse, particularly for women, and parents.

  1. Present and Future of Nonlinear Dynamics According to a Nonlinear Dynamicist

    Science.gov (United States)

    Yagasaki, Kazuyuki

    The present state and future of “nonlinear dynamics” is explained in this review. First, chaotic vibrations of nonlinear beams are used as a material to demonstrate our present understanding of chaos, compared with the situation of the early stage of its research. Second, two topics, microcantilever dynamics of tapping-mode atomic force microscopy and design of Earth to the Moon transfer trajectories of spacecrafts, are chosen for describing the importance and usefulness of “nonlinear dynamics” in new technologies. Moreover, two applications of “nonlinear dynamics” to biped walking robots and nonlinear optimal control are briefly addressed.

  2. 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

  3. 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.

  4. 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.

  5. Explaining wartime rape.

    Science.gov (United States)

    Gottschall, Jonathan

    2004-05-01

    In the years since the first reports of mass rapes in the Yugoslavian wars of secession and the genocidal massacres in Rwanda, feminist activists and scholars, human rights organizations, journalists, and social scientists have dedicated unprecedented efforts to document, explain, and seek solutions for the phenomenon of wartime rape. While contributors to this literature agree on much, there is no consensus on causal factors. This paper provides a brief overview of the literature on wartime rape in historical and ethnographical societies and a critical analysis of the four leading explanations for its root causes: the feminist theory, the cultural pathology theory, the strategic rape theory, and the biosocial theory. The paper concludes that the biosocial theory is the only one capable of bringing all the phenomena associated with wartime rape into a single explanatory context.

  6. Explaining moral religions.

    Science.gov (United States)

    Baumard, Nicolas; Boyer, Pascal

    2013-06-01

    Moralizing religions, unlike religions with morally indifferent gods or spirits, appeared only recently in some (but not all) large-scale human societies. A crucial feature of these new religions is their emphasis on proportionality (between deeds and supernatural rewards, between sins and penance, and in the formulation of the Golden Rule, according to which one should treat others as one would like others to treat oneself). Cognitive science models that account for many properties of religion can be extended to these religions. Recent models of evolved dispositions for fairness in cooperation suggest that proportionality-based morality is highly intuitive to human beings. The cultural success of moralizing movements, secular or religious, could be explained based on proportionality. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. 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...

  8. 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

  9. 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 ·    ...

  10. 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.

  11. 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 ...

  12. 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 ...

  13. 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.

  14. Explaining gender segregation.

    Science.gov (United States)

    Blackburn, Robert M; Browne, Jude; Brooks, Bradley; Jarman, Jennifer

    2002-12-01

    Occupational gender segregation--the tendency for women and men to work in different occupations--is an important feature of all societies, and particularly the wealthy industrialized ones. To understand this segregation, and to explain its significance, we need to distinguish between vertical segregation entailing inequality and horizontal segregation representing difference without inequality, with overall segregation being the resultant of these components. Three major theoretical approaches to understanding occupational gender segregation are examined: human capital/rational choice, patriarchy, and preference theories. All are found to be inadequate; they tend to confuse overall segregation with its vertical component, and each entails a number of other faults. It is generally assumed or implied that greater empowerment of women would reduce gender segregation. This is the reverse of what actually happens; in countries where the degree of women's empowerment is greater, the level of gender segregation is also greater. An alternative theoretical approach based on processes of social reproduction is shown to be more useful.

  15. Explaining Synthesized Software

    Science.gov (United States)

    VanBaalen, Jeffrey; Robinson, Peter; Lowry, Michael; Pressburger, Thomas; Lau, Sonie (Technical Monitor)

    1998-01-01

    Motivated by NASA's need for high-assurance software, NASA Ames' Amphion project has developed a generic program generation system based on deductive synthesis. Amphion has a number of advantages, such as the ability to develop a new synthesis system simply by writing a declarative domain theory. However, as a practical matter, the validation of the domain theory for such a system is problematic because the link between generated programs and the domain theory is complex. As a result, when generated programs do not behave as expected, it is difficult to isolate the cause, whether it be an incorrect problem specification or an error in the domain theory. This paper describes a tool we are developing that provides formal traceability between specifications and generated code for deductive synthesis systems. It is based on extensive instrumentation of the refutation-based theorem prover used to synthesize programs. It takes augmented proof structures and abstracts them to provide explanations of the relation between a specification, a domain theory, and synthesized code. In generating these explanations, the tool exploits the structure of Amphion domain theories, so the end user is not confronted with the intricacies of raw proof traces. This tool is crucial for the validation of domain theories as well as being important in everyday use of the code synthesis system. It plays an important role in validation because when generated programs exhibit incorrect behavior, it provides the links that can be traced to identify errors in specifications or domain theory. It plays an important role in the everyday use of the synthesis system by explaining to users what parts of a specification or of the domain theory contribute to what pieces of a generated program. Comments are inserted into the synthesized code that document these explanations.

  16. 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...

  17. [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

  18. 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.)

  19. 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.

  20. Anti-Clotting Agents Explained

    Science.gov (United States)

    ... Simple Techniques Can Help Memory after a Stroke Self-Esteem after Stroke Cognitive Challenges After Stroke Depression Trumps ... on 04/30/2014. Let's Talk About Stroke Fact Sheets Our stroke fact sheets cover treatments, recovery, ...

  1. 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

  2. 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

  3. Depression Treatment

    Science.gov (United States)

    ... Health Infertility White Paper CDC Programs and Activities Assisted Reproductive Technology (ART) Depression Among Women Depression Treatment ... department for emergency medical treatment. Call the National Suicide Prevention Lifeline at 1-800-273-TALK (8255), ...

  4. 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 ...

  5. Incorporating nonlinearity into mediation analyses.

    Science.gov (United States)

    Knafl, George J; Knafl, Kathleen A; Grey, Margaret; Dixon, Jane; Deatrick, Janet A; Gallo, Agatha M

    2017-03-21

    Mediation is an important issue considered in the behavioral, medical, and social sciences. It addresses situations where the effect of a predictor variable X on an outcome variable Y is explained to some extent by an intervening, mediator variable M. Methods for addressing mediation have been available for some time. While these methods continue to undergo refinement, the relationships underlying mediation are commonly treated as linear in the outcome Y, the predictor X, and the mediator M. These relationships, however, can be nonlinear. Methods are needed for assessing when mediation relationships can be treated as linear and for estimating them when they are nonlinear. Existing adaptive regression methods based on fractional polynomials are extended here to address nonlinearity in mediation relationships, but assuming those relationships are monotonic as would be consistent with theories about directionality of such relationships. Example monotonic mediation analyses are provided assessing linear and monotonic mediation of the effect of family functioning (X) on a child's adaptation (Y) to a chronic condition by the difficulty (M) for the family in managing the child's condition. Example moderated monotonic mediation and simulation analyses are also presented. Adaptive methods provide an effective way to incorporate possibly nonlinear monotonicity into mediation relationships.

  6. Incorporating nonlinearity into mediation analyses

    Directory of Open Access Journals (Sweden)

    George J. Knafl

    2017-03-01

    Full Text Available Abstract Background Mediation is an important issue considered in the behavioral, medical, and social sciences. It addresses situations where the effect of a predictor variable X on an outcome variable Y is explained to some extent by an intervening, mediator variable M. Methods for addressing mediation have been available for some time. While these methods continue to undergo refinement, the relationships underlying mediation are commonly treated as linear in the outcome Y, the predictor X, and the mediator M. These relationships, however, can be nonlinear. Methods are needed for assessing when mediation relationships can be treated as linear and for estimating them when they are nonlinear. Methods Existing adaptive regression methods based on fractional polynomials are extended here to address nonlinearity in mediation relationships, but assuming those relationships are monotonic as would be consistent with theories about directionality of such relationships. Results Example monotonic mediation analyses are provided assessing linear and monotonic mediation of the effect of family functioning (X on a child’s adaptation (Y to a chronic condition by the difficulty (M for the family in managing the child's condition. Example moderated monotonic mediation and simulation analyses are also presented. Conclusions Adaptive methods provide an effective way to incorporate possibly nonlinear monotonicity into mediation relationships.

  7. Nonlinear mechanics of rigidifying curves.

    Science.gov (United States)

    Al Mosleh, Salem; Santangelo, Christian

    2017-07-01

    Thin shells are characterized by a high cost of stretching compared to bending. As a result isometries of the midsurface of a shell play a crucial role in their mechanics. In turn, curves on the midsurface with zero normal curvature play a critical role in determining the number and behavior of isometries. In this paper, we show how the presence of these curves results in a decrease in the number of linear isometries. Paradoxically, shells are also known to continuously fold more easily across these rigidifying curves than other curves on the surface. We show how including nonlinearities in the strain can explain these phenomena and demonstrate folding isometries with explicit solutions to the nonlinear isometry equations. In addition to explicit solutions, exact geometric arguments are given to validate and guide our analysis in a coordinate-free way.

  8. Nonlinear elliptic differential equations with multivalued nonlinearities

    Indian Academy of Sciences (India)

    Springer Verlag Heidelberg #4 2048 1996 Dec 15 10:16:45

    Nonlinear elliptic differential equations with multivalued ... has a solution. Finally in the last part we consider an eigenvalue problem with a nonmonotone multivalued nonlinearity. Using the critical point theory for nonsmooth .... A is upper semicontinuous (as a set-valued map) from every finite dimensional subspace of X into ...

  9. Periodic and solitary wave solutions of cubic–quintic nonlinear ...

    Indian Academy of Sciences (India)

    odic, double-kink, bell and antikink-type solutions for cubic–quintic nonlinear reaction-diffusion equation are extracted. Such solutions can be used to explain various biological and physical phenomena. Keywords. Variable coefficient reaction-diffusion equation; solitary wave solution; cubic–quintic nonlinearity. PACS No.

  10. 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.

  11. 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

  12. 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.

  13. 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...

  14. Your Radiologist Explains CT Colonography

    Medline Plus

    Full Text Available ... Radiology and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains CT Colonography (Virtual ... to allow for inflation with air while CT images are being taken. If you’re scheduled for ...

  15. Your Radiologist Explains Nuclear Medicine

    Medline Plus

    Full Text Available ... Radiology and You Take our survey 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’ ...

  16. Your Radiologist Explains Nuclear Medicine

    Medline Plus

    Full Text Available ... Abdominal Ultrasound Video: Pelvic Ultrasound Medical Imaging Costs Radiology and You Take our survey Sponsored by Image/ ... Your Radiologist Explains Nuclear Medicine Transcript Welcome to Radiology Info dot org Hello! I’m Dr. Ramji ...

  17. Your Radiologist Explains CT Colonography

    Medline Plus

    Full Text Available ... Abdominal Ultrasound Video: Pelvic Ultrasound Medical Imaging Costs Radiology and You Take our survey Sponsored by Image/ ... Explains CT Colonography (Virtual colonoscopy) Transcript Welcome to Radiology Info dot org! Hi, I’m Dr. Elliot ...

  18. Your Radiologist Explains CT Colonography

    Medline Plus

    Full Text Available ... and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains CT Colonography (Virtual colonoscopy) ... Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound Radiology and You ...

  19. Your Radiologist Explains Nuclear Medicine

    Medline Plus

    Full Text Available ... and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript Welcome ... Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound Radiology and You ...

  20. 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

  1. 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 ...

  2. 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 ...

  3. Your Radiologist Explains Nuclear Medicine

    Science.gov (United States)

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

  4. 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 nonlinear...

  5. Nonlinear Microwave Optomechanics

    NARCIS (Netherlands)

    Shevchuk, O.

    2017-01-01

    The nonlinearity is essential for creation of non-classical states of the cavity or mechanical resonator such as squeezed or cat states. A microwave cavity can be made nonlinear by, for instance, adding Josephson junctions. The mechanical resonator is inherently nonlinear. The radiation pressure

  6. 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.

  7. New Treatment Strategies of Depression: Based on Mechanisms Related to Neuroplasticity

    OpenAIRE

    Huang, Yu-Jhen; Lane, Hsien-Yuan; Lin, Chieh-Hsin

    2017-01-01

    Major depressive disorder is a severe and complex mental disorder. Impaired neurotransmission and disrupted signalling pathways may influence neuroplasticity, which is involved in the brain dysfunction in depression. Traditional neurobiological theories of depression, such as monoamine hypothesis, cannot fully explain the whole picture of depressive disorders. In this review, we discussed new treatment directions of depression, including modulation of glutamatergic system and noninvasive brai...

  8. 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…

  9. Postpartum Depression

    Science.gov (United States)

    ... first. The risk increases if: You have a history of depression, either during pregnancy or at other times You have bipolar disorder ... common as well. Prevention If you have a history of depression — ... pregnant. During pregnancy, your doctor can monitor you closely for signs ...

  10. Factors explaining variance in perceived pain in women with fibromyalgia

    OpenAIRE

    Malt, Eva Albertsen; Olafsson, Snorri; Lund, Anders; Ursin, Holger

    2002-01-01

    Abstract Background We hypothesized that a substantial proportion of the subjectively experienced variance in pain in fibromyalgia patients would be explained by psychological factors alone, but that a combined model, including neuroendocrine and autonomic factors, would give the most parsimonious explanation of variance in pain. Methods Psychometric assessment included McGill Pain Questionnaire, General Health Questionnaire, Hospital Anxiety and Depression Rating Scale, Eysenck personality I...

  11. 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)

  12. 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

  13. 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.

  14. 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 Hello! ... I’d like to talk to you about nuclear medicine. Nuclear medicine offers the potential to identify disease ...

  15. 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.

  16. Reduction of nonlinear patterning effects in SOA-based All-optical Switches using Optical filtering

    DEFF Research Database (Denmark)

    Nielsen, Mads Lønstrup; Mørk, Jesper; Skaguchi, J.

    2005-01-01

    We explain theoretically, and demonstrate and quantify experimentally, how appropriate filtering can reduce the dominant nonlinear patterning effect, which limits the performance of differential-mode SOA-based switches.......We explain theoretically, and demonstrate and quantify experimentally, how appropriate filtering can reduce the dominant nonlinear patterning effect, which limits the performance of differential-mode SOA-based switches....

  17. 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.

  18. 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.

  19. 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 ...

  20. 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.

  1. Can bootstrapping explain concept learning?

    Science.gov (United States)

    Beck, Jacob

    2017-01-01

    Susan Carey's account of Quinean bootstrapping has been heavily criticized. While it purports to explain how important new concepts are learned, many commentators complain that it is unclear just what bootstrapping is supposed to be or how it is supposed to work. Others allege that bootstrapping falls prey to the circularity challenge: it cannot explain how new concepts are learned without presupposing that learners already have those very concepts. Drawing on discussions of concept learning from the philosophical literature, this article develops a detailed interpretation of bootstrapping that can answer the circularity challenge. The key to this interpretation is the recognition of computational constraints, both internal and external to the mind, which can endow empty symbols with new conceptual roles and thus new contents. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. 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...

  3. 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

  4. 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.

  5. 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

  6. 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

  7. Postpartum Depression

    Science.gov (United States)

    ... develop after childbirth. Postpartum depression isn't a character flaw or a weakness. Sometimes it's simply a ... eating difficulties, excessive crying, and attention-deficit/hyperactivity disorder (ADHD). Delays in language development are more common as well. Prevention If ...

  8. Teen Depression

    Science.gov (United States)

    ... t you just ‘snap out’ of depression? Well-meaning friends or family members may try to tell ... in ways that will jeopardize the integrity and “brand” when using the publication. The addition of non- ...

  9. Postpartum depression

    Science.gov (United States)

    ... the pregnancy Had depression, bipolar disorder , or an anxiety disorder before your pregnancy, or with a past pregnancy Had a stressful event during the pregnancy or delivery, including personal illness, death or illness of a loved one, a ...

  10. Psychosocial factors associated with depressive mood in Israeli obese adolescents.

    Science.gov (United States)

    Yackobovitch-Gavan, Michal; Meshy-Tamir, Revital; Nagelberg, Nessia; Phillip, Moshe; Meyerovitch, Joseph

    2014-04-01

    This study aimed to compare levels of depressive symptoms between normal-weight and obese Israeli adolescents and to identify sociodemographic factors that may explain differences in depression between these groups. Thirty normal-weight and 49 obese patients aged 12-18 years participated in this study. The obese group had a significantly higher depression score. On linear regression analysis, obesity, lower parental income, and lower self-esteem were significantly associated with a higher depression score. This model explained 32.4 percent of the variance. The results indicate that psychosocial assessment and identification of depressive signs should be considered integral components in the management of adolescent obesity.

  11. Flying Into Depression.

    Science.gov (United States)

    O'Hagan, Anna Donnla; Issartel, Johann; Nevill, Alan; Warrington, Giles

    2017-03-01

    A growing body of evidence suggests long work hours adversely affect mental health across a variety of domains. Mental health issues have been found to negatively affect work performance. This finding was highlighted in the aviation industry by the 2015 Germanwings incident in which 150 people died. Further investigation into work hours and their associated factors (e.g., demographic characteristics and experiences of sleep and fatigue in the cockpit) contributing to mental health issues among pilots is warranted. A cross-sectional survey investigating attitudes and experiences of fatigue was developed and distributed to commercial airline pilots. Results found pilots who reported typically spending longer hours on duty per week were twice as likely to report feeling depressed or anxious. Pilots' experiences of job-related sleep disturbance and fatigue may explain why pilots who typically spend long hours on duty each week are more likely to report feeling depressed or anxious.

  12. 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

  13. 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.

  14. 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.

  15. 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...

  16. Spacecraft nonlinear control

    Science.gov (United States)

    Sheen, Jyh-Jong; Bishop, Robert H.

    1992-01-01

    The feedback linearization technique is applied to the problem of spacecraft attitude control and momentum management with control moment gyros (CMGs). The feedback linearization consists of a coordinate transformation, which transforms the system to a companion form, and a nonlinear feedback control law to cancel the nonlinear dynamics resulting in a linear equivalent model. Pole placement techniques are then used to place the closed-loop poles. The coordinate transformation proposed here evolves from three output functions of relative degree four, three, and two, respectively. The nonlinear feedback control law is presented. Stability in a neighborhood of a controllable torque equilibrium attitude (TEA) is guaranteed and this fact is demonstrated by the simulation results. An investigation of the nonlinear control law shows that singularities exist in the state space outside the neighborhood of the controllable TEA. The nonlinear control law is simplified by a standard linearization technique and it is shown that the linearized nonlinear controller provides a natural way to select control gains for the multiple-input, multiple-output system. Simulation results using the linearized nonlinear controller show good performance relative to the nonlinear controller in the neighborhood of the TEA.

  17. 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.

  18. Lasers for nonlinear microscopy.

    Science.gov (United States)

    Wise, Frank

    2013-03-01

    Various versions of nonlinear microscopy are revolutionizing the life sciences, almost all of which are made possible because of the development of ultrafast lasers. In this article, the main properties and technical features of short-pulse lasers used in nonlinear microscopy are summarized. Recent research results on fiber lasers that will impact future instruments are also discussed.

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

    Science.gov (United States)

    Pedrelli, Paola; Collado, Anahi; Shapero, Benjamin G; Brill, Charlotte; MacPherson, Laura

    2016-10-01

    Comprehensive models elucidating the intricate associations of depressive symptoms, coping motives, alcohol use, alcohol-related problems (ARPs), and gender among young adults have been scarcely examined. This study investigated relationships among these variables and the effect of gender on these pathways. College students (N = 163; 49.7% female) completed self-report measures on alcohol consumption, depressive symptoms, coping motives, and ARPs. 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. 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.

  20. 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

  1. 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.

  2. Nonlinear optics and photonics

    CERN Document Server

    He, Guang S

    2015-01-01

    This book provides a comprehensive presentation on most of the major topics in nonlinear optics and photonics, with equal emphasis on principles, experiments, techniques, and applications. It covers many major new topics including optical solitons, multi-photon effects, nonlinear photoelectric effects, fast and slow light , and Terahertz photonics. Chapters 1-10 present the fundamentals of modern nonlinear optics, and could be used as a textbook with problems provided at the end of each chapter. Chapters 11-17 cover the more advanced topics of techniques and applications of nonlinear optics and photonics, serving as a highly informative reference for researchers and experts working in related areas. There are also 16 pages of color photographs to illustrate the visual appearances of some typical nonlinear optical effects and phenomena. The book could be adopted as a textbook for both undergraduates and graduate students, and serve as a useful reference work for researchers and experts in the fields of physics...

  3. Whites’ Depression More Hopeless than Blacks’ Depression; a National Study of Older Adults

    Directory of Open Access Journals (Sweden)

    Shervin eAssari

    2016-05-01

    Full Text Available AbstractBACKGROUND: Hopelessness is a core component of depression. Our information is, however, very limited on ethnic variations in the magnitude of the link between depression and hopelessness. Using a national sample of older adults in United States, we compared Blacks and Whites for the magnitude of the association between depressive symptoms and hopelessness. METHODS: With a cross-sectional design, we used baseline data of the Religion, Aging, and Health Survey, 2001. Linear regression models were used for data analysis. Depressive symptoms (CES-D and hopelessness were conceptualized as independent and dependent variables in different models. Demographic factors (age and gender, socio-economic status (education and marital status, and health (self-rated health were covariates. Ethnicity was the moderator.RESULTS: In the pooled sample, higher depressive symptoms were predictive of hopelessness, above and beyond all covariates. We also found significant interactions suggesting that the association between depressive symptoms and hopelessness is weaker among Blacks compared to Whites. In ethnic- specific models, there were significant associations between depressive symptoms and hopelessness among Whites but not Blacks. CONCLUSIONS: Depressive symptoms accompany more hopelessness among Whites than Blacks. This finding may explain why Blacks with depression have a lower tendency to commit suicide. Future research should test whether or not Whites with depression better respond to psychotherapies and cognitive behavioral therapies that focus on hope enhancement. This finding may explain differential correlates of depression based on race and ethnicity.

  4. 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.…

  5. Obsessive-Compulsive and Depressive Symptoms: The Role of Depressive Cognitive Styles.

    Science.gov (United States)

    Shaw, Ashley M; Carbonella, Julia Y; Arditte Hall, Kimberly A; Timpano, Kiara R

    2017-08-18

    Obsessive-compulsive disorder (OCD) commonly co-occurs with depression, resulting in heightened severity and poorer treatment response. Research on the associations between specific obsessive-compulsive symptoms (OCS) and depressive symptoms has utilized measures that have not fully considered the relationship across OCS dimensions. Little is known about which factors explain the overlap between OCS and depressive symptoms. OCS and depressive symptoms may be related via depressive cognitive styles, such as rumination or dampening (i.e., down-regulating positive emotions). We evaluated the associations of OCS dimensions with depressive symptoms and cognitive styles. We also examined the indirect effects of rumination and dampening in the relationship between OCS and depressive symptoms. Participants (N = 250) completed questionnaires online. Greater depressive symptoms, rumination, and dampening were associated with greater levels of all OCS dimensions. Path analysis was utilized to examine a model including the direct effect of depressive symptoms on overall OCS and two indirect effects (through rumination and dampening). There was a significant indirect effect of depressive cognitive styles on the relationship between OCS and depressive symptoms, through rumination and dampening. Replication in a clinical sample and experimental manipulations may bear important implications for targeting depressive cognitive styles in treatments for OCD and depression.

  6. Overview of Depression

    Directory of Open Access Journals (Sweden)

    Ni Nyoman Wistya Tri Mayasari

    2013-11-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Depression is a state of disorder tone generally feeling characterized by feelings of sadness, apathy, pessimism, and loneliness. Epidemiology of depression showed a lifetime prevalence of 7-12% for men and 20-25% for women. The reason for the prevalence differences between men and women not much can be explained, but biological factors and socio-cultural influences. In the depression is sadness lasts for days so that it can disrupt work, study, eat, sleep, and enjoyment. The cause of depression is not just one, but multifactorial. Most of the cause may arise from or the people themselves. Because it is not clear on anatomy, biochemistry, or physiology. To diagnose depression may use criteria of PPDGJ or using DSM-IV-TR /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  7. Nonlinear dimensionality reduction in climate data

    OpenAIRE

    Gámez, A. J.; Zhou, C. S.; Timmermann, A.; Kurths, J.

    2004-01-01

    International audience; Linear methods of dimensionality reduction are useful tools for handling and interpreting high dimensional data. However, the cumulative variance explained by each of the subspaces in which the data space is decomposed may show a slow convergence that makes the selection of a proper minimum number of subspaces for successfully representing the variability of the process ambiguous. The use of nonlinear methods can improve the embedding of multivariate data into lower di...

  8. Inflammatory mechanisms in major depressive disorder.

    Science.gov (United States)

    Raedler, Thomas J

    2011-11-01

    As the 'monoamine hypothesis of depression' fails to explain all aspects of major depression, additional causes are being investigated. Several observations suggest that inflammatory mechanisms pay a role in the cause of major depressive disorder (MDD). This article reviews their role in major depression. Recent studies support the concept that inflammatory mechanisms play a crucial role in the pathomechanisms of major depression. Major depression shares similarities with 'sickness behavior', a normal response to inflammatory cytokines. Elevations in proinflammatory cytokines and other inflammation-related proteins in major depression were found in plasma and cerebrospinal fluid (CSF) as well as in postmortem studies. Elevated levels of proinflammatory cytokines persist after clinical symptoms of depression are in remission and can also predict the onset of a depressive episode. Antidepressant treatment can lead to a normalization of elevated cytokine levels in major depression. Finally, we understand how inflammatory mechanisms affect the metabolism of tryptophan and how nonsteroidal antiinflammatory drugs (NSAIDs) can interfere with the effects of antidepressants. Further studies are needed to fully understand the role of inflammatory mechanisms in major depression and the potential treatment implications.

  9. Rumination, anxiety, depressive symptoms and subsequent depression in adolescents at risk for psychopathology: a longitudinal cohort study.

    Science.gov (United States)

    Wilkinson, Paul O; Croudace, Tim J; Goodyer, Ian M

    2013-10-08

    A ruminative style of responding to low mood is associated with subsequent high depressive symptoms and depressive disorder in children, adolescents and adults. Scores on self-report rumination scales correlate strongly with scores on anxiety and depression symptom scales. This may confound any associations between rumination and subsequent depression. Our sample comprised 658 healthy adolescents at elevated risk for psychopathology. This study applied ordinal item (non-linear) factor analysis to pooled items from three self-report questionnaires to explore whether there were separate, but correlated, constructs of rumination, depression and anxiety. It then tested whether rumination independently predicted depressive disorder and depressive symptoms over the subsequent 12 months, after adjusting for confounding variables. We identified a single rumination factor, which was correlated with factors representing cognitive symptoms of depression, somatic symptoms of depression and anxiety symptoms; and one factor representing adaptive responses to low mood. Elevated rumination scores predicted onset of depressive disorders over the subsequent year (p = 0.035), and levels of depressive symptoms 12 months later (p depressive and anxiety symptoms. High rumination predicts onset of depressive disorder in healthy adolescents. Therapy that reduces rumination and increases distraction/problem-solving may reduce onset and relapse rates of depression.

  10. Rumination, anxiety, depressive symptoms and subsequent depression in adolescents at risk for psychopathology: a longitudinal cohort study

    Science.gov (United States)

    2013-01-01

    Background A ruminative style of responding to low mood is associated with subsequent high depressive symptoms and depressive disorder in children, adolescents and adults. Scores on self-report rumination scales correlate strongly with scores on anxiety and depression symptom scales. This may confound any associations between rumination and subsequent depression. Methods Our sample comprised 658 healthy adolescents at elevated risk for psychopathology. This study applied ordinal item (non-linear) factor analysis to pooled items from three self-report questionnaires to explore whether there were separate, but correlated, constructs of rumination, depression and anxiety. It then tested whether rumination independently predicted depressive disorder and depressive symptoms over the subsequent 12 months, after adjusting for confounding variables. Results We identified a single rumination factor, which was correlated with factors representing cognitive symptoms of depression, somatic symptoms of depression and anxiety symptoms; and one factor representing adaptive responses to low mood. Elevated rumination scores predicted onset of depressive disorders over the subsequent year (p = 0.035), and levels of depressive symptoms 12 months later (p depressive and anxiety symptoms. Conclusion High rumination predicts onset of depressive disorder in healthy adolescents. Therapy that reduces rumination and increases distraction/problem-solving may reduce onset and relapse rates of depression. PMID:24103296

  11. Explaining (Missing) Regulator Paradigm Shifts

    DEFF Research Database (Denmark)

    Wigger, Angela; Buch-Hansen, Hubert

    2014-01-01

    The global financial and economic crisis has prompted some scholars to suggest that a fundamental regulatory shift away from neoliberalism will take place – both in general and in the field of EU competition regulation. This paper shows that so far no radical break with the neoliberal type...... of competition regulation is heaving into sight. It sets out to explain this from the vantage point of a critical political economy perspective, which identifies the circumstances under which a crisis can result in a regulatory paradigm shift. Contrasting the current situation with the shift in EC/EU competition...... regulation after the crisis in the 1970s, the paper argues that the preconditions for a fundamental shift in this issue area are not present this time around. Several reasons account for this: the current crisis has been construed by economic and political elites as a crisis within and not of neoliberal...

  12. Postpartum Depression

    DEFF Research Database (Denmark)

    Smith-Nielsen, Johanne

    not only buffer or amplify effects , but which may also increase the risk of recurrent or persistent depression in the mother. These findings are also important in terms of providing appropriate help with the aim of preventing adverse developmental outcomes in the child. For a large group of PPD mothers......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...... months with the Bayley Scales of Infant and Toddler Development, third edition. Additionally, at 13 months infant-mother attachment security was assessed using Strange Situation Procedure. Results: We found that even in a well-functioned sample, symptoms of depression in the postpartum period...

  13. 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

  14. What explains consciousness? Or…What consciousness explains?

    Science.gov (United States)

    Dulany, Donelson E

    2014-01-01

    In this invited commentary I focus on the topic addressed in three papers: De Sousa's (2013[1617]) Toward an Integrative Theory of Consciousness, a monograph with Parts 1 & 2, as well as commentaries by Pereira (2013a[59]) and Hirstein (2013[42]). All three are impressively scholarly and can stand-and shout-on their own. But theory of consciousness? My aim is to slice that topic into the two fundamentally different kinds of theories of consciousness, say what appears to be an ideology, out of behaviourism into cognitivism, now also influencing the quest for an "explanation of consciousness" in cognitive neuroscience. I will then say what can be expected given what we know of the complexity of brain structure, the richness of a conscious "vocabulary", and current technological limits of brain imaging. This will then turn to the strategy for examining "what consciousness explains"-metatheory, theories, mappings, and a methodology of competitive support, a methodology especially important where there are competing commitments. There are also increasingly common identifications of methodological bias in, along with failures to replicate, studies reporting unconscious controls in decision, social priming-as there have been in perception, learning, problem solving, etc. The literature critique has provided evidence taken as reducing, and in some cases eliminating, a role for conscious controls-a position consistent with that ideology out of behaviourism into cognitivism. It is an ideological position that fails to recognize the fundamental distinction between theoretical and metaphysical assertions.

  15. Nonlinear fitness landscape of a molecular pathway.

    Directory of Open Access Journals (Sweden)

    Lilia Perfeito

    2011-07-01

    Full Text Available Genes are regulated because their expression involves a fitness cost to the organism. The production of proteins by transcription and translation is a well-known cost factor, but the enzymatic activity of the proteins produced can also reduce fitness, depending on the internal state and the environment of the cell. Here, we map the fitness costs of a key metabolic network, the lactose utilization pathway in Escherichia coli. We measure the growth of several regulatory lac operon mutants in different environments inducing expression of the lac genes. We find a strikingly nonlinear fitness landscape, which depends on the production rate and on the activity rate of the lac proteins. A simple fitness model of the lac pathway, based on elementary biophysical processes, predicts the growth rate of all observed strains. The nonlinearity of fitness is explained by a feedback loop: production and activity of the lac proteins reduce growth, but growth also affects the density of these molecules. This nonlinearity has important consequences for molecular function and evolution. It generates a cliff in the fitness landscape, beyond which populations cannot maintain growth. In viable populations, there is an expression barrier of the lac genes, which cannot be exceeded in any stationary growth process. Furthermore, the nonlinearity determines how the fitness of operon mutants depends on the inducer environment. We argue that fitness nonlinearities, expression barriers, and gene-environment interactions are generic features of fitness landscapes for metabolic pathways, and we discuss their implications for the evolution of regulation.

  16. 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.

  17. 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)…

  18. Propagation of nonlinear reactive contaminants in porous media

    Science.gov (United States)

    Serrano, Sergio E.

    2003-08-01

    A study on the effect of nonlinear reactions on the space and time distribution of contaminant plumes governed by the advective-dispersive equation in porous media was conducted. Several models of nonlinear reactions were considered: the irreversible nonlinear first-order kinetic sorption model, the nonlinear Freundlich sorption isotherm model, the nonlinear Langmuir sorption isotherm model, and the reversible nonlinear kinetic sorption model. Each of these models was coupled with the advective-dispersive equation with dimensionless concentration and an approximate analytical series solutions was obtained. Comparison between linear and nonlinear plumes indicated that nonlinear reactions may have a significant effect on the shape and spatial distribution of a contaminant at a given time and in certain cases may explain quantitatively the occurrence of scaled (e.g., concentration change while preserving shape), retarded, and nonsymmetric plumes as well as the presence of back tails and sharp front ends usually observed in the field. By adopting a nonlinear model of contaminant migration a more realistic representation of contaminant propagation is possible than that obtained with a linear model.

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

    DEFF Research Database (Denmark)

    Köhler, Karl 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...

  20. Depression and African Americans

    Science.gov (United States)

    ... You are here Home » Depression And African Americans Depression And African Americans Not “Just the Blues” Clinical ... or spiritual communities. Commonly Asked Questions about Clinical Depression How do I get help for clinical depression? ...

  1. 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 ...

  2. 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 common mental disorders in the United States. For some individuals, major depression can result in severe impairments that interfere with ...

  3. parametric nonlinear quasivariational inequalities

    Directory of Open Access Journals (Sweden)

    Zeqing Liu

    2005-01-01

    uniqueness results and sensitivity analysis of solutions are also established for the system of generalized nonlinear parametric quasivariational inequalities and some convergence results of iterative sequence generated by the algorithm with errors are proved.

  4. Nonlinear Source Emulator

    DEFF Research Database (Denmark)

    Nguyen-Duy, Khiem

    and remains the prime source of energy in non-terrestrial applications such as those in sky-explorers. However, a renewable energy source is expensive, bulky, and its performance is weather dependent, which make testing of downstream converters very difficult. As a result, a nonlinear source emulator (NSE...... 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...... simulation of nonlinear source systems with higher output power. In this work, a module will consist of two fundamental units: an isolated power supply and an NSE. The isolated power supply has to possess a very low circuit input-to-output capacitance (very low Cio) in order to reduce the effect...

  5. Cognitive Nonlinear Radar

    Science.gov (United States)

    2013-01-01

    filter, Bayesian decision theory, Generalized Likelihood Ratio Test (GLRT), and constant false alarm rate ( CFAR ) processing (31). Once the...Abbreviations, and Acronyms CFAR constant false alarm rate CNR cognitive nonlinear radar EM electromagnetic FCC Federal Communications Comission

  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. Nonlinear ambipolar diffusion waves

    Energy Technology Data Exchange (ETDEWEB)

    Mendonca, J.T.; Rowlands, G.

    1985-07-01

    The evolution of a plasma perturbation in a neutral gas is considered using the ambipolar diffusion approximation. A nonlinear diffusion equation is derived and, in the one-dimensional case, exact solutions of shock type are obtained.

  9. 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...

  10. Crossing a Nonlinear Resonance

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 9. Crossing a Nonlinear Resonance: Adiabatic Invariants and the Melnikov-Arnold Integral. Sudhir R Jain. General Article Volume 19 Issue 9 September 2014 pp 797-813 ...

  11. 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...

  12. Explain bioinformatics to your grandmother!

    Directory of Open Access Journals (Sweden)

    Virginie Bernard

    2013-10-01

    Full Text Available What are you working on? You have certainly been asked that question many times, whether it be at a Saturday night party, during a discussion with your neighbors, or at a family gathering. Communicating with a lay audience about scientific subjects and making them attractive is a difficult task. But difficult or not, you will have to do it for many years, not only with your family and friends, but also with your colleagues and collaborators. So, better learn now! Although not usually taught, the ability to explain your work to others is an essential skill in science, where communication plays a key role. Using some examples of the French Regional Student Group activities, we discuss here (i why it is important to have such communication skills, (ii how you can get involved in these activities by using existing resources or working with people who have previous experience, and (iii what you get out of this amazing experience. We aim to motivate you and provide you with tips and ideas to get involved in promoting scientific activities while getting all the benefits.

  13. 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.

  14. Nonlinear Optical Absorption and Refraction Study of Metallophthalocyanine Dyes.

    Science.gov (United States)

    Wei, Tai-Huei

    Metallophthalocyanines and related conjugated ring molecules have attracted recent interest because, as confined, reduced-dimensionality (2D) delocalized electronic systems, large electronic nonlinearities are expected. This has led to interest in: (1) developing a fundamental understanding of the mechanisms which contribute to the nonlinear optical response, (2) obtaining well defined and accurate measurements of the refractive and absorptive contributions to the observed nonlinearities, and (3) identifying means of enhancing and maximizing the nonlinear susceptibilities. This dissertation deals with the characterization of the nonlinear absorption and refraction of two representative metallophthalocyanine dyes: chloro aluminum phthalocyanine dissolved in methanol, referred to as CAP, and a silicon naphthalocyanine derivative dissolved in toluene, referred to as SiNc. Using the Z -scan technique, the experiments are performed on both the picosecond and nanosecond timescales at a wavelength of 0.532 mum. The Z-scan technique separates nonlinear absorption and nonlinear refraction by measuring both the total transmittance and far field axial transmittance of a focused Gaussian beam as a function of the position (z) of the material relative to the beam waist. In the picosecond regime, Z-scan experiments using pulses of different widths indicate that both nonlinear absorption and refraction are fluence dependent. Therefore, we determine the dominant nonlinearities are excited state absorption (ESA) and excited state refraction (ESR). Through nanosecond Z-scan measurements, we see additional nonlinear absorption and nonlinear refraction. By power limiting measurements using single picosecond pulses and trains of picosecond pulses separated by 7 nanosecond, this additional nonlinear absorption is determined due to intersystem crossing to the triplet state with subsequent triplet state ESA. Therefore, a five state model is used to explain the nonlinear absorption. On the

  15. 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.

  16. [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.

  17. 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.

  18. 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...

  19. 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)

  20. Factors explaining variance in perceived pain in women with fibromyalgia

    Directory of Open Access Journals (Sweden)

    Lund Anders

    2002-04-01

    Full Text Available Abstract Background We hypothesized that a substantial proportion of the subjectively experienced variance in pain in fibromyalgia patients would be explained by psychological factors alone, but that a combined model, including neuroendocrine and autonomic factors, would give the most parsimonious explanation of variance in pain. Methods Psychometric assessment included McGill Pain Questionnaire, General Health Questionnaire, Hospital Anxiety and Depression Rating Scale, Eysenck personality Inventory, Neuroticism and Lie subscales, Toronto Alexithymia Scale, and Multidimensional Health Locus of Control Scale and was performed in 42 female patients with fibromyalgia and 48 female age matched random sample population controls. A subgroup of the original sample (22 fibromyalgia patients and 13 controls underwent a pharmacological challenge test with buspirone to assess autonomic and adrenocortical reactivity to serotonergic challenge. Results Although fibromyalgia patients scored high on neuroticism, anxiety, depression and general distress, only a minor part of variance in pain was explained by psychological factors alone. High pain score was associated with high neuroticism, low baseline cortisol level and small drop in systolic blood pressure after buspirone challenge test. This model explained 41.5% of total pain in fibromyalgia patients. In population controls, psychological factors alone were significant predictors for variance in pain. Conclusion Fibromyalgia patients may have reduced reactivity in the central sympathetic system or perturbations in the sympathetic-parasympathetic balance. This study shows that a biopsychosocial model, including psychological factors as well as factors related to perturbations of the autonomic nervous system and hypothalamic-pituitary-adrenal axis, is needed to explain perceived pain in fibromyalgia patients.

  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. Does depression moderate handwashing in children?

    Directory of Open Access Journals (Sweden)

    Jurgita Slekiene

    2017-08-01

    Full Text Available Abstract Background Although diarrheal diseases are preventable and treatable, they are the leading cause of child mortality and morbidity as a consequence of poor hygiene and contaminated water. Handwashing with soap is an effective method for preventing and decreasing the incidence of diarrhea. However, mental disorders such as depression can substantially moderate an individual’s ability to cope with daily life and can exert a negative influence on daily hygiene activities such as handwashing with soap, especially in children. The aim of this study was to explain the influence of depression on pupils’ hand-washing behavior in Zimbabwe. Methods In a cross-sectional study, face-to-face interviews were carried out with primary school pupils in peri-urban Harare, Zimbabwe (n = 556 using a quantitative questionnaire to assess handwashing and its behavioral determinants in school settings. The Center for Epidemiological Studies Depression Scale for Children (CES-DC was used to assess depression. Results More than half of the assessed children were depressed. Self-reported handwashing with soap among depressed children was significantly lower than among non-depressed children. Almost all behavioral determinants of hand-washing behavior were significantly lower in depressed children. The behavioral determinants worked differently in the depressed children than in the non-depressed children’s group. The effects of important behavioral determinants on handwashing were moderated by depression. Conclusions Depression exerts a negative influence on handwashing in children. These results suggest depression-relieving measures should be conducted together with any water, sanitation, and hygiene (WASH interventions to make such interventions more effective.

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

    Science.gov (United States)

    Assari, Shervin; Moazen-Zadeh, Ehsan

    2016-01-01

    The 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. Data came from the National Survey of American Life, 2001-2003. We included 3570 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 major depressive disorder (MDD), lifetime major depressive episode (MDE), 12-month MDE, 30-day MDE, and 30-day major depressive disorder with hierarchy (MDDH) based on the Composite International Diagnostic Interview (CIDI). Logistic regression models were applied in the pooled sample as well as Blacks and Whites. Regarding 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-day 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 problems domains, suggesting stronger associations for Blacks compared to Whites. The CES-D total score and CES-D positive affect domain did not interact with ethnicity on CIDI-based depressive diagnoses. Stronger associations between multiple domains of depressive symptoms and clinical depression may be due to higher severity of depression among Blacks, when they endorse the CIDI criteria for 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

  4. 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...

  5. 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.  

  6. Borderline personality features in depressed or anxious patients.

    Science.gov (United States)

    Distel, Marijn A; Smit, Johannes H; Spinhoven, Philip; Penninx, Brenda W J H

    2016-07-30

    Anxiety and depression frequently co-occur with borderline personality disorder. Relatively little research examined the presence of borderline personality features and its main domains (affective instability, identity problems, negative relationships and self-harm) in individuals with remitted and current anxiety and depression. Participants with current (n=597) or remitted (n=1115) anxiety and/or depression and healthy controls (n=431) were selected from the Netherlands Study of Depression and Anxiety. Assessments included the Personality Assessment Inventory - Borderline Features Scale and several clinical characteristics of anxiety and depression. Borderline personality features were more common in depression than in anxiety. Current comorbid anxiety and depression was associated with most borderline personality features. Anxiety and depression status explained 29.7% of the variance in borderline personality features and 3.8% (self-harm) to 31% (identity problems) of the variance in the four domains. A large part of the variance was shared between anxiety and depression but both disorders also explained a significant amount of unique variance. The severity of anxiety and depression and the level of daily dysfunctioning was positively associated with borderline personality features. Individuals with a longer duration of anxiety and depression showed more affective instability and identity problems. These findings suggest that patients with anxiety and depression may benefit from an assessment of personality pathology as it may have implications for psychological and pharmacological treatment. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  7. 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...

  8. Fundamentals of nonlinear optics

    CERN Document Server

    Powers, Peter E

    2011-01-01

    Peter Powers's rigorous but simple description of a difficult field keeps the reader's attention throughout. … All chapters contain a list of references and large numbers of practice examples to be worked through. … By carefully working through the proposed problems, students will develop a sound understanding of the fundamental principles and applications. … the book serves perfectly for an introductory-level course for second- and third-order nonlinear optical phenomena. The author's writing style is refreshing and original. I expect that Fundamentals of Nonlinear Optics will fast become pop

  9. 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

  10. Fully nonlinear elliptic equations

    CERN Document Server

    Caffarelli, Luis A

    1995-01-01

    The goal of the book is to extend classical regularity theorems for solutions of linear elliptic partial differential equations to the context of fully nonlinear elliptic equations. This class of equations often arises in control theory, optimization, and other applications. The authors give a detailed presentation of all the necessary techniques. Instead of treating these techniques in their greatest generality, they outline the key ideas and prove the results needed for developing the subsequent theory. Topics discussed in the book include the theory of viscosity solutions for nonlinear equa

  11. 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...

  12. Nonlinearity in nanomechanical cantilevers

    DEFF Research Database (Denmark)

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

    2013-01-01

    predictions deviate strongly from our measurements for the nonlinearity of the fundamental flexural mode, which show a systematic dependence on aspect ratio (length/width) together with random scatter. This contrasts with the second mode, which is always found to be in good agreement with theory....... 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...

  13. Monitoring improvement using a patient-rated depression scale during treatment with anti-depressants in general practice. A validation study on the Goldberg Depression Scale.

    Science.gov (United States)

    Holm, J; Holm, L; Bech, P

    2001-12-01

    To perform a pilot study on the value of the Goldberg Depression Scale as an instrument for monitoring improvement in depressed patients treated with anti-depressants in general practice. A comparative study using simultaneous ratings on the observer-based 17-item Hamilton Depression Scale and the patient-rated Goldberg Depression Scale. General practice. Twenty-one patients meeting the ICD-10 criteria of a moderate depressive episode were assessed at the time of inclusion and through three follow-up visits. Scores on the Goldberg Depression Scale compared to the Hamilton Depression Scale. An acceptable internal and external validity of the Goldberg Depression Scale was demonstrated. The Loevinger coefficient varied from 0.25 at the time of diagnosis to 0.57, 0.65 and 0.69 by visits two, three and four. Factor analysis identified only one general factor explaining 50% or more of the variants, except at visit 1. When the Goldberg Depression Scale was correlated to the Hamilton Depression Scales, a coefficient of 0.74 was obtained (p Depression Scale is suitable for monitoring improvement in depressed patients treated in general practice. Further studies are recommended.

  14. 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

  15. 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.

  16. 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.

  17. Serotonin & Depression

    OpenAIRE

    Axholm, Ida; Haxgart, Nina; Ranum, Kasper; Svendsen, Astrid Helmer

    2014-01-01

    350.000.000 people worldwide have a depression and 150.000 Danes are affected every year. Depresion is defined by WHO from it’s syptoms. The diagnose is given from a point system for the patient’s symptoms, for instance HAM-D scale and MADRS scale Serotonin in the brain is synthesized from L-tryptophan in the presynaptic parts of the neuron and is released into the synapse as a transmitter drug. According to the serotonin theory, the concentration of serotonin in the brain is low in depressio...

  18. Nutritional interventions in depression and perinatal depression.

    Science.gov (United States)

    Rechenberg, Kaitlyn; Humphries, Debbie

    2013-06-01

    Depression is the leading cause of mental disability worldwide. Women who are depressed during pregnancy are at a higher risk for preterm delivery, preeclampsia, birth difficulties, and postpartum depression. The treatment of depression in conventional medicine has focused on physiological factors that lead to impaired neurotransmitter function and treatments to improve neurotransmitter function. Pharmaceutical substances pose risks for pregnant and lactating women, and lower risk options are preferred. Micronutrients, including certain B vitamins, folate, and docosahexaenoic acid (DHA), play a role in the synthesis and absorption of neurotransmitters. Experimental studies suggest that supplementation with specific micronutrients may alleviate depressive symptoms and improve birth outcomes in patients with perinatal depression. Alternative treatments for depression, including nutritional supplements, are an important treatment option for depressive symptoms while limiting potential side effects and treatment costs. This article explores the biological basis of perinatal depression and reviews the potential benefits of non-pharmacological interventions.

  19. Nonlinear dimensionality reduction in climate data

    Directory of Open Access Journals (Sweden)

    A. J. Gámez

    2004-01-01

    Full Text Available Linear methods of dimensionality reduction are useful tools for handling and interpreting high dimensional data. However, the cumulative variance explained by each of the subspaces in which the data space is decomposed may show a slow convergence that makes the selection of a proper minimum number of subspaces for successfully representing the variability of the process ambiguous. The use of nonlinear methods can improve the embedding of multivariate data into lower dimensional manifolds. In this article, a nonlinear method for dimensionality reduction, Isomap, is applied to the sea surface temperature and thermocline data in the tropical Pacific Ocean, where the El Niño-Southern Oscillation (ENSO phenomenon and the annual cycle phenomena interact. Isomap gives a more accurate description of the manifold dimensionality of the physical system. The knowledge of the minimum number of dimensions is expected to improve the development of low dimensional models for understanding and predicting ENSO.

  20. Nonlinear dimensionality reduction in climate data

    Science.gov (United States)

    Gámez, A. J.; Zhou, C. S.; Timmermann, A.; Kurths, J.

    2004-09-01

    Linear methods of dimensionality reduction are useful tools for handling and interpreting high dimensional data. However, the cumulative variance explained by each of the subspaces in which the data space is decomposed may show a slow convergence that makes the selection of a proper minimum number of subspaces for successfully representing the variability of the process ambiguous. The use of nonlinear methods can improve the embedding of multivariate data into lower dimensional manifolds. In this article, a nonlinear method for dimensionality reduction, Isomap, is applied to the sea surface temperature and thermocline data in the tropical Pacific Ocean, where the El Niño-Southern Oscillation (ENSO) phenomenon and the annual cycle phenomena interact. Isomap gives a more accurate description of the manifold dimensionality of the physical system. The knowledge of the minimum number of dimensions is expected to improve the development of low dimensional models for understanding and predicting ENSO.

  1. Methods of nonlinear kinetics

    OpenAIRE

    Gorban, A. N.; Karlin, I. V.

    2003-01-01

    Nonlinear kinetic equations are reviewed for a wide audience of specialists and postgraduate students in physics, mathematical physics, material science, chemical engineering and interdisciplinary research. Contents: The Boltzmann equation, Phenomenology and Quasi-chemical representation of the Boltzmann equation, Kinetic models, Discrete velocity models, Direct simulation, Lattice Gas and Lattice Boltzmann models, Minimal Boltzmann models for flows at low Knudsen number, Other kinetic equati...

  2. Nonlinear fractional relaxation

    Indian Academy of Sciences (India)

    Abstract. We define a nonlinear model for fractional relaxation phenomena. We use ε-expansion method to analyse this model. By studying the fundamental solutions of this model we find that when t → 0 the model exhibits a fast decay rate and when t → ∞ the model exhibits a power-law decay. By analysing the frequency ...

  3. 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.

  4. Nonlinear Control System

    Directory of Open Access Journals (Sweden)

    Jaydeep Jesur

    2000-01-01

    and features are added such a way that it can be also used for design of nonlinear control systems to achieve desired performance. It is very simple to learn this tool. One can easily use it with preliminary knowledge of DF and PPT methods.

  5. Nonlinear collisionless magnetic reconnection

    Science.gov (United States)

    Ottaviani, M.; Porcelli, F.

    1993-12-01

    Collisionless magnetic reconnection in regimes where the mode structure is characterized by global convection cells is found to exhibit a quasiexplosive time behavior in the early nonlinear stage where the fluid displacement is smaller than the equilibrium scale length. This process is accompanied by the formation of a current density sublayer narrower than the skin depth. This sublayer keeps shrinking with time.

  6. 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.

  7. 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

  8. 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...

  9. A nonlinear screen as an element for sound absorption and frequency conversion systems

    Science.gov (United States)

    Rudenko, O. V.

    2016-01-01

    The paper discusses a model for a screen with dissipative and nonlinear elastic properties that can be used in acoustic sound absorption and frequency conversion systems. Calculation and estimation schemes are explained that are necessary for understanding the functional capabilities of the device. Examples of the nonlinear elements in the screen and promising applications are described.

  10. 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...

  11. Alcoholism & depression.

    Science.gov (United States)

    Hall, Mellisa

    2012-10-01

    One out of 2 Americans report drinking on a routine basis, making the excessive consumption of alcohol the third leading cause of preventable death in America (). Alcoholism and depression are common comorbidities that home healthcare professionals frequently encounter. To achieve the best patient outcomes, alcoholism should be addressed initially. Although all age groups are at risk, alcoholism and depression occur in more than 8 percent of older adults. Prevention through identifying alcohol use early in adolescence is vital to reduce the likelihood of alcohol dependence. This article provides an overview of the long-term effects of alcohol abuse, including alcoholic cirrhosis and hepatic encephalopathy. The diagnostic criteria for substance dependence and ideas for nonthreatening screening questions to use with patients who are adolescent or older are discussed. While providing patient care, home healthcare nurses share the patient's intimate home environment. This environment is perceived as a safe haven by the patient and home care nurses can take advantage of counseling and treatment opportunities in this nonthreatening environment.

  12. 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.

  13. 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.)

  14. A nonlinear approach to analyse the development of tropical ...

    Indian Academy of Sciences (India)

    The development of atmospheric disturbances in the tropical region is explained using vibrational resonance, a nonlinear phenomenon. As the Lorenz system is the most plausible model to describe the convective process in a tropical region, the influence of vertical wind shear and tropical waves on the system leading to ...

  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. On nonlinear Fourier transform: towards the nonlinear superposition

    Science.gov (United States)

    Saksida, Pavle

    2017-01-01

    In the paper we consider the nonlinear Fourier transform associated to the AKNSZS systems. In particular, we discuss the construction of the nonlinear Fourier modes of this transform by means of a perturbation scheme. The linearization of the AKNS-ZS nonlinear Fourier transform is the usual, linear Fourier transform and the linearization of a nonlinear Fourier mode of frequency d is the linear Fourier mode of the same frequency. We show that the first non-trivial term in the perturbation expression of any nonlinear Fourier mode is given by the dilogarithm function.

  17. Nonlinearity, Conservation Law and Shocks

    Indian Academy of Sciences (India)

    Nonlinearity, Conservation Law and Shocks. Part I : Genuine Nonlinearity and Discontinuous Solutions. Phoolan Prasad is with the. Department of. Mathematics, Indian. Institute of Science and has been working in the area of nonlinear waves and hyperbolic partial differential equations. He is deeply interested in.

  18. 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....

  19. 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.

  20. Fault Detection for Nonlinear Systems

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.H.

    1998-01-01

    The paper describes a general method for designing fault detection and isolation (FDI) systems for nonlinear processes. For a rich class of nonlinear systems, a nonlinear FDI system can be designed using convex optimization procedures. The proposed method is a natural extension of methods based o...

  1. 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.

  2. Physical inactivity, depression, and risk of cardiovascular mortality

    NARCIS (Netherlands)

    Kamphuis, M.H.; Geerlings, M.I.; Tijhuis, M.A.R.; Giampaoli, S.; Nissinen, A.; Grobbee, D.E.; Kromhout, D.

    2007-01-01

    Purpose: Studies indicate that depression may increase risk of cardiovascular disease (CVD) in addition to classical risk factors. One of the hypotheses to explain this relation is that depressed subjects become physically inactive. We set out to determine the role of physical inactivity in the

  3. Child Abuse and Revictimization: Depression and Dissociation as Mediator Variables.

    Science.gov (United States)

    Becker-Lausen, Evvie; And Others

    Based on a review of prior research, a causal model was proposed to explain the relationship between child abuse, dissociation, depression, and revictimization. In the model, dissociation and depression were proposed as mediator variables, developing out of child abuse and leading to revictimization. Subjects were 301 male and female university…

  4. A Component Analysis of Cognitive-Behavioral Treatment for Depression.

    Science.gov (United States)

    Jacobson, Neil S.; And Others

    1996-01-01

    Tested Beck's theory explaining efficacy of cognitive- behavioral therapy (CT) for depression. Involved randomly assigning 150 outpatients with major depression to a treatment focused on the behavioral activation (BA) component of CT, a treatment including BA and teaching skills to modify automatic thoughts, but excluding the components of CT…

  5. Depressive Symptoms and Cigarette Smoking in a College Sample

    Science.gov (United States)

    Kenney, Brent A.; Holahan, Charles J.

    2008-01-01

    Objective and Participants: The authors examined (1) the relationship between depressive symptoms and cigarette smoking in a college sample and (2) the role of smoking self-efficacy (one's perceived ability to abstain from smoking) in explaining the relationship between depressive symptoms and cigarette smoking. Methods: Predominantly first-year…

  6. [Alexithymia and depression in eating disorders].

    Science.gov (United States)

    Guilbaud, O; Corcos, M; Chambry, J; Paterniti, S; Loas, G; Jeammet, P

    2000-01-01

    Patients suffering from eating disorder show elevated rates of alexithymia and depression. We compared alexithymia and depression ratings for non-hospitalized women meeting DSM IV criteria for anorexia nervosa (n = 32) and bulimia nervosa (n = 32) to healthy women (n = 74). Alexithymia was evaluated by the Toronto Alexithymia Scale (TAS-20) and depression by the Hospital Anxiety and Depression Scale (HAD). We found that TAS and HAD scores were significantly higher in anorexic compared to bulimic patients, although alexithymia and depression, as evaluated, were significantly and positively correlated with each other (r = 0.53, p = 0.001). Finally, a logistic regression with alexithymia and depression as independent variables showed a strong correlations between the HAD ratings and anorexia, but no correlations between TAS score and the eating disorder subgroups. In eating disorder patients, alexithymia, as evaluated by the Toronto Alexithymia Scale, seems to exhibit a thymo-dependent component which could be secondary to concurrent depression. Through recent studies and results of our research, we analyze and give several interpretations which may explain this correlation between alexithymia and depression.

  7. 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.

  8. 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.

  9. Nonlinear terahertz superconducting plasmonics

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jingbo; Liang, Lanju; Jin, Biaobing, E-mail: bbjin@nju.edu.cn, E-mail: tonouchi@ile.osaka-u.ac.jp, E-mail: phwu@nju.edu.cn; Kang, Lin; Xu, Weiwei; Chen, Jian; Wu, Peiheng, E-mail: bbjin@nju.edu.cn, E-mail: tonouchi@ile.osaka-u.ac.jp, E-mail: phwu@nju.edu.cn [Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Zhang, Caihong; Kawayama, Iwao; Murakami, Hironaru; Tonouchi, Masayoshi, E-mail: bbjin@nju.edu.cn, E-mail: tonouchi@ile.osaka-u.ac.jp, E-mail: phwu@nju.edu.cn [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Wang, Huabing [Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); National Institute for Materials Science, Tsukuba 305-0047 (Japan)

    2014-10-20

    Nonlinear terahertz (THz) transmission through subwavelength hole array in superconducting niobium nitride (NbN) film is experimentally investigated using intense THz pulses. The good agreement between the measurement and numerical simulations indicates that the field strength dependent transmission mainly arises from the nonlinear properties of the superconducting film. Under weak THz pulses, the transmission peak can be tuned over a frequency range of 145 GHz which is attributed to the high kinetic inductance of 50 nm-thick NbN film. Utilizing the THz pump-THz probe spectroscopy, we study the dynamic process of transmission spectra and demonstrate that the transition time of such superconducting plasmonic device is within 5 ps.

  10. 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.

  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. 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.

  13. 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.

  14. Nonlinear chiral transport phenomena

    Science.gov (United States)

    Chen, Jiunn-Wei; Ishii, Takeaki; Pu, Shi; Yamamoto, Naoki

    2016-06-01

    We study the nonlinear responses of relativistic chiral matter to the external fields such as the electric field E , gradients of temperature and chemical potential, ∇T and ∇μ . Using the kinetic theory with Berry curvature corrections under the relaxation time approximation, we compute the transport coefficients of possible new electric currents that are forbidden in usual chirally symmetric matter but are allowed in chirally asymmetric matter by parity. In particular, we find a new type of electric current proportional to ∇μ ×E due to the interplay between the effects of the Berry curvature and collisions. We also derive an analog of the "Wiedemann-Franz" law specific for anomalous nonlinear transport in relativistic chiral matter.

  15. 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.)

  16. Nonlinear gyrokinetic tokamak physics

    International Nuclear Information System (INIS)

    Brizard, A.J.

    1990-01-01

    The gyrokinetic reduced description of low-frequency and small-perpendicular-wavelength nonlinear tokamak dynamics is presented in three different versions: the reduced dynamical description of test particles moving in electromagnetic fields; the reduced gyrokinetic description of the self-consistent interaction of particles and fields through the Maxwell-Vlasov equations; and the reduced description of nonlinear fluid motion. The unperturbed tokamak plasma is described in terms of a noncanonical Hamiltonian guiding-center theory. The unperturbed guiding-center tokamak plasma is then perturbed by gyrokinetic electromagnetic fields and consequently the perturbed guiding-center dynamical system acquires new gyrophase dependence. The perturbation analysis that follows makes extensive use of Lie-transform perturbation techniques. Because the electromagnetic perturbations affect both the Hamiltonian and the Poisson-bracket structure, the Phase-space Lagrangian Lie perturbation method is used. The description of the reduced test-particle dynamics is given in terms of a non-canonical Hamiltonian gyrocenter theory. The description of the reduced kinetic dynamics is concerned with the self consistent response of the guiding-center plasma and is described in terms of the nonlinear gyrokinetic Maxwell-Vlasov equations. It is also shown that the gyrokinetic Maxwell-Vlasov system possesses a gyrokinetic energy adiabatic invariant and that, in both the linear and nonlinear (quadratic) approximations, the corresponding energy invariants are exact. The description of the reduced fluid dynamics is concerned with the derivation of a closed set of reduced fluid equations. Three generations of reduced fluid models are presented: the reduced MHD equations; the reduced FLR-MHD equations; and the gyrofluid equations

  17. 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

  18. Interpersonal processes in depression.

    Science.gov (United States)

    Hames, Jennifer L; Hagan, Christopher R; Joiner, Thomas E

    2013-01-01

    Humans have an intrinsic need for social connection; thus, it is crucial to understand depression in an interpersonal context. Interpersonal theories of depression posit that depressed individuals tend to interact with others in a way that elicits rejection, which increases their risk for future depression. In this review, we summarize the interpersonal characteristics, risk factors, and consequences of depression in the context of the relevant theories that address the role of interpersonal processes in the onset, maintenance, and chronicity of depression. Topics reviewed include social skills, behavioral features, communication behaviors, interpersonal feedback seeking, and interpersonal styles as they relate to depression. Treatment implications are discussed in light of the current research on interpersonal processes in depression, and the following future directions are discussed: developing integrative models of depression, improving measurement of interpersonal constructs, examining the association between interpersonal processes in depression and suicide, and tailoring interventions to target interpersonal processes in depression.

  19. Strongly nonlinear oscillators analytical solutions

    CERN Document Server

    Cveticanin, Livija

    2014-01-01

    This book provides the presentation of the motion of pure nonlinear oscillatory systems and various solution procedures which give the approximate solutions of the strong nonlinear oscillator equations. The book presents the original author’s method for the analytical solution procedure of the pure nonlinear oscillator system. After an introduction, the physical explanation of the pure nonlinearity and of the pure nonlinear oscillator is given. The analytical solution for free and forced vibrations of the one-degree-of-freedom strong nonlinear system with constant and time variable parameter is considered. Special attention is given to the one and two mass oscillatory systems with two-degrees-of-freedom. The criteria for the deterministic chaos in ideal and non-ideal pure nonlinear oscillators are derived analytically. The method for suppressing chaos is developed. Important problems are discussed in didactic exercises. The book is self-consistent and suitable as a textbook for students and also for profess...

  20. Etiology and Diagnosis of Major Depression - A Novel Quantitative Approach

    DEFF Research Database (Denmark)

    Ottesen, Johnny T.

    2013-01-01

    Background: Classical psychiatric opinions are relative uncertain and treatment results are not impressive when dealing with major depression. Depression is related to the endocrine system, but despite much effort a good quantitative measure for characterizing depression has not yet emerged...... we compare the O-index with opinions reach by classical psychiatric diagnostic procedure (sensitivity 83%, specificity 59%, likelihood ratio positive 2.0, and likelihood ratio negative 0.29). The O-index nicely refines the etiology of depression: Combined with clinical data for 29 subjects earlier...... reported three categories emerge (p = 4.4 × 10-13): hypocortisolemic depressed, non-depressed, and hypercotisolemic depressed. The O-index also reveals why it has been difficult to obtain good markers earlier. It explains that healthy subjects may have an elevated (suppressed) level of cortisol or ACTH...

  1. 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…

  2. Parkinson's disease and depression.

    Science.gov (United States)

    Rihmer, Zoltán; Seregi, Krisztina; Rihmer, Annamária

    2004-06-01

    The prevalence of depression in Parkinson's disease is around 40%, but, unfortunately, such depression is frequently unrecognized and untreated. However, recognition and appropriate treatment of depression in patients with Parkinson's disease is essential for clinical practice. This review focuses on the epidemiology, pathophysiology and treatment of depression associated with Parkinson's disease.

  3. 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…

  4. 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.

  5. Anti-depressants and suicide.

    Science.gov (United States)

    Ludwig, Jens; Marcotte, Dave E; Norberg, Karen

    2009-05-01

    Suicide takes the lives of around a million people each year, most of whom suffer from depression. In recent years there has been growing controversy about whether one of the best-selling anti-depressants - selective serotonin reuptake inhibitors (SSRIs) - increases or decreases the risk of completed suicide. Randomized clinical trials are not informative in this application because of small samples and other problems. We present what we believe are the most scientifically credible estimates to date on how SSRI sales affect suicide mortality using data from 26 countries for up to 25 years. We exploit just the variation in SSRI sales that can be explained by institutional differences in how drugs are regulated, priced, and distributed, as reflected by the sales growth of new drugs more generally. We find an increase in SSRI sales of 1 pill per capita (12% of 2000 sales levels) reduces suicide by 5%.

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

    DEFF Research Database (Denmark)

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

    2006-01-01

    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......-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....

  7. 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)

  8. Nonlinearity of bituminous mixtures

    Science.gov (United States)

    Mangiafico, S.; Babadopulos, L. F. A. L.; Sauzéat, C.; Di Benedetto, H.

    2018-02-01

    This paper presents an experimental characterization of the strain dependency of the complex modulus of bituminous mixtures for strain amplitude levels lower than about 110 μm/m. A series of strain amplitude sweep tests are performed at different temperatures (8, 10, 12 and 14°C) and frequencies (0.3, 1, 3 and 10 Hz), during which complex modulus is monitored. For each combination of temperature and frequency, four maximum strain amplitudes are targeted (50, 75, 100 and 110 μm/m). For each of them, two series of 50 loading cycles are applied, respectively at decreasing and increasing strain amplitudes. Before each decreasing strain sweep and after each increasing strain sweep, 5 cycles are performed at constant maximum targeted strain amplitude. Experimental results show that the behavior of the studied material is strain dependent. The norm of the complex modulus decreases and phase angle increases with strain amplitude. Results are presented in Black and Cole-Cole plots, where characteristic directions of nonlinearity can be identified. Both the effects of nonlinearity in terms of the complex modulus variation and of the direction of nonlinearity in Black space seem to validate the time-temperature superposition principle with the same shift factors as for linear viscoelasticity. The comparison between results obtained during increasing and decreasing strain sweeps suggests the existence of another phenomenon occurring during cyclic loading, which appears to systematically induce a decrease of the norm of the complex modulus and an increase of the phase angle, regardless of the type of the strain sweep (increasing or decreasing).

  9. Overweight status and depressive symptoms during adolescence.

    Science.gov (United States)

    Needham, Belinda L; Crosnoe, Robert

    2005-01-01

    To: (a) extend previous research on the association between overweight status and depressive symptoms among adults to adolescents, (b) consider whether this association varies across social structural contexts and school context, and (c) explore additional mechanisms linking overweight status to depressive symptoms. We used survey regression procedures to analyze data from the first wave of the National Longitudinal Study of Adolescent Health. Degree of overweight was indicated by body mass index (BMI), which we calculated using self-reported height and weight information, whereas depressive symptoms were assessed with the Center for Epidemiological Studies Depression Scale (CES-D). Data were analyzed to determine (a) the social groups in which being overweight was least common, (b) the association between overweight status and depressive symptoms, and (c) potential mediators of the association between relative weight and symptoms of depression, including dieting and self-rated health. The analytic sample contained 18,924 adolescents aged 11 to 21 years (mean age was 15.68). Approximately half the sample consisted of females (n = 9634). Adjusting for exercise and sociodemographic characteristics, we found that relative weight was associated with depressive symptoms for girls but not boys. For both, the association between overweight status and symptoms of depression was stronger among adolescents in lower grades. Dieting explained the positive association between relative weight and depressive symptoms for girls, whereas self-rated health mediated the association between relative weight and symptoms of depression for adolescents in lower grades. To fully understand both the physical and mental health consequences of adolescent obesity, the social dimension of weight must be examined.

  10. 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

  11. 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....

  12. 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

  13. 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...... ability to produce efficient search algorithms. Such algorithms may be completely problem-independent (which is the case for the so-called 'meta-heuristics' or 'blind-search' algorithms), or they may be designed with the structure of the concrete problem in mind. We show that pure meta...

  14. Nonlinear backreaction in cosmology

    Science.gov (United States)

    Green, Stephen Roland

    This thesis, based on two papers by Green and Wald, investigates the problem of nonlinear backreaction in cosmology. We first analyze the problem in a general context by developing a new, mathematically precise framework for treating the effects of nonlinear phenomena occurring on small scales in general relativity. Our framework requires the metric to be close to a background metric (not necessarily a cosmological metric), but allows arbitrarily large stress-energy fluctuations on small scales. We prove that, within our framework, if the matter stress-energy tensor satisfies the weak energy condition (i.e., positivity of energy density in all frames), then the only effect that small-scale inhomogeneities can have on the background metric is to provide an effective stress-energy tensor that is traceless and satisfies the weak energy condition itself—corresponding to the presence of gravitational radiation. In particular, nonlinear effects produced by small-scale inhomogeneities cannot mimic the effects of dark energy. We also develop perturbation theory off of the background metric. We derive an equation for the long-wavelength part of the leading order deviation of the metric from the background metric, which contains the usual terms occurring in linearized perturbation theory plus additional contributions from the small-scale inhomogeneities. Next, we apply our framework to the cosmological context, specializing our background metric to be of the Friedmann-Lemaitre-Robertson-Walker form. We demonstrate that, in the case of dust matter, a cosmological constant, and vanishing spatial curvature (i.e., our universe today), Newtonian gravity alone provides a good global description of an inhomogeneous general relativistic cosmology, even when there is significant nonlinear dynamical behavior at small scales. Namely, we find a relatively straightforward dictionary—which is exact at the linearized level—that maps Newtonian dust cosmologies into general

  15. 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

  16. 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.

  17. 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...... background explain only a limited part. However, when conducting an extensive control for confounding, a significantly higher morbidity was identified amongst shelter users for infectious diseases, lung, skin, blood and digestive diseases, injuries, and poisoning. CONCLUSIONS: Ill health amongst homeless...... shelter users is widely explained by substance abuse problems and other risk factors. Nonetheless, for many diseases homelessness poses an additional risk to the health....

  18. Nonlinear Trivelpiece--Gould waves: Recurrence, harmonic cascade, and sidebands

    Energy Technology Data Exchange (ETDEWEB)

    Cabral, J.A.C.; Lapao, L.M.; Mendonca, J.T. (Centro de Electrodinamica, Instituto Superior Tecnico, 1096 Lisboa Codex (Portugal))

    1993-03-01

    A theoretical and experimental study of Trivelpiece--Gould waves propagating in a magnetized plasma column is presented in this paper. In the experiments, these waves are excited by a radio frequency (rf) source, which also serves to create the plasma. Observation of nonlinear effects includes space and time recurrence effects, a wave spectrum containing a large number (up to 25) harmonics, and low-frequency sidebands. The theoretical model explains the recurrence effects as a consequence of multiple nonlinear interactions between the fundamental wave and its harmonics. A good agreement is found between theory and the experiments.

  19. 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.  

  20. Nonlinear evolution of drift instabilities

    International Nuclear Information System (INIS)

    Lee, W.W.; Krommes, J.A.; Oberman, C.R.; Smith, R.A.

    1984-01-01

    The nonlinear evolution of collisionless drift instabilities in a shear-free magnetic field has been studied by means of gyrokinetic particle simulation as well as numerical integration of model mode-coupling equations. The purpose of the investigation is to identify relevant nonlinear mechanisms responsible for the steady-state drift wave fluctuations. It is found that the saturation of the instability is mainly caused by the nonlinear E x B convection of the resonant electrons and their associated velocity space nonlinearity. The latter also induces energy exchange between the competing modes, which, in turn, gives rise to enhanced diffusion. The nonlinear E x B convection of the ions, which contributes to the nonlinear frequency shift, is also an important ingredient for the saturation

  1. Efferent feedback can explain many hearing phenomena

    Science.gov (United States)

    Holmes, W. Harvey; Flax, Matthew R.

    2015-12-01

    The mixed mode cochlear amplifier (MMCA) model was presented at the last Mechanics of Hearing workshop [4]. The MMCA consists principally of a nonlinear feedback loop formed when an efferent-controlled outer hair cell (OHC) is combined with the cochlear mechanics and the rest of the relevant neurobiology. Essential elements of this model are efferent control of the OHC motility and a delay in the feedback to the OHC. The input to the MMCA is the passive travelling wave. In the MMCA amplification is localized where both the neural and tuned mechanical systems meet in the Organ of Corti (OoC). The simplest model based on this idea is a nonlinear delay line resonator (DLR), which is mathematically described by a nonlinear delay-differential equation (DDE). This model predicts possible Hopf bifurcations and exhibits its most interesting behaviour when operating near a bifurcation. This contribution presents some simulation results using the DLR model. These show that various observed hearing phenomena can be accounted for by this model, at least qualitatively, including compression effects, two-tone suppression and some forms of otoacoustic emissions (OAEs).

  2. Nonlinear Analysis and Variational Problems

    CERN Document Server

    Pardalos, Panos M

    2010-01-01

    The chapters in this volume, written by international experts from different fields of mathematics, are devoted to honoring George Isac, a renowned mathematician. These contributions focus on recent developments in complementarity theory, variational principles, stability theory of functional equations, nonsmooth optimization, and several other important topics at the forefront of nonlinear analysis and optimization. "Nonlinear Analysis and Variational Problems" is organized into two parts. Part I, Nonlinear Analysis, centers on stability issues for functional equations, fixed point

  3. 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

  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. 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.

  6. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Radiology and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography ( ... pictures of the major blood vessels throughout your body. It may be performed with or without contrast ...

  7. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

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

  8. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Abdominal Ultrasound Video: Pelvic Ultrasound Medical Imaging Costs Radiology and You Take our survey Sponsored by Image/ ... Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot org Hello, I’m Dr. Elliot ...

  9. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) ... Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound Radiology and You ...

  10. 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.

  11. 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

  12. 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.

  13. Nonlinear acoustic tomography

    International Nuclear Information System (INIS)

    Monk, P.

    1993-01-01

    The use of acoustic waves as probes to determine otherwise inaccessible properties of a medium is extremely widespread. Applications include sonar, medical imaging and non-destructive testing. Despite the importance of the applications, there is as yet no acceptable method for solving the full non-linear problem at resonance frequencies (frequencies at which the size of the features under investigations are approximately the wavelength of the incident acoustic field). The medical imaging problem, which consists in trying to determine the sound speed, density and absorption properties of a bounded inhomogeneous medium from scattered acoustic waves is the motivaiton for the investigation described in this paper. We shall present a solution technique for a standard model inverse acoustic scattering problem which consists of reconstructing the refractive index of an inhomogeneity from given far field data (far field data is essentially the measured scattered field at considerable distance from the inhomogeneity). This model inverse problem simplifies the inhomogeneity by neglecting density and absorption but includes two important features of the real problem: nonlinearity and illposedness. Furthermore the method we present can easily by extended to more general problems

  14. Explainers – New energy for the museum

    Directory of Open Access Journals (Sweden)

    Sebastian Martin

    2008-12-01

    Full Text Available The Exploratorium explainer program is not only important to the young people involved, but is an integral part of the museum culture. This initiative that started to help the youth of our community has blossomed into a program that has been very helpful to the science centre. In fact, the institution would not be complete without the fresh energy of the explainers. They help the Exploratorium to continue to give the real pear to its public.

  15. Control design of a nonlinear controller to stabilize the nonlinear ...

    African Journals Online (AJOL)

    This article presents the design of a highly efficient nonlinear0 controller which is a kind of an Active Queue Management (AQM) scheme to stabilize the nonlinear TCP model dynamics. Specific boundary conditions have been considered for stability occurrences and have been compared with other existing Active Queue ...

  16. 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.

  17. 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...

  18. 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...... of doping, use a microstructure of air and glass to obtain a refractive index difference between the core and the cladding. This air/glass microstructure lends the photonic crystal fibers a range of unique and highly usable properties, which are very different from those found in solid standard fibers......, leading to reduced mode confinement and dispersion flexibility. In this thesis, we treat the nonlinear photonic crystal fiber – a special sub-class of photonic crystal fibers, the core of which has a diameter comparable to the wavelength of the light guided in the fiber. The small core results in a large...

  19. 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

  20. 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).

  1. 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.

  2. Adaptive nonlinear flight control

    Science.gov (United States)

    Rysdyk, Rolf Theoduor

    1998-08-01

    Research under supervision of Dr. Calise and Dr. Prasad at the Georgia Institute of Technology, School of Aerospace Engineering. has demonstrated the applicability of an adaptive controller architecture. The architecture successfully combines model inversion control with adaptive neural network (NN) compensation to cancel the inversion error. The tiltrotor aircraft provides a specifically interesting control design challenge. The tiltrotor aircraft is capable of converting from stable responsive fixed wing flight to unstable sluggish hover in helicopter configuration. It is desirable to provide the pilot with consistency in handling qualities through a conversion from fixed wing flight to hover. The linear model inversion architecture was adapted by providing frequency separation in the command filter and the error-dynamics, while not exiting the actuator modes. This design of the architecture provides for a model following setup with guaranteed performance. This in turn allowed for convenient implementation of guaranteed handling qualities. A rigorous proof of boundedness is presented making use of compact sets and the LaSalle-Yoshizawa theorem. The analysis allows for the addition of the e-modification which guarantees boundedness of the NN weights in the absence of persistent excitation. The controller is demonstrated on the Generic Tiltrotor Simulator of Bell-Textron and NASA Ames R.C. The model inversion implementation is robustified with respect to unmodeled input dynamics, by adding dynamic nonlinear damping. A proof of boundedness of signals in the system is included. The effectiveness of the robustification is also demonstrated on the XV-15 tiltrotor. The SHL Perceptron NN provides a more powerful application, based on the universal approximation property of this type of NN. The SHL NN based architecture is also robustified with the dynamic nonlinear damping. A proof of boundedness extends the SHL NN augmentation with robustness to unmodeled actuator

  3. Variable coefficient nonlinear systems derived from an atmospheric dynamical system

    International Nuclear Information System (INIS)

    Xiao-Yan, Tang; Yuan, Gao; Sen-Yue, Lou; Fei, Huang

    2009-01-01

    Variable coefficient nonlinear systems, the Korteweg de Vries (KdV), the modified KdV (mKdV) and the nonlinear Schrödinger (NLS) type equations, are derived from the nonlinear inviscid barotropic nondivergent vorticity equation in a beta-plane by means of the multi-scale expansion method in two different ways, with and without the so-called y-average trick. The non-auto-Bäcklund transformations are found to transform the derived variable coefficient equations to the corresponding standard KdV, mKdV and NLS equations. Thus, many possible exact solutions can be obtained by taking advantage of the known solutions of these standard equations. Further, many approximate solutions of the original model are ready to be yielded which might be applied to explain some real atmospheric phenomena, such as atmospheric blocking episodes. (general)

  4. 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

  5. Nonlinear evolution of oblique whistler waves in radiation belts

    Science.gov (United States)

    Sharma, R. P.; Nandal, P.; Yadav, N.; Sharma, Swati

    2017-02-01

    Magnetic power spectrum and formation of coherent structures have been investigated in the present work applicable to Van Allen radiation belt. The nonlinear interaction of high frequency oblique whistler wave and low frequency magnetosonic wave has been investigated. Simulation was performed of the coupled equation of these two waves. The nonlinear interaction of these waves leads to the formation of the localized structures. These resulting localized structures are of complex nature. The associated magnetic power spectrum has also been studied. Dispersive nonlinear processes account for the high frequency part of the spectrum. The resulting magnetic power spectrum shows a scaling of k^{ - 4.5}. The energy transfer process from injection scales to smaller scales is explained by the results.

  6. 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

  7. 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

  8. Oscillating solitons in nonlinear optics

    Indian Academy of Sciences (India)

    Abstract. Oscillating solitons are obtained in nonlinear optics. Analytical study of the variable- coefficient nonlinear Schrödinger equation, which is used to describe the soliton propagation in those systems, is carried out using the Hirota's bilinear method. The bilinear forms and analytic soliton solutions are derived, and the ...

  9. 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.

  10. 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

  11. Depression and College Students

    Science.gov (United States)

    ... on thoughts, behaviors, and feelings related to depression Interpersonal psychotherapy , or IPT, which focuses on working on relationships Dialectical behavior therapy , or DBT, which is especially useful when depression ...

  12. Men and Depression

    Science.gov (United States)

    ... or making it worse. Cognitive behavioral therapy (CBT), interpersonal therapy (IPT), and problem-solving therapy are examples of evidence-based talk therapy treatments for depression. Treatment for depression should be personalized. Some men, ...

  13. Depression - older adults

    Science.gov (United States)

    ... active and engaged. The most worrisome complication of depression is suicide. Men make up most suicides among older adults. ... such as 911) if you are thinking about suicide (taking your own ... and think they may have depression, contact their provider.

  14. Postpartum Depression - Multiple Languages

    Science.gov (United States)

    ... Are Here: Home → Multiple Languages → All Health Topics → Postpartum Depression URL of this page: https://medlineplus.gov/languages/ ... V W XYZ List of All Topics All Postpartum Depression - Multiple Languages To use the sharing features on ...

  15. Screening for Depression

    Science.gov (United States)

    Depression and Bipolar Support Alliance Crisis Hotline Information Coping with a Crisis Suicide Prevention Information Psychiatric Hospitalization ... sign-up Education info, training, events Mood Disorders Depression Bipolar Disorder Anxiety Screening Center Co-occurring Illnesses/ ...

  16. Help With Depression

    Science.gov (United States)

    ... a Psychiatrist Addiction and Substance Use Disorders ADHD Anxiety Disorders Autism ... Depression (major depressive disorder) is a common and serious medical illness that negatively affects how you feel, the way ...

  17. 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 ...

  18. Recognizing teen depression

    Science.gov (United States)

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

  19. 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 ...

  20. 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 ...

  1. Depression and Pregnancy

    Science.gov (United States)

    ... best live chat Live Help Fact Sheets Share Depression Thursday, 01 September 2016 In every pregnancy, a ... risk. This sheet talks about whether exposure to depression may increase the risk for birth defects over ...

  2. 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.

  3. 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 ...

  4. Dealing With Depression: Antidepressant Skills for Teens

    OpenAIRE

    Bilsker, Dan; Gilbert, Merv; Worling, David; Garland, Jane

    2005-01-01

      Dealing with Depression is a workbook for teens that explains depression and teaches three main antidepressant skills you can use to help overcome or prevent it. The skills are presented in a step-by-step way so that you may learn them easily and apply them to your life. Sometimes these antidepressant skills can be used on their own, when the mood problem isn't too severe, and sometimes they have to be used along with treatments prescribed by professionals. Either way, practicing th...

  5. Depression and body mass index, a u-shaped association

    Directory of Open Access Journals (Sweden)

    Penninx Brenda WJH

    2009-01-01

    Full Text Available Abstract Background Results of studies concerning the association between obesity and depression are conflicting. Some find a positive association, some a negative association and some find no association at all. Most studies, however, examine a linear association between Body Mass Index (BMI and depression. The present study investigates if a nonlinear (U-shaped trend is preferable over a linear trend to describe the relationship between BMI and depression, which means that both underweight and obesity are associated with depression. Methods We investigated the existence of such a U-curve in a sample of 43,534 individuals, aged between 18–90 years, who participated in a cross-sectional study (Continuous Survey of Living Conditions of physical and mental health in the general population of the Netherlands. We calculated linear and nonlinear (quadratic ANOVA with polynomial contrast and curve fit regression statistics to investigate whether there was a U-shaped trend in the association between BMI and depression. Results We find a very significant U-shaped association between BMI categories (underweight, normal, overweight and obesity and depression (p ≤ 0.001. There is a trend indicating a significant difference in the association between males and females (p = 0.05. We find a very significant U-shaped (quadratic association between BMI (BMI2 and depression (p ≤ 0.001, continuous BMI is not linearly associated with depression (p = 0.514. Conclusion The results of this study give evidence for a significant U-shaped trend in the association between BMI and depression.

  6. Preventing Depression in Adults With Subthreshold Depression

    DEFF Research Database (Denmark)

    Buntrock, Claudia; Berking, Matthias; Smit, Filip

    2017-01-01

    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......-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...

  7. Mining and Explaining Relationships in Wikipedia

    Science.gov (United States)

    Zhang, Xinpeng; Asano, Yasuhito; Yoshikawa, Masatoshi

    Mining and explaining relationships between concepts are challenging tasks in the field of knowledge search. We propose a new approach for the tasks using disjoint paths formed by links in Wikipedia. Disjoint paths are easy to understand and do not contain redundant information. To achieve this approach, we propose a naive method, as well as a generalized flow based method, and a technique for mining more disjoint paths using the generalized flow based method. We also apply the approach to classification of relationships. Our experiments reveal that the generalized flow based method can mine many disjoint paths important for understanding a relationship, and the classification is effective for explaining relationships.

  8. Genetic biomarkers of depression

    OpenAIRE

    Anand Tamatam; Farhath Khanum; Amarinder Singh Bawa

    2012-01-01

    Depression is a term that has been used to describe a variety of ailments, ranging from minor to incapacitating. Clinically significant depression, termed as major depression, is a serious condition characterized not only by depressed mood but also by a cluster of somatic, cognitive, and motivational symptoms. Significant research efforts are aimed to understand the neurobiological as well as psychiatric disorders, and the evaluation of treatment of these disorders is still based solely on th...

  9. Depression in cerebrovascular diseases

    OpenAIRE

    Voskresenskaya, Tatyana

    2009-01-01

    The paper discusses the topical problem of depression in cerebrovascular diseases. It shows its possible causes, mechanisms of occurrence, clinical picture and negative impact on the course of cerebrovascular disease and recovery of neurological functions. There is a bilateral association between stroke and depression: on the one hand, stroke is a risk factor for the development of depression and, on the other, depression is a both direct and indirect risk factor for the development of stroke...

  10. 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.

  11. 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

  12. Basic considerations on surface optical nonlinearities

    International Nuclear Information System (INIS)

    Guyot-Sionnest, P.; Chen, W.; Shen, Y.R.

    1986-01-01

    The origins of the surface nonlinearity in surface second harmonic generation are discussed. It is shown that this second-order nonlinear optical process is characterized by a surface nonlinear susceptibility tensor containing both local and nonlocal contributions

  13. 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...

  14. 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.

  15. Vision in depressive disorder

    DEFF Research Database (Denmark)

    Bubl, E.; Tebartz Van Elst, L.; Ebert, D.

    2009-01-01

    plays a role in major depression we measured contrast sensitivity in patients with major depression and in healthy control subjects. Methods. Twenty-eight patients diagnosed with major depressive disorder were compared to 21 age-matched control subjects on their ability to detect a Gabor target...

  16. 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, ...

  17. 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?

  18. 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....

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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....

  4. 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…

  5. 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 ...

  6. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Recently posted: Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound Radiology and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot ...

  7. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Radiology and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography ( ... problems, recent surgeries and allergies. If you’re female and there’s a possibility that you’re pregnant ...

  8. 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.

  9. 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 ... I’d like to talk with you about magnetic resonance angiography, or as it’s commonly known, MRA. ...

  10. How Contracts and Enforcement Explain Transaction Outcomes

    NARCIS (Netherlands)

    Mooi, E.A.; Gilliland, D.I.

    2013-01-01

    This study considers the influence of contracts on enforcement and the subsequent performance impact of aligned and misaligned enforcement. We define enforcement as a corrective action aimed at remedying problems occurring in the transaction. First we explain the role of contracts and show that at

  11. 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

  12. Explaining quality of life with crisis theory

    NARCIS (Netherlands)

    Sprangers, M.A.G.; van den Heuvel, W.J.A.; de Haes, H.C.J.M.

    2002-01-01

    Based on the premises of crisis theory. we expected cancer patients in-crisis to report a poorer quality of life (QL) and cancer patients post-crisis to report a similar level of overall QL in comparison to healthy individuals. To explain these hypothesized findings, we expected the coping resources

  13. 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

  14. 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.

  15. Additive genetic contribution to symptom dimensions in major depressive disorder.

    Science.gov (United States)

    Pearson, Rahel; Palmer, Rohan H C; Brick, Leslie A; McGeary, John E; Knopik, Valerie S; Beevers, Christopher G

    2016-05-01

    Major depressive disorder (MDD) is a phenotypically heterogeneous disorder with a complex genetic architecture. In this study, genomic-relatedness-matrix restricted maximum-likelihood analysis (GREML) was used to investigate the extent to which variance in depression symptoms/symptom dimensions can be explained by variation in common single nucleotide polymorphisms (SNPs) in a sample of individuals with MDD (N = 1,558) who participated in the National Institute of Mental Health Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study. A principal components analysis of items from the Hamilton Rating Scale for Depression (HRSD) obtained prior to treatment revealed 4 depression symptom components: (a) appetite, (b) core depression symptoms (e.g., depressed mood, anhedonia), (c) insomnia, and (d) anxiety. These symptom dimensions were associated with SNP-based heritability (hSNP2) estimates of 30%, 14%, 30%, and 5%, respectively. Results indicated that the genetic contribution of common SNPs to depression symptom dimensions were not uniform. Appetite and insomnia symptoms in MDD had a relatively strong genetic contribution whereas the genetic contribution was relatively small for core depression and anxiety symptoms. While in need of replication, these results suggest that future gene discovery efforts may strongly benefit from parsing depression into its constituent parts. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  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. 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. 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.

  19. 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...... the diverse operational regimes and indicates principal areas of applications, making it a very important guide for researchers and graduate students. With contributions from major figures and groups who have pioneered research in this field, the book describes the historical development of the subject...

  20. 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

  1. Control Design of a Nonlinear Controller to Stabilize the Nonlinear ...

    African Journals Online (AJOL)

    inyangs

    AQM) scheme employing .... A nonlinear control design is considered for application in this case, so that when there is any change in network .... shows that the system is asymptotically stable with a negative definite solution in equation (14).

  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. 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.

  4. 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.

  5. 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...

  6. Nonlinear Frequency Compression

    Science.gov (United States)

    Scollie, Susan; Glista, Danielle; Seelisch, Andreas

    2013-01-01

    Frequency lowering technologies offer an alternative amplification solution for severe to profound high frequency hearing losses. While frequency lowering technologies may improve audibility of high frequency sounds, the very nature of this processing can affect the perceived sound quality. This article reports the results from two studies that investigated the impact of a nonlinear frequency compression (NFC) algorithm on perceived sound quality. In the first study, the cutoff frequency and compression ratio parameters of the NFC algorithm were varied, and their effect on the speech quality was measured subjectively with 12 normal hearing adults, 12 normal hearing children, 13 hearing impaired adults, and 9 hearing impaired children. In the second study, 12 normal hearing and 8 hearing impaired adult listeners rated the quality of speech in quiet, speech in noise, and music after processing with a different set of NFC parameters. Results showed that the cutoff frequency parameter had more impact on sound quality ratings than the compression ratio, and that the hearing impaired adults were more tolerant to increased frequency compression than normal hearing adults. No statistically significant differences were found in the sound quality ratings of speech-in-noise and music stimuli processed through various NFC settings by hearing impaired listeners. These findings suggest that there may be an acceptable range of NFC settings for hearing impaired individuals where sound quality is not adversely affected. These results may assist an Audiologist in clinical NFC hearing aid fittings for achieving a balance between high frequency audibility and sound quality. PMID:23539261

  7. 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.

  8. Kerr nonlinear coupler and entanglement

    International Nuclear Information System (INIS)

    Leonski, Wieslaw; Miranowicz, Adam

    2004-01-01

    We discuss a model comprising two coupled nonlinear oscillators (Kerr-like nonlinear coupler) with one of them pumped by an external coherent excitation. Applying the method of nonlinear quantum scissors we show that the quantum evolution of the coupler can be closed within a finite set of n-photon Fock states. Moreover, we show that the system is able to generate Bell-like states and, as a consequence, the coupler discussed behaves as a two-qubit system. We also analyse the effects of dissipation on entanglement of formation parametrized by concurrence

  9. 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

  10. 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.

  11. Depression in adolescence

    Science.gov (United States)

    Thapar, Anita; Collishaw, Stephan; Pine, Daniel S; Thapar, Ajay K

    2012-01-01

    Unipolar depressive disorder in adolescence is common worldwide but often unrecognised. The incidence, notably in girls, rises sharply after puberty and, by the end of adolescence, the 1 year prevalence rate exceeds 4%. The burden is highest in low-income and middle-income countries. Depression is associated with sub stantial present and future morbidity, and heightens suicide risk. The strongest risk factors for depression in adolescents are a family history of depression and exposure to psychosocial stress. Inherited risks, developmental factors, sex hormones, and psychosocial adversity interact to increase risk through hormonal factors and associated perturbed neural pathways. Although many similarities between depression in adolescence and depression in adulthood exist, in adolescents the use of antidepressants is of concern and opinions about clinical management are divided. Effective treatments are available, but choices are dependent on depression severity and available resources. Prevention strategies targeted at high-risk groups are promising. PMID:22305766

  12. John Watson's paradoxical struggle to explain Freud.

    Science.gov (United States)

    Rilling, M

    2000-03-01

    John Watson was fascinated by the discoveries of psychoanalysis, but he rejected Freud's central concept of the unconscious as incompatible with behaviorism. After failing to explain psychoanalysis in terms of William James's concept of habit, Watson borrowed concepts from classical conditioning to explain Freud's discoveries. Watson's famous experiment with Little Albert is interpreted not only in the context of Pavlovian conditioning but also as a psychoanalytically inspired attempt to capture simplified analogues of adult phobic behavior, including the "transference" of emotion in an infant. Watson used his behavioristic concept of conditioned emotional responses to compete with Freud's concepts of displacement and the unconscious transference of emotion. Behind a mask of anti-Freudian bias, Watson surprisingly emerges as a psychologist who popularized Freud and pioneered the scientific appraisal of his ideas in the laboratory.

  13. 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...

  14. 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.

  15. Explaining money creation by commercial banks

    DEFF Research Database (Denmark)

    Ravn, Ib

    2015-01-01

    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......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...... 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...

  16. Major depressive disorder: reification and (maybe) rheostasis.

    Science.gov (United States)

    Patten, S B

    2015-12-01

    The heterogeneity of clinical syndromes subsumed by diagnostic criteria for major depressive disorder (MDD) is regarded by some as a reason to abandon or modify the criteria. However, heterogeneity may be unavoidable because of the biopsychosocial complexity of depression. MDD may be characterised by complexities that cannot be distilled down to any brief set of diagnostic criteria. Psychiatrists and psychiatric epidemiologists may need to revise their expectations of this diagnosis in order to avoid over-estimating its ability to guide the selection of treatments and prediction of prognosis. An opposing perspective is that of reification, in which the diagnosis is viewed as being more real than it really is. The concept of rheostasis may help to explain some features of this condition, such as why major depressive episodes sometimes seem understandable or even adaptive (e.g. in the context of bereavement) whereas at other times such episodes are inexplicable and maladaptive.

  17. Multi-dimensional modulations of α and γ cortical dynamics following mindfulness-based cognitive therapy in Major Depressive Disorder

    OpenAIRE

    Schoenberg, Poppy L. A.; Speckens, Anne E. M.

    2014-01-01

    To illuminate candidate neural working mechanisms of Mindfulness-Based Cognitive Therapy (MBCT) in the treatment of recurrent depressive disorder, parallel to the potential interplays between modulations in electro-cortical dynamics and depressive symptom severity and self-compassionate experience. Linear and nonlinear α and γ EEG oscillatory dynamics were examined concomitant to an affective Go/NoGo paradigm, pre-to-post MBCT or natural wait-list, in 51 recurrent depressive patients. Specifi...

  18. Explaining the gender wage gap in Georgia

    OpenAIRE

    Khitarishvili, Tamar

    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...

  19. 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

  20. 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...

  1. Spatial inequalities explained - Evidence from Burkina Faso

    OpenAIRE

    Johannes Gräb; Michael Grimm

    2008-01-01

    The literature shows that regional disparities in growth and poverty are often relatively high, that these regional disparities do not necessarily disappear as the economies grow and develop and that these disparities are itself in many cases an important driver of the overall performance of an economy. In this paper we make use of the advantage of a multilevel random coefficient model to explain spatial disparities in incomes among Burkinab`e households. Our findings show that it is not a ge...

  2. 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.

  3. Nonlinear integral operators and applications

    CERN Document Server

    Musielak, Julian; Bardaro, Carlo

    2003-01-01

    In 1903 Fredholm published his famous paper on integral equations. Since then linear integral operators have become an important tool in many areas, including the theory of Fourier series and Fourier integrals, approximation theory and summability theory, and the theory of integral and differential equations. As regards the latter, applications were soon extended beyond linear operators. In approximation theory, however, applications were limited to linear operators mainly by the fact that the notion of singularity of an integral operator was closely connected with its linearity. This book represents the first attempt at a comprehensive treatment of approximation theory by means of nonlinear integral operators in function spaces. In particular, the fundamental notions of approximate identity for kernels of nonlinear operators and a general concept of modulus of continuity are developed in order to obtain consistent approximation results. Applications to nonlinear summability, nonlinear integral equations and ...

  4. Optical Computing With Nonlinear Optics

    Science.gov (United States)

    Khitrova, Galina; Gibbs, Hyatt; Peyghambarian, Nasser

    1987-01-01

    Nonlinear optics is becoming a new thrust in the field of optical computing and signal processing.14 Optical nonlinearity makes the device's transmission intensity dependent, so one can obtain the thresholding needed for logic decisionmaking. Thresholding is essential to digital optical computing, neural nets, and associative memories. GaAs etalons exhibit many of the characteristics desirable for the nonlinear devices including high speed (picosecond) and diode-laser compatability. However, demonstrations of the use of nonlinear decisionmaking for optical computing have used ZnS or ZnSe interference filters. They are slow (millisecond), but they can be used with the visible 514.5-nm output of an argon laser. We have used such filters to demonstrate all-optical logic operations, one-bit addition by symbolic substitution, and recognition of a three-spot pattern in an arbitrary 2 x 8 array of input beams. The application to associative memories is under study.

  5. 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.

  6. Equivalent linearization of nonlinear forces

    Science.gov (United States)

    Meng, Guang; Xue, Zhongqing

    1987-07-01

    A method used for equivalent linearization of the two orthogonal squeeze-film forces is extended here to the general case of n degrees of freedom and n components of nonlinear forces, and the expressions for equivalent linear coefficients are derived. Nonlinear forces can be linearized by the methods of Fourier expansion, active and reactive powers, or mean-square error. The n components of nonlinear forces can all be expressed formally as the sum of an average force, a linear spring force, and a linear damping force. This paper also gives a flow chart for calculating the steady-state responses of a nonlinear system with many degrees of freedom, using the method of equivalent linearization. The resulting saving in computation time is demonstrated by a numerical example of a flexible rotor-bearing system with a noncentralized squeeze-film damper.

  7. 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...

  8. 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.

  9. 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.

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

    Science.gov (United States)

    Graham, Louis F; Aronson, Robert E; Nichols, Tracy; Stephens, Charles F; Rhodes, Scott D

    2011-01-01

    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.

  11. A Nonlinear Transfer Operator Theorem

    Science.gov (United States)

    Pollicott, Mark

    2017-02-01

    In recent papers, Kenyon et al. (Ergod Theory Dyn Syst 32:1567-1584 2012), and Fan et al. (C R Math Acad Sci Paris 349:961-964 2011, Adv Math 295:271-333 2016) introduced a form of non-linear thermodynamic formalism based on solutions to a non-linear equation using matrices. In this note we consider the more general setting of Hölder continuous functions.

  12. 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...

  13. 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.

  14. Major Depression as a Complex Dynamic System.

    Directory of Open Access Journals (Sweden)

    Angélique O J Cramer

    Full Text Available In this paper, we characterize major depression (MD as a complex dynamic system in which symptoms (e.g., insomnia and fatigue are directly connected to one another in a network structure. We hypothesize that individuals can be characterized by their own network with unique architecture and resulting dynamics. With respect to architecture, we show that individuals vulnerable to developing MD are those with strong connections between symptoms: e.g., only one night of poor sleep suffices to make a particular person feel tired. Such vulnerable networks, when pushed by forces external to the system such as stress, are more likely to end up in a depressed state; whereas networks with weaker connections tend to remain in or return to a non-depressed state. We show this with a simulation in which we model the probability of a symptom becoming 'active' as a logistic function of the activity of its neighboring symptoms. Additionally, we show that this model potentially explains some well-known empirical phenomena such as spontaneous recovery as well as accommodates existing theories about the various subtypes of MD. To our knowledge, we offer the first intra-individual, symptom-based, process model with the potential to explain the pathogenesis and maintenance of major depression.

  15. 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

  16. The effect of compression on tuning estimates in a simple nonlinear auditory filter model

    DEFF Research Database (Denmark)

    Marschall, Marton; MacDonald, Ewen; Dau, Torsten

    2013-01-01

    Behavioral experiments using auditory masking have been used to characterize frequency selectivity, one of the basic properties of the auditory system. However, due to the nonlinear response of the basilar membrane, the interpretation of these experiments may not be straightforward. Specifically...... consists of a compressor between two bandpass filters. The BPNL forms the basis of the dual-resonance nonlinear (DRNL) filter that has been used in a number of modeling studies. The location of the nonlinear element and its effect on estimated tuning in the two measurement paradigms was investigated......, then compression alone may explain a large part of the behaviorally observed differences in tuning between simultaneous and forward-masking conditions....

  17. Nonlinear gravity-capillary water waves

    Science.gov (United States)

    Jiang, Lei

    1997-11-01

    Two-dimensional gravity-capillary water waves are analyzed using a fully-nonlinear Cauchy-integral method with spectral accuracy. Standing waves are generated in experiments by vertical oscillation and measured by a non-intrusive optical system along with a wave probe. Nonlinear resonance of standing waves with non-wetting contact line effects are discussed in detail. Amplitude- dependent wave frequency and damping in a glass rectangular tank suggest a new contact-line model. A new type of sideband resonance due to modulated forcing is discovered and explained by weakly-nonlinear analysis. This analytical solution is verified by our numerical simulations and physical experiments. New standing waveforms with dimpled or sharp crests are observed in experiments and computations. These new waveforms have strong symmetry breaking in time as a result of nonlinear harmonic interaction. With increasing wave steepness, steep standing waves experience period- tripling with three distinct forms: sharp crest, dimpled or flat crest, and round crest. Significant breaking occurs in the sharp-crest mode and the dimpled-crest mode. Using a complex-demodulation technique, I find that these breaking waves are related to the same 1:2 internal resonance (harmonic interaction) that causes the new steep waveforms. Novel approaches are used to estimate the (breaking and non-breaking) wave dissipation in steep and breaking standing waves. The breaking events (spray, air entrainment, and plunging) approximately double the wave dissipation. Weak capillarity significantly affects the limiting wave height and the form of standing waves, as demonstrated by both computations and small-scale Faraday-wave experiments. Capillary ripple generation on traveling waves is shown to be significant even at moderate wave steepness. The ubiquitous horizontal asymmetry of traveling waves is shown to be critical to capillary ripple generation. Two new asymmetric modes are identified and are shown to have an

  18. 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.

  19. 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

  20. Study of freezing-point depression of selected food extracts

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Fumihiko [Kagoshima Univ. (Japan). Dept. of Agricultural Systems Engineering; Murata, Satoshi; Habara, Kazuhiro; Amaratunga, K.S.P. [Kyushu Univ., Fukuoka (Japan). Dept. of Agricultural Engineering

    1996-12-31

    The phenomenon of freezing-point depression that accompanies the solute concentration of selected food extracts was investigated to reveal the characteristics of solid-liquid phase equilibrium. The freezing curves of various food extracts did not exhibit ideal solution behavior in the higher concentration range. The experimental data were fitted to new freezing-point depression equations by the method of nonlinear least squares, and the results clearly indicated that the calculated freezing points at various concentrations were in good agreement with the experimental data. Furthermore, by using the determined parameters, the freezing ratio and the activation coefficient were derived.

  1. 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.

  2. 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

  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. 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...... on ethnographic fieldwork among adults diagnosed with depression in Denmark, and consists of three articles that provide glimpses into experiences of depression and diagnostic processes. The articles deal with creativity, variability and resistance in diagnostic processes and illustrates how these not are once......-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...

  5. What is depression?

    DEFF Research Database (Denmark)

    Davidsen, Annette Sofie; Fosgerau, Christina Fogtmann

    2014-01-01

    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...... 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...... 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...

  6. Pulsed depressed collector

    Science.gov (United States)

    Kemp, Mark A

    2015-11-03

    A high power RF device has an electron beam cavity, a modulator, and a circuit for feed-forward energy recovery from a multi-stage depressed collector to the modulator. The electron beam cavity include a cathode, an anode, and the multi-stage depressed collector, and the modulator is configured to provide pulses to the cathode. Voltages of the electrode stages of the multi-stage depressed collector are allowed to float as determined by fixed impedances seen by the electrode stages. The energy recovery circuit includes a storage capacitor that dynamically biases potentials of the electrode stages of the multi-stage depressed collector and provides recovered energy from the electrode stages of the multi-stage depressed collector to the modulator. The circuit may also include a step-down transformer, where the electrode stages of the multi-stage depressed collector are electrically connected to separate taps on the step-down transformer.

  7. [Depression in cancer patients].

    Science.gov (United States)

    Sperner-Unterweger, Barbara

    2015-08-01

    Cancer patients often suffer from major depression or depressive syndromes. Although it is well known that depressive symptoms can appear at any time during the course of an oncological disease, certain periods for instance time after diagnosis carry a higher risk. Reported prevalence rates differ widely (up to 60%), reflecting also diagnostic difficulties. Oncologists recognize depression in their patients only in 15 to 50% and the percentage of patients who receive adequate therapy is even lower. Consequently, this leads to a reduced quality of life. Furthermore, impaired compliance/adherence and consequently a poorer prognosis of the oncological disease are discussed in this context. It should be also emphasized, that concomitant depression increases the risk of suicide in cancer patients. Although the number of clinical trials using either psychotherapy or antidepressant medication for the therapy of depression in cancer patients is limited, good therapeutic options are available.

  8. 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...

  9. Nonlinear optical properties and nonlinear optical probes of organic materials

    Science.gov (United States)

    Meredith, Gerald R.

    1992-02-01

    Nonlinear optical processes and electro-optical effects are expected to have increasing importance as the information age matures and photonics augment electronics in various high density and high bandwidth technologies. Whereas for electronics the emphasis is in construction of smaller device structures from a few parent materials, for organic materials the direction of materials research has been reversed. For some time it's been known that some molecular structures engender exceptionally large molecular nonlinear-polarization responses. If such molecules could be assembled in convenient, versatile, and reliable ways, the resulting materials would be very useful or even enabling in various photonics applications. The mature science and art of chemistry allows very good control over molecular composition and structure and, as will be illustrated in this talk, our knowledge of hyperpolarizability structure- property relationships is advancing rapidly. However, the science of fabrication and arrangement in molecular ensembles and polymers is rather primitive. Thus the goal to develop the appropriately structured materials for utilization in nonlinear and electro-optics has fostered the widespread use of nonlinear optical processes to probe the nature of supramolecular order and assembly. Examples of intrinsic and artificially assembled structures of crystals, molecular aggregates, polymeric orientational electrets and molecular mono- and multi-layer thin films will be shown. Nonlinear optical processes, primarily second-harmonic generation, provide unique probes of these structures, their assembly, and evolution.

  10. Maternal postadoption depression, unmet expectations, and personality traits.

    Science.gov (United States)

    Foli, Karen J; South, Susan C; Lim, Eunjung; Hebdon, Megan

    2012-01-01

    There are approximately 2 million adoptive parents in the United States and some struggle with depressive symptoms postplacement. We know little about personality traits that may be associated with depression in adoptive parents. This study describes the relationships between personality traits, unmet expectations, and maternal postadoption depression. Adoptive mothers (N = 136) were surveyed for depressive symptoms using the Center for Epidemiologic Studies-Depression Scale (CES-D) and the Edinburgh Postnatal Depression Scale (EPDS). Analyses included correlations and a regression analysis between depressive symptoms and unmet expectations with the Five-Factor Model personality traits (extraversion, agreeableness, conscientiousness, emotional stability, openness to experience) as measured by the Ten-Item Personality Inventory. Both the CES-D and EPDS were significantly, negatively correlated with all five personality dimensions. Mothers whose expectations of themselves as parents matched pre- and postplacement were more likely to be emotionally stable and extraverted. Approximately 36% of the variance in depressive symptoms was explained by personality traits (emotional stability: p adoptive mothers for depressive symptoms, emotional stability, and unmet expectations.

  11. Final report. [Nonlinear magnetohydrodynamics

    International Nuclear Information System (INIS)

    Montgomery, D.C.

    1998-01-01

    This is a final report on the research activities carried out under the above grant at Dartmouth. During the period considered, the grant was identified as being for nonlinear magnetohydrodynamics, considered as the most tractable theoretical framework in which the plasma problems associated with magnetic confinement of fusion plasmas could be studied. During the first part of the grant's lifetime, the author was associated with Los Alamos National Laboratory as a consultant and the work was motivated by the reversed-field pinch. Later, when that program was killed at Los Alamos, the problems became ones that could be motivated by their relation to tokamaks. Throughout the work, the interest was always on questions that were as fundamental as possible, compatible with those motivations. The intent was always to contribute to plasma physics as a science, as well as to the understanding of mission-oriented confined fusion plasmas. Twelve Ph.D. theses were supervised during this period and a comparable number of postdoctoral research associates were temporarily supported. Many of these have gone on to distinguished careers, though few have done so in the context of the controlled fusion program. Their work was a combination of theory and numerical computation, in gradually less and less idealized settings, moving from rectangular periodic boundary conditions in two dimensions, through periodic straight cylinders and eventually, before the grant was withdrawn, to toroids, with a gradually more prominent role for electrical and mechanical boundary conditions. The author never had access to a situation where he could initiate experiments and relate directly to the laboratory data he wanted. Computers were the laboratory. Most of the work was reported in referred publications in the open literature, copies of which were transmitted one by one to DOE at the time they appeared. The Appendix to this report is a bibliography of published work which was carried out under the

  12. 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.

  13. Prevalence and associated factors of depression among people living with HIV in two cities in China.

    Science.gov (United States)

    Su, Xiaoyou; Lau, Joseph T F; Mak, Winnie W S; Choi, K C; Chen, Lin; Song, Junmin; Zhang, Yan; Zhao, Guanglu; Feng, Tiejian; Chen, Xi; Liu, Chuliang; Liu, Jun; Liu, De; Cheng, Jinquan

    2013-07-01

    Depression has significant effects on morbidity and mortality in people living with HIV (PLWH). Current study estimated the rate of depressive disorder and identified the correlates of depressive disorder among PLWH in China. 258 PLWH in China were recruited and interviewed with a structured questionnaire including measurements testing perceived stress, social support, perceived discrimination, and depression. Mediating effect of perceived stress between perceived discrimination and depression and moderating effect of social support on effect of perceived discrimination and perceived stress to depression were tested. Multivariate regression was used to examine the determinants of depression. The prevalence of mild to severe depression is 71.9%. The relationship between the perceived discrimination and depression is fully mediated by perceived stress (perceived discrimination that was statistically significant (β=0.153) to depression became non-significant after adding perceived stress in the regression model). Interaction term between social support and perceived stress has negative effects (β=-0.117) and explained a significant amount of variance (R(2)=0.018) in depression. Lower income, and higher perceived stress predicted more depressive symptoms. Cross-sectional study and self-report bias are major limitations of this study. Depression among PLWH is a severe problem in China. Primary health care workers need to be trained in recognition and treatment in depression. Stress management skills and social support for PLWH are warranted. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. 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....... First, we show that there is very strong evidence of convergence across all categories of social expenditure when conditional factors are taken into account. Second, we demonstrate that the speed of convergence is highly driven by globalization and European Union membership and shaped by existing...

  15. 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.

  16. 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)

  17. A mechanism-based pharmacokinetic model of fenofibrate for explaining increased drug absorption after food consumption.

    Science.gov (United States)

    Back, Hyun-Moon; Song, Byungjeong; Pradhan, Sudeep; Chae, Jung-Woo; Han, Nayoung; Kang, Wonku; Chang, Min Jung; Zheng, Jiao; Kwon, Kwang-Il; Karlsson, Mats O; Yun, Hwi-Yeol

    2018-01-25

    Oral administration of drugs is convenient and shows good compliance but it can be affected by many factors in the gastrointestinal (GI) system. Consumption of food is one of the major factors affecting the GI system and consequently the absorption of drugs. The aim of this study was to develop a mechanistic GI absorption model for explaining the effect of food on fenofibrate pharmacokinetics (PK), focusing on the food type and calorie content. Clinical data from a fenofibrate PK study involving three different conditions (fasting, standard meals and high-fat meals) were used. The model was developed by nonlinear mixed effect modeling method. Both linear and nonlinear effects were evaluated to explain the impact of food intake on drug absorption. Similarly, to explain changes in gastric emptying time for the drug due to food effects was evaluated. The gastric emptying rate increased by 61.7% during the first 6.94 h after food consumption. Increased calories in the duodenum increased the absorption rate constant of the drug in fed conditions (standard meal = 16.5%, high-fat meal = 21.8%) compared with fasted condition. The final model displayed good prediction power and precision. A mechanistic GI absorption model for quantitatively evaluating the effects of food on fenofibrate absorption was successfully developed, and acceptable parameters were obtained. The mechanism-based PK model of fenofibrate can quantify the effects of food on drug absorption by food type and calorie content.

  18. 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...

  19. Coping Styles and Depression Among Undocumented Hispanic Immigrants.

    Science.gov (United States)

    Cobb, Cory L; Xie, Dong; Sanders, Gardiner L

    2016-08-01

    This cross-sectional study examined coping strategies and their relationship with depression among undocumented Hispanic immigrants. A community sample of 122 self-identified undocumented Hispanics filled out questionnaires measuring coping and depression. The authors categorized coping strategies as problem-focused, active-emotional, or avoidant-emotional. Findings indicated that coping through "prayer and meditation" (problem-focused), "get comfort from someone" (active-emotional), and "see bad things positively" (active-emotional) were more frequently used by undocumented Hispanics. Contrary to past research and predictions, problem-focused and active-emotional coping were both positively related to depression. What is more, problem-focused coping accounted for additional variance of depression above and beyond active-emotional coping. The insoluble nature of many of the problems faced by undocumented immigrants may explain the counterintuitive finding that as problem-focused and active-emotional coping increased, so too did depression.

  20. Unique contributions of metacognition and cognition to depressive symptoms.

    Science.gov (United States)

    Yilmaz, Adviye Esin; Gençöz, Tülin; Wells, Adrian

    2015-01-01

    This study attempts to examine the unique contributions of "cognitions" or "metacognitions" to depressive symptoms while controlling for their intercorrelations and comorbid anxiety. Two-hundred-and-fifty-one university students participated in the study. Two complementary hierarchical multiple regression analyses were performed, in which symptoms of depression were regressed on the dysfunctional attitudes (DAS-24 subscales) and metacognition scales (Negative Beliefs about Rumination Scale [NBRS] and Positive Beliefs about Rumination Scale [PBRS]). Results showed that both NBRS and PBRS individually explained a significant amount of variance in depressive symptoms above and beyond dysfunctional schemata while controlling for anxiety. Although dysfunctional attitudes as a set significantly predicted depressive symptoms after anxiety and metacognitions were controlled for, they were weaker than metacognitive variables and none of the DAS-24 subscales contributed individually. Metacognitive beliefs about ruminations appeared to contribute more to depressive symptoms than dysfunctional beliefs in the "cognitive" domain.

  1. 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

  2. Complex motions and chaos in nonlinear systems

    CERN Document Server

    Machado, José; Zhang, Jiazhong

    2016-01-01

    This book brings together 10 chapters on a new stream of research examining complex phenomena in nonlinear systems—including engineering, physics, and social science. Complex Motions and Chaos in Nonlinear Systems provides readers a particular vantage of the nature and nonlinear phenomena in nonlinear dynamics that can develop the corresponding mathematical theory and apply nonlinear design to practical engineering as well as the study of other complex phenomena including those investigated within social science.

  3. The effects of sense of belonging, social support, conflict, and loneliness on depression.

    Science.gov (United States)

    Hagerty, B M; Williams, R A

    1999-01-01

    A number of interpersonal phenomena have been linked to depression, including sense of belonging, social support, conflict, and loneliness. To examine the effects of the interpersonal phenomena of sense of belonging, social support, loneliness, and conflict on depression, and to describe the predictive value of sense of belonging for depression in the context of other interpersonal phenomenon. A sample of clients with major depressive disorder and students in a midwestern community college participated in the study by completing questionnaires. Path analysis showed significant direct paths as postulated, with 64% of the variance of depression explained by the variables in the model. Social support had only an indirect effect on depression, and this finding supported the buffer theory of social support. Sense of belonging was a better predictor of depression. The study findings emphasize the importance of relationship-oriented experiences as part of assessment and intervention strategies for individuals with depression.

  4. 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

  5. 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.

  6. 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.

  7. [Depression and treatment. Apoptosis, neuroplasticity and antidepressants].

    Science.gov (United States)

    Arantes-Gonçalves, Filipe; Coelho, Rui

    2006-01-01

    Depression's neurobiology begins to be better understood. The last decade data considers neuroplasticity and stress as implicated factors on the pathophisiology of depression. Because antidepressants have a lag-time on their action it is possible that inhibition of neurotransmitters recaptation is not sufficient to explain long term changes. For that purpose, neurogenesis increase, nervous fibers sprouting, new synapses and stabilization of the old ones can be responsible for those changes. AMPc-MAPcinases-CREB-BDNF cellular cascade can play a significant role in the mechanisms of dendritic restructuration, hippocampal neurogenesis increase and nervous cells survival. The aim of this article is to discuss if apoptosis could play a key role as an ethiopathogenic factor on the patogenesis of depression. It was done a medline search for references with apoptosis, stress, neuroplasticity, depression and antidepressants key-words. It were found 101 original or review references about these subjects. Stress plays a key role in the etiopathogeny of depression. Its deletery effects on apoptosis and neuroplasticity can be changed by antidepressants. Neurogenesis' increase is necessary for their action. This increase is reached with chronic antidepressant treatment and not with other psychotropic drugs which means some pharmacological specificity of antidepressants. AMPc, CREB, BDNF and Bcl-2 can be considered as target genes in antidepressant synthesis. At the level of this neurotrophic factors apoptosis might be included in the neuroplastic model of depression and play a prominent role in etiopathogeny of depression. To confirm that, we need more research on the field to know which are the mechanisms that trigger apoptosis and its biological significance. In relation to the last one, we can say that is possible to be physiological apoptosis in deteriorated neurons death which cannot make strong connections and pathological apoptosis because of stress via, namely, HPA axis.

  8. Nonlinear screening of dust grains and structurization of dusty plasma

    Energy Technology Data Exchange (ETDEWEB)

    Tsytovich, V. N., E-mail: tsytov@lpi.ru; Gusein-zade, N. G. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)

    2013-07-15

    A review of theoretical ideas on the physics of structurization instability of a homogeneous dusty plasma, i.e., the formation of zones with elevated and depressed density of dust grains and their arrangement into different structures observed in laboratory plasma under microgravity conditions, is presented. Theoretical models of compact dust structures that can form in the nonlinear stage of structurization instability, as well as models of a system of voids (both surrounding a compact structure and formed in the center of the structure), are discussed. Two types of structures with very different dimensions are possible, namely, those smaller or larger than the characteristic mean free path of ions in the plasma flow. Both of them are characterized by relatively regular distributions of dust grains; however, the first ones usually require external confinement, while the structures of the second type can be self-sustained (which is of particular interest). In this review, they are called dust clusters and self-organized dust structures, respectively. Both types of the structures are characterized by new physical processes that take place only in the presence of the dust component. The role of nonlinearities in the screening of highly charged dust grains that are often observed in modern laboratory experiments turns out to be great, but these nonlinearities have not received adequate study as of yet. Although structurization takes place upon both linear and nonlinear screening, it can be substantially different under laboratory and astrophysical conditions. Studies on the nonlinear screening of large charges in plasma began several decades ago; however, up to now, this effect was usually disregarded when interpreting the processes occurring in laboratory dusty plasma. One of the aims of the present review was to demonstrate the possibility of describing the nonlinear screening of individual grains and take it into account with the help of the basic equations for the

  9. 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...

  10. Surrogate markers of visceral fat and response to anti-depressive treatment in patients with major depressive disorder

    DEFF Research Database (Denmark)

    Tønning, Morten; Petersen, Dorthe; Steglich-Petersen, Marie

    2017-01-01

    was to prospectively investigate whether visceral fat, as measured by hip-to-waist ratio and waist circumference, affects treatment outcome in patients with major depressive disorder in patients attending a hospital psychiatric care unit in Denmark. Methods: The study was conducted as an observational prospective......Background: Body mass index (BMI) and body weight have been shown to be associated to treatment outcome in patients with major depressive disorder, but this relationship is not clear. Visceral fat might be an underlying mechanism explaining this relationship. Aims: The aim of this study...... study including 33 patients with major depressive disorder. Assessments were made at enrolment and after 8 weeks. Primary variables were hip-to-waist ratio and waist circumference. Outcome were remission or response of depressive symptoms measured with the Hamilton Depression Rating Scale (HAM-D17...

  11. Mitochondrial respiration in peripheral blood mononuclear cells correlates with depressive subsymptoms and severity of major depression.

    Science.gov (United States)

    Karabatsiakis, A; Böck, C; Salinas-Manrique, J; Kolassa, S; Calzia, E; Dietrich, D E; Kolassa, I-T

    2014-06-10

    Mitochondrial dysfunction might have a central role in the pathophysiology of depression. Phenotypically, depression is characterized by lack of energy, concentration problems and fatigue. These symptoms might be partially explained by reduced availability of adenosine triphosphate (ATP) as a consequence of impaired mitochondrial functioning. This study investigated mitochondrial respiration in peripheral blood mononuclear cells (PBMCs), an established model to investigate the pathophysiology of depression. Mitochondrial respiration was assessed in intact PBMCs in 22 individuals with a diagnosis of major depression (MD) compared with 22 healthy age-matched controls using high-resolution respirometry. Individuals with MD showed significantly impaired mitochondrial functioning: routine and uncoupled respiration as well as spare respiratory capacity, coupling efficiency and ATP turnover-related respiration were significantly lower in the MD compared with the control group. Furthermore, mitochondrial respiration was significantly negatively correlated with the severity of depressive symptoms, in particular, with loss of energy, difficulties concentrating and fatigue. The results suggest that mitochondrial dysfunction contributes to the biomolecular pathophysiology of depressive symptoms. The decreased immune capability observed in MD leading to a higher risk of comorbidities could be attributable to impaired energy supply due to mitochondrial dysfunction. Thus mitochondrial respiration in PBMCs and its functional consequences might be an interesting target for new therapeutical approaches in the treatment of MD and immune-related comorbidities.

  12. Introduction to nonlinear dispersive equations

    CERN Document Server

    Linares, Felipe

    2015-01-01

    This textbook introduces the well-posedness theory for initial-value problems of nonlinear, dispersive partial differential equations, with special focus on two key models, the Korteweg–de Vries equation and the nonlinear Schrödinger equation. A concise and self-contained treatment of background material (the Fourier transform, interpolation theory, Sobolev spaces, and the linear Schrödinger equation) prepares the reader to understand the main topics covered: the initial-value problem for the nonlinear Schrödinger equation and the generalized Korteweg–de Vries equation, properties of their solutions, and a survey of general classes of nonlinear dispersive equations of physical and mathematical significance. Each chapter ends with an expert account of recent developments and open problems, as well as exercises. The final chapter gives a detailed exposition of local well-posedness for the nonlinear Schrödinger equation, taking the reader to the forefront of recent research. The second edition of Introdu...

  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......, it is the universality and robustness of the main models with respect to perturbations that developped the field. This is true for both continuous and discrete equations. In this volume we keep this broad view and draw new perspectives for nonlinear waves in complex systems. In particular we address energy flow...... in Fourier space and equipartition, the role of inhomogeneities and complex geometry and the importance of coupled systems....

  14. 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.

  15. Maternal distress explains the relationship of young African American mothers' violence exposure with their preschoolers' behavior.

    Science.gov (United States)

    Mitchell, Stephanie J; Lewin, Amy; Rasmussen, Andrew; Horn, Ivor B; Joseph, Jill G

    2011-02-01

    Adolescent mothers and their children are particularly susceptible to witnessing or directly experiencing violence. Such violence exposure predicts maternal distress, parenting, and child behavior problems. The current study examined how mothers' depressive symptoms, aggression, harsh disciplinary practices, and home environment independently explain the association between mothers' violence exposure and children's externalizing and internalizing behavior, controlling for their children's violence exposure. Data were collected from 230 African American mothers living in Washington, DC who gave birth as adolescents and whose children were 3 to 5 years old. Path analysis revealed that the effect of mothers' experienced violence on children's externalizing and internalizing behavior was mediated by mothers' depressive symptoms and aggression. However, neither harsh discipline nor stimulation in the home environment acted as significant mediators, and there were no direct or indirect effects of mothers' witnessed violence on child behavior. This study builds on previous work by identifying an association between maternal violence exposure and children's behavior, independent of children's own violence exposure that is explained by mothers' increased distress but not their parenting. These findings suggest that a potential means of preventing behavior problems in minority children born to adolescent mothers is to identify mothers who have been directly exposed to violence and treat their depressive symptoms and aggressive behaviors.

  16. 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

  17. 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...

  18. 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.

  19. 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.

  20. Alcohol and breast cancer: the mechanisms explained.

    Science.gov (United States)

    Al-Sader, Hassen; Abdul-Jabar, Hani; Allawi, Zahra; Haba, Yasser

    2009-08-01

    Breast cancer is a leading cause of death amongst women, several studies have shown significant association between alcohol consumption and breast cancer. The aim of this overview is to highlight some of the mechanisms by which alcohol consumption could increase the risk of developing breast cancer. Using online Medline search engine, article containing details about mechanisms which explain the link between alcohol and breast cancer were examined. A number of mechanisms were found by which alcohol could increase the risk of breast cancer, alcohol's interaction and effect on oestrogen secretion; number of oestrogen receptors; the generation of acetaldehyde and hydroxyl free radicals; cells migration and metastasis; secretion of IGF1 and interaction with HRT and folate metabolism. In conclusion, it is essential for clinicians to understand these mechanisms and inform patients of the link between alcohol and breast cancer. Breast cancer; Alcohol; Mechanisms.

  1. Explaining the gender difference in nightmare frequency.

    Science.gov (United States)

    Schredl, Michael

    2014-01-01

    A recent meta-analysis showed a robust gender difference in nightmare frequency of medium effect size in adolescents and young adults: Women tend to report nightmares more frequently than men. The present study, carried out in an unselected student sample, indicates that 2 factors mediate the gender difference in nightmare frequency: neuroticism and overall dream recall frequency. The effect of neuroticism on the gender difference and the finding that the gender difference in nightmare frequency emerges at an age of about 10 years suggest that gender-specific socialization processes may play an important role in explaining the gender differences in nightmare frequency in adolescents and young to middle-aged adults. This idea is supported by the previous finding that nightmare frequency is related to sex role orientation. However, longitudinal studies are necessary to validate these hypotheses.

  2. 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.

  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 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

    BACKGROUND: The offer of prenatal Down's syndrome screening is part of routine antenatal care in most of Europe; however screening uptake varies significantly across countries. Although a decision to accept or reject screening is a personal choice, it is unlikely that the widely differing uptake...... rates across countries can be explained by variation in individual values alone.The aim of this study was to compare Down's syndrome screening policies and programmes in the Netherlands, where uptake is relatively low ( 90% respectively....... 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...

  5. Explaining African Participation in International Courts

    DEFF Research Database (Denmark)

    Gissel, Line Engbo; Brett, Peter

    2018-01-01

    Africa has more international courts than any other continent, yet International Relations scholarship has failed to explain this move to law on the African continent. This article provides such an explanation using Jean-François Bayart’s concept of extraversion. It shows how the creation...... of international courts in the 1990s and early 2000s was the result of extraverted strategies for attracting international resources and pre-empting donor pressures for political and legal reforms. By adopting these strategies, African states failed to behave in the ‘strategic’ manner anticipated by both...... Tribunal and International Criminal Court. Using the case studies of Zimbabwe and Kenya, it shows how global scripts were repeated by even those states which have, in recent years, most vocally asserted their national interests against these courts....

  6. [Results of the Benton Visual Retention Test and the Bender Visual--Motor Gestalt Test among patients suffer from depressive disorders and organic depressive disorders].

    Science.gov (United States)

    Talarowska, Monika; Florkowski, Antoni; Zboralski, Krzysztof; Gałecki, Piotr

    2011-01-01

    The comorbidity of depression and dementia has been extensively studied. Four main hypotheses have been suggested to explain the relationship between depression and dementia: 1. depression may be a psychological reaction to perceived cognitive decline, 2. depression may be an early symptom of dementia, 3. depression may be an etiologic risk factor for the onset of dementia, and 4. dementia and depression share common risk factors. The objective of this study was to examine the differences between depressive disorders and organic depressive disorders by using two neuropsychological tests. A sample of 61 persons aged 23-62 years participated in the study. Patients who took part in the investigation were divided into two groups: depressive disorders (DD, n = 30), organic depressive disorders (ODD, n = 31). Cognitive functions were evaluated by the Benton Visual Retention Test (BVRT) and Bender Visual-Motor Gestalt Test (BVMGT). Relevant statistical differences among examined group were observed: in BVRT correct answers (p = 0.006), errors (p psychological test than ODD patients. DD group (average) in BVRT: correct answers (-1.33), errors (2.31); BVMGT (average): (50.37). ODD group (average) in BVRT: correct answers (-2.71), errors (5.81); BVMGT (average): (72.01). Patients with organic depressive disorders achieved significantly lower results than patients with depressive disorders in BVRT and BVMGT.

  7. 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.

  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. Viscosity Depressants for Coal Liquefaction

    Science.gov (United States)

    Kalfayan, S. H.

    1983-01-01

    Proposed process modification incorporates viscosity depressants to prevent coal from solidifying during liquefaction. Depressants reduce amount of heat needed to liquefy coal. Possible depressants are metallic soaps, such as stearate, and amides, such as stearamide and dimer acid amides.

  11. Depression and Spinal Cord Injury

    Science.gov (United States)

    ... Urinary Tract Infections: Indwelling (Foley) Catheter Depression and Spinal Cord Injury [ Download this pamphlet: “Depression and Spinal Cord Injury” (PDF - 477KB)] Depression is a common illness that ...

  12. Helping your teen with depression

    Science.gov (United States)

    Teen depression - helping; Teen depression - talk therapy; Teen depression - medicine ... You, your teen, and your health care provider should discuss what might help your teen the most. The most effective treatments ...

  13. Depression During and After Pregnancy

    Science.gov (United States)

    ... Z Health Topics Depression during and after pregnancy Depression during and after pregnancy > A-Z Health Topics ... To receive Publications email updates Enter email Submit Depression during and after pregnancy When you are pregnant ...

  14. The Inverted Pendulum Benchmark in Nonlinear Control Theory: A Survey

    Directory of Open Access Journals (Sweden)

    Olfa Boubaker

    2013-05-01

    Full Text Available Abstract For at least fifty years, the inverted pendulum has been the most popular benchmark, among others, in nonlinear control theory. The fundamental focus of this work is to enhance the wealth of this robotic benchmark and provide an overall picture of historical and current trend developments in nonlinear control theory, based on its simple structure and its rich nonlinear model. In this review, we will try to explain the high popularity of such a robotic benchmark, which is frequently used to realize experimental models, validate the efficiency of emerging control techniques and verify their implementation. We also attempt to provide details on how many standard techniques in control theory fail when tested on such a benchmark. More than 100 references in the open literature, dating back to 1960, are compiled to provide a survey of emerging ideas and challenging problems in nonlinear control theory accomplished and verified using this robotic system. Possible future trends that we can envision based on the review of this area are also presented.

  15. Exposing the nonlinear viscoelastic behavior of asphalt-aggregate mixes

    Science.gov (United States)

    Levenberg, Eyal; Uzan, Jacob

    2012-05-01

    In this study asphalt-aggregate mixes are treated as both viscoelastic and viscoplastic. Following a damage mechanics approach, a nonlinear viscoelastic constitutive formulation is generated from a linear formulation by replacing `applied stresses' with `effective viscoelastic stresses'. A non-dimensional scalar entity called `relative viscoelastic stiffness' is introduced; it is defined as the ratio of applied to effective viscoelastic stress and encapsulates different types of nonlinearities. The paper proposes a computational scheme for exposing these nonlinearities by uncovering, through direct analysis of any test data, changes experienced by the `relative viscoelastic stiffness'. In general terms, the method is based on simultaneous application of creep and relaxation formulations while preserving the interrelationship between the corresponding time functions. The proposed scheme is demonstrated by analyzing a uniaxial tension test and a uniaxial compression test (separately). Results are presented and discussed, unveiling and contrasting the character of viscoelastic nonlinearities in both cases. A conceptual viewpoint is offered to explain the observations, illustrating the requirements from any candidate constitutive theory.

  16. Nonlinear dynamics and plasma transport

    Energy Technology Data Exchange (ETDEWEB)

    Antonsen, T.M. Jr.; Drake, J.F.; Finn, J.M.; Guzdar, P.N.; Hassam, A.B.; Sageev, R.Z.

    1993-01-01

    This progress report details work done on a program in nonlinear dynamical aspects of plasma turbulence and transport funded by DOE since 1989. This program has been in cooperation with laboratories in theUSSR [now Russia and the Confederation of Independent States (CIS)]. The purpose of this program has been: To promote the utilization of recent pathbreaking developments in nonlinear science in plasma turbulence and transport. To promote cooperative scientific investigations between the US and CIS in the related areas of nonlinear science and plasma turbulence and transport. In the work reported in our progress report, we have studied simple models which are motivated by observation on actual fusion devices. The models focus on the important physical processes without incorporating the complexity of the geometry of real devices. This allows for a deeper analysis and understanding of the system both analytically and numerically.

  17. Nonlinear Deformable-body Dynamics

    CERN Document Server

    Luo, Albert C J

    2010-01-01

    "Nonlinear Deformable-body Dynamics" mainly consists in a mathematical treatise of approximate theories for thin deformable bodies, including cables, beams, rods, webs, membranes, plates, and shells. The intent of the book is to stimulate more research in the area of nonlinear deformable-body dynamics not only because of the unsolved theoretical puzzles it presents but also because of its wide spectrum of applications. For instance, the theories for soft webs and rod-reinforced soft structures can be applied to biomechanics for DNA and living tissues, and the nonlinear theory of deformable bodies, based on the Kirchhoff assumptions, is a special case discussed. This book can serve as a reference work for researchers and a textbook for senior and postgraduate students in physics, mathematics, engineering and biophysics. Dr. Albert C.J. Luo is a Professor of Mechanical Engineering at Southern Illinois University, Edwardsville, IL, USA. Professor Luo is an internationally recognized scientist in the field of non...

  18. Optimization for nonlinear inverse problem

    International Nuclear Information System (INIS)

    Boyadzhiev, G.; Brandmayr, E.; Pinat, T.; Panza, G.F.

    2007-06-01

    The nonlinear inversion of geophysical data in general does not yield a unique solution, but a single model, representing the investigated field, is preferred for an easy geological interpretation of the observations. The analyzed region is constituted by a number of sub-regions where the multi-valued nonlinear inversion is applied, which leads to a multi-valued solution. Therefore, combining the values of the solution in each sub-region, many acceptable models are obtained for the entire region and this complicates the geological interpretation of geophysical investigations. In this paper are presented new methodologies, capable to select one model, among all acceptable ones, that satisfies different criteria of smoothness in the explored space of solutions. In this work we focus on the non-linear inversion of surface waves dispersion curves, which gives structural models of shear-wave velocity versus depth, but the basic concepts have a general validity. (author)

  19. NONLINEAR DYNAMICS OF ORGANIZATION DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Денис Антонович БУШУЕВ

    2016-02-01

    Full Text Available The nonlinear behavior of organizations in development projects is considered. The nonlinear behavior is initiated in the growth of organizations and requires a restructuring of governance in identifying dysfunctions. Such a restructuring is needed in the area of soft components, determining the organizational levels of competence in the management of projects, programs, portfolios and heads of the Project Management Office. An important component of the strategic development of the organization is the proposed concept for formation and management of development programs in the context according to their life cycle. It should take into account the non-linear behavior of the soft components of the system and violation of functional processes of the organization. The specific management syndromes of projects and programs are considered. Such as syndromes time management project linked to the singular points of the project. These syndromes are "shift to the right", "point of no return", "braking at the end of the project" and others.

  20. Nonlinear dynamics in biological systems

    CERN Document Server

    Carballido-Landeira, Jorge

    2016-01-01

    This book presents recent research results relating to applications of nonlinear dynamics, focusing specifically on four topics of wide interest: heart dynamics, DNA/RNA, cell mobility, and proteins. The book derives from the First BCAM Workshop on Nonlinear Dynamics in Biological Systems, held in June 2014 at the Basque Center of Applied Mathematics (BCAM). At this international meeting, researchers from different but complementary backgrounds, including molecular dynamics, physical chemistry, bio-informatics and biophysics, presented their most recent results and discussed the future direction of their studies using theoretical, mathematical modeling and experimental approaches. Such was the level of interest stimulated that the decision was taken to produce this publication, with the organizers of the event acting as editors. All of the contributing authors are researchers working on diverse biological problems that can be approached using nonlinear dynamics. The book will appeal especially to applied math...

  1. Nonlinear photoacoustic spectroscopy of hemoglobin

    International Nuclear Information System (INIS)

    Danielli, Amos; Maslov, Konstantin; Favazza, Christopher P.; Xia, Jun; Wang, Lihong V.

    2015-01-01

    As light intensity increases in photoacoustic imaging, the saturation of optical absorption and the temperature dependence of the thermal expansion coefficient result in a measurable nonlinear dependence of the photoacoustic (PA) signal on the excitation pulse fluence. Here, under controlled conditions, we investigate the intensity-dependent photoacoustic signals from oxygenated and deoxygenated hemoglobin at varied optical wavelengths and molecular concentrations. The wavelength and concentration dependencies of the nonlinear PA spectrum are found to be significantly greater in oxygenated hemoglobin than in deoxygenated hemoglobin. These effects are further influenced by the hemoglobin concentration. These nonlinear phenomena provide insights into applications of photoacoustics, such as measurements of average inter-molecular distances on a nm scale or with a tuned selection of wavelengths, a more accurate quantitative PA tomography

  2. Nonlinear photoacoustic spectroscopy of hemoglobin

    Energy Technology Data Exchange (ETDEWEB)

    Danielli, Amos; Maslov, Konstantin; Favazza, Christopher P.; Xia, Jun; Wang, Lihong V., E-mail: LHWANG@WUSTL.EDU [Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130 (United States)

    2015-05-18

    As light intensity increases in photoacoustic imaging, the saturation of optical absorption and the temperature dependence of the thermal expansion coefficient result in a measurable nonlinear dependence of the photoacoustic (PA) signal on the excitation pulse fluence. Here, under controlled conditions, we investigate the intensity-dependent photoacoustic signals from oxygenated and deoxygenated hemoglobin at varied optical wavelengths and molecular concentrations. The wavelength and concentration dependencies of the nonlinear PA spectrum are found to be significantly greater in oxygenated hemoglobin than in deoxygenated hemoglobin. These effects are further influenced by the hemoglobin concentration. These nonlinear phenomena provide insights into applications of photoacoustics, such as measurements of average inter-molecular distances on a nm scale or with a tuned selection of wavelengths, a more accurate quantitative PA tomography.

  3. Training science centre Explainers. The Techniquest experience

    Directory of Open Access Journals (Sweden)

    Colin Johnson

    2005-12-01

    Full Text Available Techniquest was established in 1986, and in 1995 moved to its current premises at Cardiff Bay, South Wales. This was the first purpose-built science centre in the UK. It receives around 200,000 visitors every year to its exhibition, and to its programmes for schools and public audiences in the theatre, laboratory, discovery room and planetarium. The author joined the Techniquest project in 1985, became a staff member in 1990 and was the Chief Executive from 1997 until his retirement in 2004. Techniquest has three “out-stations” in Wales, and is responsible for the supply and maintenance of exhibits to the Look Out Discovery Centre in Bracknell, England. There is a Techniquest gallery at the Lisbon Pavilhão do Conhecimento - Ciência Viva, and a traveling exhibition, SciQuest, in South Africa which was also supplied by Techniquest. All these centres rely on the effective intervention of “Explainers” (at Techniquest we call them “Helpers” to provide the best possible experience for visitors. At its most demanding, the tasks of an Explainer are varied and intensive, yet there may be times when the duties are mundane or even dull. When you rely on people to act as both hosts and housekeepers, to provide both support and stimulus, and to be both welcoming and watchful, you are asking a great deal. This article raises some of the issues concerned with the recruitment and retention of Explainers, their training and management, and the way in which their role is recognized and valued by the science centre as a whole.

  4. Explaining polarization reversals in STEREO wave data

    Science.gov (United States)

    Breneman, A.; Cattell, C.; Wygant, J.; Kersten, K.; Wilson, L. B., III; Dai, L.; Colpitts, C.; Kellogg, P. J.; Goetz, K.; Paradise, A.

    2012-04-01

    Recently, Breneman et al. (2011) reported observations of large amplitude lightning and transmitter whistler mode waves from two STEREO passes through the inner radiation belt (L plane transverse to the magnetic field showed that the transmitter waves underwent periodic polarization reversals. Specifically, their polarization would cycle through a pattern of right-hand to linear to left-hand polarization at a rate of roughly 200 Hz. The lightning whistlers were observed to be left-hand polarized at frequencies greater than the lower hybrid frequency and less than the transmitter frequency (21.4 kHz) and right-hand polarized otherwise. Only right-hand polarized waves in the inner radiation belt should exist in the frequency range of the whistler mode and these reversals were not explained in the previous paper. We show, with a combination of observations and simulated wave superposition, that these polarization reversals are due to the beating of an incident electromagnetic whistler mode wave at 21.4 kHz and linearly polarized, symmetric lower hybrid sidebands Doppler-shifted from the incident wave by ±200 Hz. The existence of the lower hybrid waves is consistent with the parametric decay mechanism of Lee and Kuo (1984) whereby an incident whistler mode wave decays into symmetric, short wavelength lower hybrid waves and a purely growing (zero-frequency) mode. Like the lower hybrid waves, the purely growing mode is Doppler-shifted by ˜200 Hz as observed on STEREO. This decay mechanism in the upper ionosphere has been previously reported at equatorial latitudes and is thought to have a direct connection with explosive spread F enhancements. As such it may represent another dissipation mechanism of VLF wave energy in the ionosphere and may help to explain a deficit of observed lightning and transmitter energy in the inner radiation belts as reported by Starks et al. (2008).

  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. Depression in Kraepelinian schizophrenia

    African Journals Online (AJOL)

    Today there is still considerable symptom overlap between schizophrenia and mood disorders, and the relationship between depression and schizophrenia remains controversial.4. Many patients carry chart diagnoses of both disorders in the clinical setting. Some of the difficulty with the term 'depression' in schizophrenia ...

  7. Depression and Suicide Risk

    Science.gov (United States)

    ... Box — Depression, Antidepressants, and the Risk of Suicide. New England Journal of Medicine, 356:2343-2346. xiii http://psychcentral.com/blog/ ... Box — Depression, Antidepressants, and the Risk of Suicide. New England Journal of Medicine, 356:2343-2346.

  8. CIRCADIAN RHYTMICITY AND DEPRESSION

    Directory of Open Access Journals (Sweden)

    Peter Pregelj

    2008-11-01

    There is a grooving evidence that dysfunction in circadian rhythm regulation andmelatonergic system function is involved in depression pathogenesis. It is known thatclinically used antidepressants have influence on melatonergic system, probably throughchanged ratio between melatonergic type 1 and 2 receptors. With the clinical use of newcompounds like agomelatine that directly regulates melatonergic system new opportunities in depression treatment emerged

  9. 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…

  10. 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.

  11. Depression (For Teens)

    Science.gov (United States)

    ... Feelings Expert Answers Q&A Movies & More for Teens Teens site Sitio para adolescentes Body Mind Sexual Health ... for Educators Search English Español Depression KidsHealth / For Teens / Depression What's in this article? Regular Sadness vs. ...

  12. 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.

  13. 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.

  14. Depressive Symptoms Are Associated with More Hopelessness among White than Black Older Adults.

    Science.gov (United States)

    Assari, Shervin; Lankarani, Maryam Moghani

    2016-01-01

    Hopelessness is a core component of depression. Our information is, however, very limited on ethnic variations in the magnitude of the link between depression and hopelessness. Using a national sample of older adults in United States, we compared Blacks and Whites for the magnitude of the association between depressive symptoms and hopelessness. With a cross-sectional design, we used baseline data of the Religion, Aging, and Health Survey, 2001. Linear regression models were used for data analysis. Depressive symptoms (CES-D) and hopelessness were conceptualized as independent and dependent variables in different models, respectively. Demographic factors (age and gender), socioeconomic status (education and marital status), and health (self-rated health) were covariates. Ethnicity was the moderator. In the pooled sample, higher depressive symptoms were predictive of hopelessness, above and beyond all covariates. We also found significant interactions suggesting that the association between depressive symptoms and hopelessness is weaker among Blacks compared to Whites. In ethnic-specific models, there were significant associations between depressive symptoms and hopelessness among Whites but not Blacks. Depressive symptoms accompany more hopelessness among Whites than Blacks. This finding may explain why Blacks with depression have a lower tendency to commit suicide. Future research should test whether or not Whites with depression better respond to psychotherapies and cognitive behavioral therapies that focus on hope enhancement. This finding may explain differential correlates of depression based on race and ethnicity.

  15. Personality modulates the efficacy of treatment in patients with Major Depressive Disorder

    NARCIS (Netherlands)

    Wardenaar, K.J.; Conradi, H.J.; Bos, E.H.; de Jonge, P.

    2014-01-01

    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

  16. 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

  17. Sleep deprivation in depression.

    Science.gov (United States)

    Hemmeter, Ulrich-Michael; Hemmeter-Spernal, Julia; Krieg, Jürgen-Christian

    2010-07-01

    Sleep deprivation (SD) is a powerful antidepressant treatment that shows antidepressant responses within hours in 40-60% of depressed patients. In more than 80% of responders to SD, a relapse into depression occurred after the recovery night. In addition, it serves as an excellent tool to examine the neurobiological disturbance of depression and may profoundly contribute to the development of new specific and more rapidly acting antidepressants. The reason why SD works and relapses occur is still unclear. A key to solve this problem is to include the current knowledge about the neurobiological disturbance of depression in research, with a focus on neurobiological aspects of sleep and SD (sleep EEG, neuroendocrinology, neurochemistry and chronobiology). Based on findings from these different areas, different strategies to stabilize the antidepressant effect of SD have been applied. This article provides an overview of clinical and neurobiological responses related to SD in depression.

  18. Depression following myocardial infarction

    DEFF Research Database (Denmark)

    Larsen, Karen Kjær

    2013-01-01

    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...... 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...... thorough understanding of the mechanisms that influence the prognosis as well as knowledge of the present care provided. The purpose of this PhD thesis is accordingly subdivided into four specific aims: 1. To estimate the prevalence of depression in people with MI after three months, and to estimate...

  19. Depression and Political Participation*

    Science.gov (United States)

    Ojeda, Christopher

    2015-01-01

    In this paper, I propose that depression is a political phenomenon insofar as it has political sources and consequences. I then investigate one aspect of this argument—whether depression reduces participation. I hypothesize that individuals with depression lack the motivation and physical capacity to vote and engage in other forms of political participation due to somatic problems and feelings of hopelessness and apathy. Moreover, I examine how depression in adolescence can have downstream consequences for participation in young adulthood. The analyses, using both cross-sectional and longitudinal data, show that voter turnout and other forms of participation decrease as the severity of depressed mood increases. These findings are discussed in light of disability rights and potential efforts to boost participation among this group. PMID:26924857

  20. Nonlinear Optics: Principles and Applications

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Tidemand-Lichtenberg, Peter

    As nonlinear optics further develops as a field of research in electromagnetic wave propagation, its state-of-the-art technologies will continue to strongly impact real-world applications in a variety of fields useful to the practicing scientist and engineer. From basic principles to examples...... 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...

  1. Topics in nonlinear functional analysis

    CERN Document Server

    Nirenberg, Louis

    2001-01-01

    Since its first appearance as a set of lecture notes published by the Courant Institute in 1974, this book served as an introduction to various subjects in nonlinear functional analysis. The current edition is a reprint of these notes, with added bibliographic references. Topological and analytic methods are developed for treating nonlinear ordinary and partial differential equations. The first two chapters of the book introduce the notion of topological degree and develop its basic properties. These properties are used in later chapters in the discussion of bifurcation theory (the possible br

  2. Nonlinear Multigrid for Reservoir Simulation

    DEFF Research Database (Denmark)

    Christensen, Max la Cour; Eskildsen, Klaus Langgren; Engsig-Karup, Allan Peter

    2016-01-01

    modeled after local linearization, leading to a nonlinear multigrid method in the form of the full-approximation scheme (FAS). It is demonstrated through numerical experiments that, without loss of robustness, the FAS method can outperform the conventional techniques in terms of algorithmic and numerical...... efficiency for a black-oil model. Furthermore, the use of the FAS method enables a significant reduction in memory usage compared with conventional techniques, which suggests new possibilities for improved large-scale reservoir simulation and numerical efficiency. Last, nonlinear multilevel preconditioning...

  3. Nonlinear Optics of Hexaphenyl Nanofibers

    DEFF Research Database (Denmark)

    Balzer, Frank; Al-Shamery, Katharina; Neuendorf, Rolf

    2003-01-01

    The nonlinear optical response of films of needle-shaped para-hexaphenyl nanoaggregates on mica surfaces is investigated. Two-photon luminescence as well as optical second harmonic generation (SHG) are observed following excitation with femtosecond pulses at 770 nm. Polarization dependent...... measurements reveal that the nonlinear optical transition dipole moment is oriented with an angle of 75° with respect to the needles long axes. The absolute value of the macroscopic second-order susceptibility, averaged over a size distribution of p-6P nanoaggregates, is estimated to be of the order of 6...

  4. Nonlinear waves and weak turbulence

    CERN Document Server

    Zakharov, V E

    1997-01-01

    This book is a collection of papers on dynamical and statistical theory of nonlinear wave propagation in dispersive conservative media. Emphasis is on waves on the surface of an ideal fluid and on Rossby waves in the atmosphere. Although the book deals mainly with weakly nonlinear waves, it is more than simply a description of standard perturbation techniques. The goal is to show that the theory of weakly interacting waves is naturally related to such areas of mathematics as Diophantine equations, differential geometry of waves, Poincaré normal forms, and the inverse scattering method.

  5. Periodic waves in nonlinear metamaterials

    International Nuclear Information System (INIS)

    Liu, Wen-Jun; Xiao, Jing-Hua; Yan, Jie-Yun; Tian, Bo

    2012-01-01

    Periodic waves are presented in this Letter. With symbolic computation, equations for monochromatic waves are studied, and analytic periodic waves are obtained. Factors affecting properties of periodic waves are analyzed. Nonlinear metamaterials, with the continuous distribution of the dielectric permittivity obtained, are different from the ones with the discrete distribution. -- Highlights: ► Equations for the monochromatic waves in transverse magnetic polarization have been studied. ► Analytic periodic waves for the equations have been obtained. ► Periodic waves are theoretically presented and studied in the nonlinear metamaterials.

  6. Field guide to nonlinear optics

    CERN Document Server

    Powers, Peter E

    2013-01-01

    Optomechanics is a field of mechanics that addresses the specific design challenges associated with optical systems. This [i]Field Guide [/i]describes how to mount optical components, as well as how to analyze a given design. It is intended for practicing optical and mechanical engineers whose work requires knowledge in both optics and mechanics. This Field Guide is designed for those looking for a condensed and concise source of key concepts, equations, and techniques for nonlinear optics. Topics covered include technologically important effects, recent developments in nonlinear optics

  7. Stability analysis of nonlinear systems

    CERN Document Server

    Lakshmikantham, Vangipuram; Martynyuk, Anatoly A

    2015-01-01

    The book investigates stability theory in terms of two different measure, exhibiting the advantage of employing families of Lyapunov functions and treats the theory of a variety of inequalities, clearly bringing out the underlying theme. It also demonstrates manifestations of the general Lyapunov method, showing how this technique can be adapted to various apparently diverse nonlinear problems. Furthermore it discusses the application of theoretical results to several different models chosen from real world phenomena, furnishing data that is particularly relevant for practitioners. Stability Analysis of Nonlinear Systems is an invaluable single-sourse reference for industrial and applied mathematicians, statisticians, engineers, researchers in the applied sciences, and graduate students studying differential equations.

  8. Nonlinear Control of Heartbeat Models

    Directory of Open Access Journals (Sweden)

    Witt Thanom

    2011-02-01

    Full Text Available This paper presents a novel application of nonlinear control theory to heartbeat models. Existing heartbeat models are investigated and modified by incorporating the control input as a pacemaker to provide the control channel. A nonlinear feedback linearization technique is applied to force the output of the systems to generate artificial electrocardiogram (ECG signal using discrete data as the reference inputs. The synthetic ECG may serve as a flexible signal source to assess the effectiveness of a diagnostic ECG signal-processing device.

  9. Black- White Differences in Predictive Validity of Depressive Symptoms for Subsequent Major Depression

    Directory of Open Access Journals (Sweden)

    Ehsan eMoazen Zadeh

    2016-02-01

    Full Text Available BackgroundBlack- White differences are shown in psychosocial and medical correlates of depressive symptoms and major depressive disorder (MDD. The current longitudinal study compared Blacks and Whites for the association between baseline depressive symptoms and subsequent risk of MDD 15 years later. MethodsData came from the Americans’ Changing Lives (ACL Study that followed 3,361 individuals (2,205 Whites and 1,156 Blacks from 1986 to 2001. Predictor was baseline depressive symptoms measured using an 11-item Center for Epidemiological Studies-Depression (CES-D in 1986. Outcome was 12 month MDD measured using the Composite International Diagnostic Interview (CIDI at 2001. Covariates included baseline socio-demographics, financial difficulty, chronic medical conditions, and self-rated health (SRH measured at 1986. We used logistic regression to evaluate the association between baseline CES-D score and CIDI-based MDD 15 years later net of demographics, SES, CMCs and SRH. The models were applied in the pooled sample, as well as Blacks and Whites. We also reported data on reliability and factor structure of CES-D based on ethnicity. ResultsAccording to the logistic regression models, baseline CES-D scores were predictive of subsequent CIDI- based 12 month MDD 15 years later among Whites but not Blacks. Ethnic differences in predictive validity of CES-D scores on MDD could not be attributed to the ethnic differences in reliability of the CES-D which was even higher for Blacks than Whites. ConclusionBlack–White differences exist in the association between baseline depressive symptoms and subsequent risk of MDD over 15 years. Ethnic differences in the longitudinal link between baseline CES-D and subsequent risk of MDD among Blacks may explain some of the Black - White differences in social, psychological, and medical correlates of depressive symptoms and depression. Future research is still needed to compare Blacks and Whites for confirmatory

  10. Prevalence, Work-Loss Days and Quality of Life of Community Dwelling Subjects with Depressive Symptoms

    Science.gov (United States)

    Sohn, Jee Hoon; Ahn, Seung Hee; Seong, Su Jeong; Ryu, Ji Min

    2013-01-01

    The nationwide prevalence of major depressive disorder in Korea is lower than most countries, despite the high suicide rate. To explain this unexpectedly low prevalence, we examined the functional disability and quality of life in community-dwelling subjects with significant depressive symptoms not diagnosable as depressive disorder. A total of 1,029 subjects, randomly chosen from catchment areas, were interviewed with the Center for Epidemiologic Studies Depression scale, Mini International Neuropsychiatric Interview, WHO Quality of Life scale, and the WHO Disability Assessment Schedule. Those with scores over 21 on the depression scale were interviewed by a psychiatrist for diagnostic confirmation. Among community-dwelling subjects, the 1-month prevalence of major depressive disorder was 2.2%, but the 1-month prevalence of depressive symptoms not diagnosable as depressive disorder was 14.1%. Depressive disorders were the cause of 24.7% of work loss days, while depressive symptoms not diagnosable as depressive disorder were the cause of 17.2% of work loss days. These findings support the dimensional or spectrum approach to depressive disorder in the community and might be the missing link between the apparent low prevalence of depressive disorder and high suicide rate in Korea. PMID:23399785

  11. Major depression with psychotic features

    Science.gov (United States)

    ... depression References American Psychiatric Association. Major depressive disorder. Diagnostic and Statistical Manual of Mental Disorders: DSM-5 . 5th ed. Arlington, VA: American Psychiatric Publishing. 2013; ...

  12. Adaptive enhancement for nonuniform illumination images via nonlinear mapping

    Science.gov (United States)

    Wang, Yanfang; Huang, Qian; Hu, Jing

    2017-09-01

    Nonuniform illumination images suffer from degenerated details because of underexposure, overexposure, or a combination of both. To improve the visual quality of color images, underexposure regions should be lightened, whereas overexposure areas need to be dimmed properly. However, discriminating between underexposure and overexposure is troublesome. Compared with traditional methods that produce a fixed demarcation value throughout an image, the proposed demarcation changes as local luminance varies, thus is suitable for manipulating complicated illumination. Based on this locally adaptive demarcation, a nonlinear modification is applied to image luminance. Further, with the modified luminance, we propose a nonlinear process to reconstruct a luminance-enhanced color image. For every pixel, this nonlinear process takes the luminance change and the original chromaticity into account, thus trying to avoid exaggerated colors at dark areas and depressed colors at highly bright regions. Finally, to improve image contrast, a local and image-dependent exponential technique is designed and applied to the RGB channels of the obtained color image. Experimental results demonstrate that our method produces good contrast and vivid color for both nonuniform illumination images and images with normal illumination.

  13. Nonlinearity and nonclassicality in a nanomechanical resonator

    Energy Technology Data Exchange (ETDEWEB)

    Teklu, Berihu [Clermont Universite, Blaise Pascal University, CNRS, PHOTON-N2, Institut Pascal, Aubiere Cedex (France); Universita degli Studi di Milano, Dipartimento di Fisica, Milano (Italy); Ferraro, Alessandro; Paternostro, Mauro [Queen' s University, Centre for Theoretical Atomic, Molecular, and Optical Physics, School of Mathematics and Physics, Belfast (United Kingdom); Paris, Matteo G.A. [Universita degli Studi di Milano, Dipartimento di Fisica, Milano (Italy)

    2015-12-15

    We address quantitatively the relationship between the nonlinearity of a mechanical resonator and the nonclassicality of its ground state. In particular, we analyze the nonclassical properties of the nonlinear Duffing oscillator (being driven or not) as a paradigmatic example of a nonlinear nanomechanical resonator. We first discuss how to quantify the nonlinearity of this system and then show that the nonclassicality of the ground state, as measured by the volume occupied by the negative part of the Wigner function, monotonically increases with the nonlinearity in all the working regimes addressed in our study. Our results show quantitatively that nonlinearity is a resource to create nonclassical states in mechanical systems. (orig.)

  14. Topology optimization of nonlinear optical devices

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard

    2011-01-01

    This paper considers the design of nonlinear photonic devices. The nonlinearity stems from a nonlinear material model with a permittivity that depends on the local time-averaged intensity of the electric field. A finite element model is developed for time-harmonic wave propagation and an incremen......This paper considers the design of nonlinear photonic devices. The nonlinearity stems from a nonlinear material model with a permittivity that depends on the local time-averaged intensity of the electric field. A finite element model is developed for time-harmonic wave propagation...

  15. 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

  16. BDNF serum levels are not related to cognitive functioning in older depressed patients and controls

    NARCIS (Netherlands)

    Dols, A.; Thesing, C.S.; 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

  17. Heritability of Anxious-Depressive and Withdrawn Behavior: Age-Related Changes during Adolescence

    Science.gov (United States)

    Lamb, Diane J.; Middeldorp, Christel M.; van Beijsterveldt, Catarina E. M.; Bartels, Meike; van der Aa, Niels; Polderman, Tinca J. C.; Boomsma, Dorret I.

    2010-01-01

    Objective: To explain the differential course of anxiety and depression in individuals from childhood to adulthood by examining age-related changes in the genetic and environmental etiology of anxious and depressive symptoms. Method: A sample of 1470, 1839, and 2023 Dutch twins aged 12, 14, and 16 years reported on symptoms of anxious depression…

  18. Testing a Gender Additive Model: The Role of Body Image in Adolescent Depression

    Science.gov (United States)

    Bearman, Sarah Kate; Stice, Eric

    2008-01-01

    Despite consistent evidence that adolescent girls are at greater risk of developing depression than adolescent boys, risk factor models that account for this difference have been elusive. The objective of this research was to examine risk factors proposed by the "gender additive" model of depression that attempts to partially explain the increased…

  19. Advanced glycation end product (AGE) accumulation in the skin is associated with depression : The maastricht study

    NARCIS (Netherlands)

    Van Dooren, F.E.P.; Pouwer, F.; Schalkwijk, C.G.; Sep, S.J.S.; Stehouwer, C.D.A.; Henry, R.M.A.; Dagnelie, P.C.; Schaper, N.C.; Van Der Kallen, C.J.H.; Koster, A.; Denollet, J.K.L.; Verhey, F.R.J.; Schram, M.T.

    2017-01-01

    Background: depression is a highly prevalent disease with a high morbidity and mortality risk. Its pathophysiology is not entirely clear. However, type 2 diabetes is an important risk factor for depression. One mechanism that may explain this association may include the formation of advanced

  20. 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.