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Sample records for assimilating assorted acquaintance

  1. Agent Persuasion Mechanism of Acquaintance

    Science.gov (United States)

    Jinghua, Wu; Wenguang, Lu; Hailiang, Meng

    Agent persuasion can improve negotiation efficiency in dynamic environment based on its initiative and autonomy, and etc., which is being affected much more by acquaintance. Classification of acquaintance on agent persuasion is illustrated, and the agent persuasion model of acquaintance is also illustrated. Then the concept of agent persuasion degree of acquaintance is given. Finally, relative interactive mechanism is elaborated.

  2. Assortative fertilization in Drosophila.

    Science.gov (United States)

    Markow, T A

    1997-07-22

    The concept of gametic isolation has its origins in the 1937 edition of T. Dobzhansky's Genetics and the Origin of Species. Involving either positive assortative fertilization (as opposed to self-incompatibility) or negative assortative fertilization, it occurs after mating but prior to fertilization. Gametic isolation is generally subsumed under either prezygotic or postmating isolation and thus has not been the subject of extensive investigation. Examples of assortative fertilization in Drosophila are reviewed and compared with those of other organisms. Potential mechanisms leading to assortative fertilization are discussed, as are their evolutionary implications.

  3. Optimizing retail assortments

    NARCIS (Netherlands)

    R.P. Rooderkerk (Robert); H.J. van Heerde (Harald); T.H.A. Bijmolt (Tammo)

    2013-01-01

    markdownabstract__Abstract__ Retailers face the problem of finding the assortment that maximizes category profit. This is a challenging task because the number of potential assortments is very large when there are many stock-keeping units (SKUs) to choose from. Moreover, SKU sales can be

  4. Optimizing retail assortments

    NARCIS (Netherlands)

    Bijmolt, T.H.A.; van Heerde, H.J.; Rooderkerk, R.P.

    2013-01-01

    Retailers face the problem of finding the assortment that maximizes category profit. This is a challenging task because the number of potential assortments is very large when there are many stock-keeping units (SKUs) to choose from. Moreover, SKU sales can be cannibalized by other SKUs in the

  5. Optimizing Retail Assortments

    NARCIS (Netherlands)

    Rooderkerk, Robert P.; van Heerde, Harald J.; Bijmolt, Tammo H. A.

    2013-01-01

    Retailers face the problem of finding the assortment that maximizes category profit. This is a challenging task because the number. of potential assortments is very large when there are many stock-keeping units (SKUs) to choose from. Moreover, SKIT sales can be cannibalized by other SKUs in the

  6. Do assortative preferences contribute to assortative mating for adiposity?

    OpenAIRE

    Fisher, Claire I.; Fincher, Corey L.; Hahn, Amanda C.; Little, Anthony C.; DeBruine, Lisa M; Jones, Benedict C

    2013-01-01

    Assortative mating for adiposity, whereby levels of adiposity in romantic partners tend to be positively correlated, has implications for population health due to the combined effects of partners' levels of adiposity on fertility and/or offspring health. Although assortative preferences for cues of adiposity, whereby leaner people are inherently more attracted to leaner individuals, have been proposed as a factor in assortative mating for adiposity, there have been no direct tests of this iss...

  7. Do assortative preferences contribute to assortative mating for adiposity?

    OpenAIRE

    Fisher, Claire I.; Fincher, Corey L.; Hahn, Amanda C.; Little, Anthony C.; DeBruine, Lisa M; Jones, Benedict C

    2014-01-01

    Assortative mating for adiposity, whereby levels of adiposity in romantic partners tend to be positively correlated, has implications for population health due to the combined effects of partners' levels of adiposity on fertility and/or offspring health. Although assortative preferences for cues of adiposity, whereby leaner people are inherently more attracted to leaner individuals, have been proposed as a factor in assortative mating for adiposity, there have been no direct tests of this iss...

  8. Opinion evolution in different social acquaintance networks

    Science.gov (United States)

    Chen, Xi; Zhang, Xiao; Wu, Zhan; Wang, Hongwei; Wang, Guohua; Li, Wei

    2017-11-01

    Social acquaintance networks influenced by social culture and social policy have a great impact on public opinion evolution in daily life. Based on the differences between socio-culture and social policy, three different social acquaintance networks (kinship-priority acquaintance network, independence-priority acquaintance network, and hybrid acquaintance network) incorporating heredity proportion ph and variation proportion pv are proposed in this paper. Numerical experiments are conducted to investigate network topology and different phenomena during opinion evolution, using the Deffuant model. We found that in kinship-priority acquaintance networks, similar to the Chinese traditional acquaintance networks, opinions always achieve fragmentation, resulting in the formation of multiple large clusters and many small clusters due to the fact that individuals believe more in their relatives and live in a relatively closed environment. In independence-priority acquaintance networks, similar to Western acquaintance networks, the results are similar to those in the kinship-priority acquaintance network. In hybrid acquaintance networks, similar to the Chinese modern acquaintance networks, only a few clusters are formed indicating that in modern China, opinions are more likely to reach consensus on a large scale. These results are similar to the opinion evolution phenomena in modern society, proving the rationality and applicability of network models combined with social culture and policy. We also found a threshold curve pv+2 ph=2.05 in the results for the final opinion clusters and evolution time. Above the threshold curve, opinions could easily reach consensus. Based on the above experimental results, a culture-policy-driven mechanism for the opinion dynamic is worth promoting in this paper, that is, opinion dynamics can be driven by different social cultures and policies through the influence of heredity and variation in interpersonal relationship networks. This

  9. Opinion evolution in different social acquaintance networks.

    Science.gov (United States)

    Chen, Xi; Zhang, Xiao; Wu, Zhan; Wang, Hongwei; Wang, Guohua; Li, Wei

    2017-11-01

    Social acquaintance networks influenced by social culture and social policy have a great impact on public opinion evolution in daily life. Based on the differences between socio-culture and social policy, three different social acquaintance networks (kinship-priority acquaintance network, independence-priority acquaintance network, and hybrid acquaintance network) incorporating heredity proportion ph and variation proportion pv are proposed in this paper. Numerical experiments are conducted to investigate network topology and different phenomena during opinion evolution, using the Deffuant model. We found that in kinship-priority acquaintance networks, similar to the Chinese traditional acquaintance networks, opinions always achieve fragmentation, resulting in the formation of multiple large clusters and many small clusters due to the fact that individuals believe more in their relatives and live in a relatively closed environment. In independence-priority acquaintance networks, similar to Western acquaintance networks, the results are similar to those in the kinship-priority acquaintance network. In hybrid acquaintance networks, similar to the Chinese modern acquaintance networks, only a few clusters are formed indicating that in modern China, opinions are more likely to reach consensus on a large scale. These results are similar to the opinion evolution phenomena in modern society, proving the rationality and applicability of network models combined with social culture and policy. We also found a threshold curve pv+2ph=2.05 in the results for the final opinion clusters and evolution time. Above the threshold curve, opinions could easily reach consensus. Based on the above experimental results, a culture-policy-driven mechanism for the opinion dynamic is worth promoting in this paper, that is, opinion dynamics can be driven by different social cultures and policies through the influence of heredity and variation in interpersonal relationship networks. This finding

  10. Do assortative preferences contribute to assortative mating for adiposity?

    Science.gov (United States)

    Fisher, Claire I; Fincher, Corey L; Hahn, Amanda C; Little, Anthony C; DeBruine, Lisa M; Jones, Benedict C

    2014-01-01

    Assortative mating for adiposity, whereby levels of adiposity in romantic partners tend to be positively correlated, has implications for population health due to the combined effects of partners' levels of adiposity on fertility and/or offspring health. Although assortative preferences for cues of adiposity, whereby leaner people are inherently more attracted to leaner individuals, have been proposed as a factor in assortative mating for adiposity, there have been no direct tests of this issue. Because of this, and because of recent work suggesting that facial cues of adiposity convey information about others' health that may be particularly important for mate preferences, we tested the contribution of assortative preferences for facial cues of adiposity to assortative mating for adiposity (assessed from body mass index, BMI) in a sample of romantic couples. Romantic partners' BMIs were positively correlated and this correlation was not due to the effects of age or relationship duration. However, although men and women with leaner partners showed stronger preferences for cues of low levels of adiposity, controlling for these preferences did not weaken the correlation between partners' BMIs. Indeed, own BMI and preferences were uncorrelated. These results suggest that assortative preferences for facial cues of adiposity contribute little (if at all) to assortative mating for adiposity. PMID:24168811

  11. Assortative fertilization in Drosophila

    OpenAIRE

    Markow, Therese Ann

    1997-01-01

    The concept of gametic isolation has its origins in the 1937 edition of T. Dobzhansky’s Genetics and the Origin of Species. Involving either positive assortative fertilization (as opposed to self-incompatibility) or negative assortative fertilization, it occurs after mating but prior to fertilization. Gametic isolation is generally subsumed under either prezygotic or postmating isolation and thus has not been the subject of extensive investigation. Examples of asso...

  12. Immunity of multiplex networks via acquaintance vaccination

    Science.gov (United States)

    Wang, Zhen; Zhao, Da-Wei; Wang, Lin; Sun, Gui-Quan; Jin, Zhen

    2015-11-01

    How to find the effective approach of immunizing a population is one open question in the research of complex systems. Up to now, there have been a great number of works focusing on the efficiency of various immunization strategies. However, the majority of these existing achievements are limited to isolated networks, how immunization affects disease spreading in multiplex networks seems to need further exploration. In this letter, we explore the impact of the acquaintance immunization in multiplex networks, where two kinds of immunization strategies, multiplex node-based acquaintance immunization and layer node-based acquaintance immunization, are proposed. With the generating function method, our theoretical framework is able to accurately calculate the critical immunization threshold which is one of the most important indexes to predict the epidemic regime. Moreover, we further uncover that, with the increment of degree correlation between network layers, the immunization threshold declines for multiplex node-based acquaintance immunization, but slowly increases for layer node-based acquaintance immunization.

  13. Japanese International Students' Attitudes toward Acquaintance Rape.

    Science.gov (United States)

    Motoike, Janice; Stockdale, Margaret

    This study looked at the influence of an Asian sociocultural variable, loss of face or social integrity, as a predictor of perceptions of acquaintance rape among Japanese students. In addition to the expected associations between gender, sexism, and perceptions of rape, loss of face was predicted to interact with the perpetrator's reference group…

  14. Taking a chance: Sex, alcohol & acquaintance rape

    DEFF Research Database (Denmark)

    Demant, Jakob; Heinskou, Marie Bruvik

    2011-01-01

    to grasp more of the complexities of the situation. By analyzing a single case of acquaintance rape and then reflect this case in the light of interviews on young people's drinking habits it is argued that the complexities within the analytical frame of chance is crucial in understanding reported...

  15. INVESTMENT DECISION BASED ON ACQUAINTANCE STRATEGY

    OpenAIRE

    Dr. N Babitha Thimmaiah

    2017-01-01

    Everywhere people talk about money and investment. The investor makes an investment to yield high returns with minimum risk. Generally the acquaintance refers to the neighbours. The investment decisions which is seen as continuous process of interactions between the investor, investor’s behaviour and the investment environment. This investment process is influenced by a number of variables and driven by peer influence (including neighbours, friends, relatives, etc.). The experimental results ...

  16. Acquaintance molestation and youth-serving organizations.

    Science.gov (United States)

    Lanning, Kenneth V; Dietz, Park

    2014-10-01

    This article is based not only on the research literature but also on the extensive field experience of the authors in consulting with investigators, attorneys, and organizations on the prevention, investigation, prosecution, and civil litigation of molestation of children within or in connection with youth-serving organizations. Acquaintance molesters have often pursued careers or sought out paid or volunteer work with organizations through which they can meet children. To address the problem of such offenders, it is necessary for youth-serving organizations to recognize the diversity of sexual activity, the phenomena of "nice-guy" offenders and compliant child victims, and the grooming/seduction process, each of which is reviewed here. The four most important protection practices for organizations are screening; management, and supervision; response to suspicions, allegations, and complaints; and prevention and awareness programs. The authors recommend general approaches to each of these and describe the reasons many organizations resist implementing available preventive measures. © The Author(s) 2014.

  17. Modeling acquaintance networks based on balance theory

    Directory of Open Access Journals (Sweden)

    Vukašinović Vida

    2014-09-01

    Full Text Available An acquaintance network is a social structure made up of a set of actors and the ties between them. These ties change dynamically as a consequence of incessant interactions between the actors. In this paper we introduce a social network model called the Interaction-Based (IB model that involves well-known sociological principles. The connections between the actors and the strength of the connections are influenced by the continuous positive and negative interactions between the actors and, vice versa, the future interactions are more likely to happen between the actors that are connected with stronger ties. The model is also inspired by the social behavior of animal species, particularly that of ants in their colony. A model evaluation showed that the IB model turned out to be sparse. The model has a small diameter and an average path length that grows in proportion to the logarithm of the number of vertices. The clustering coefficient is relatively high, and its value stabilizes in larger networks. The degree distributions are slightly right-skewed. In the mature phase of the IB model, i.e., when the number of edges does not change significantly, most of the network properties do not change significantly either. The IB model was found to be the best of all the compared models in simulating the e-mail URV (University Rovira i Virgili of Tarragona network because the properties of the IB model more closely matched those of the e-mail URV network than the other models

  18. Spectral graph analysis of modularity and assortativity.

    Science.gov (United States)

    Van Mieghem, P; Ge, X; Schumm, P; Trajanovski, S; Wang, H

    2010-11-01

    Expressions and bounds for Newman's modularity are presented. These results reveal conditions for or properties of the maximum modularity of a network. The influence of the spectrum of the modularity matrix on the maximum modularity is discussed. The second part of the paper investigates how the maximum modularity, the number of clusters, and the hop count of the shortest paths vary when the assortativity of the graph is changed via degree-preserving rewiring. Via simulations, we show that the maximum modularity increases, the number of clusters decreases, and the average hop count and the effective graph resistance increase with increasing assortativity.

  19. Multi-Agent Information Classification Using Dynamic Acquaintance Lists.

    Science.gov (United States)

    Mukhopadhyay, Snehasis; Peng, Shengquan; Raje, Rajeev; Palakal, Mathew; Mostafa, Javed

    2003-01-01

    Discussion of automated information services focuses on information classification and collaborative agents, i.e. intelligent computer programs. Highlights include multi-agent systems; distributed artificial intelligence; thesauri; document representation and classification; agent modeling; acquaintances, or remote agents discovered through…

  20. Arranging the assortment to arouse choice

    NARCIS (Netherlands)

    Herpen, van Erica; Bosmans, Anick

    2018-01-01

    Food retailers can present specific products in a separate category (e.g., separate section for organic products) or integrated into the mainstream shelf. This study investigates how assortment organization influences consumers' variety perceptions and product choice. We argue and show that when

  1. Species Assortment and Biodiversity Conservation in Homegardens ...

    African Journals Online (AJOL)

    user

    that the urban gardens are a storehouse of biodiversity including species that run the risk of disappearance in the natural habitat. ... Species assortment and biodiversity conservation in homegardens of Bahir Dar. [33] consumption, and significantly ... Nile River and the Mediterranean Sea. The topography of the City is ...

  2. Marketing Analytics for High-Dimensional Assortments

    NARCIS (Netherlands)

    B.J.D. Jacobs (Bruno)

    2017-01-01

    textabstractOver the past two decades online retailing has become ubiquitous and today’s large online retailers enable customers to purchase virtually any product. As a consequence product assortments at such retailers are of a different order of magnitude compared to the traditional

  3. Anticipated identification costs: Improving assortment evaluation by diagnostic attributes

    NARCIS (Netherlands)

    Herpen, van E.; Pieters, F.G.M.

    2007-01-01

    Abstract Consumers often make quick assessments of product assortments, to determine if these are worthwhile for further investigation. They anticipate how difficult it will be to distinguish the various options in the assortment, which will influence their assortment evaluations. We reason that

  4. Assortative marriage for physical characteristics in newlyweds.

    Science.gov (United States)

    Pennock-Roman, M

    1984-06-01

    The objective of this study was to estimate the degree of spouse resemblance in the first 6 months of marriage and to compare these estimates with those of previous studies on long-standing marriages. The participants, 215 couples, were selected from the marriage licenses issued in two counties within the San Francisco Bay Area. They attended one of several group sessions in which questionnaires were filled out and forearm length measurements were taken. Only the results for the couples of European ancestry (N = 164) are presented here since the other subsamples were too small to analyze separately. The husband-wife correlations for body size were found to be essentially equal to those in long-standing marriages. Thus, it appears that physical resemblance in couples is the result of initial assortment rather than convergence arising from long cohabitation. A significant residual husband-wife correlation for weight was found after statistically partialing out height. It may be that assortative marriage for food habits and attractiveness produces spouse resemblance in weight, independently of height. Alternatively, convergence in eating habits may occur during courtship and the early months of marriage which may increase the resemblance in weight. There was very little homogamy for eye color independently of race, and no evidence of assortative marriage for handedness.

  5. Acquaintance Rape on Campus: The Problem, the Victims, and Prevention.

    Science.gov (United States)

    Neff, Laurie

    1988-01-01

    Asserts that, although providing educational programs and materials on acquaintance rape and prevention strategies is important, attention must also be given to victims. Discusses recognition of stress response pattern of victims suffering from Rape Trauma Syndrome and provision of appropriate referral and support services. Includes selected list…

  6. Gender Norms and Retaliatory Violence against Spouses and Acquaintances

    Science.gov (United States)

    Feld, Scott L.; Felson, Richard B.

    2008-01-01

    This article examines an experiment embedded within a nationally representative survey of adult Americans to investigate gender norms regarding retaliatory violence between spouses and acquaintances. Contrary to claims that societal norms permit violence within marriage, respondents disapproved of retaliatory violence against spouses more than…

  7. Women’s Situational Coping With Acquaintance Sexual Assault

    Science.gov (United States)

    NURIUS, PAULA S.; NORRIS, JEANETTE; MACY, REBECCA J.; HUANG, BU

    2015-01-01

    Drawing on theories of appraisal-based coping, the present study applied structural modeling to examine relationships among personal goal orientations, primary and secondary appraisals of acquaintance sexual assault, and women’s emotional and behavioral responses to it. Based on 415 college women’s reports of a sexual assault experience, the model shows both direct and indirect effects. Assertive, diplomatic, and immobilized responding were each predicted by a unique profile of appraisals and orientations; personal goal orientations and primary appraisals were completely mediated by secondary appraisals. Ways that these findings can facilitate self-protective coping in an acquaintance sexual assault situation, leading to the development of effective, well-tailored self-defense and resistance programs, are discussed. PMID:26345173

  8. Negative-assortative mating for color in wolves.

    Science.gov (United States)

    Hedrick, Philip W; Smith, Douglas W; Stahler, Daniel R

    2016-04-01

    There is strong negative-assortative mating for gray and black pelage color in the iconic wolves in Yellowstone National Park. This is the first documented case of significant negative-assortative mating in mammals and one of only a very few cases in vertebrates. Of 261 matings documented from 1995 to 2015, 63.6% were between gray and black wolves and the correlation between mates for color was -0.266. There was a similar excess of matings of both gray males × black females and black males × gray females. Using the observed frequency of negative-assortative mating in a model with both random and negative-assortative mating, the estimated proportion of negative-assortative mating was 0.430. The estimated frequency of black wolves in the population from 1996 to 2014 was 0.452 and these frequencies appear stable over this 19-year period. Using the estimated level of negative-assortative mating, the predicted equilibrium frequency of the dominant allele was 0.278, very close to the mean value of 0.253 observed. In addition, the patterns of genotype frequencies, that is, the observed proportion of black homozygotes and the observed excess of black heterozygotes, are consistent with negative-assortative mating. Importantly these results demonstrate that negative-assortative mating could be entirely responsible for the maintenance of this well-known color polymorphism. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  9. ASSORTMENT AND PRICE POLICY OF STATE PHARMACIES OF MOSCOW

    Directory of Open Access Journals (Sweden)

    I. V. Voronovich

    2015-01-01

    Full Text Available The most important index which determines the level and quality of pharmaceutical support is the correspondence of assortment to consumers needs. Assortment policy is determined by the functions implemented, and the problems of organization of pharmaceutical support of medicinal organizations within the frameworks of substantiated and reasonable expenditure of budget funds, and affordable pharmaceutical support of the population. The purpose of this research was the study of assortment and price policy of state pharmacies of Moscow. The objects were pharmacy subdivisions of state pharmacy network of Moscow. We have used sociological methods (questionnaire, interviewing, method of marketing, and statistic analysis. We have studied the assortment structure, assortment groups’ distribution on price segments. We have established that the drugs, more than 60% of which are foreign-made occupied more than a half of the assortment. Medicinal drugs in 50 rubles price spectrum occupy the biggest share of pharmacy assortment. Distribution within every assortment group revealed that more than a half of drugs are in average price spectrum from 50 to 500 rubles. Average charge for VED amounts to 21.87%, and for drugs which were not included in VED list – 34.07%. The charge for the goods, the price of which is not regulated, trade charge is more. 

  10. Spatial assimilation?

    DEFF Research Database (Denmark)

    Andersen, Hans Skifter

    a stronger preference for renting, because of insecurity about their future situation, and that especially newly arrived immigrants live in immigrant dense, so-called multi-ethnic, neighbourhoods. The spatial assimilation theory claims that during the course of time immigrants will move to other kinds....... Part of the initial increase in the frequency of living in multi-ethnic neighbourhoods can be ascribed to the increasing concentration of ethnic minorities in neighbourhoods instead of individual choice among immigrants. The study confirms spatial assimilation, but the change is not dramatic within...

  11. Assortative mating and fragmentation within dog breeds

    Directory of Open Access Journals (Sweden)

    Hailer Frank

    2008-01-01

    Full Text Available Abstract Background There are around 400 internationally recognized dog breeds in the world today, with a remarkable diversity in size, shape, color and behavior. Breeds are considered to be uniform groups with similar physical characteristics, shaped by selection rooted in human preferences. This has led to a large genetic difference between breeds and a large extent of linkage disequilibrium within breeds. These characteristics are important for association mapping of candidate genes for diseases and therefore make dogs ideal models for gene mapping of human disorders. However, genetic uniformity within breeds may not always be the case. We studied patterns of genetic diversity within 164 poodles and compared it to 133 dogs from eight other breeds. Results Our analyses revealed strong population structure within poodles, with differences among some poodle groups as pronounced as those among other well-recognized breeds. Pedigree analysis going three generations back in time confirmed that subgroups within poodles result from assortative mating imposed by breed standards as well as breeder preferences. Matings have not taken place at random or within traditionally identified size classes in poodles. Instead, a novel set of five poodle groups was identified, defined by combinations of size and color, which is not officially recognized by the kennel clubs. Patterns of genetic diversity in other breeds suggest that assortative mating leading to fragmentation may be a common feature within many dog breeds. Conclusion The genetic structure observed in poodles is the result of local mating patterns, implying that breed fragmentation may be different in different countries. Such pronounced structuring within dog breeds can increase the power of association mapping studies, but also represents a serious problem if ignored. In dog breeding, individuals are selected on the basis of morphology, behaviour, working or show purposes, as well as geographic

  12. Assortative mixing in functional brain networks during epileptic seizures

    Science.gov (United States)

    Bialonski, Stephan; Lehnertz, Klaus

    2013-09-01

    We investigate assortativity of functional brain networks before, during, and after one-hundred epileptic seizures with different anatomical onset locations. We construct binary functional networks from multi-channel electroencephalographic data recorded from 60 epilepsy patients; and from time-resolved estimates of the assortativity coefficient, we conclude that positive degree-degree correlations are inherent to seizure dynamics. While seizures evolve, an increasing assortativity indicates a segregation of the underlying functional network into groups of brain regions that are only sparsely interconnected, if at all. Interestingly, assortativity decreases already prior to seizure end. Together with previous observations of characteristic temporal evolutions of global statistical properties and synchronizability of epileptic brain networks, our findings may help to gain deeper insights into the complicated dynamics underlying generation, propagation, and termination of seizures.

  13. Educational assortative mating and income inequality in Denmark.

    Science.gov (United States)

    Breen, Richard; Andersen, Signe Hald

    2012-08-01

    Many writers have expressed a concern that growing educational assortative mating will lead to greater inequality between households in their earnings or income. In this article, we examine the relationship between educational assortative mating and income inequality in Denmark between 1987 and 2006. Denmark is widely known for its low level of income inequality, but the Danish case provides a good test of the relationship between educational assortative mating and inequality because although income inequality increased over the period we consider, educational homogamy declined. Using register data on the exact incomes of the whole population, we find that change in assortative mating increased income inequality but that these changes were driven by changes in the educational distributions of men and women rather than in the propensity for people to choose a partner with a given level of education.

  14. Lower bound of assortativity coefficient in scale-free networks

    Science.gov (United States)

    Yang, Dan; Pan, Liming; Zhou, Tao

    2017-03-01

    The degree-degree correlation is important in understanding the structural organization of a network and dynamics upon a network. Such correlation is usually measured by the assortativity coefficient r, with natural bounds r ∈ [ - 1 , 1 ] . For scale-free networks with power-law degree distribution p ( k ) ˜ k - γ , we analytically obtain the lower bound of assortativity coefficient in the limit of large network size, which is not -1 but dependent on the power-law exponent γ. This work challenges the validation of the assortativity coefficient in heterogeneous networks, suggesting that one cannot judge whether a network is positively or negatively correlated just by looking at its assortativity coefficient alone.

  15. Expectations Regarding Acquaintance Sexual Aggression Among Sorority and Fraternity Members.

    Science.gov (United States)

    Nurius, Paula S; Norris, Jeanette; Dimeff, Linda A; Graham, Thomas L

    1996-10-01

    Among women, college is a high risk period for sexual assault by male acquaintances. Differences in expectations held by men and women may contribute to misinterpretation of social cues and subsequent sexual aggression and may impair women's ability to respond effectively. This paper presents findings from a predominantly Caucasian sample (85.9%) of college sorority (n = 66) and fraternity (n = 34) members regarding the social context within which they interact and their expectations regarding perpetration of and response to sexual aggression. Results showed differences in men's and women's expectations and responses, and in particular highlighted how men's expectations were related to women's resistance of unwanted sex. Understanding the cognitive processes that men and women draw upon in social interactions can be useful for developing sexual aggression prevention and resistance interventions.

  16. Change in BMI accurately predicted by social exposure to acquaintances.

    Science.gov (United States)

    Oloritun, Rahman O; Ouarda, Taha B M J; Moturu, Sai; Madan, Anmol; Pentland, Alex Sandy; Khayal, Inas

    2013-01-01

    Research has mostly focused on obesity and not on processes of BMI change more generally, although these may be key factors that lead to obesity. Studies have suggested that obesity is affected by social ties. However these studies used survey based data collection techniques that may be biased toward select only close friends and relatives. In this study, mobile phone sensing techniques were used to routinely capture social interaction data in an undergraduate dorm. By automating the capture of social interaction data, the limitations of self-reported social exposure data are avoided. This study attempts to understand and develop a model that best describes the change in BMI using social interaction data. We evaluated a cohort of 42 college students in a co-located university dorm, automatically captured via mobile phones and survey based health-related information. We determined the most predictive variables for change in BMI using the least absolute shrinkage and selection operator (LASSO) method. The selected variables, with gender, healthy diet category, and ability to manage stress, were used to build multiple linear regression models that estimate the effect of exposure and individual factors on change in BMI. We identified the best model using Akaike Information Criterion (AIC) and R(2). This study found a model that explains 68% (pchange in BMI. The model combined social interaction data, especially from acquaintances, and personal health-related information to explain change in BMI. This is the first study taking into account both interactions with different levels of social interaction and personal health-related information. Social interactions with acquaintances accounted for more than half the variation in change in BMI. This suggests the importance of not only individual health information but also the significance of social interactions with people we are exposed to, even people we may not consider as close friends.

  17. Change in BMI accurately predicted by social exposure to acquaintances.

    Directory of Open Access Journals (Sweden)

    Rahman O Oloritun

    Full Text Available Research has mostly focused on obesity and not on processes of BMI change more generally, although these may be key factors that lead to obesity. Studies have suggested that obesity is affected by social ties. However these studies used survey based data collection techniques that may be biased toward select only close friends and relatives. In this study, mobile phone sensing techniques were used to routinely capture social interaction data in an undergraduate dorm. By automating the capture of social interaction data, the limitations of self-reported social exposure data are avoided. This study attempts to understand and develop a model that best describes the change in BMI using social interaction data. We evaluated a cohort of 42 college students in a co-located university dorm, automatically captured via mobile phones and survey based health-related information. We determined the most predictive variables for change in BMI using the least absolute shrinkage and selection operator (LASSO method. The selected variables, with gender, healthy diet category, and ability to manage stress, were used to build multiple linear regression models that estimate the effect of exposure and individual factors on change in BMI. We identified the best model using Akaike Information Criterion (AIC and R(2. This study found a model that explains 68% (p<0.0001 of the variation in change in BMI. The model combined social interaction data, especially from acquaintances, and personal health-related information to explain change in BMI. This is the first study taking into account both interactions with different levels of social interaction and personal health-related information. Social interactions with acquaintances accounted for more than half the variation in change in BMI. This suggests the importance of not only individual health information but also the significance of social interactions with people we are exposed to, even people we may not consider as

  18. Assortative mating for human height: A meta-analysis.

    Science.gov (United States)

    Stulp, Gert; Simons, Mirre J P; Grasman, Sara; Pollet, Thomas V

    2017-01-01

    The study of assortative mating for height has a rich history in human biology. Although the positive correlation between the stature of spouses has often been noted in western populations, recent papers suggest that mating patterns for stature are not universal. The objective of this paper was to review the published evidence to examine the strength of and universality in assortative mating for height. We conducted an extensive literature review and meta-analysis. We started with published reviews but also searched through secondary databases. Our search led to 154 correlations of height between partners. We classified the populations as western and non-western based on geography. These correlations were then analyzed via meta-analytic techniques. 148 of the correlations for partner heights were positive and the overall analysis indicates moderate positive assortative mating (r = .23). Although assortative mating was slightly stronger in countries that can be described as western compared to non-western, this difference was not statistically significant. We found no evidence for a change in assortative mating for height over time. There was substantial residual heterogeneity in effect sizes and this heterogeneity was most pronounced in western countries. Positive assortative mating for height exists in human populations, but is modest in magnitude suggesting that height is not a major factor in mate choice. Future research is necessary to understand the underlying causes of the large amount of heterogeneity observed in the degree of assortative mating across human populations, which may stem from a combination of methodological and ecological differences. © 2016 The Authors American Journal of Human Biology Published by Wiley Periodicals, Inc.

  19. The Influence of Scheduling Style on Assortment Size

    Directory of Open Access Journals (Sweden)

    Rai Dipankar

    2016-12-01

    Full Text Available People use two types of scheduling styles to schedule their daily activities, namely clock-time or event-time. When people use clock time, they organize tasks based on a clock. When they use event-time, they organize tasks based on their order of completion. This research shows that adopting different scheduling styles influence consumers’ assortment size preferences. We demonstrate, through two studies, that consumers using event-time scheduling style prefer a larger assortment size whereas consumers using clock-time scheduling style prefer a smaller assortment size. We also show that this effect is mediated by desirability-feasibility consideration. Specifically, event-time scheduling style leads consumers to focus on the desirability considerations, which leads them to prefer larger assortment size while shopping. On the other hand, clock-time scheduling style leads consumers to focus on the feasibility considerations, which leads them to prefer smaller assortment size while shopping. We also discuss the theoretical and managerial implications of our research.

  20. The Nature of Interactions between Students with Severe Disabilities and Their Friends and Acquaintances without Disabilities.

    Science.gov (United States)

    Grenot-Scheyer, Marquita

    1994-01-01

    This study of 20 elementary-school children with severe disabilities examined differences in their interactions with friends without disabilities compared with interactions with acquaintances without disabilities. Friends and acquaintances did not differ in developmental level, language age, functional movement, or social competence. Group…

  1. Where Do I Start?: A Parents' Guide for Talking to Teens about Acquaintance Rape.

    Science.gov (United States)

    Bateman, Py; Stringer, Gayle M.

    This is a booklet designed for parents interested in helping their teenage children avoid the possibility of sexual assault. The first section of the booklet provides background on acquaintance rape, discussing attitudes about acquaintance rape, what boys and girls learn about sexual activity, gender different perceptions, and teenagers and peer…

  2. Emotional reactions to the mentally ill are positively influenced by personal acquaintance.

    Science.gov (United States)

    Arikan, K; Uysal, O

    1999-01-01

    The study sought to evaluate whether personal acquaintance with a psychiatric patient increases or decreases stigmatization. The research was carried out in a Turkish university. The Social Distance Scale and the Affective Reaction Scale were completed by final year students. The subjects were then asked whether they have ever been acquainted with a patient with a mental disorder. Subjects who had not been acquainted with a patient with mental disorder had a higher score on the Affective Reaction Scale than subjects who had been acquainted. This finding suggests that acquaintance with a psychiatric patient reduces negative emotions towards people with mental disorders. It is suggested that this result is related to the resolution of sensitization.

  3. Emergence of scaling and assortative mixing through altruism

    Science.gov (United States)

    Li, Ping; Zhang, Jie; Small, Michael

    2011-06-01

    Many social networks, apart from displaying scale-free characteristics observed in some instances, possess another remarkable feature that distinguishes them from those that appear in biological and technological context-assortativity. However, little or no attention has been payed to the mechanism of assortativity in modeling these networks. Inspired by individuals' altruistic behavior in sociology, we develop a model with a different growth mechanism called “altruistic attachment”, which can reproduce not only the power law degree distribution but degree correlations. We study in detail the statistical properties of our network model, which we also demonstrate striking differences with the BA model, and can portray real social networks more precisely.

  4. A framework for analyzing contagion in assortative banking networks.

    Science.gov (United States)

    Hurd, Thomas R; Gleeson, James P; Melnik, Sergey

    2017-01-01

    We introduce a probabilistic framework that represents stylized banking networks with the aim of predicting the size of contagion events. Most previous work on random financial networks assumes independent connections between banks, whereas our framework explicitly allows for (dis)assortative edge probabilities (i.e., a tendency for small banks to link to large banks). We analyze default cascades triggered by shocking the network and find that the cascade can be understood as an explicit iterated mapping on a set of edge probabilities that converges to a fixed point. We derive a cascade condition, analogous to the basic reproduction number R0 in epidemic modelling, that characterizes whether or not a single initially defaulted bank can trigger a cascade that extends to a finite fraction of the infinite network. This cascade condition is an easily computed measure of the systemic risk inherent in a given banking network topology. We use percolation theory for random networks to derive a formula for the frequency of global cascades. These analytical results are shown to provide limited quantitative agreement with Monte Carlo simulation studies of finite-sized networks. We show that edge-assortativity, the propensity of nodes to connect to similar nodes, can have a strong effect on the level of systemic risk as measured by the cascade condition. However, the effect of assortativity on systemic risk is subtle, and we propose a simple graph theoretic quantity, which we call the graph-assortativity coefficient, that can be used to assess systemic risk.

  5. Assortative mating for human height : A meta-analysis

    NARCIS (Netherlands)

    Stulp, Gert; Simons, Mirre J. P.; Grasman, Sara; Pollet, Thomas V.

    ObjectivesThe study of assortative mating for height has a rich history in human biology. Although the positive correlation between the stature of spouses has often been noted in western populations, recent papers suggest that mating patterns for stature are not universal. The objective of this

  6. High incidence of GJB2 gene mutations among assortatively mating ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 93; Issue 1. High incidence of GJB2 gene mutations among assortatively mating hearing impaired families in Kerala: future implications. Amritkumar Pavithra Justin Margret Jeffrey Jayasankaran Chandru Arabandi Ramesh C. R. Srikumari Srisailapathy. Research Note Volume ...

  7. Social Structure and Personality Assortment Among Married Couples

    NARCIS (Netherlands)

    Bekkers, René; Aken, Marcel A.G. van; Denissen, Jaap

    2006-01-01

    We study the influence of social structure on assortative mating for personality in a large national sample (n=3616) of married and cohabitating couples in the Netherlands. We find that couples with higher levels of education and from dissimilar religious origins are more similar with regard to

  8. Second-Order Assortative Mixing in Social Networks

    DEFF Research Database (Denmark)

    Zhou, Shi; Cox, Ingemar; Hansen, Lars Kai

    2017-01-01

    In a social network, the number of links of a node, or node degree, is often assumed as a proxy for the node’s importance or prominence within the network. It is known that social networks exhibit the (first-order) assortative mixing, i.e. if two nodes are connected, they tend to have similar nod...

  9. Examining assortativity in the mental lexicon: Evidence from word associations.

    Science.gov (United States)

    Van Rensbergen, Bram; Storms, Gert; De Deyne, Simon

    2015-12-01

    Words are characterized by a variety of lexical and psychological properties, such as their part of speech, word-frequency, concreteness, or affectivity. In this study, we examine how these properties relate to a word's connectivity in the mental lexicon, the structure containing a person's knowledge of words. In particular, we examine the extent to which these properties display assortative mixing, that is, the extent to which words in the lexicon are more likely to be connected to words that share these properties. We investigated three types of word properties: 1) subjective word covariates: valence, dominance, arousal, and concreteness; 2) lexical information: part of speech; and 3) distributional word properties: age-of-acquisition, word frequency, and contextual diversity. We assessed which of these factors exhibit assortativity using a word association task, where the probability of producing a certain response to a cue is a measure of the associative strength between the cue and response in the mental lexicon. Our results show that the extent to which these aspects exhibit assortativity varies considerably, with a high cue-response correspondence on valence, dominance, arousal, concreteness, and part of speech, indicating that these factors correspond to the words people deem as related. In contrast, we find that cues and responses show only little correspondence on word frequency, contextual diversity, and age-of-acquisition, indicating that, compared to subjective and lexical word covariates, distributional properties exhibit only little assortativity in the mental lexicon. Possible theoretical accounts and implications of these findings are discussed.

  10. Accuracy of Self-Esteem Judgments at Zero Acquaintance.

    Science.gov (United States)

    Hirschmüller, Sarah; Schmukle, Stefan C; Krause, Sascha; Back, Mitja D; Egloff, Boris

    2017-03-20

    Perceptions of strangers' self-esteem can have wide-ranging interpersonal consequences. Aiming to reconcile inconsistent results from previous research that had predominantly suggested that self-esteem is a trait that can hardly be accurately judged at zero acquaintance, we examined unaquainted others' accuracy in inferring individuals' actual self-esteem. Ninety-nine target participants (77 female; M age  = 23.5 years) were videotaped in a self-introductory situation, and self-esteem self-reports and reports by well-known informants were obtained as separate accuracy criteria. Forty unacquainted observers judged targets' self-esteem on the basis of these short video sequences (M = 23s, SD = 7.7). Results showed that both self-reported (r = .31, p = .002) and informant-reported self-esteem (r = .21, p = .040) of targets could be inferred by strangers. The degree of accuracy in self-esteem judgments could be explained with lens model analyses: Self- and informant-reported self-esteem predicted nonverbal and vocal friendliness, both of which predicted self-esteem judgments by observers. In addition, observers' accuracy in inferring informant-reported self-esteem was mediated by the utilization of targets' physical attractiveness. Besides using valid behavioral information to infer strangers' self-esteem, observers inappropriately relied on invalid behavioral information reflecting nonverbal, vocal, and verbal self-assuredness. Our findings show that strangers can quite accurately detect individuals' self-reported and informant-reported self-esteem when targets are observed in a public self-presentational situation. © 2017 Wiley Periodicals, Inc.

  11. The Variety of An Assortment : An Extension to the Attribute-Based Approach

    NARCIS (Netherlands)

    Herpen, van H.W.I.; Pieters, F.G.M.

    2002-01-01

    In recent years, interest in category management has surged, and as a consequence, large retailers now systematically review their product assortments. Variety is a key property of assortments. Assortment variety can determine consumers' store choice and is only gaining in importance with today's

  12. Whom would you rather help: an acquaintance not responsible for her plight or a responsible sibling?

    Science.gov (United States)

    Greitemeyer, Tobias; Rudolph, Udo; Weiner, Bernard

    2003-06-01

    When 2 persons--an acquaintance who could not have avoided a problem and a close relative who is responsible for her own plight--ask for help, attribution theory and sociobiology conflict about who will receive help. Attribution theorists assume that the nonresponsible acquaintance will be supported, but sociobiologists argue that the responsible sibling will receive help. The authors tested the hypothesis that characteristics of the situation affect which theory better predicts help giving. The results confirmed that in situations that do not affect life and death, a nonresponsible acquaintance would receive more help than a responsible sibling. But in life-or-death situations, inasmuch as the reproductive fitness of the person in need is in danger, a responsible sibling would be supported more than a nonresponsible acquaintance.

  13. Thermospheric Data Assimilation

    Science.gov (United States)

    2016-05-05

    AFRL-AFOSR-VA-TR-2016-0193 Thermospheric Data Assimilation Tomoko Matsuo REGENTS OF THE UNIVERSITY OF COLORADO THE Final Report 05/05/2016...Thermospheric Data Assimilation 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-13-1-0058 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Dr. Tomoko...thermosphere-ionosphere first-principles model. An ensemble data assimilation procedure, constructed with the NCAR Data Assimilation Research Testbed

  14. Management of Assortment Inventory Groups in Selected Foundry

    Directory of Open Access Journals (Sweden)

    Szymszal J.

    2015-09-01

    Full Text Available As experience shows the practical, reliable assessment and optimisation of total costs of logistical processes implemented in supply chains of foundry plants is a quite complex and complicated process, because it requires to enclose all, without exception, performed actions, including them in various reference cross-sections, systematic activities and finally transforming them in a totally homogenous collection. Only solid analysis and assessment of assortment management in logistical supply systems in foundry plants of particular assortment groups allows to lower the supply costs significantly. In the article the analysis and assessment of the newest implemented optimising algorithms are presented in the process stock management of selected material groups used in a production process of a chosen foundry plant. A practical solution to solve a problem of rotary stock cost minimisation is given as well as of costs while creating a stock with the usage of economical volume and value of order.

  15. The role of psychopathology in stalking by adult strangers and acquaintances.

    Science.gov (United States)

    McEwan, Troy E; Strand, Susanne

    2013-06-01

    Individuals who stalk strangers and acquaintances are under-studied, although there is some evidence suggesting a greater prevalence of psychopathology than is present in those who stalk former partners. This study investigated the nature and prevalence of psychopathology in a sample of stranger and acquaintance stalkers and whether psychopathology was associated with increased duration or serial stalking in this group. It was hypothesised that mental illness, and specifically psychosis, would be more prevalent among strangers and acquaintances than among ex-intimate stalkers. Two hundred and eleven stalkers (10% female; mean age = 35, SD = 10.8; 71 ex-intimates) were recruited between 2002 and 2007 from a specialist service in Melbourne, Australia. Each underwent psychiatric and psychological assessment and disorders were diagnosed according to DMS-IV-TR criteria. Non-parametric independent sample tests were used to examine associations between relationship type and psychopathology, and to identify individual and stalking-related characteristics associated with increased duration and serial stalking. Axis I disorders were significantly more prevalent among strangers and acquaintances than ex-intimates (71% vs 48%, OR = 2.6, 95% CI = 1.4 to 4.7), as were psychotic disorders (29% vs 9%, OR = 4.4, 95% CI = 1.8 to 10.9). Psychosis was significantly associated with increased duration of stalking behaviour (U = 3043, p stalked multiple times (OR = 2.4, 95% CI = 1.2 to 5.0). Those who stalk strangers and acquaintances are often mentally ill and psychopathology is associated with more persistent and recurrent stalking behaviour. Although limited by the use of clinical interview rather than structured assessment, these findings strongly support the argument for routine mental health assessment of stranger and acquaintance stalkers who become involved with the criminal justice system.

  16. Assortativity and leadership emergence from anti-preferential attachment in heterogeneous networks

    OpenAIRE

    Sendiña-Nadal, I.; Danziger, M. M.; Z. Wang; Havlin, S.; Boccaletti, S.

    2015-01-01

    Real-world networks have distinct topologies, with marked deviations from purely random networks. Many of them exhibit degree-assortativity, with nodes of similar degree more likely to link to one another. Though microscopic mechanisms have been suggested for the emergence of other topological features, assortativity has proven elusive. Assortativity can be artificially implanted in a network via degree-preserving link permutations, however this destroys the graph?s hierarchical clustering an...

  17. Widespread positive but weak assortative mating by diet within stickleback populations

    OpenAIRE

    Ingram, Travis; Jiang, Yuexin; Rangel, Racine; Bolnick, Daniel I.

    2015-01-01

    Assortative mating – correlation between male and female traits – is common within populations and has the potential to promote genetic diversity and in some cases speciation. Despite its importance, few studies have sought to explain variation in the extent of assortativeness across populations. Here, we measure assortative mating based on an ecologically important trait, diet as inferred from stable isotopes, in 16 unmanipulated lake populations of three-spine stickleback. As predicted, we ...

  18. The Sex and the Uni: Educational Assortative Matching the Over-Education*

    OpenAIRE

    Alessandro Tampieri

    2010-01-01

    Educational assortative matching encourages individuals to acquire education so as to increase the probability of marrying a high-income partner. But since everyone is more educated, the chances of a good match do not change. Hence over education emerges, as in absence of educational assortative matching individuals could reach their optimal level of education by exploiting less educational resources. Over-education is stronger the higher the probability of educational assortative matching, t...

  19. Evaluating stranger and acquaintance rape: the role of benevolent sexism in perpetrator blame and recommended sentence length.

    Science.gov (United States)

    Viki, G Tendayi; Abrams, Dominic; Masser, Barbara

    2004-06-01

    In most jurisdictions, the law does not recognize the distinction between stranger and acquaintance rape. However, these two types of rape seem to elicit different responses from both lay observers and legal practitioners. Two studies investigating the role of benevolent sexism (BS) in accounting for participants' responses to acquaintance vs. stranger rape perpetrators are reported. Participants were presented with vignettes describing either an acquaintance rape or a stranger rape. As predicted, relative to low-BS individuals, participants who scored high in BS attributed less blame (Study 1) and recommended shorter sentences (Study 2) for the acquaintance rape perpetrator. Benevolent sexism was unrelated to reactions to the perpetrator in the stranger rape condition.

  20. Models of cultural niche construction with selection and assortative mating.

    Science.gov (United States)

    Creanza, Nicole; Fogarty, Laurel; Feldman, Marcus W

    2012-01-01

    Niche construction is a process through which organisms modify their environment and, as a result, alter the selection pressures on themselves and other species. In cultural niche construction, one or more cultural traits can influence the evolution of other cultural or biological traits by affecting the social environment in which the latter traits may evolve. Cultural niche construction may include either gene-culture or culture-culture interactions. Here we develop a model of this process and suggest some applications of this model. We examine the interactions between cultural transmission, selection, and assorting, paying particular attention to the complexities that arise when selection and assorting are both present, in which case stable polymorphisms of all cultural phenotypes are possible. We compare our model to a recent model for the joint evolution of religion and fertility and discuss other potential applications of cultural niche construction theory, including the evolution and maintenance of large-scale human conflict and the relationship between sex ratio bias and marriage customs. The evolutionary framework we introduce begins to address complexities that arise in the quantitative analysis of multiple interacting cultural traits.

  1. Measuring the robustness of network community structure using assortativity

    Science.gov (United States)

    Shizuka, Daizaburo; Farine, Damien R.

    2016-01-01

    The existence of discrete social clusters, or ‘communities’, is a common feature of social networks in human and nonhuman animals. The level of such community structure in networks is typically measured using an index of modularity, Q. While modularity quantifies the degree to which individuals associate within versus between social communities and provides a useful measure of structure in the social network, it assumes that the network has been well sampled. However, animal social network data is typically subject to sampling errors. In particular, the associations among individuals are often not sampled equally, and animal social network studies are often based on a relatively small set of observations. Here, we extend an existing framework for bootstrapping network metrics to provide a method for assessing the robustness of community assignment in social networks using a metric we call community assortativity (rcom). We use simulations to demonstrate that modularity can reliably detect the transition from random to structured associations in networks that differ in size and number of communities, while community assortativity accurately measures the level of confidence based on the detectability of associations. We then demonstrate the use of these metrics using three publicly available data sets of avian social networks. We suggest that by explicitly addressing the known limitations in sampling animal social network, this approach will facilitate more rigorous analyses of population-level structural patterns across social systems. PMID:26949266

  2. Emergence of Assortative Mixing between Clusters of Cultured Neurons

    Science.gov (United States)

    Teller, Sara; Granell, Clara; De Domenico, Manlio; Soriano, Jordi; Gómez, Sergio; Arenas, Alex

    2014-01-01

    The analysis of the activity of neuronal cultures is considered to be a good proxy of the functional connectivity of in vivo neuronal tissues. Thus, the functional complex network inferred from activity patterns is a promising way to unravel the interplay between structure and functionality of neuronal systems. Here, we monitor the spontaneous self-sustained dynamics in neuronal cultures formed by interconnected aggregates of neurons (clusters). Dynamics is characterized by the fast activation of groups of clusters in sequences termed bursts. The analysis of the time delays between clusters' activations within the bursts allows the reconstruction of the directed functional connectivity of the network. We propose a method to statistically infer this connectivity and analyze the resulting properties of the associated complex networks. Surprisingly enough, in contrast to what has been reported for many biological networks, the clustered neuronal cultures present assortative mixing connectivity values, meaning that there is a preference for clusters to link to other clusters that share similar functional connectivity, as well as a rich-club core, which shapes a ‘connectivity backbone’ in the network. These results point out that the grouping of neurons and the assortative connectivity between clusters are intrinsic survival mechanisms of the culture. PMID:25188377

  3. The Acquaintance Level of Turkish Prospective Teachers with Qualified Works of Children's Literature

    Science.gov (United States)

    Çer, Erkan; Sahin, Ertugrul

    2016-01-01

    The aim of this cross-sectional study is investigate to what extent acquainted prospective Turkish teachers are with qualified works of children's literature. A convenience sample of 146 university students studying at the Turkish teaching department at a university in the Central Black Sea Region completed a questionnaire to determine the…

  4. Acquaintance Rape and Alcohol Consumption on College Campuses: How Are They Linked?

    Science.gov (United States)

    Abbey, Antonia

    1991-01-01

    Explores the links between acquaintance rape and alcohol consumption among college students, two serious problems on campus. Seven explanations for the relationship focus on alcohol consumption by the perpetrator and by the victim. The need to conduct further studies and develop prevention programs is addressed. (Author/SM)

  5. Methods of forming and realization of assortment policy of retail business enterprises

    Directory of Open Access Journals (Sweden)

    Kudenko Kiril

    2016-07-01

    Full Text Available Within the framework of the article systematisation of methods of forming and realisation of assortment policy of enterprises of retail business is done. Recommendations concerning the priority of the use of separate methods of forming and realisation of assortment policy with different purposes, taking into account their content, advantages and disadvantages are developed.

  6. Over-Education and Assortative Matching in Partnerships: A Theoretical Analysis

    Science.gov (United States)

    Tampieri, Alessandro

    2016-01-01

    This paper argues that assortative matching may explain over-education. Education determines individuals' income and, due to the presence of assortative matching, the quality of partners in personal, social and working life. Thus, an individual acquires education to improve the expected partners' quality. However, since every individual of the…

  7. Computing assortative mixing by degree with the s-metric in networks using linear programming

    NARCIS (Netherlands)

    Waldorp, L.J.; Schmittmann, V.D.

    2015-01-01

    Calculation of assortative mixing by degree in networks indicates whether nodes with similar degree are connected to each other. In networks with scale-free distribution high values of assortative mixing by degree can be an indication of a hub-like core in networks. Degree correlation has generally

  8. Displacement Data Assimilation

    Science.gov (United States)

    Restrepo, J. M.; Rosenthal, S.; Venkataramani, S.

    2013-05-01

    Geometric corrections are blended with nonlinear/non-Gaussian estimation methods to produced improved data assimilation outcomes on problems where features are critical. Problems of this sort are the estimation of hurricane tracks, tracking jet meandering, front propagation, among many others. The geometric correction is made possible by a data preserving map. It makes corrections on phase, primarily, as well as in the amplitude. The displacement assimilation is embedded in the analysis stage of a nonlinear/non-Gaussian Bayesian data assimilation scheme, such as the path integral method. In addition to showing how the method improves upon the results, as compared to more standard methodologies.

  9. Lunar and Planetary Science XXXV: Achondrites: An Awesome Assortment

    Science.gov (United States)

    2004-01-01

    The session "chondrites: An Awesome Assortment" included the following reports:Nucleation of the Widmanstatten Pattern in Iron Meteorites; Compositions of the Group IVB Iron Meteorites; Sm-Nd Age and Initial 87Sr/86Sr for Yamato 980318: An Old Cumulate Eucrite; Petrology of New Stannern-trend Eucrites and Eucrite Genesis; The Dichotomous HED Meteorite Suite; Early Thermal Evolution of HED Parent Body; Thermal History of the Lodranite Yamato 74357: Constraints from Compositional Zoning and Fe-Mg Ordering; Late Thermal Evolution of Acapulcoites-Lodranites Parent Body: Evidence from Sm-Nd Isotopes and Trace Elements of the LEW 86220 Acapulcoite; Partial Melting Under Reducing Conditions: How are Primitive Achondrites Formed?; Evolution of the Ureilite Parent Body; Complex, Contrasting Behavior of Chromium During Late-Stage Processes in Ureilites; Sahara 99555 and D Orbigny: Possible Pristine Parent Magma of Quenched Angrites; and Devolatilized-Allende Partial Melts as an Analog for Primitive Angrite Magmas.

  10. Assortative and modular networks are shaped by adaptive synchronization processes.

    Science.gov (United States)

    Avalos-Gaytán, Vanesa; Almendral, Juan A; Papo, David; Schaeffer, Satu Elisa; Boccaletti, Stefano

    2012-07-01

    Modular organization and degree-degree correlations are ubiquitous in the connectivity structure of biological, technological, and social interacting systems. So far most studies have concentrated on unveiling both features in real world networks, but a model that succeeds in generating them simultaneously is needed. We consider a network of interacting phase oscillators, and an adaptation mechanism for the coupling that promotes the connection strengths between those elements that are dynamically correlated. We show that, under these circumstances, the dynamical organization of the oscillators shapes the topology of the graph in such a way that modularity and assortativity features emerge spontaneously and simultaneously. In turn, we prove that such an emergent structure is associated with an asymptotic arrangement of the collective dynamical state of the network into cluster synchronization.

  11. Phenotypic robustness and the assortativity signature of human transcription factor networks.

    Directory of Open Access Journals (Sweden)

    Dov A Pechenick

    2014-08-01

    Full Text Available Many developmental, physiological, and behavioral processes depend on the precise expression of genes in space and time. Such spatiotemporal gene expression phenotypes arise from the binding of sequence-specific transcription factors (TFs to DNA, and from the regulation of nearby genes that such binding causes. These nearby genes may themselves encode TFs, giving rise to a transcription factor network (TFN, wherein nodes represent TFs and directed edges denote regulatory interactions between TFs. Computational studies have linked several topological properties of TFNs - such as their degree distribution - with the robustness of a TFN's gene expression phenotype to genetic and environmental perturbation. Another important topological property is assortativity, which measures the tendency of nodes with similar numbers of edges to connect. In directed networks, assortativity comprises four distinct components that collectively form an assortativity signature. We know very little about how a TFN's assortativity signature affects the robustness of its gene expression phenotype to perturbation. While recent theoretical results suggest that increasing one specific component of a TFN's assortativity signature leads to increased phenotypic robustness, the biological context of this finding is currently limited because the assortativity signatures of real-world TFNs have not been characterized. It is therefore unclear whether these earlier theoretical findings are biologically relevant. Moreover, it is not known how the other three components of the assortativity signature contribute to the phenotypic robustness of TFNs. Here, we use publicly available DNaseI-seq data to measure the assortativity signatures of genome-wide TFNs in 41 distinct human cell and tissue types. We find that all TFNs share a common assortativity signature and that this signature confers phenotypic robustness to model TFNs. Lastly, we determine the extent to which each of the four

  12. Women's Situational Coping With Acquaintance Sexual Assault: Applying an Appraisal-Based Model.

    Science.gov (United States)

    Nurius, Paula S; Norris, Jeanette; Macy, Rebecca J; Huang, B U

    2004-05-01

    Drawing on theories of appraisal-based coping, the present study applied structural modeling to examine relationships among personal goal orientations, primary and secondary appraisals of acquaintance sexual assault, and women's emotional and behavioral responses to it. Based on 415 college women's reports of a sexual assault experience, the model shows both direct and indirect effects. Assertive, diplomatic, and immobilized responding were each predicted by a unique profile of appraisals and orientations; personal goal orientations and primary appraisals were completely mediated by secondary appraisals. Ways that these findings can facilitate self-protective coping in an acquaintance sexual assault situation, leading to the development of effective, well-tailored self-defense and resistance programs, are discussed.

  13. THROUGH HER EYES: Factors Affecting Women's Perception of and Resestance to Acquaintance Sexual Aggression Threat

    Science.gov (United States)

    Norris, Jeanette; Nurius, Paula S.; Dimeff, Linda A.

    2015-01-01

    A major component of a woman's ability to resist assaults by strangers versus acquaintances lies in the social and cognitive context in which she is engaged with the perpetrator and within which she must recognize potential threat before engaging in a behavioral response. This paper presents questionnaire and focus group findings of heterosexual college sorority women's social contexts, perceived risks, responses, and psychological barriers to protecting themselves from sexual aggression threat by fraternity acquaintances. Several social and cognitive factors, including alcohol consumption and psychological barriers, were related to projected responses to sexual aggression. Participants in general held a high sense of invulnerability to victimization and an optimistic belief in their ability to resist sexual aggression. Several differences between previously victimized and nonvictimized women also emerged. PMID:25705073

  14. Reflective acquaintance with other minds and the double-sided disclosure of the lived-body

    DEFF Research Database (Denmark)

    Farley, Adam

    2014-01-01

    This paper will consider the phenomenological disclosure of the reflecting-body vis-à-vis subject’s reflective acquaintance with other minds. To this end, phenomenological accounts regarding the double-sided disclosure of the lived-body will be expounded and developed. It will be argued...... that the latter can, and must, be considered as synchronously disclosed across the subject’s pre-reflective and reflective modes of acquaintance. Further, in order to maintain the distinction between these modes, it will be argued that a differential configuration of the lived-body’s double-sidedness must...... be admitted across these modes. To this end, observations regarding the lived disclosure of reflective acts vis-à-vis their embodied conduct are provided; suggesting that a partial inversion of the lived-body’s double-sidedness occurs during the transition to the reflective mode. Directions for future...

  15. Determination of timber assortments obtainable from coppice chestnut stands (Susa Valley, Northern Italy

    Directory of Open Access Journals (Sweden)

    Nosenzo A

    2007-01-01

    Full Text Available Chestnut (Castanea sativa L. coppice stands currently cover about 195.000 ha of Piedmont (North-Western Italy surface, corresponding to 22.4 % of the overall forested area in the region. Most of these forest stands are usually older than the typical rotation period. As a consequence from these stands timber assortments with a higher value could be obtained. The purpose of this study is to assess the amount of timber assortments and to propose a sorting methodology based on measurements on standing trees within these chestnut stands.Five study areas were selected in the Susa Valley, where forest measurements were realized within sampling plots. Timber assortments obtainable from each coppice shoot were then determined by means of the Bitterlich’s relascope. More than 1.000 timber logs were measured. The data elaboration allowed to assess the timber assortment production of the investigated stands. The proposed methodology makes it possible to better exploit timber assortments. In fact, while usually the whole production from chestnut coppices is directly destined to secondary products, the subdivision into assortments could result in a 20 % of products with higher commercial value. It is important to notice that within these stands no tending operation is currently realized. The definition of qualitative features to classify timber assortments can provide useful suggestions on the main yield targets that could be reached through silvicultural management.

  16. [Temporal dynamics of ethnic assortativeness in the Tsivil'sk region of Chuvashia].

    Science.gov (United States)

    El'chinova, G I; Znichenko, R A; Ginter, E K

    2003-04-01

    Based on marriage records for 1950-1959, 1970-1979, and 1990-1999, ethnic assortativeness of Chuvash and Russian inhabitants of Tsivil'sk raion of the Chuvash Republic was calculated. It was shown that in half a century ethnic assortativeness of Chuvashes did not change (1.18, 1.15, and 1.15), while in Russians a clear downward trend was observed (4.20, 2.18, and 1.28). The data on ethnic assortativeness obtained were compared with those for the same populations from other regions of the Chuvashia examined earlier.

  17. Religion, Marriage Markets, and Assortative Mating in the United States

    Science.gov (United States)

    McClendon, David

    2016-01-01

    As interfaith marriage has become more common, religion is thought to be less important for sorting partners. However, prior studies on religious assortative mating use samples of prevailing marriages, which miss how local marriage markets shape both partner selection and marriage timing. Drawing on search theory and data from 8,699 young adults (ages 18–31) in the National Longitudinal Study of Youth 1997, the author examined the association between the concentration of co-religionists in local marriage markets and marriage timing and partner selection using event history methods. Religious concentration is associated with higher odds of transitioning to marriage and religious homogamy (conditional on marriage) for women and men at older ages (24–31) but not at younger ages (18–23). The association was also stronger for non-Hispanic Whites compared to other race-ethnic groups. The findings indicate that religion remains relevant in sorting partners for many young adults in today’s marriage market. PMID:27818530

  18. Trends in educational assortative marriage from 1940 to 2003.

    Science.gov (United States)

    Schwartz, Christine R; Mare, Robert D

    2005-11-01

    This paper reports trends in educational assortative marriage from 1940 to 2003 in the United States. Analyses of census and Current Population Survey data show that educational homogamy decreased from 1940 to 1960 but increased from 1960 to 2003. From 1960 to the early 1970s, increases in educational homogamy were generated by decreasing intermarriage among groups of relatively well-educated persons. College graduates, in particular; were increasingly likely to marry each other rather than those with less education. Beginning in the early 1970s, however; continued increases in the odds of educational homogamy were generated by decreases in intermarriage at both ends of the education distribution. Most striking is the decline in the odds that those with very low levels of education marry up. Intermarriage between college graduates and those with "some college" continued to decline but at a more gradual pace. As intermarriage declined at the extremes of the education distribution, intermarriage among those in the middle portion of the distribution increased. These trends, which are similar for a broad cross section of married couples and for newlyweds, are consistent with a growing social divide between those with very low levels of education and those with more education in the United States.

  19. Assortativity and leadership emergence from anti-preferential attachment in heterogeneous networks

    CERN Document Server

    Sendiña-Nadal, I; Wang, Z; Havlin, S; Boccaletti, S

    2015-01-01

    Many real-world networks exhibit degree-assortativity, with nodes of similar degree more likely to link to one another. Particularly in social networks, the contribution to the total assortativity varies with degree, featuring a distinctive peak slightly past the average degree. The way traditional models imprint assortativity on top of pre-defined topologies is via degree-preserving link permutations, which however destroy the particular graph's hierarchical traits of clustering. Here, we propose the first generative model which creates heterogeneous networks with scale-free-like properties and tunable realistic assortativity. In our approach, two distinct populations of nodes are added to an initial network seed: one (the followers) that abides by usual preferential rules, and one (the potential leaders) connecting via anti-preferential attachments, i.e. selecting lower degree nodes for their initial links. The latter nodes come to develop a higher average degree, and convert eventually into the final hubs....

  20. Actuality of assortment policy in the modern management of retail business enterprise

    Directory of Open Access Journals (Sweden)

    Yefimova Yevheniia

    2016-07-01

    Full Text Available In the result of research it has been found, that the assortment policy defines the course of actions for managing a point-of-sale assortment which foresees clarification and specification of strategic purpose and current tasks; development and grounding of facilities, methods and forms of activity for their achievement; determination of the real resources providing the realization of the plan. The constituents of assortment policy of enterprise of retail business are identified. It is well-proved that with the help of assortment policy achievement of ultimate goals of an enterprise is provided, the constituents of commercial strategy associate together and the possibility of the most effective usage of resources has arrived.

  1. Understanding the Impact of Brand Delistings on Assortment Evaluations and Store Switching and Complaining Intentions

    NARCIS (Netherlands)

    L.M. Sloot (Laurens); P.C. Verhoef (Peter)

    2004-01-01

    textabstractRecently, retailers have begun considering which brands they can delist without reducing customer satisfaction, losing category sales, or increasing store switching behavior. Although several studies have considered assortment reductions, none has explicitly investigated the impact of

  2. Educational Assortative Mating and Economic Inequality: A Comparative Analysis of Three Latin American Countries

    Science.gov (United States)

    TORCHE, FLORENCIA

    2010-01-01

    Educational assortative mating and economic inequality are likely to be endogenously determined, but very little research exists on their empirical association. Using census data and log-linear and log-multiplicative methods, I compare the patterns of educational assortative mating in Brazil, Chile, and Mexico, and explore the association between marital sorting and earnings inequality across countries. The analysis finds substantial variation in the strength of specific barriers to educational intermarriage between countries, and a close association between these barriers and the earnings gaps across educational categories within countries. This finding suggests an isomorphism between assortative mating and economic inequality. Furthermore, educational marital sorting is remarkably symmetric across gender in spite of the different resources that men and women bring to the union. This study highlights the limitations of using single aggregate measures of spousal educational resemblance (such as the correlation coefficient between spouses’ schooling) to capture variation in assortative mating and its relationship with socioeconomic inequality. PMID:20608107

  3. Assortative Mating for Psychopathy Components and its Effects on the Relationship Quality in Intimate Partners

    Directory of Open Access Journals (Sweden)

    Igor Kardum

    2017-05-01

    Full Text Available In three studies, we examined assortative mating for psychopathy components as well as its effects on the relationship quality in intimate partners. Compared to the original structure we confirmed three factors of psychopathy: criminal tendencies (CT, erratic lifestyle (ELS and interpersonal manipulation (IM, while callous affect (CA was not replicated. Hypotheses regarding positive versus negative assortment, initial assortment versus convergence, and active assortment versus social homogamy were tested. All hypotheses were examined using both variable-centered approach (VCA and couple-centered approach (CCA. We found moderate positive assortment between intimate partners in psychopathy as a latent construct estimated by structural modelling. Furthermore, positive assortment for all three components of psychopathy was found either by using only VCA (CT, only CCA (IM or both approaches (ELS. Additionally, initial assortment rather than convergence hypothesis and active assortment rather than social homogamy hypothesis was confirmed for all three psychopathy components, with a slight tendency towards divergence and social homogamy. We explored the effects of similarity in psychopathy components on the women and men' relationship quality by using profile similarity and polynomial regression analyses. Profile similarity in IM was significantly positively related to women's relationship quality, while the results of the polynomial regression analyses were more complex, and showed that only (dissimilarity in CT did not exert any effect on women and men's relationship quality. Greater disagreement between women and men's ELS was related with more sharp decrease of women's relationship quality, while men's relationship quality decreased at the higher levels of women and men's ELS. Greater disagreement between women and men's IM results in a lower women's relationship quality, while women and men's relationship quality was higher when women's IM was

  4. Optimality in Data Assimilation

    Science.gov (United States)

    Nearing, Grey; Yatheendradas, Soni

    2016-04-01

    It costs a lot more to develop and launch an earth-observing satellite than it does to build a data assimilation system. As such, we propose that it is important to understand the efficiency of our assimilation algorithms at extracting information from remote sensing retrievals. To address this, we propose that it is necessary to adopt completely general definition of "optimality" that explicitly acknowledges all differences between the parametric constraints of our assimilation algorithm (e.g., Gaussianity, partial linearity, Markovian updates) and the true nature of the environmetnal system and observing system. In fact, it is not only possible, but incredibly straightforward, to measure the optimality (in this more general sense) of any data assimilation algorithm as applied to any intended model or natural system. We measure the information content of remote sensing data conditional on the fact that we are already running a model and then measure the actual information extracted by data assimilation. The ratio of the two is an efficiency metric, and optimality is defined as occurring when the data assimilation algorithm is perfectly efficient at extracting information from the retrievals. We measure the information content of the remote sensing data in a way that, unlike triple collocation, does not rely on any a priori presumed relationship (e.g., linear) between the retrieval and the ground truth, however, like triple-collocation, is insensitive to the spatial mismatch between point-based measurements and grid-scale retrievals. This theory and method is therefore suitable for use with both dense and sparse validation networks. Additionally, the method we propose is *constructive* in the sense that it provides guidance on how to improve data assimilation systems. All data assimilation strategies can be reduced to approximations of Bayes' law, and we measure the fractions of total information loss that are due to individual assumptions or approximations in the

  5. Assortative mating by colored ornaments in blue tits: space and time matter.

    Science.gov (United States)

    Fargevieille, Amélie; Grégoire, Arnaud; Charmantier, Anne; Del Rey Granado, Maria; Doutrelant, Claire

    2017-04-01

    Assortative mating is a potential outcome of sexual selection, and estimating its level is important to better understand local adaptation and underlying trait evolution. However, assortative mating studies frequently base their conclusions on small numbers of individuals sampled over short periods of time and limited spatial scales even though spatiotemporal variation is common. Here, we characterized assortative mating patterns over 10 years in four populations of the blue tit (Cyanistes caeruleus), a passerine bird. We focused on two plumage ornaments-the blue crown and the yellow breast patch. Based on data for 1,657 pairs of birds, we found large interannual variation: assortative mating varied from positive to negative. To determine whether there was nonetheless a general trend in the data, we ran a within-study meta-analysis. It revealed that assortative mating was moderately positive for both ornaments. It also showed that mating patterns differed among populations and especially between two neighboring populations that displayed phenotypic divergence. Our results therefore underscore that long-term studies are needed to draw broad conclusions about mating patterns in natural populations. They also call for studying the potential role of assortative mating in local adaptation and evolution of ornaments in both sexes.

  6. Widespread positive but weak assortative mating by diet within stickleback populations.

    Science.gov (United States)

    Ingram, Travis; Jiang, Yuexin; Rangel, Racine; Bolnick, Daniel I

    2015-08-01

    Assortative mating - correlation between male and female traits - is common within populations and has the potential to promote genetic diversity and in some cases speciation. Despite its importance, few studies have sought to explain variation in the extent of assortativeness across populations. Here, we measure assortative mating based on an ecologically important trait, diet as inferred from stable isotopes, in 16 unmanipulated lake populations of three-spine stickleback. As predicted, we find a tendency toward positive assortment on the littoral-pelagic axis, although the magnitude is consistently weak. These populations vary relatively little in the strength of assortativeness, and what variation occurs is not explained by hypothesized drivers including habitat cosegregation, the potential for disruptive selection, costs to choosiness, and the strength of the relationship between diet and body size. Our results support recent findings that most assortative mating is positive, while suggesting that new approaches may be required to identify the environmental variables that drive the evolution of nonrandom mating within populations.

  7. Divergence and evolution of assortative mating in a polygenic trait model of speciation with gene flow.

    Science.gov (United States)

    Sachdeva, Himani; Barton, Nicholas H

    2017-06-01

    Assortative mating is an important driver of speciation in populations with gene flow and is predicted to evolve under certain conditions in few-locus models. However, the evolution of assortment is less understood for mating based on quantitative traits, which are often characterized by high genetic variability and extensive linkage disequilibrium between trait loci. We explore this scenario for a two-deme model with migration, by considering a single polygenic trait subject to divergent viability selection across demes, as well as assortative mating and sexual selection within demes, and investigate how trait divergence is shaped by various evolutionary forces. Our analysis reveals the existence of sharp thresholds of assortment strength, at which divergence increases dramatically. We also study the evolution of assortment via invasion of modifiers of mate discrimination and show that the ES assortment strength has an intermediate value under a range of migration-selection parameters, even in diverged populations, due to subtle effects which depend sensitively on the extent of phenotypic variation within these populations. The evolutionary dynamics of the polygenic trait is studied using the hypergeometric and infinitesimal models. We further investigate the sensitivity of our results to the assumptions of the hypergeometric model, using individual-based simulations. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  8. Spatial Assimilation in Denmark?

    DEFF Research Database (Denmark)

    Andersen, Hans Skifter

    2010-01-01

    . In traditional research literature about immigration it has been shown that for many immigrants living in enclaves has been a temporary situation. The 'spatial assimilation theory' says that this situation ends when the family has become more integrated in the new society and then moves to other parts...

  9. Displacement data assimilation

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, W. Steven [Pacific Northwest Laboratory, Richland, WA 99354 (United States); Venkataramani, Shankar [Department of Mathematics and Program in Applied Mathematics, University of Arizona, Tucson, AZ 85721 (United States); Mariano, Arthur J. [Rosenstiel School of Marine & Atmospheric Science, University of Miami, Miami, FL 33149 (United States); Restrepo, Juan M., E-mail: restrepo@math.oregonstate.edu [Department of Mathematics, Oregon State University, Corvallis, OR 97331 (United States)

    2017-02-01

    We show that modifying a Bayesian data assimilation scheme by incorporating kinematically-consistent displacement corrections produces a scheme that is demonstrably better at estimating partially observed state vectors in a setting where feature information is important. While the displacement transformation is generic, here we implement it within an ensemble Kalman Filter framework and demonstrate its effectiveness in tracking stochastically perturbed vortices.

  10. Genome assortment, not serogroup, defines Vibrio cholerae pandemic strains

    Energy Technology Data Exchange (ETDEWEB)

    Brettin, Thomas S [Los Alamos National Laboratory; Bruce, David C [Los Alamos National Laboratory; Challacombe, Jean F [Los Alamos National Laboratory; Detter, John C [Los Alamos National Laboratory; Han, Cliff S [Los Alamos National Laboratory; Munik, A C [Los Alamos National Laboratory; Chertkov, Olga [Los Alamos National Laboratory; Meincke, Linda [Los Alamos National Laboratory; Saunders, Elizabeth [Los Alamos National Laboratory; Choi, Seon Y [SEOUL NATL. UNIV.; Haley, Bradd J [U. MARYLAND; Taviani, Elisa [U. MARYLAND; Jeon, Yoon - Seong [INTL. VACCINE INST. SEOUL; Kim, Dong Wook [INTL. VACCINE INST. SEOUL; Lee, Jae - Hak [SEOUL NATL. UNIV.; Walters, Ronald A [PNNL; Hug, Anwar [NATL. INST. CHOLERIC ENTERIC DIS.; Colwell, Rita R [U. MARYLAND

    2009-01-01

    Vibrio cholerae, the causative agent of cholera, is a bacterium autochthonous to the aquatic environment, and a serious public health threat. V. cholerae serogroup O1 is responsible for the previous two cholera pandemics, in which classical and El Tor biotypes were dominant in the 6th and the current 7th pandemics, respectively. Cholera researchers continually face newly emerging and re-emerging pathogenic clones carrying combinations of new serogroups as well as of phenotypic and genotypic properties. These genotype and phenotype changes have hampered control of the disease. Here we compare the complete genome sequences of 23 strains of V. cholerae isolated from a variety of sources and geographical locations over the past 98 years in an effort to elucidate the evolutionary mechanisms governing genetic diversity and genesis of new pathogenic clones. The genome-based phylogeny revealed 12 distinct V. cholerae phyletic lineages, of which one, designated the V. cholerae core genome (CG), comprises both O1 classical and EI Tor biotypes. All 7th pandemic clones share nearly identical gene content, i.e., the same genome backbone. The transition from 6th to 7th pandemic strains is defined here as a 'shift' between pathogenic clones belonging to the same O1 serogroup, but from significantly different phyletic lineages within the CG clade. In contrast, transition among clones during the present 7th pandemic period can be characterized as a 'drift' between clones, differentiated mainly by varying composition of laterally transferred genomic islands, resulting in emergence of variants, exemplified by V.cholerae serogroup O139 and V.cholerae O1 El Tor hybrid clones that produce cholera toxin of classical biotype. Based on the comprehensive comparative genomics presented in this study it is concluded that V. cholerae undergoes extensive genetic recombination via lateral gene transfer, and, therefore, genome assortment, not serogroup, should be used to

  11. Influenced but unaware: social influence on alcohol drinking among social acquaintances.

    Science.gov (United States)

    Dallas, Rebecca; Field, Matt; Jones, Andrew; Christiansen, Paul; Rose, Abi; Robinson, Eric

    2014-05-01

    Drinking partners may be influenced by each other's alcohol consumption. However, these effects have only been shown in artificially created social pairings and typically among same-sex young adults. Here, we test whether similarly strong influence effects occur among "real" pairs of social acquaintances (friends and partners) and whether people are aware of this influence on their alcohol consumption. Forty-six pairs of social acquaintances aged between 19 and 60 years old participated in a between-subjects experiment, in a semi-naturalistic bar laboratory setting. One member of each pair (the confederate) was randomly selected and asked to consume only alcoholic (alcohol condition) or soft drinks (nonalcohol condition), while the pair completed a game together in a bar setting. The other participant (naïve) was unaware of these drinking instructions. Postconsumption, we measured the extent to which naïve participants believed that their partner had influenced their own drinking behavior. A large effect of condition on alcohol consumption was observed, χ² (2) = 15.8, p V = 0.59, whereby the number of alcoholic drinks selected by naïve participants in the alcohol confederate condition was significantly greater than in the nonalcohol confederate condition. The majority of naïve participants (81%) also tended to be unaware that their partner had influenced their alcohol consumption. Social acquaintances are influenced by each other's alcohol consumption and may not be aware of this influence on their behavior. Copyright © 2014 by the Research Society on Alcoholism.

  12. A Study on Yu Kilchun and His Network of Acquaintances (1881–1907)

    OpenAIRE

    Masutani Yuichi

    2016-01-01

    From the time of his studies in Japan until his return to Korea in 1907, Yu Kilchun’s acquaintances can be divided into three categories: people Yu met during his studies at Keio Gijuku, people Yu met to plan a coup during his exile, and people who participated in Tonga Ch’ŏngnyŏnhoe and Irhan Tongjihoe from 1906.Although his time at Keio Gijuku was not long, the people he met during his studies bonded strongly, and a network of academic contacts was formed through reunions. These connectio...

  13. Personality as manifest in word use: correlations with self-report, acquaintance report, and behavior.

    Science.gov (United States)

    Fast, Lisa A; Funder, David C

    2008-02-01

    The use of words is one of the most direct means of expressing thoughts and feelings. However, past studies have had limited success in correlating word use with personality. The purpose of the present study was to identify categories of word use relevant to personality using a broad range of personality data. Using data from 181 participants, the present study correlated word use within a 1-hr life history interview with self-judgments of personality, judgments of personality provided by close acquaintances (who were not exposed to the language sample), and behavioral ratings based on direct observation from a context entirely separate from that from which the language sample was derived. Several categories of word use yielded a large number of correlates with self- and acquaintance personality ratings and behavior. It is suggested that word use is related to personality to a larger degree than previously observed and deserves increased attention as a source of data in personality assessment. (c) 2008 APA, all rights reserved

  14. Low relational mobility leads to greater motivation to understand enemies but not friends and acquaintances.

    Science.gov (United States)

    Li, Liman Man Wai; Masuda, Takahiko; Lee, Hajin

    2018-01-01

    Enemyship occurs across societies, but it has not received as much attention as other types of relationships such as friendship in previous research. This research examined the influence of relational mobility on people's motivation to understand their personal enemies by measuring different dependent variables across three studies. First, a cross-cultural comparison study found that Hong Kong Chinese, from a low-relational-mobility society, reported a stronger desire to seek proximity to enemies relative to European Canadians, from a high-relational-mobility society (Study 1). To test causality, two manipulation studies were conducted. Participants were presented with images of co-workers, including enemies, friends, and acquaintances, in a hypothetical company. The results showed that the participants who perceived lower relational mobility paid more attention to their enemies in an eye-tracking task (Study 2) and had a higher accuracy rate for recognizing the faces of the enemies in an incidental memory test (Study 3). In contrast, the influence of relational mobility on motivation to understand friends and acquaintances was minimal. Implications for research on interpersonal relationships and relational mobility are discussed. © 2017 The British Psychological Society.

  15. Similarity and assumed similarity in personality reports of well-acquainted persons.

    Science.gov (United States)

    Lee, Kibeom; Ashton, Michael C; Pozzebon, Julie A; Visser, Beth A; Bourdage, Joshua S; Ogunfowora, Babatunde

    2009-02-01

    The authors obtained self- and observer reports of personality from pairs of well-acquainted college students. Consistent with previous findings, results of Study 1 showed strong cross-source agreement for all 6 HEXACO personality factors (rs approximately .55). In addition, the authors found modest levels of similarity (r approximately .25) between dyad members' self-reports on each of 2 dimensions, Honesty-Humility and Openness to Experience. For these same 2 factors, dyad members' self-reports were correlated with their observer reports of the other dyad member (r approximately .40), thus indicating moderately high assumed similarity. In Study 2, Honesty-Humility and Openness to Experience were the 2 personality factors most strongly associated with the 2 major dimensions of personal values, which also showed substantial assumed similarity. In Study 3, assumed similarity was considerably stronger for close friends than for nonfriend acquaintances. Results suggest that assumed similarity for Honesty-Humility and Openness to Experience reflects a tendency to overestimate one's similarity to persons with whom one has a close relationship, but only on those personality characteristics whose relevance to values gives them central importance to one's identity.

  16. When Plentiful Platforms Pay Off: Assessment Orientation Moderates the Effect of Assortment Size on Choice Engagement and Product Valuation

    OpenAIRE

    Mathmann, F.; Chylinski, M.; DE RUYTER, K; Higgins, T

    2017-01-01

    Popular digital platforms, such as Netflix and GrubHub, purposefully aggregate offerings, according to the premise that customers value products chosen from plentiful assortments. Yet academic literature provides little clarity about when, for whom, or how larger online retail assortments affect the value of the products. To provide new insights, the current article aims to address ambiguous extant findings about the effects of larger product assortments. Specifically, this research tests whe...

  17. The Cognitive Social Network in Dreams: Transitivity, Assortativity, and Giant Component Proportion Are Monotonic.

    Science.gov (United States)

    Han, Hye Joo; Schweickert, Richard; Xi, Zhuangzhuang; Viau-Quesnel, Charles

    2016-04-01

    For five individuals, a social network was constructed from a series of his or her dreams. Three important network measures were calculated for each network: transitivity, assortativity, and giant component proportion. These were monotonically related; over the five networks as transitivity increased, assortativity increased and giant component proportion decreased. The relations indicate that characters appear in dreams systematically. Systematicity likely arises from the dreamer's memory of people and their relations, which is from the dreamer's cognitive social network. But the dream social network is not a copy of the cognitive social network. Waking life social networks tend to have positive assortativity; that is, people tend to be connected to others with similar connectivity. Instead, in our sample of dream social networks assortativity is more often negative or near 0, as in online social networks. We show that if characters appear via a random walk, negative assortativity can result, particularly if the random walk is biased as suggested by remote associations. Copyright © 2015 Cognitive Science Society, Inc.

  18. Using Social Network Methods to Test for Assortment of Prosociality among Korean High School Students.

    Directory of Open Access Journals (Sweden)

    Jun-Hong Kim

    Full Text Available Assortative interaction among altruistic individuals is a necessary condition for the evolution of cooperation. The requirement for assortment holds regardless of whether a meta-population is subdivided into distinct and isolated subgroups or has ephemeral boundaries with a high migration rate. The assumption, however, is rarely tested directly. In this paper, we develop a method to test for assortment of prosociality in network-structured data. The method is applied to a friendship network collected from 238 Korean students attending the same high school. A mixing matrix was used to explore the presence of assortative friendship among more prosocial individuals. An exponential random graph model of network structure that accounts for additional observed relational propensities (higher-than-expected number of people nominating no friends and sampling constraints (upper bound on friendship nominations found that individual prosociality predicted friendship propensity, and that individuals with higher prosocial scores had a higher probability of befriending other more prosocial individuals. The results reveal that a considerable level of assortment of prosociality characterizes this population.

  19. Using Social Network Methods to Test for Assortment of Prosociality among Korean High School Students.

    Science.gov (United States)

    Kim, Jun-Hong; Holman, Darryl J; Goodreau, Steven M

    2015-01-01

    Assortative interaction among altruistic individuals is a necessary condition for the evolution of cooperation. The requirement for assortment holds regardless of whether a meta-population is subdivided into distinct and isolated subgroups or has ephemeral boundaries with a high migration rate. The assumption, however, is rarely tested directly. In this paper, we develop a method to test for assortment of prosociality in network-structured data. The method is applied to a friendship network collected from 238 Korean students attending the same high school. A mixing matrix was used to explore the presence of assortative friendship among more prosocial individuals. An exponential random graph model of network structure that accounts for additional observed relational propensities (higher-than-expected number of people nominating no friends) and sampling constraints (upper bound on friendship nominations) found that individual prosociality predicted friendship propensity, and that individuals with higher prosocial scores had a higher probability of befriending other more prosocial individuals. The results reveal that a considerable level of assortment of prosociality characterizes this population.

  20. METHODOLOGY OF KNOWLEDGE RESOURCES AUDIT FOR FORMATION OF PHARMACY ORGANIZATION ASSORTMENT

    Directory of Open Access Journals (Sweden)

    I. M. Razdorskaya

    2015-01-01

    Full Text Available The timeliness of this subject is conditioned by the increase of a role of knowledge in pharmacy organizations (PO management, significance increase of non-material assets in a competition on the pharmaceutical market. The development and substantiation of methodology of knowledge resources audit significance on the example of drug assortment formation for allergic rhinitis treatment. We have used sociological, statistic, expert methods of a study. Close attention was paid to the method of target management, construction of target tree. The construction of the target tree of the knowledge resources audit was based on the main target establishment, targets of the first level, and eight subtargets. We have offered new special positions of assortment formation. “Formation of consumers’ loyalty” is the target of the first level, subtargets “Analysis of clients preferences”, “Transformation of clients preferences”, “Positioning of consumers by the compliance degree”. We have determined the relevance significance by the main target achievement – rational assortment formation. We have shown that the achievement of the first level target “Formation of consumers’  loyalty” conduce the achievement of the main target by 40%. The analysis of the current assortment and a process of assortment upgrading guarantee the achievement of the target by 30% each. The methodology is prospective for knowledge resources audit by the principal business processes of pharmacy organizations.  

  1. Assortative marriages by body mass index have increased simultaneously with the obesity epidemic

    DEFF Research Database (Denmark)

    Adeltoft, Teresa Ajslev; Ängquist, Lars Henrik; Silventoinen, Karri

    2012-01-01

    Background: The genetic predisposition to obesity may have contributed to the obesity epidemic through assortative mating. We investigated whether spouses were positively assorted by body mass index (BMI; = kg/m(2)) in late childhood, and whether changes in assorted marriage by upper BMI......-percentiles occurred during the obesity epidemic. Methods: In the Copenhagen School Health Records Register (CSHRR) boys and girls with measures of BMI at age 13 years later became 37,792 spousal-pairs who married between 1945 and 2010. Trends in the spousal BMI correlations using sex-, age-, and birth cohort......-specific BMI z-scores across time were investigated. Odds ratios (ORs) of marriage among spouses both with BMI z-scores >90th or >95th percentile compared with marriage among spouses ≤90th percentile were analyzed for marriages entered during the years prior to (1945-1970), and during the obesity epidemic...

  2. Assortativity and Mixing by Sexual Behaviors and Sociodemographic Characteristics in Young Adult Heterosexual Dating Partnerships.

    Science.gov (United States)

    Malagón, Talía; Burchell, Ann; El-Zein, Mariam; Tellier, Pierre-Paul; Coutlée, François; Franco, Eduardo L

    2017-06-01

    Assortative sexual mixing, the tendency for individuals to choose partners with similar characteristics to themselves, may be an important contributor to the unequal distribution of sexually transmitted infections in populations. We analyzed the tendency for assortative mixing on demographic and sexual behaviors characteristics in newly formed young adults dating partnerships. Women aged 18 to 24 years and their male sexual partners of no more than 6 months were recruited during 2005 to 2010 at universities in Montreal, Canada. New dating partners were also prospectively recruited during the 2-year follow-up. We used Spearman and Newman coefficients to examine correlations between partners' demographic characteristics and sexual behaviors, and multivariable logistic modeling to determine which characteristics were assortative. Participants in 502 recruited partnerships were assortative on age (Spearman P = 0.60), smoking behavior (P = 0.43), ethnicity (Newman coefficient=0.39), lifetime number of sexual partners (P = 0.36), sex partner acquisition rates (P = 0.22), gap length between partnerships (P = 0.20), and on whether they had concurrent partners (P = 0.33). Partners were assortative on number of lifetime partners, sexual partner acquisition rates, concurrency, and gap length between partnerships even after adjustment for demographic characteristics. Reported condom use was correlated between initial and subsequently recruited partners (P = 0.35). There was little correlation between the frequencies of vaginal/oral/digital/anal sex between subsequent partnerships. Dating partnerships were substantially assortative on various sexual behaviors as well as demographic characteristics. Though not a representative population sample, our recruitment of relatively new partnerships reduces survivor bias inherent to cross-sectional surveys where stable long-term partnerships are more likely to be sampled.

  3. Co-assortment in integron-associated gene cassette assemblages in environmental DNA samples

    Directory of Open Access Journals (Sweden)

    Michael Carolyn A

    2010-08-01

    Full Text Available Abstract Background It has been shown that integron-associated gene cassettes exist largely in tandem arrays of variable size, ranging from antibiotic resistance arrays of three to five cassettes up to arrays of more than 100 cassettes associated with the vibrios. Further, the ecology of the integron/gene cassette system has been investigated by showing that very many different cassettes are present in even small environmental samples. In this study, we seek to extend the ecological perspective on the integron/gene cassette system by investigating the way in which this diverse cassette metagenome is apportioned amongst prokaryote lineages in a natural environment. Results We used a combination of PCR-based techniques applied to environmental DNA samples and ecological analytical techniques to establish co-assortment within cassette populations, then establishing the relationship between this co-assortment and genomic structures. We then assessed the distribution of gene cassettes within the environment and found that the majority of gene cassettes existed in large co-assorting groups. Conclusions Our results suggested that the gene cassette diversity of a relatively pristine sampling environment was structured into co-assorting groups, predominantly containing large numbers of cassettes per group. These co-assorting groups consisted of different gene cassettes in stoichiometric relationship. Conservatively, we then attributed co-assorting cassettes to the gene cassette complements of single prokaryote lineages and by implication, to large integron-associated arrays. The prevalence of large arrays in the environment raises new questions about the assembly, maintenance and utility of large cassette arrays in prokaryote populations.

  4. Assortative mating among Lake Malawi cichlid fish populations is not simply predictable from male nuptial colour

    Directory of Open Access Journals (Sweden)

    Taylor Martin I

    2009-03-01

    Full Text Available Abstract Background Research on the evolution of reproductive isolation in African cichlid fishes has largely focussed on the role of male colours and female mate choice. Here, we tested predictions from the hypothesis that allopatric divergence in male colour is associated with corresponding divergence in preference. Methods We studied four populations of the Lake Malawi Pseudotropheus zebra complex. We predicted that more distantly-related populations that independently evolved similar colours would interbreed freely while more closely-related populations with different colours mate assortatively. We used microsatellite genotypes or mesh false-floors to assign paternity. Fisher's exact tests as well as Binomial and Wilcoxon tests were used to detect if mating departed from random expectations. Results Surprisingly, laboratory mate choice experiments revealed significant assortative mating not only between population pairs with differently coloured males, but between population pairs with similarly-coloured males too. This suggested that assortative mating could be based on non-visual cues, so we further examined the sensory basis of assortative mating between two populations with different male colour. Conducting trials under monochromatic (orange light, intended to mask the distinctive male dorsal fin hues (blue v orange of these populations, did not significantly affect the assortative mating by female P. emmiltos observed under control conditions. By contrast, assortative mating broke down when direct contact between female and male was prevented. Conclusion We suggest that non-visual cues, such as olfactory signals, may play an important role in mate choice and behavioural isolation in these and perhaps other African cichlid fish. Future speciation models aimed at explaining African cichlid radiations may therefore consider incorporating such mating cues in mate choice scenarios.

  5. Co-assortment in integron-associated gene cassette assemblages in environmental DNA samples.

    Science.gov (United States)

    Michael, Carolyn A; Andrew, Nigel R

    2010-08-10

    It has been shown that integron-associated gene cassettes exist largely in tandem arrays of variable size, ranging from antibiotic resistance arrays of three to five cassettes up to arrays of more than 100 cassettes associated with the vibrios. Further, the ecology of the integron/gene cassette system has been investigated by showing that very many different cassettes are present in even small environmental samples. In this study, we seek to extend the ecological perspective on the integron/gene cassette system by investigating the way in which this diverse cassette metagenome is apportioned amongst prokaryote lineages in a natural environment. We used a combination of PCR-based techniques applied to environmental DNA samples and ecological analytical techniques to establish co-assortment within cassette populations, then establishing the relationship between this co-assortment and genomic structures. We then assessed the distribution of gene cassettes within the environment and found that the majority of gene cassettes existed in large co-assorting groups. Our results suggested that the gene cassette diversity of a relatively pristine sampling environment was structured into co-assorting groups, predominantly containing large numbers of cassettes per group. These co-assorting groups consisted of different gene cassettes in stoichiometric relationship. Conservatively, we then attributed co-assorting cassettes to the gene cassette complements of single prokaryote lineages and by implication, to large integron-associated arrays. The prevalence of large arrays in the environment raises new questions about the assembly, maintenance and utility of large cassette arrays in prokaryote populations.

  6. Perceptions of stranger and acquaintance rape: the role of benevolent and hostile sexism in victim blame and rape proclivity.

    Science.gov (United States)

    Abrams, Dominic; Viki, G Tendayi; Masser, Barbara; Bohner, Gerd

    2003-01-01

    In Studies 1 and 2, after reading an acquaintance-rape but not a stranger-rape scenario, higher benevolent sexist but not hostile sexist participants blamed the victim significantly more. In Study 2, higher hostile sexist but not benevolent sexist male participants showed significantly greater proclivity to commit acquaintance (but not stranger) rape. Studies 3 and 4 supported the hypothesis that the effects of benevolent sexism and hostile sexism are mediated by different perceptions of the victim, as behaving inappropriately and as really wanting sex with the rapist. These findings show that benevolent sexism and hostile sexism underpin different assumptions about women that generate sexist reactions toward rape victims.

  7. Multi-agent Contracting and Reconfiguration in Competitive Environments using Acquaintance Models

    Directory of Open Access Journals (Sweden)

    J. Bíba

    2006-01-01

    Full Text Available Cooperation of agents in competitive environments is more complicated than in collaborative environments. Both replanning and reconfiguration play a crucial role in cooperation, and introduce a means for implementating a system flexibility. The concepts of commitments, decommitments with penalties and subcontracting may facilitate effective reconfiguration and replanning. Agents in competitive environments are fully autonomous and selfinterested. Therefore the setting of penalties and profit computation cannot be provided centrally. Both the costs and the gain differ from agent to agent with respect to contracts already agreed and resources load. This paper proposes an acquaintance model for contracting in competitive environments and introduces possibilities of reconfigurating in competitive environments as a means of decommitment optimization with respect to resources load and profit maximization. The presented algorithm for contract price setting does not use any centralized knowledge and provides results corresponding to a realistic environment. A simple customerprovider scenario proves this algorithm in competitive contracting. 

  8. Maintaining shared knowledge of acquaintance: methods people use to establish who knows whom.

    Science.gov (United States)

    Ekberg, Stuart

    2014-12-01

    Acquaintance is a fundamental determinant of how people behave when interacting with one another. This article focuses on how this type of personal knowledge is an important consideration for people as social actors. Studying naturally occurring social encounters, I describe how speakers use particular references to convey whether a recipient should be able to recognize a non-present third party. On some occasions, however, the presumption of recognizability or non-recognizability that underpins the use of a particular reference proves questionable. By exploring how recipients can challenge reference forms, and thereby reject claims of either recognizability or non-recognizability, I explain how people establish and maintain a shared understanding of who knows whom. I conclude by discussing motivations for this behaviour, and thereby contribute to understanding the commonsense reasoning that underpins orderly conduct in this aspect of social encounters. © 2013 The British Psychological Society.

  9. Expectations Regarding Acquaintance Sexual Aggression Among Sorority and Fraternity Members1

    Science.gov (United States)

    Nurius, Paula S.; Norris, Jeanette; Dimeff, Linda A.; Graham, Thomas L.

    2015-01-01

    Among women, college is a high risk period for sexual assault by male acquaintances. Differences in expectations held by men and women may contribute to misinterpretation of social cues and subsequent sexual aggression and may impair women’s ability to respond effectively. This paper presents findings from a predominantly Caucasian sample (85.9%) of college sorority (n = 66) and fraternity (n = 34) members regarding the social context within which they interact and their expectations regarding perpetration of and response to sexual aggression. Results showed differences in men’s and women’s expectations and responses, and in particular highlighted how men’s expectations were related to women’s resistance of unwanted sex. Understanding the cognitive processes that men and women draw upon in social interactions can be useful for developing sexual aggression prevention and resistance interventions. PMID:25705071

  10. Regional Ocean Data Assimilation

    KAUST Repository

    Edwards, Christopher A.

    2015-01-03

    This article reviews the past 15 years of developments in regional ocean data assimilation. A variety of scientific, management, and safety-related objectives motivate marine scientists to characterize many ocean environments, including coastal regions. As in weather prediction, the accurate representation of physical, chemical, and/or biological properties in the ocean is challenging. Models and observations alone provide imperfect representations of the ocean state, but together they can offer improved estimates. Variational and sequential methods are among the most widely used in regional ocean systems, and there have been exciting recent advances in ensemble and four-dimensional variational approaches. These techniques are increasingly being tested and adapted for biogeochemical applications.

  11. Assimilation Dynamic Network (ADN) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Assimilation Dynamic Network (ADN) is a dynamic inter-processor communication network that spans heterogeneous processor architectures, unifying components,...

  12. Cultural Assimilation versus Cultural Pluralism.

    Science.gov (United States)

    Mohl, Raymond A.

    1981-01-01

    Examines the historical role of American schools as instruments of Americanization and assimilation processes. Traces the origins of cultural pluralism and discusses its implications for minority education. (SK)

  13. Integrated Data Assimilation Architecture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Integrated Data Assimilation Architecture (IDAA) is a middleware architecture that facilitates the incorporation of heterogeneous sensing and control devices...

  14. Integrated Data Assimilation Architecture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Integrated Data Assimilation Architecture (IDAA) addresses the fundamental problem of command, control, and communications systems interoperability....

  15. A Study on Yu Kilchun and His Network of Acquaintances (1881–1907

    Directory of Open Access Journals (Sweden)

    Masutani Yuichi

    2016-08-01

    Full Text Available From the time of his studies in Japan until his return to Korea in 1907, Yu Kilchun’s acquaintances can be divided into three categories: people Yu met during his studies at Keio Gijuku, people Yu met to plan a coup during his exile, and people who participated in Tonga Ch’ŏngnyŏnhoe and Irhan Tongjihoe from 1906.Although his time at Keio Gijuku was not long, the people he met during his studies bonded strongly, and a network of academic contacts was formed through reunions. These connections played a crucial role when Yu was active in the political scene in 1894 during the Kabo Reform period. After Yu left Korea on an exile following Emperor Kojong’s flight to the Russian legation in February 1896, he established a new network of acquaintances. Specifically, his journals from 1901 revealed that Yu was searching for people in Shizuoka, Gifu, and Hokkaido, who would take part in his conspiracy. Since he came to Tokyo after serving his time at the Ogasawara Islands, he worked with Tonga Ch’ŏngnyŏnhoe and Irhan Tongjihoe. Additionally, this paper demonstrated that he had connections with the Tonghak Order, and that it was possible for Yu to express his opinions in the press through O Sech’ang and Yi Inchik, who were residing in Korea. Around the same time, he also traveled around Yamanashi, Nagano, Toyama, and Fukui, and made efforts to facilitate trade between Korea and Japan. Such efforts were feasible thanks to the network of collaborators in Korea.

  16. Assimilating seizure dynamics.

    Directory of Open Access Journals (Sweden)

    Ghanim Ullah

    2010-05-01

    Full Text Available Observability of a dynamical system requires an understanding of its state-the collective values of its variables. However, existing techniques are too limited to measure all but a small fraction of the physical variables and parameters of neuronal networks. We constructed models of the biophysical properties of neuronal membrane, synaptic, and microenvironment dynamics, and incorporated them into a model-based predictor-controller framework from modern control theory. We demonstrate that it is now possible to meaningfully estimate the dynamics of small neuronal networks using as few as a single measured variable. Specifically, we assimilate noisy membrane potential measurements from individual hippocampal neurons to reconstruct the dynamics of networks of these cells, their extracellular microenvironment, and the activities of different neuronal types during seizures. We use reconstruction to account for unmeasured parts of the neuronal system, relating micro-domain metabolic processes to cellular excitability, and validate the reconstruction of cellular dynamical interactions against actual measurements. Data assimilation, the fusing of measurement with computational models, has significant potential to improve the way we observe and understand brain dynamics.

  17. Choosing mates based on the diet of your ancestors: replication of non-genetic assortative mating in Drosophila melanogaster.

    Science.gov (United States)

    Najarro, Michael A; Sumethasorn, Matt; Lamoureux, Alexandra; Turner, Thomas L

    2015-01-01

    Assortative mating has been a focus of considerable research because of its potential to influence biodiversity at many scales. Sharon et al. (2010) discovered that an inbred strain of Drosophila melanogaster mated assortatively based on the diet of previous generations, leading to initial reproductive isolation without genetic evolution. This behavior was reproduced by manipulating the microbiome independently of the diet, pointing to extracellular bacterial symbionts as the assortative mating cue. To further investigate the biological significance of this result, we attempted to reproduce this phenomenon in an independent laboratory using different genotypes and additional mating assays. Supporting the previous result, we found that a different inbred strain also mated assortatively based on the diets of previous generations. However, we were unable to generate assortative mating in an outbred strain from North Carolina. Our results support the potential for non-genetic mechanisms to influence reproductive isolation, but additional work is needed to investigate the importance of this mechanism in natural populations of Drosophila.

  18. "Well Acquainted with Books." The Founding Framers of 1787. With James Madison's List of Books for Congress.

    Science.gov (United States)

    Rutland, Robert A.

    Published to commemorate the Constitution's bicentennial year and remind Americans that books and the life of the mind are vital national traditions, this volume contains both an essay, "Well Acquainted with Books: The Founding Framers of 1787," by Robert A. Rutland, and James Madison's List of Books for Congress, 1783. The essay…

  19. The Impact of Product Assortment Size and Attribute Quantity on Information Searches

    DEFF Research Database (Denmark)

    Dörnyei, Krisztina Rita; Chrysochou, Polymeros; Krystallis, Athanasios

    2017-01-01

    Purpose: This paper investigates the impact of assortment size and attribute quantity on the depth and content of consumer information searches. Design/methodology/approach: For a computer-aided experiment using an information display board, participants (n=393) were placed in a simulated shopping...

  20. Assortativity and leadership emerge from anti-preferential attachment in heterogeneous networks

    Science.gov (United States)

    Sendiña-Nadal, I.; Danziger, M. M.; Wang, Z.; Havlin, S.; Boccaletti, S.

    2016-02-01

    Real-world networks have distinct topologies, with marked deviations from purely random networks. Many of them exhibit degree-assortativity, with nodes of similar degree more likely to link to one another. Though microscopic mechanisms have been suggested for the emergence of other topological features, assortativity has proven elusive. Assortativity can be artificially implanted in a network via degree-preserving link permutations, however this destroys the graph’s hierarchical clustering and does not correspond to any microscopic mechanism. Here, we propose the first generative model which creates heterogeneous networks with scale-free-like properties in degree and clustering distributions and tunable realistic assortativity. Two distinct populations of nodes are incrementally added to an initial network by selecting a subgraph to connect to at random. One population (the followers) follows preferential attachment, while the other population (the potential leaders) connects via anti-preferential attachment: they link to lower degree nodes when added to the network. By selecting the lower degree nodes, the potential leader nodes maintain high visibility during the growth process, eventually growing into hubs. The evolution of links in Facebook empirically validates the connection between the initial anti-preferential attachment and long term high degree. In this way, our work sheds new light on the structure and evolution of social networks.

  1. Importance of small-degree nodes in assortative networks with degree-weight correlations

    Science.gov (United States)

    Ma, Sijuan; Feng, Ling; Monterola, Christopher Pineda; Lai, Choy Heng

    2017-10-01

    It has been known that assortative network structure plays an important role in spreading dynamics for unweighted networks. Yet its influence on weighted networks is not clear, in particular when weight is strongly correlated with the degrees of the nodes as we empirically observed in Twitter. Here we use the self-consistent probability method and revised nonperturbative heterogenous mean-field theory method to investigate this influence on both susceptible-infective-recovered (SIR) and susceptible-infective-susceptible (SIS) spreading dynamics. Both our simulation and theoretical results show that while the critical threshold is not significantly influenced by the assortativity, the prevalence in the supercritical regime shows a crossover under different degree-weight correlations. In particular, unlike the case of random mixing networks, in assortative networks, the negative degree-weight correlation leads to higher prevalence in their spreading beyond the critical transmissivity than that of the positively correlated. In addition, the previously observed inhibition effect on spreading velocity by assortative structure is not apparent in negatively degree-weight correlated networks, while it is enhanced for that of the positively correlated. Detailed investigation into the degree distribution of the infected nodes reveals that small-degree nodes play essential roles in the supercritical phase of both SIR and SIS spreadings. Our results have direct implications in understanding viral information spreading over online social networks and epidemic spreading over contact networks.

  2. Computing Assortative Mixing by Degree with the s-Metric in Networks Using Linear Programming

    Directory of Open Access Journals (Sweden)

    Lourens J. Waldorp

    2015-01-01

    Full Text Available Calculation of assortative mixing by degree in networks indicates whether nodes with similar degree are connected to each other. In networks with scale-free distribution high values of assortative mixing by degree can be an indication of a hub-like core in networks. Degree correlation has generally been used to measure assortative mixing of a network. But it has been shown that degree correlation cannot always distinguish properly between different networks with nodes that have the same degrees. The so-called s-metric has been shown to be a better choice to calculate assortative mixing. The s-metric is normalized with respect to the class of networks without self-loops, multiple edges, and multiple components, while degree correlation is always normalized with respect to unrestricted networks, where self-loops, multiple edges, and multiple components are allowed. The challenge in computing the normalized s-metric is in obtaining the minimum and maximum value within a specific class of networks. We show that this can be solved by using linear programming. We use Lagrangian relaxation and the subgradient algorithm to obtain a solution to the s-metric problem. Several examples are given to illustrate the principles and some simulations indicate that the solutions are generally accurate.

  3. 76 FR 14115 - Culturally Significant Objects Imported for Exhibition Determinations: “Assorted Greek and Roman...

    Science.gov (United States)

    2011-03-15

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Culturally Significant Objects Imported for Exhibition Determinations: ``Assorted Greek and Roman Objects... Greek and Roman Objects'' imported from abroad for temporary exhibition within the United States, are of...

  4. Spotting altruistic dictator game players and mingling with them : the elective assortation of classmates

    NARCIS (Netherlands)

    Pradel, Julia; Euler, Harald A.; Fetchenhauer, Detlef

    Altruism can evolve through assortation if the selfish advantage of egoistic individuals is outcompeted by the benefits of mutual cooperation between altruists. This selection process is possible if (a) individuals can distinguish altruists from egoists and (b) altruists cooperate electively with

  5. METHODS OF DETERMINATION THE INTERIOR POTENTIAL OF ENTERPRISE IN MAKING STRATEGICAL ASSORTMENT DECISIONS

    Directory of Open Access Journals (Sweden)

    Svitlana Malyuk

    2015-11-01

    Full Text Available The analysis of the internal environment of the enterprise is aimed at assessing the strategic potential of the enterprise as a whole and its individual functional subsystems. The efficient activity of enterprise cannot be realized without a systematic definition and using the existing capabilities since, as a rule, the potential of the organization is higher than its actual implementation. It is not possible to put forward long-term goals, to form the most optimal strategy to achieve them without the characteristics of accumulated enterprises potential. From this point, the purpose of the paper is to study and establish the criteria that characterize the inner potential of the company during the implementation of assortment strategies. The method of evaluating of these indicators, as well as the selection of the assortment strategy according to the results has been suggested. Methods. The research of the internal potential of PJSC “Mykolaiv bakery № 1” is based on the expert questionnaire, which made it possible not only to identify a number of criteria for internal enterprises environment, which made it possible not only to identify a number of criteria for internal environment, as well as by experts to determine the parameter and boundary values of coefficients influencing the choice of the assortment strategy. The results of questionnaire showed that the main criteria of the characteristics of the internal potential of the company are: primary phases of the life cycle of the goods (were determined on the basis of the matrix "Market growth – Market Share"; prospects of producing the assortment groups of goods (calculated using the integral coefficient of goods assortment; changes in sales amount (described by trigonometric dependencies; degree of the goods assortment realization (evaluated using the coefficient of realization; assortments balance according to the Pareto rule (based on the Pareto rule, as well as expert survey; the

  6. 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.

  7. Convenience stores and the marketing of foods and beverages through product assortment.

    Science.gov (United States)

    Sharkey, Joseph R; Dean, Wesley R; Nalty, Courtney

    2012-09-01

    Product assortment (presence and variety) is a key in-store marketing strategy to influence consumer choice. Quantifying the product assortment of healthier and less-healthy foods and beverages in convenience stores can inform changes in the food environment. To document product assortment (i.e., presence and variety of specific foods and beverages) in convenience stores. Observational survey data were collected onsite in 2011 by trained promotora-researchers in 192 convenience stores. Frequencies of presence and distributions of variety were calculated in 2012. Paired differences were examined using the Wilcoxon matched-pairs signed-rank test. Convenience stores displayed a large product assortment of sugar-sweetened beverages (median 86.5 unique varieties); candy (76 varieties); salty snacks (77 varieties); fried chips (44 varieties); cookies and pastries (19 varieties); and frozen sweets (21 varieties). This compared with 17 varieties of non-sugar sweetened beverages and three varieties of baked chips. The Wilcoxon signed-rank test confirmed a (pstores included milk (84% of stores); fresh fruit (33%); fresh vegetables (35%); canned vegetables (78%); white bread (71%); and deli-style packaged meat (57%). Healthier versions of milk, canned fruit, canned tuna, bread, and deli-style packaged meat were displayed in 17%-71% of convenience stores. Convenience stores in this area provide a greater assortment of less-healthy compared with healthier foods and beverages. There are opportunities to influence consumer food choice through programs that alter the balance between healthier and less-healthy foods and beverages in existing convenience stores that serve rural and underserved neighborhoods and communities. Copyright © 2012 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  8. Mobility can promote the evolution of cooperation via emergent self-assortment dynamics.

    Science.gov (United States)

    Joshi, Jaideep; Couzin, Iain D; Levin, Simon A; Guttal, Vishwesha

    2017-09-01

    The evolution of costly cooperation, where cooperators pay a personal cost to benefit others, requires that cooperators interact more frequently with other cooperators. This condition, called positive assortment, is known to occur in spatially-structured viscous populations, where individuals typically have low mobility and limited dispersal. However many social organisms across taxa, from cells and bacteria, to birds, fish and ungulates, are mobile, and live in populations with considerable inter-group mixing. In the absence of information regarding others' traits or conditional strategies, such mixing may inhibit assortment and limit the potential for cooperation to evolve. Here we employ spatially-explicit individual-based evolutionary simulations to incorporate costs and benefits of two coevolving costly traits: cooperative and local cohesive tendencies. We demonstrate that, despite possessing no information about others' traits or payoffs, mobility (via self-propulsion or environmental forcing) facilitates assortment of cooperators via a dynamically evolving difference in the cohesive tendencies of cooperators and defectors. We show analytically that this assortment can also be viewed in a multilevel selection framework, where selection for cooperation among emergent groups can overcome selection against cooperators within the groups. As a result of these dynamics, we find an oscillatory pattern of cooperation and defection that maintains cooperation even in the absence of well known mechanisms such as kin interactions, reciprocity, local dispersal or conditional strategies that require information on others' strategies or payoffs. Our results offer insights into differential adhesion based mechanisms for positive assortment and reveal the possibility of cooperative aggregations in dynamic fission-fusion populations.

  9. An Evaluation of Practical Applicability of Multi-Assortment Production Break-Even Analysis based on Mining Companies

    Science.gov (United States)

    Fuksa, Dariusz; Trzaskuś-Żak, Beata; Gałaś, Zdzisław; Utrata, Arkadiusz

    2017-03-01

    In the practice of mining companies, the vast majority of them produce more than one product. The analysis of the break-even, which is referred to as CVP (Cost-Volume-Profit) analysis (Wilkinson, 2005; Czopek, 2003) in their case is significantly constricted, given the necessity to include multi-assortment structure in the analysis, which may have more than 20 types of assortments (depending on the grain size) in their offer, as in the case of open-pit mines. The article presents methods of evaluation of break-even (volume and value) for both a single-assortment production and a multi-assortment production. The complexity of problem of break-even evaluation for multi-assortment production has resulted in formation of many methods, and, simultaneously, various approaches to its analysis, especially differences in accounting fixed costs, which may be either totally accounted for among particular assortments, relating to the whole company or partially accounted for among particular assortments and partially relating to the company, as a whole. The evaluation of the chosen methods of break-even analysis, given the availability of data, was based on two examples of mining companies: an open-pit mine of rock materials and an underground hard coal mine. The selection of methods was set by the available data provided by the companies. The data for the analysis comes from internal documentation of the mines - financial statements, breakdowns and cost calculations.

  10. The Influence of Gender Ideology, Victim Resistance, and Spiking a Drink on Acquaintance Rape Attributions.

    Science.gov (United States)

    Angelone, D J; Mitchell, Damon; Smith, Danielle

    2016-02-24

    The current study examined observer's attributions about the victim and perpetrator of an alleged acquaintance rape. Participants included 504 college students from a public university in the northeastern United States who read a brief crime report and completed a series of questionnaires for course credit. While men tended to attribute more blame to the victim than women, gender ideology emerged as a stronger predictor of rape attributions, and some types of sexist beliefs were associated with greater victim blaming and others with less victim blaming. Endorsement of hostile sexism, rape myths, and heterosexual intimacy was generally associated with the attribution of greater victim culpability, as well as less perpetrator culpability, perpetrator criminality, and victim credibility. However, complementary gender differentiation was associated with greater perpetrator culpability and criminality, while protective paternalism was associated with greater victim credibility. Observers attributed lower victim culpability and greater perpetrator criminality when the victim's drink was spiked, and attributed greater perpetrator culpability when the victim verbally resisted the perpetrator's advances. Given the implications that observer attitudes can have on professional and personal support for survivors, as well as juror decision making, the ongoing examination of the complex interplay between the person and situational factors affecting attributions of rape is essential. Sexual assault prevention programs may also benefit from a psychoeducational component that targets reducing traditional gender ideology. © The Author(s) 2016.

  11. Explicating Alcohol’s Role in Acquaintance Sexual Assault: Complementary Perspectives and Convergent Findings

    Science.gov (United States)

    Zawacki, Tina; Norris, Jeanette; George, William H.; Abbey, Antonia; Martell, Joel; Stoner, Susan A.; Davis, Kelly Cue; Buck, Philip O.; Masters, N. Tatiana; McAuslan, Pamela; Beshears, Renee; Parkhill, Michele R.; Clinton-Sherrod, A. Monique

    2015-01-01

    This article summarizes the proceedings of a symposium presented at the 2004 meeting of the Research Society on Alcoholism (RSA) in Vancouver, British Columbia, Canada. There were four presentations and a discussant. The symposium was co-chaired by Tina Zawacki and Jeanette Norris. The first presentation was made by Jeanette Norris, who found that alcohol consumption and preexisting alcohol expectancies affected women’s hypothetical responses to a vignette depicting acquaintance sexual aggression. The second presentation was made by Joel Martell, who reported that alcohol-induced impairment of executive cognitive functioning mediated the effect of intoxication on men’s perceptions of a sexual assault vignette. In the third presentation, Antonia Abbey found that the experiences of women whose sexual assault involved intoxication or force were more negative than were the experiences of women whose sexual assault involved verbal coercion. The fourth presentation was made by Tina Zawacki, who reported that men who perpetrated sexual assault only in adolescence differed from men who continued perpetration into adulthood in terms of their drinking patterns and attitudes toward women. William H. George discussed these findings in terms of their implications for theory development and prevention programming. PMID:15714049

  12. Explicating alcohol's role in acquaintance sexual assault: complementary perspectives and convergent findings.

    Science.gov (United States)

    Zawacki, Tina; Norris, Jeanette; George, William H; Abbey, Antonia; Martell, Joel; Stoner, Susan A; Davis, Kelly Cue; Buck, Philip O; Masters, N Tatiana; McAuslan, Pamela; Beshears, Renee; Parkhill, Michele R; Clinton-Sherrod, A Monique

    2005-02-01

    This article summarizes the proceedings of a symposium presented at the 2004 meeting of the Research Society on Alcoholism (RSA) in Vancouver, British Columbia, Canada. There were four presentations and a discussant. The symposium was co-chaired by Tina Zawacki and Jeanette Norris. The first presentation was made by Jeanette Norris, who found that alcohol consumption and preexisting alcohol expectancies affected women's hypothetical responses to a vignette depicting acquaintance sexual aggression. The second presentation was made by Joel Martell, who reported that alcohol-induced impairment of executive cognitive functioning mediated the effect of intoxication on men's perceptions of a sexual assault vignette. In the third presentation, Antonia Abbey found that the experiences of women whose sexual assault involved intoxication or force were more negative than were the experiences of women whose sexual assault involved verbal coercion. The fourth presentation was made by Tina Zawacki, who reported that men who perpetrated sexual assault only in adolescence differed from men who continued perpetration into adulthood in terms of their drinking patterns and attitudes toward women. William H. George discussed these findings in terms of their implications for theory development and prevention programming.

  13. Aerosol Data Assimilation at GMAO

    Science.gov (United States)

    da Silva, Arlindo M.; Buchard, Virginie

    2017-01-01

    This presentation presents an overview of the aerosol data assimilation work performed at GMAO. The GMAO Forward Processing system and the biomass burning emissions from QFED are first presented. Then, the current assimilation of Aerosol Optical Depth (AOD), performed by means of the analysis splitting method is briefly described, followed by some results on the quality control of observations using a Neural Network trained using AERONET AOD. Some applications are shown such as the Mount Pinatubo eruption in 1991 using the MERRA-2 aerosol dataset. Finally preliminary results on the EnKF implementation for aerosol assimilation are presented.

  14. CATEGORY MANAGEMENT IN THE MANAGEMENT OF MINIMUM ASSORTMENT OF THE PHARMACEUTICAL ORGANIZATION

    Directory of Open Access Journals (Sweden)

    I. F. Samoshchenkova

    2017-01-01

    Full Text Available The main principle of the category management is the management of product category as a separate business unit. Category management directs the activities of the pharmaceutical organization to meet the consumer requirements and to provide customers with maximum benefits, which are expressed in the improved assortment,the attractive prices, the reduction of cases of lack of necessary goods, the simplifiedpurchase process. In article the structure of the category management and its role inthe minimum pharmaceutical assortment, a complex of the theoretical and practical issues affecting interrelation of the list of vital and essential medicines and the minimum range of medicines are considered. A number of the new elements supplementing the concept of category management is offered, and the corresponding generalizations are made. The objective of the research is to study the influence of category management on the structure in management of the minimum assortment of medicines of the pharmaceutical organization. Materials and methods. In the course of the solution of the set tasks, the methods of marketing and economic-mathematical analysis were used. Results and discussion. In the analysis of the assortment list of medicines for medical application, which is obligatory for the pharmaceutical enterprises of all forms of ownership, it was revealed that this assortment list is based on the List of Vital Essential and Necessary (VEN Drugs. The results of the analysis of the obligatory assortment list from the position of internal category management showed that 77.45% are medicines of the list of VEN Drugs; 46.08% are medicines of non-prescription dispensing. Proceeding from this it follows that the worthy, profitable price policy can be conducted only with 22.55% of the list; to develop standards of merchandising with 46.05%. The category management gives an opportunity to the pharmaceutical organization to specify its competitive strategy and to

  15. Data Assimilation in Marine Models

    DEFF Research Database (Denmark)

    Frydendall, Jan

    This thesis consists of six research papers published or submitted for publication in the period 2006-2009 together with a summary report. The main topics of this thesis are nonlinear data assimilation techniques and estimation in dynamical models. The focus has been on the nonlinear filtering...... techniques for large scale geophysical numerical models and making them feasible to work with in the data assimilation framework. The filtering techniques investigated are all Monte Carlo simulation based. Some very nice features that can be exploited in the Monte Carlo based data assimilation framework from...... the nonlinearities encountered in data assimilation and at the same time are robust and reliable enough given the constraints and difficulties that can arise. These problems were addressed in the papers A, E and D. The other topic of this thesis is estimation in dynamical geophysical numerical models. The challenge...

  16. Global Land Data Assimilation System

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The goal of the Global Land Data Assimilation System (GLDAS) is to ingest satellite- and ground-based observational data products, using advanced land surface...

  17. Global Data Assimilation System (GDAS)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Data Assimilation System (GDAS) is the system used by the Global Forecast System (GFS) model to place observations into a gridded model space for the...

  18. Instant RubyMine assimilation

    CERN Document Server

    Jones, Dave

    2013-01-01

    Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. Get the job done and learn as you go. A practical guide comprising of easy-to-follow recipes which provide concise and clear steps to help you enter the world of RubyMine.Instant RubyMine is ideal for you, if you are new to RubyMine or well acquainted with the technology. All you need is basic knowledge of writing in Ruby or Ruby on Rails.

  19. Ethnic Goods and Immigrant Assimilation

    OpenAIRE

    Abdulloev, Ilhom; Gil S. Epstein; Ira N. Gang

    2014-01-01

    Some immigrants try to keep their ethnicity hidden while others become ever deeply more mired in their home culture. We argue that among immigrants this struggle manifests itself in the ethnic goods they choose to consume. Different types of ethnic goods have vastly different effects on immigrant assimilation. We develop a simple theoretical model useful for capturing the consequences of this struggle, illustrating it with examples of Central Asian assimilation into the Muscovite economy.

  20. Physical education teachers' attitudes towards children with intellectual disability: the impact of time in service, gender, and previous acquaintance.

    Science.gov (United States)

    Ozer, D; Nalbant, S; Aǧlamıș, E; Baran, F; Kaya Samut, P; Aktop, A; Hutzler, Y

    2013-11-01

    This study investigated attitudes towards teaching students with intellectual disability (ID) within a representative sample of secondary school physical education (PE) teachers, and to determine the effects of age, gender, teaching experience, and having acquaintance with ID and students with ID on their attitudes. Participants were 729 secondary school PE teachers who worked in 81 major cities of Turkey. The Teachers Attitudes towards Children with Intellectual Disability Scale was administered. The statistical analysis revealed that there was no significant effect on factors and total attitudes scores of gender and having students with ID. Significant effects on factors and total attitudes score were found in teaching experiences and having acquaintance with ID. It is encouraged to maintain and further develop in-service education programmes of adapted physical activity for PE teachers. © 2012 The Authors. Journal of Intellectual Disability Research © John Wiley & Sons Ltd, MENCAP & IASSID.

  1. Income inequality and educational assortative mating: Evidence from the Luxembourg Income Study.

    Science.gov (United States)

    Monaghan, David

    2015-07-01

    Though extensive research has explored the prevalence of educational assortative mating, what causes its variation across countries and over time is not well understood. Using data from the Luxembourg Income Study Database, I investigate the hypothesis that assortative mating by income is influenced by income inequality between educational strata. I find that in countries with greater returns to education, the odds of any sort of union that crosses educational boundaries is substantially reduced. However, I do not find substantial evidence of an effect of changes in returns to education on marital sorting within countries. Educational and labor market parity between males and females appear to be negatively related to marital sorting. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. From sparse to dense and from assortative to disassortative in online social networks.

    Science.gov (United States)

    Li, Menghui; Guan, Shuguang; Wu, Chensheng; Gong, Xiaofeng; Li, Kun; Wu, Jinshan; Di, Zengru; Lai, Choy-Heng

    2014-05-06

    Inspired by the analysis of several empirical online social networks, we propose a simple reaction-diffusion-like coevolving model, in which individuals are activated to create links based on their states, influenced by local dynamics and their own intention. It is shown that the model can reproduce the remarkable properties observed in empirical online social networks; in particular, the assortative coefficients are neutral or negative, and the power law exponents γ are smaller than 2. Moreover, we demonstrate that, under appropriate conditions, the model network naturally makes transition(s) from assortative to disassortative, and from sparse to dense in their characteristics. The model is useful in understanding the formation and evolution of online social networks.

  3. Interactive computer program for learning genetic principles of segregation and independent assortment through meiosis.

    Science.gov (United States)

    Yang, Xiaoli; Ge, Rong; Yang, Yufei; Shen, Hao; Li, Yingjie; Tseng, Charles C

    2009-01-01

    Teaching fundamental principles of genetics such as segregation and independent assortment of genes could be challenging for high school and college biology instructors. Students without thorough knowledge in meiosis often end up of frustration and failure in genetics courses. Although all textbooks and laboratory manuals have excellent graphic demonstrations and photographs of meiotic process, students may not always master the concept due to the lack of hands-on exercise. In response to the need for an effective lab exercise to understand the segregation of allelic genes and the independent assortment of the unlinked genes, we developed an interactive program for students to manually manipulate chromosome models and visualize each major step of meiosis so that these two genetic principles can be thoroughly understood.

  4. Women's Preference for a Male Acquaintance Enhances Social Reward Processing of Material Goods in the Anterior Cingulate Cortex.

    Science.gov (United States)

    Nakagawa, Jun; Takahashi, Muneyoshi; Okada, Rieko; Matsushima, Eisuke; Matsuda, Tetsuya

    2015-01-01

    Men, like the male of many animal species, use gifts to build satisfactory relationships with a desired woman. From the woman's perspective, all gifts are not always equally rewarding; the reward value of a gift depends on two factors: (1) the giver and (2) the type of the gift (the gift's social meaning). In this study, we investigated how these two factors interactively determine the reward value of a gift. Specifically, we examined how the neural processing for understanding a gift's social meaning is modulated by preferences for the giver. We performed a functional magnetic resonance imaging (fMRI) study in which a female participant was asked to judge a gift from a male she was acquainted with in real life. We examined the interactive effects between (1) the female participant's attitude toward the male acquaintance (liked vs. uninteresting) and (2) the type of the gift (romantic [e.g., bouquet, earrings, and perfumes] vs. non-romantic [e.g., pencils, memo pad, and moneybox]). We found that preference for an acquaintance selectively modulated activity in the anterior cingulate cortex (ACC) in response to romantic gifts, compared to non-romantic gifts. In contrast, if the woman was indifferent toward an acquaintance, no activity modulation was observed in this area for the same gifts. In addition, the ACC showed functional connectivity with the supplementary motor area/dorsal ACC (SMA/dACC), an area within the dorsal mediofrontal cortex, suggesting that it integrates action monitoring and emotional and cognitive processing in decision-making. These results suggest that attitude toward an opposite sex member has a modulatory role in recognizing the social meaning of material goods--preference for the member is a powerful modulator of social reward processing.

  5. Women's Preference for a Male Acquaintance Enhances Social Reward Processing of Material Goods in the Anterior Cingulate Cortex.

    Directory of Open Access Journals (Sweden)

    Jun Nakagawa

    Full Text Available Men, like the male of many animal species, use gifts to build satisfactory relationships with a desired woman. From the woman's perspective, all gifts are not always equally rewarding; the reward value of a gift depends on two factors: (1 the giver and (2 the type of the gift (the gift's social meaning. In this study, we investigated how these two factors interactively determine the reward value of a gift. Specifically, we examined how the neural processing for understanding a gift's social meaning is modulated by preferences for the giver. We performed a functional magnetic resonance imaging (fMRI study in which a female participant was asked to judge a gift from a male she was acquainted with in real life. We examined the interactive effects between (1 the female participant's attitude toward the male acquaintance (liked vs. uninteresting and (2 the type of the gift (romantic [e.g., bouquet, earrings, and perfumes] vs. non-romantic [e.g., pencils, memo pad, and moneybox]. We found that preference for an acquaintance selectively modulated activity in the anterior cingulate cortex (ACC in response to romantic gifts, compared to non-romantic gifts. In contrast, if the woman was indifferent toward an acquaintance, no activity modulation was observed in this area for the same gifts. In addition, the ACC showed functional connectivity with the supplementary motor area/dorsal ACC (SMA/dACC, an area within the dorsal mediofrontal cortex, suggesting that it integrates action monitoring and emotional and cognitive processing in decision-making. These results suggest that attitude toward an opposite sex member has a modulatory role in recognizing the social meaning of material goods--preference for the member is a powerful modulator of social reward processing.

  6. Assortative marriages by body mass index have increased simultaneously with the obesity epidemic

    Directory of Open Access Journals (Sweden)

    Teresa Adeltoft Ajslev

    2012-07-01

    Full Text Available Background: The genetic predisposition to obesity may have contributed to the obesity epidemic through assortative mating. We investigated whether spouses were positively assorted by body mass index (BMI; =kg/m2 in late childhood, and whether changes in assorted marriage by upper BMI-percentiles occurred during the obesity epidemic. Methods: In the Copenhagen School Health Records Register boys and girls with measures of BMI at age 13 years later became 37 792 spousal-pairs who married from 1945–2010. Trends in the spousal BMI correlations using sex-, age- and birth cohort-specific BMI z-scores across time were investigated. Odds ratios (ORs of marriage among spouses both with BMI z-scores >90th or >95th percentile compared with marriage among spouses ≤90th percentile were analysed for marriages entered during the years prior to (1945–1970, and during the obesity epidemic (1971–2010.Findings: Spousal BMI correlations were small and stayed similar across time. ORs of marriage among spouses with BMIs >90th percentile at age 13 were 1.21, 1.05–1.39, in 1945–1970, and increased to 1.63, 1.40–1.91, in 1971–2010 (p=0.006. ORs of marriage among spouses both >95th BMI percentile were higher and increased more; from 1.39, 1.10–1.81, to 2.39, 1.85–3.09 (p=0.004.Interpretation: Spousal correlations by pre-marital BMIs were stable during the past 65 years. Yet, assorted marriages between spouses with BMIs in the upper percentiles were observed and increased significantly across the two marriage periods, and this may possibly influence the following generations’ susceptibility to obesity.

  7. From Assortative to Ashortative Coupling: Men's Height, Height Heterogamy, and Relationship Dynamics in the United States

    OpenAIRE

    Abigail Weitzman; Dalton Conley

    2014-01-01

    Studies of online dating suggest that physical attraction is a key factor in early relationship formation, but say little about the role of attractiveness in longer-term relationships. Meanwhile, assortative coupling and exchange models widely employed in demographic research overlook the powerful sorting function of initial and sustained physical attraction. This article observes the effects of one physical characteristic of men--height--on various relationship outcomes in longer-term relati...

  8. Growth and yield models, assortment type and analysis of deadwood in chestnut coppice

    Directory of Open Access Journals (Sweden)

    Marziliano PA

    2013-02-01

    Full Text Available Chestnut (Castanea sativa MILL. is one of the most important forest tree species in Europe, and it is considered a symbol of the natural vegetation in southern Europe. In Calabria (southern Italy chestnut forest covers an area of approximately 87000 hectares, most of which (about 80% managed as coppice. In this study a growth and yield table has been elaborated. Thurthermore, assortment type and quantity of deadwood have been evaluated according to age of coppice and forest fire prevention, respectively. The study site is located in the “Presila of Catanzaro” and the research was carried out in 15 plots; the age of the examined stands ranged from 2 to 50 years old. More than 30000 shoots per hectare were recorded in the first two years after coppicing. As opposed, about 2300 and 1000 shoots per hectare were observed 15 and 50 years after coppicing, respectively. The culmination of the mean annual increment of the forest standing volume (16 m3 ha-1 year-1 was highlighted 25 years after coppicing, while the current annual increment culmination (21 m3 ha-1 year-1 was observed at 15 years. Fifteen years after coppicing, most of the wood production was constituted by small dimension assortments. Twenty five years after coppicing small and large poles were the prevailing assortments while telegraph poles and timber beams increased after 50 years. The amount of deadwood in forest ranged between 11.9 and 68.7 m3 ha-1. The largest component was represented by standing dead shoots. The results show that coppice management can be adopted even if the main purpose of the chestnut stand is the production of large size assortments. In chestnut coppice, highly vulnerable to fire, the reduction of stand density with silvicultural practices (thinning and displacement is the main way to promote the efficiency of forest and a higher strength and resiliency against forest fire.

  9. VA-Index: Quantifying Assortativity Patterns in Networks with Multidimensional Nodal Attributes (Open Access)

    Science.gov (United States)

    2016-01-27

    comparison. In this work we introduce a novel network metric, which we call VA-index, for quantify- ing the multi-dimensional assortativity. In a nutshell ...network randomization with statistical hypothesis testing. In a nutshell , the intuition of our approach is based on comparing the pairwise average...1)), we would need to normalize the VA-index with the maximum possible average similarity that Fig 2. The computation of VA-index in a nutshell . VA

  10. The cultural context of nondisclosure of alcohol-involved acquaintance rape among Asian American college women: a qualitative study.

    Science.gov (United States)

    Koo, Kelly H; Nguyen, Hong V; Andrasik, Michele P; George, William H

    2015-01-01

    With high college enrollment and increasing alcohol use, Asian American (AA) college women may be at particular risk for experiencing alcohol-involved acquaintance rape. Although AA women have expressed the weakest intentions to report rape when compared to other ethnic groups, cultural factors influencing these intentions remain unexamined. Guided by grounded theory, 17 self-identified AA college women were interviewed about how the average AA college woman would respond to an alcohol-involved acquaintance rape. Despite awareness of benefits of disclosing rape, participants emphasized that nondisclosure would be the normative response. Three themes emerged from participants: institutional, sociocultural, and psychological contexts of nondisclosure. At an institutional level, nondisclosure referenced mental health and police services, which included Asian stereotypes and mistrust of police. Within a sociocultural context, rape nondisclosure focused on negative consequences on relationships with parents and, to a lesser extent, on friendships. Emotional avoidance and not labeling an acquaintance rape as rape were psychological strategies for rape nondisclosure. Participant's conceptualizations of mental and physical health concerns, specifically post-rape concerns, were framed within sociocultural/macrostructural contexts and may not match that of the more individualistic U.S. mainstream conceptualizations of health. Culturally sensitive rape education may be more effective in increasing rape prevention and support.

  11. Transcendental Spirituality and Acquaintance With the Activities of the Domestic National Transplant Center as Factors Shaping Attitudes Toward Organ Donation.

    Science.gov (United States)

    Melnikov, Semyon; Ashkenazi, Tamar; Amara, Muhammad; Peles Bortz, Anat

    2017-06-01

    Organ donation has been shown to be perceived as inappropriate by religiously observant individuals. The impact of spirituality level on attitudes toward organ donation has not been broadly explored. To explore the contribution of ethnicity, spirituality, level of religious observance, and acquaintance with the activities of the Israel National Transplant Center (INTC) to forming attitudes toward organ donation among Jews and Muslim Arabs in Israel. A descriptive cross-sectional survey. Three hundred five (65.2%) Jewish and 163 (34.8%) Muslim Arab respondents living in Israel. Jewish respondents had more positive attitudes toward organ donation than Muslim Arabs. Muslim Arabs had a higher mean spirituality score than Jews. Gender, age, ethnicity, level of religious observance, education, 4 spirituality dimensions, and acquaintance with the activities of the INTC explained 41.5% of the variance in attitudes to organ donation. Transcendental spirituality, acquaintance with the activities of the INTC, and level of religious observance had the highest contribution to explaining attitudes to organ donation, while gender and age had a low contribution. Ethnicity, education, and the 3 other spirituality dimensions were not found to have a significant contribution. A multifaceted approach to improving attitudes toward organ donation among Jews and Muslim Arabs in Israel is important.

  12. The Impact of Product Assortment Size and Attribute Quantity on Information Searches

    DEFF Research Database (Denmark)

    Dörnyei, Krisztina Rita; Chrysochou, Polymeros; Krystallis, Athanasios

    2017-01-01

    Purpose: This paper investigates the impact of assortment size and attribute quantity on the depth and content of consumer information searches. Design/methodology/approach: For a computer-aided experiment using an information display board, participants (n=393) were placed in a simulated shoppin...... policy. Originality/value: Information searches are measured by means of three different variables (searched cues, searched products, and searched attributes), which enables a more complex exploration of the consumer information search process.......Purpose: This paper investigates the impact of assortment size and attribute quantity on the depth and content of consumer information searches. Design/methodology/approach: For a computer-aided experiment using an information display board, participants (n=393) were placed in a simulated shopping...... situation that involved choosing a product among three sets of frequently purchased, low-involvement, FMCG alternatives. Findings: The findings show that when the assortment size increases, consumers acquire information from more products and cues but sacrifice product attributes. In particular...

  13. Time-dependent degree-degree correlations in epileptic brain networks: from assortative to dissortative mixing

    Directory of Open Access Journals (Sweden)

    Christian eGeier

    2015-08-01

    Full Text Available We investigate the long-term evolution of degree-degree correlations (assortativity in functional brain networks from epilepsy patients. Functional networks are derived from continuous multi-day, multi-channel electroencephalographic data, which capture a wide range of physiological and pathophysiological activities. In contrast to previous studies which all reported functional brain networks to be assortative on average, even in case of various neurological and neurodegenerative disorders, we observe large fluctuations in time-resolved degree-degree correlations ranging from assortative to dissortative mixing. Moreover, in some patients these fluctuations exhibit some periodic temporal structure which can be attributed, to a large extent, to daily rhythms. Relevant aspects of the epileptic process, particularly possible pre-seizure alterations, contribute marginally to the observed long-term fluctuations. Nevertheless, our findings suggest that physiological and pathophysiological activity may modify functional brain networks in a different and process-specific way. We evaluate factors that possibly influence the long-term evolution of degree-degree correlations.

  14. Assortative mating and the reversal of gender inequality in education in europe: an agent-based model

    National Research Council Canada - National Science Library

    Grow, André; Van Bavel, Jan

    2015-01-01

    .... We develop an agent-based computational model that explicates the mechanisms that may have linked the reversal of gender inequality in education with observed changes in educational assortative mating...

  15. Assortative Mating and the Reversal of Gender Inequality in Education in Europe: An Agent-Based Model: e0127806

    National Research Council Canada - National Science Library

    André Grow; Jan Van Bavel

    2015-01-01

    .... We develop an agent-based computational model that explicates the mechanisms that may have linked the reversal of gender inequality in education with observed changes in educational assortative mating...

  16. On the sources of the height–intelligence correlation: New insights from a bivariate ACE model with assortative mating

    OpenAIRE

    Beauchamp, Jonathan P; Cesarini, David; Johannesson, Magnus; Lindqvist, Erik; Apicella, Coren Lee

    2010-01-01

    A robust positive correlation between height and intelligence, as measured by IQ tests, has been established in the literature. This paper makes several contributions toward establishing the causes of this association. First, we extend the standard bivariate ACE model to account for assortative mating. The more general theoretical framework provides several key insights, including formulas to decompose a cross-trait genetic correlation into components attributable to assortative mating and pl...

  17. Active phenotypic assortment in mate selection: self-descriptions and sought-for attributes of mates in dating advertisements.

    Science.gov (United States)

    Sakai, D K; Johnson, R C

    1997-01-01

    Assortative mating results both from social homogamy (coming for similar environments) and active phenotypic assortment (seeking a mate with desired attributes). Dating advertisements provide a means of assessing the role of active phenotypic assortment in the absence of social homogamy. The relative frequency of mention of different attributes (given limited advertising space) is informative regarding the salience of these attributes in active phenotypic assortment. Sex differences in self descriptions and in attributes desired in others in dating advertisements provide a means of evaluating sociobiological issues. Data were analyzed from 191 ads placed by females and 253 ads placed by males seeking to meet members of the opposite sex. The most frequently mentioned attributes are age, race, occupation, moral characteristics, and physical attractiveness. While close to 80 per cent of the advertisers provided information concerning their own race/ethnicity, only a minority of those providing such information limited their quest for a partner to members of their own race/ethnicity. There is substantial assortative mating for religion, family background, status, and educational attainment, yet these attributes are rarely (religion and education) or never (family background) mentioned in advertisements, suggesting that assortative mating on these dimensions may be solely a consequence of social homogamy.

  18. Assortative mating and differential male mating success in an ash hybrid zone population

    Directory of Open Access Journals (Sweden)

    Frascaria-Lacoste Nathalie

    2006-11-01

    Full Text Available Abstract Background The structure and evolution of hybrid zones depend mainly on the relative importance of dispersal and local adaptation, and on the strength of assortative mating. Here, we study the influence of dispersal, temporal isolation, variability in phenotypic traits and parasite attacks on the male mating success of two parental species and hybrids by real-time pollen flow analysis. We focus on a hybrid zone population between the two closely related ash species Fraxinus excelsior L. (common ash and F. angustifolia Vahl (narrow-leaved ash, which is composed of individuals of the two species and several hybrid types. This population is structured by flowering time: the F. excelsior individuals flower later than the F. angustifolia individuals, and the hybrid types flower in-between. Hybrids are scattered throughout the population, suggesting favorable conditions for their local adaptation. We estimate jointly the best-fitting dispersal kernel, the differences in male fecundity due to variation in phenotypic traits and level of parasite attack, and the strength of assortative mating due to differences in flowering phenology. In addition, we assess the effect of accounting for genotyping error on these estimations. Results We detected a very high pollen immigration rate and a fat-tailed dispersal kernel, counter-balanced by slight phenological assortative mating and short-distance pollen dispersal. Early intermediate flowering hybrids, which had the highest male mating success, showed optimal sex allocation and increased selfing rates. We detected asymmetry of gene flow, with early flowering trees participating more as pollen donors than late flowering trees. Conclusion This study provides striking evidence that long-distance gene flow alone is not sufficient to counter-act the effects of assortative mating and selfing. Phenological assortative mating and short-distance dispersal can create temporal and spatial structuring that appears

  19. Assimilation of Unusual Carbon Compounds

    Science.gov (United States)

    Middelhoven, Wouter J.

    Yeast taxa traditionally are distinguished by growth tests on several sugars and organic acids. During the last decades it became apparent that many yeast species assimilate a much greater variety of naturally occurring carbon compounds as sole source of carbon and energy. These abilities are indicative of a greater role of yeasts in the carbon cycle than previously assumed. Especially in acidic soils and other habitats, yeasts may play a role in the degradation of carbon compounds. Such compounds include purines like uric acid and adenine, aliphatic amines, diamines and hydroxyamines, phenolics and other benzene compounds and polysaccharides. Assimilation of purines and amines is a feature of many ascomycetes and basidiomycetes. However, benzene compounds are degraded by only a few ascomycetous yeasts (e.g. the Stephanoascus/ Blastobotrys clade and black yeastlike fungi) but by many basidiomycetes, e.g. Filobasidiales, Trichosporonales, red yeasts producing ballistoconidia and related species, but not by Tremellales. Assimilation of polysaccharides is wide-spread among basidiomycetes

  20. Acquaintance ratings of the Big Five personality traits: incremental validity beyond and interactive effects with self-reports in the prediction of workplace deviance.

    Science.gov (United States)

    Kluemper, Donald H; McLarty, Benjamin D; Bing, Mark N

    2015-01-01

    It is widely established that the Big Five personality traits of conscientiousness, agreeableness, and emotional stability are antecedents to workplace deviance (Berry, Ones, & Sackett, 2007). However, these meta-analytic findings are based on self-reported personality traits. A recent meta-analysis by Oh, Wang, and Mount (2011) identified the value of acquaintance-reported personality in the prediction of job performance. The current investigation extends prior work by comparing the validities of self- and acquaintance-reported personality in the prediction of workplace deviance across 2 studies. We also hypothesized and tested an interactive, value-added integration of self- with acquaintance-reported personality using socioanalytic personality theory (R. T. Hogan, 1991). Both studies assessed self- and acquaintance-rated Big Five traits, along with supervisor-rated workplace deviance. However, the studies varied the measures of workplace deviance, and the 2nd study also included a self-rated workplace deviance criterion for additional comparison. Across both studies, the traits of conscientiousness and agreeableness were strong predictors of workplace deviance, and acquaintance-reported personality provided incremental validity beyond self-reports. Additionally, acquaintance-reported conscientiousness and agreeableness moderated the prediction of workplace deviance by interacting with the corresponding self-reported traits. Implications for personality theory and measurement are discussed along with applications for practice. (c) 2015 APA, all rights reserved.

  1. Data assimilation in hydrological modelling

    DEFF Research Database (Denmark)

    Drecourt, Jean-Philippe

    Data assimilation is an invaluable tool in hydrological modelling as it allows to efficiently combine scarce data with a numerical model to obtain improved model predictions. In addition, data assimilation also provides an uncertainty analysis of the predictions made by the hydrological model...... with model non-linearities and biased errors. A literature review analyzes the most popular techniques and their application in hydrological modelling. Since bias is an important problem in groundwater modelling, two bias aware Kalman filters have been implemented and compared using an artificial test case...

  2. Storm surge variational assimilation model

    Directory of Open Access Journals (Sweden)

    Shi-li HUANG

    2010-06-01

    Full Text Available To eliminate errors caused by uncertainty of parameters and further improve capability of storm surge forecasting, the variational data assimilation method is applied to the storm surge model based on unstructured grid with high spatial resolution. The method can effectively improve the forecasting accuracy of storm surge induced by typhoon through controlling wind drag force coefficient parameter. The model is first theoretically validated with synthetic data. Then, the real storm surge process induced by the TC 0515 typhoon is forecasted by the variational data assimilation model, and results show the feasibility of practical application.

  3. Data assimilation making sense of observations

    CERN Document Server

    Lahoz, William; Menard, Richard

    2010-01-01

    In recent years data assimilation methods have been applied to an increasing range of earth science disciplines. This book sets out the theoretical basis of data assimilation with contributions by top international experts in the field.

  4. Data assimilation techniques in modeling ocean processes

    Digital Repository Service at National Institute of Oceanography (India)

    Mahadevan, R.; Fernandes, A.A.; Naqvi, S.W.A.

    control theory method are discussed. Application of data assimilation technique to physical problems governed by linear and nonlinear ordinary differential equations are explained. The formulation of data assimilation technique in one-dimensional models...

  5. Data assimilation in reservoir management

    NARCIS (Netherlands)

    Rommelse, J.R.

    2009-01-01

    The research presented in this thesis aims at improving computer models that allow simulations of water, oil and gas flows in subsurface petroleum reservoirs. This is done by integrating, or assimilating, measurements into physics-bases models. In recent years petroleum technology has developed

  6. Assimilation of Unusual Carbon Compounds

    NARCIS (Netherlands)

    Middelhoven, W.J.

    2009-01-01

    Yeast taxa traditionally are distinguished by growth tests on several sugars and organic acids. During the last decades it became apparent that many yeast species assimilate a much greater variety of naturally occurring carbon compounds as sole source of carbon and energy. These abilities are

  7. Data assimilation with Chua's circuit

    Indian Academy of Sciences (India)

    noise and observational frequency, using both simulated observations and data obtained from an experimental realization of a commonly used low-dimensional dynamical system, namely, Chua circuit, in both the periodic as well as the chaotic regime. Keywords. Synchronization; ensemble Kalman filter; data assimilation.

  8. The Phonological Assimilation of Borrowing.

    Science.gov (United States)

    Suleiman, Saleh M.

    Linguistic borrowing from English to Jordanian Arabic at the lexical level is described, focusing on phonology and the extent to which Jordanian Arabic has affected the phonetic structure of English loans assimilated partially or completely into it. Conspicuous distinctive sound features in the two languages that may affect non-native speakers'…

  9. Choosing mates based on the diet of your ancestors: replication of non-genetic assortative mating in Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Michael A. Najarro

    2015-08-01

    Full Text Available Assortative mating has been a focus of considerable research because of its potential to influence biodiversity at many scales. Sharon et al. (2010 discovered that an inbred strain of Drosophila melanogaster mated assortatively based on the diet of previous generations, leading to initial reproductive isolation without genetic evolution. This behavior was reproduced by manipulating the microbiome independently of the diet, pointing to extracellular bacterial symbionts as the assortative mating cue. To further investigate the biological significance of this result, we attempted to reproduce this phenomenon in an independent laboratory using different genotypes and additional mating assays. Supporting the previous result, we found that a different inbred strain also mated assortatively based on the diets of previous generations. However, we were unable to generate assortative mating in an outbred strain from North Carolina. Our results support the potential for non-genetic mechanisms to influence reproductive isolation, but additional work is needed to investigate the importance of this mechanism in natural populations of Drosophila.

  10. Self-presentation as a function of perceived closeness and trust with romantic partners, friends, and acquaintances.

    Science.gov (United States)

    Øverup, Camilla S; Neighbors, Clayton

    2016-01-01

    Self-presentation represents behaviors used in establishing an identity with others; such behaviors may differ across various interpersonal relationships. The current article presents two studies examining differences in self-presentation to acquaintances, friends, and romantic partners among college students in relationships. Study 1 was an experiment, and Study 2 utilized a within-subject design. Results showed that individuals engaged in more self-presentation in more established types of relationships. Additionally, both closeness and trust served as moderators, such that those lower in closeness/trust reported more self-presentation in more established types of relationships than in less established types of relationships. At higher levels of closeness/trust, the results were somewhat inconsistent, with Study 1 finding no differences between relationship types and Study 2 finding more self-presentation to romantic partners than to friends and acquaintances. These results are among the first to suggest that individuals engage in differing levels of self-presentation, depending on the type of relationship and the extent to which they feel close to and trust the person.

  11. The dual lens model: a comprehensive framework for understanding self-other agreement of personality judgments at zero acquaintance.

    Science.gov (United States)

    Hirschmüller, Sarah; Egloff, Boris; Nestler, Steffen; Back, Mitja D

    2013-02-01

    An integrative framework for the examination of self-other agreement of personality judgments at zero acquaintance is outlined that integrates dualistic approaches to personality, behavior, and personality judgments within the Brunswikian (1956) lens model. The dual lens model (DLM) distinguishes between explicit and implicit self-concepts of personality, controlled and automatic cues, and deliberate and intuitive personality judgments. In a first application of the DLM, targets (N = 56) were videotaped during short self-introductions, and direct and indirect measures of extraversion as well as a number of physical, kinesic, vocal, and verbal cues were obtained. Perceivers judged targets' extraversion based on these short video sequences either in a global judgment condition (Study 1: N = 95) or in a deliberate versus an intuitive judgment condition (Study 2: N = 82). In both studies, results showed that extraversion judgments at zero acquaintance were correlated with both the explicit and the implicit self-concept of extraversion (self-other agreement). The self-other correlation for explicit extraversion was fully mediated by the utilization of valid controlled cues, and it was fully mediated by the utilization of valid automatic cues for the implicit self. Whereas judgment condition did not moderate self-other agreement, perceivers' intuitive judgment style was associated with higher levels of self-other agreement, a relation that could be explained by DLM analyses. Results underline the utility of the proposed framework for the study of interpersonal judgments. (c) 2013 APA, all rights reserved.

  12. Variation in human mate choice: simultaneously investigating heritability, parental influence, sexual imprinting, and assortative mating.

    Science.gov (United States)

    Zietsch, Brendan P; Verweij, Karin J H; Heath, Andrew C; Martin, Nicholas G

    2011-05-01

    Human mate choice is central to individuals' lives and to the evolution of the species, but the basis of variation in mate choice is not well understood. Here we looked at a large community-based sample of twins and their partners and parents ([Formula: see text] individuals) to test for genetic and family environmental influences on mate choice, while controlling for and not controlling for the effects of assortative mating. Key traits were analyzed, including height, body mass index, age, education, income, personality, social attitudes, and religiosity. This revealed near-zero genetic influences on male and female mate choice over all traits and no significant genetic influences on mate choice for any specific trait. A significant family environmental influence was found for the age and income of females' mate choices, possibly reflecting parental influence over mating decisions. We also tested for evidence of sexual imprinting, where individuals acquire mate-choice criteria during development by using their opposite-sex parent as the template of a desirable mate; there was no such effect for any trait. The main discernible pattern of mate choice was assortative mating; we found that partner similarity was due to initial choice rather than convergence and also at least in part to phenotypic matching.

  13. Extended inclusive fitness theory: synergy and assortment drives the evolutionary dynamics in biology and economics.

    Science.gov (United States)

    Jaffe, Klaus

    2016-01-01

    W.D. Hamilton's Inclusive Fitness Theory explains the conditions that favor the emergence and maintenance of social cooperation. Today we know that these include direct and indirect benefits an agent obtains by its actions, and through interactions with kin and with genetically unrelated individuals. That is, in addition to kin-selection, assortation or homophily, and social synergies drive the evolution of cooperation. An Extended Inclusive Fitness Theory (EIFT) synthesizes the natural selection forces acting on biological evolution and on human economic interactions by assuming that natural selection driven by inclusive fitness produces agents with utility functions that exploit assortation and synergistic opportunities. This formulation allows to estimate sustainable cost/benefit threshold ratios of cooperation among organisms and/or economic agents, using existent analytical tools, illuminating our understanding of the dynamic nature of society, the evolution of cooperation among kin and non-kin, inter-specific cooperation, co-evolution, symbioses, division of labor and social synergies. EIFT helps to promote an interdisciplinary cross fertilization of the understanding of synergy by, for example, allowing to describe the role for division of labor in the emergence of social synergies, providing an integrated framework for the study of both, biological evolution of social behavior and economic market dynamics. Another example is a bio-economic understanding of the motivations of terrorists, which identifies different forms of terrorism.

  14. Interspecific competition influences fitness benefits of assortative mating for territorial aggression in eastern bluebirds (Sialia sialis.

    Directory of Open Access Journals (Sweden)

    Morgan R Harris

    Full Text Available Territorial aggression influences fitness and, in monogamous pairs, the behavior of both individuals could impact reproductive success. Moreover, territorial aggression is particularly important in the context of interspecific competition. Tree swallows and eastern bluebirds are highly aggressive, secondary cavity-nesting birds that compete for limited nesting sites. We studied eastern bluebirds at a field site in the southern Appalachian Mountains that has been recently colonized (<40 yr by tree swallows undergoing a natural range expansion. The field site is composed of distinct areas where bluebirds compete regularly with tree swallows and areas where there is little interaction between the two species. Once birds had settled, we measured how interspecific competition affects the relationship between assortative mating (paired individuals that behave similarly and reproductive success in eastern bluebirds. We found a strong tendency toward assortative mating throughout the field site. In areas of high interspecific competition, pairs that behaved the most similarly and displayed either extremely aggressive or extremely non-aggressive phenotypes experienced higher reproductive success. Our data suggest that interspecific competition with tree swallows may select for bluebirds that express similar behavior to that of their mate. Furthermore, animal personality may be an important factor influencing the outcome of interactions between native and aggressive, invasive species.

  15. Acoustic discrimination of sympatric morphs in Darwin's finches: a behavioural mechanism for assortative mating?

    Science.gov (United States)

    Podos, Jeffrey

    2010-01-01

    Populations with multiple morphological or behavioural types provide unique opportunities for studying the causes and consequences of evolutionary diversification. A population of the medium ground finch (Geospiza fortis) at El Garrapatero on Santa Cruz Island, Galápagos, features two beak size morphs. These morphs produce acoustically distinctive songs, are subject to disruptive selection and mate assortatively by morph. The main goal of the present study was to assess whether finches from this population are able to use song as a cue for morph discrimination. A secondary goal of this study was to evaluate whether birds from this population discriminate songs of their own locality versus another St Cruz locality, Borrero Bay, approximately 24 km to the NW. I presented territorial males with playback of songs of their own morph, of the other morph, and of males from Borrero Bay. Males responded more strongly to same-morph than to other-morph playbacks, showing significantly shorter latencies to flight, higher flight rates and closer approaches to the playback speaker. By contrast, I found only minor effects of locality on responsiveness. Evidence for morph discrimination via acoustic cues supports the hypothesis that song can serve as a behavioural mechanism for assortative mating and sympatric evolutionary divergence. PMID:20194166

  16. Variation in human mate choice: Simultaneously investigating heritability, parental influence, sexual imprinting, and assortative mating

    Science.gov (United States)

    Zietsch, Brendan P.; Verweij, Karin J. H.; Heath, Andrew C.; Martin, Nicholas G.

    2012-01-01

    Human mate choice is central to individuals’ lives and to the evolution of the species, but the basis of variation in mate choice is not well understood. Here we look at a large community-based sample of twins and their partners and parents (N > 20,000 individuals) to test for genetic and family environmental influences on mate choice, with and without controlling for the effects of assortative mating. Key traits are analyzed, including height, body mass index, age, education, income, personality, social attitudes, and religiosity. This revealed near-zero genetic influences on male and female mate choice over all traits and no significant genetic influences on mate choice for any specific trait. A significant family environmental influence was found for the age and income of females’ mate choices, possibly reflecting parental influence over mating decisions. We also tested for evidence of sexual imprinting, where individuals acquire mate-choice criteria during development by using their opposite-sex parent as the template of a desirable mate; there was no such effect for any trait. The main discernable pattern to mate choice was assortative mating; we found that partner similarity was due to initial choice rather than convergence and also due at least in part to phenotypic matching. PMID:21508607

  17. News for assimilation or integration

    Science.gov (United States)

    Alencar, Amanda; Deuze, Mark

    2017-04-01

    This study investigates the functions of news media in shaping acculturation experiences of new economic and refugee immigrants in the Netherlands and Spain. Focus group data revealed that consumption of host country news media was mainly connected to immigrants' deliberate strategies to assimilate the culture, politics and language of the host society, while exposure to transnational news was viewed in terms of strategies of integration in both countries. We also observed that participants' educational background and language skills combined with their perceptions of the host country's news have an impact on the use they make of news for assimilating and/or integrating into the host society. Finally, important sociopolitical conditions of the context influenced the ways participants use the news media in their process of acculturation.

  18. Does the internet affect assortative mating? Evidence from the U.S. and Germany.

    Science.gov (United States)

    Potarca, Gina

    2017-01-01

    The Internet has now become a habitual channel for finding a partner, but little is known about the impact of this recent partnership market on mate selection patterns. This study revisits the supply side perspective on assortative mating by exploring the role played by online venues in breeding educational, racial/ethnic and religious endogamy. It compares couples that met online (through either online dating platforms, Internet social networking, Internet gaming website, Internet chat, Internet community, etc.) to those that met through various offline contexts of interaction. Using unique data from the U.S. for the year 2009 and data from Germany collected between 2008 and 2014, I run log-multiplicative models that allow for the strength of partners' association to vary along meeting settings. Results reveal that the Internet promotes weaker couple endogamy compared to conventional contexts typically known to foster endogamy, such as school, family, friends, or religious venues. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Assortative Mating: Encounter-Network Topology and the Evolution of Attractiveness

    Science.gov (United States)

    Dipple, S.; Jia, T.; Caraco, T.; Korniss, G.; Szymanski, B. K.

    2017-03-01

    We model a social-encounter network where linked nodes match for reproduction in a manner depending probabilistically on each node’s attractiveness. The developed model reveals that increasing either the network’s mean degree or the “choosiness” exercised during pair formation increases the strength of positive assortative mating. That is, we note that attractiveness is correlated among mated nodes. Their total number also increases with mean degree and selectivity during pair formation. By iterating over the model’s mapping of parents onto offspring across generations, we study the evolution of attractiveness. Selection mediated by exclusion from reproduction increases mean attractiveness, but is rapidly balanced by skew in the offspring distribution of highly attractive mated pairs.

  20. Manufacturer and retailer brands in food retail assortments: Notes from a shopping trip across Europe

    DEFF Research Database (Denmark)

    Esbjerg, Lars; Grunert, Klaus G.; Bech-Larsen, Tino

    retailer branded products in an attempt to differentiate themselves by offering goods only available in their stores. Despite the importance of branding to retailers, the branding literature has focused on how manufacturers develop and maintain strong brands. Relatively little work has been done...... and perform a variety of activities and services, which provide added value in the eyes of consumers (Burt 2000). In this connection, branding is becoming increasingly important, as food retailers develop their own brands within and across product categories. Many retailers are attempting to cultivate...... an overall brand identity in order to protect and identify their market offering (Burt & Sparks 2002). The assortment of products food retailers offer typically includes manufacturer brands, re-tailer brands and generic or unbranded products. In recent years, increasing competition in food retailing has made...

  1. Educational assortative mating across marriage markets: non-Hispanic whites in the United States.

    Science.gov (United States)

    Lewis, S K; Oppenheimer, V K

    2000-02-01

    Whether local marriage market conditions shape marriage behavior is a central social demographic question. Most work on this subject, however, focuses on one type of market condition--sex ratios--and on a single outcome--marital timing or sorting. We examine the impact of local marriage markets' educational composition on educational assortative mating and on how sorting varies with age. We estimate a discrete-time competing-risks model of educational sorting outcomes, using individual data from the NLSY and community descriptors aggregated from census microdata. Results show that residents of educationally less favorable marriage markets are more likely to marry down on education, and that (for women) their chance of doing so increases with age more than for residents of more favorable markets.

  2. The structure of a food product assortment modulates the effect of providing choice on food intake.

    Science.gov (United States)

    Parizel, Odile; Sulmont-Rossé, Claire; Fromentin, Gilles; Delarue, Julien; Labouré, Hélène; Benamouzig, Robert; Marsset-Baglieri, Agnès

    2016-09-01

    Several authors showed that providing choice may increase food liking and food intake. However, the impact of choice may be modulated by assortment's characteristics, such as the number of alternatives or their dissimilarity. The present study compared the impact of choice on food liking and intake under the two following conditions: (1) when choosing a product to consume from among similar products versus dissimilar products; and (2) when choosing a product to consume from among pleasant products versus unpleasant products. Two experiments were carried out using the same design: the "apple puree" experiment (n = 80), where the volunteers choose from among similar products (apple purees varying in texture) and the "dessert" experiment (n = 80), where the volunteers choose from among dissimilar products (fruit dessert, dairy dessert, custard, pudding). During the first session, participants rated their liking for 12 products (apples purees or desserts). Then the participants were divided into a "pleasant" group (n = 40) in which volunteers were assigned three pleasant products, and an "unpleasant" group (n = 40) in which volunteers were assigned three unpleasant products. Finally, all of the volunteers participated in a choice session - volunteers were presented with their three assigned products and asked to choose one of the products, and a no-choice session - volunteers were served with one product that was randomly selected from among their three assigned products. Providing choice led to an increase in food liking in both experiments and an increase in food intake only for the desserts, namely only when the volunteers chose the product to consume from among "not too similar" alternatives. No effect of assortment's pleasantness was observed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Imposing nonlinear constraints when estimating genetic and cultural transmission under assortative mating: a simulation study using Mx and BUGS

    NARCIS (Netherlands)

    van den Berg, Stéphanie Martine

    2009-01-01

    Modeling both genetic and cultural transmission in parent-offspring data in the presence of phenotypic assortment requires the imposition of nonlinear constraints. This article reports a simulation study that determined how well the structural equation modeling software package Mx and the

  4. Parasite-stress promotes in-group assortative sociality: the cases of strong family ties and heightened religiosity.

    Science.gov (United States)

    Fincher, Corey L; Thornhill, Randy

    2012-04-01

    Throughout the world people differ in the magnitude with which they value strong family ties or heightened religiosity. We propose that this cross-cultural variation is a result of a contingent psychological adaptation that facilitates in-group assortative sociality in the face of high levels of parasite-stress while devaluing in-group assortative sociality in areas with low levels of parasite-stress. This is because in-group assortative sociality is more important for the avoidance of infection from novel parasites and for the management of infection in regions with high levels of parasite-stress compared with regions of low infectious disease stress. We examined this hypothesis by testing the predictions that there would be a positive association between parasite-stress and strength of family ties or religiosity. We conducted this study by comparing among nations and among states in the United States of America. We found for both the international and the interstate analyses that in-group assortative sociality was positively associated with parasite-stress. This was true when controlling for potentially confounding factors such as human freedom and economic development. The findings support the parasite-stress theory of sociality, that is, the proposal that parasite-stress is central to the evolution of social life in humans and other animals.

  5. Organizing Products with Complements versus Substitutes: Effects on Store Preferences as a Function of Effort and Assortment Perceptions

    NARCIS (Netherlands)

    Diehl, K.; Herpen, van E.; Lamberton, C.

    2015-01-01

    Retailers often organize at least part of their assortment by displaying complementary products from different product categories together (e.g., a pair of pants with a shirt) rather than grouping items by product type (e.g., a pair of pants with other pants). However, little is known about how

  6. Effects of Early U.S. Compulsory Schooling Laws on Educational Assortative Mating: The Importance of Context.

    Science.gov (United States)

    Rauscher, Emily

    2015-08-01

    Modernization theory predicts that rising education should increase assortative mating by education and decrease sorting by race. Recent research suggests that effects of educational expansion depend on contextual factors, such as economic development. Using log-linear and log-multiplicative models of male household heads ages 36 to 75 in the 1940 U.S. census data--the first U.S. census with educational attainment information--I investigate how educational assortative mating changed with one instance of educational expansion: early U.S. compulsory school attendance laws. To improve on existing research and distinguish effects of expansion from changes due to particular years or cohorts, I capitalize on state variation in the timing of these compulsory laws (ranging from 1852 to 1918). Aggregate results suggest that compulsory laws had minimal impact on assortative mating. However, separate analyses by region (and supplemental analyses by race) reveal that assortative mating by education decreased with the laws in the South but increased in the North. Whether due to economic, legal, political, or other differences, results suggest that the implications of educational expansion for marital sorting depend on context. Contemporary implications are discussed in light of President Obama's 2012 suggested extension of compulsory schooling to age 18.

  7. Measuring Income Assimilation of Migrants to Germany

    OpenAIRE

    Ira N. Gang; John Landon-Lane; Myeong-Su Yun

    2009-01-01

    We measure the income assimilation of migrants to Germany employing a new measure of assimilation that uses the whole income distribution rather than selected moments. To do this we implement a discrete-state Markov chain to model the dynamics of the cross-sectional income distribution of migrants and natives in Germany. Bayesian methods allow us to fully characterize the limiting cross-sectional income distribution for migrants and natives, enabling us to compare our measures of assimilation...

  8. Compensation for Complete Assimilation in Speech Perception: The Case of Korean Labial-to-Velar Assimilation

    Science.gov (United States)

    Mitterer, Holger; Kim, Sahyang; Cho, Taehong

    2013-01-01

    In connected speech, phonological assimilation to neighboring words can lead to pronunciation variants (e.g., "garden bench" [arrow right] "garde'm' bench"). A large body of literature suggests that listeners use the phonetic context to reconstruct the intended word for assimilation types that often lead to incomplete assimilations (e.g., a…

  9. Data Assimilation - Advances and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Brian J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-07-30

    This presentation provides an overview of data assimilation (model calibration) for complex computer experiments. Calibration refers to the process of probabilistically constraining uncertain physics/engineering model inputs to be consistent with observed experimental data. An initial probability distribution for these parameters is updated using the experimental information. Utilization of surrogate models and empirical adjustment for model form error in code calibration form the basis for the statistical methodology considered. The role of probabilistic code calibration in supporting code validation is discussed. Incorporation of model form uncertainty in rigorous uncertainty quantification (UQ) analyses is also addressed. Design criteria used within a batch sequential design algorithm are introduced for efficiently achieving predictive maturity and improved code calibration. Predictive maturity refers to obtaining stable predictive inference with calibrated computer codes. These approaches allow for augmentation of initial experiment designs for collecting new physical data. A standard framework for data assimilation is presented and techniques for updating the posterior distribution of the state variables based on particle filtering and the ensemble Kalman filter are introduced.

  10. The Assimilation of Envisat data (ASSET project

    Directory of Open Access Journals (Sweden)

    W. A. Lahoz

    2007-01-01

    Full Text Available This paper discusses the highlights of the EU-funded "Assimilation of Envisat data" (ASSET project, which has involved assimilation of Envisat atmospheric constituent and temperature data into systems based on Numerical Weather Prediction (NWP models and chemical transport models (CTMs. Envisat was launched in 2002 and is one of the largest Earth Observation (EO satellites ever built. It carries several sophisticated EO instruments providing insights into chemistry and dynamics of the atmosphere. In this paper we focus on the assimilation of temperature and constituents from Envisat. The overarching theme of the ASSET project has been to bring together experts from all aspects of the data assimilation problem. This has allowed ASSET to address several themes comprehensively: enhancement of NWP analyses by assimilation of research satellite data; studies of the distribution of stratospheric chemical species by assimilation of research satellite data into CTM systems; objective assessment of the quality of ozone analyses; studies of the spatial and temporal evolution of tropospheric pollutants; enhanced retrievals of Envisat data; and data archival and dissemination. Among the results from the ASSET project, many of which are firsts in their field, we can mention: a positive impact on NWP analyses from assimilation of height-resolved stratospheric humidity and temperature data, and assimilation of limb radiances; the extraction of temperature information from the assimilation of chemical species into CTMs; a first intercomparison between ozone assimilation systems; the extraction of information on tropospheric pollution from assimilation of Envisat data; and the large potential of the Envisat MIPAS dataset. This paper discusses these, often novel, developments and results. Finally, achievements of, and recommendations from, the ASSET project are presented.

  11. You can't always get what you want: size assortative mating by mutual mate choice as a resolution of sexual conflict.

    Science.gov (United States)

    Baldauf, Sebastian A; Kullmann, Harald; Schroth, Stefanie H; Thünken, Timo; Bakker, Theo C M

    2009-06-10

    Assortative mating patterns for mate quality traits like body size are often observed in nature. However, the underlying mechanisms that cause assortative mating patterns are less well known. Sexual selection is one important explanation for assortment, suggesting that i) one (usually the female) or both sexes could show preferences for mates of similar size or ii) mutual mate choice could resolve sexual conflict over quality traits into assortment. We tested these hypotheses experimentally in the socially monogamous cichlid fish Pelvicachromis taeniatus, in which mate choice is mutual. In mate choice experiments, both sexes preferred large mates irrespective of own body size suggesting mating preferences are not size-assortative. Especially males were highly selective for large females, probably because female body size signals direct fitness benefits. However, when potential mates were able to interact and assess each other mutually they showed size-assortative mating patterns, i.e. the likelihood to mate was higher in pairs with low size differences between mates. Due to variation in body size, general preferences for large mating partners result in a sexual conflict: small, lower quality individuals who prefer themselves large partners are unacceptable for larger individuals. Relative size mismatches between mates translate into a lower likelihood to mate, suggesting that the threshold to accept mates depends on own body size. These results suggest that the underlying mechanism of assortment in P. taeniatus is mutual mate choice resolving the sexual conflict over mates, rather than preference for mates of similar size.

  12. The Race Race: Assimilation in America

    Science.gov (United States)

    Balis, Andrea; Aman, Michael

    2013-01-01

    Can race and assimilation be taught? Interdisciplinary pedagogy provides a methodology, context, and use of nontraditional texts culled from American cultural history such as from, theater and historical texts. This approach and these texts prove useful for an examination of race and assimilation in America. The paper describes a course that while…

  13. Deviations from Hardy-Weinberg frequencies caused by assortative mating in hybrid populations.

    Science.gov (United States)

    Shockley, W

    1973-03-01

    The conventional formulas for genotype frequencies in a hybrid population H produced by interbreeding from ancestral populations P(1) and P(2) involve only one hybrid parameter M, equal to the fraction of alleles derived from P(2). For the one-parameter model to be accurate, all individuals of H must have probabilities for alleles determined by one and the same M. When H contains subpopulations that have different values of M, the correct genotype frequencies can be predicted by use of two parameters: (i) M(H), the average of M for all individuals of H and (ii) eta(H), defined like the eta devised by C. A. B. Smith for testing the Hardy-Weinberg Law and computed with a formula like G. R. Price's eta, which involves assortative mating covariance-in this case for the M values of the parents of H. If parents of H have equal average M values for males and females, and mate at random, eta(H) vanishes. For perfect assortative mating, eta(H) is the variance of M for H. As for Smith's eta, eta(H) provides a test of fit of prediction to observed that is sensitive to signs of deviations. Using eta(H) with T. E. Reed's data for Gm in Oakland, California Negroes, his one-parameter fit ("good" by his chi-square test) is significantly rejected (P = 0.04). A simultaneous good fit of Reed's Gm data and his Duffy data results (chi-square, 1 df = 0.88, P > 0.30) from the use of previously published values of 0.23 and 0.047 for M(H) and eta(H). It is concluded that Reed's conclusion that these values were in error is itself in error, as is also his view that differences between M values from different genes and deviations from frequencies expected within genes are not likely to give significant information about variance of M.

  14. Effective assimilation of global precipitation: simulation experiments

    Directory of Open Access Journals (Sweden)

    Guo-Yuan Lien

    2013-07-01

    Full Text Available Past attempts to assimilate precipitation by nudging or variational methods have succeeded in forcing the model precipitation to be close to the observed values. However, the model forecasts tend to lose their additional skill after a few forecast hours. In this study, a local ensemble transform Kalman filter (LETKF is used to effectively assimilate precipitation by allowing ensemble members with better precipitation to receive higher weights in the analysis. In addition, two other changes in the precipitation assimilation process are found to alleviate the problems related to the non-Gaussianity of the precipitation variable: (a transform the precipitation variable into a Gaussian distribution based on its climatological distribution (an approach that could also be used in the assimilation of other non-Gaussian observations and (b only assimilate precipitation at the location where at least some ensemble members have precipitation. Unlike many current approaches, both positive and zero rain observations are assimilated effectively. Observing system simulation experiments (OSSEs are conducted using the Simplified Parametrisations, primitivE-Equation DYnamics (SPEEDY model, a simplified but realistic general circulation model. When uniformly and globally distributed observations of precipitation are assimilated in addition to rawinsonde observations, both the analyses and the medium-range forecasts of all model variables, including precipitation, are significantly improved as compared to only assimilating rawinsonde observations. The effect of precipitation assimilation on the analyses is retained on the medium-range forecasts and is larger in the Southern Hemisphere (SH than that in the Northern Hemisphere (NH because the NH analyses are already made more accurate by the denser rawinsonde stations. These improvements are much reduced when only the moisture field is modified by the precipitation observations. Both the Gaussian transformation and

  15. Data assimilation a mathematical introduction

    CERN Document Server

    Law, Kody; Zygalakis, Konstantinos

    2015-01-01

    This book provides a systematic treatment of the mathematical underpinnings of work in data assimilation, covering both theoretical and computational approaches. Specifically the authors develop a unified mathematical framework in which a Bayesian formulation of the problem provides the bedrock for the derivation, development and analysis of algorithms; the many examples used in the text, together with the algorithms which are introduced and discussed, are all illustrated by the MATLAB software detailed in the book and made freely available online. The book is organized into nine chapters: the first contains a brief introduction to the mathematical tools around which the material is organized; the next four are concerned with discrete time dynamical systems and discrete time data; the last four are concerned with continuous time dynamical systems and continuous time data and are organized analogously to the corresponding discrete time chapters. This book is aimed at mathematical researchers interested in a sy...

  16. Iron assimilation by Azomonas macrocytogenes

    Energy Technology Data Exchange (ETDEWEB)

    Collinson, S.K.

    1989-01-01

    Iron assimilation by the gram-negative, soil diazotroph Azomonas macrocytogenes ATCC 12334 was studied. A. macrocytogenes was grown in a simple defined medium and was found to excrete two iron-binding compounds. The first compound, 3,4-dihydroxybenzoic acid (3,4DHBA) was purified and chemically identified from cell-free culture supernatants and found to promote the solubilization of iron from various iron-containing minerals. Moreover, preincubation of iron-limited growth medium with olivine or glauconite in the presence of 3,4-DHBA, supported enhanced growth of A. macrocytogenes thus suggesting a role for 3,4-DHBA in mineral-iron solubilization. However, 3,4-DHBA was not a true siderophore since it was also produced by cells growing in iron-sufficient medium and did not enhance {sup 55}Fe{sup 3+} assimilation by A. macrocytogenes. A. macrocytogenes also excreted a blue-white fluorescent compound in iron-limited media. This compound, named azoverdin, was purified in the ferrated form to 98% purity. This compound exhibited a pH-independent absorption spectrum which became pH-dependent following deferration with 8-hydroxyquinoline. Preliminary FAB mass spectral results indicated a 1:1 stoichiometry for the iron complex, and a positive reaction in the Csaky assay suggested the presence of bound hydroxylamine. Although elucidation of the exact chemical structure is in progress, these results indicated that azoverdin was chemically related to pyoverdin siderophores. Electrophoretic analysis of outer membranes of A. macrocytogenes revealed that iron-limited cells overproduced two proteins of apparent molecular mass 74 kDa and 70 kDa, which were characteristic of ferrisiderophore receptor proteins isolated from other iron-limited gram negative bacteria.

  17. Assortative sociality, limited dispersal, infectious disease and the genesis of the global pattern of religion diversity

    Science.gov (United States)

    Fincher, Corey L; Thornhill, Randy

    2008-01-01

    Why are religions far more numerous in the tropics compared with the temperate areas? We propose, as an answer, that more religions have emerged and are maintained in the tropics because, through localized coevolutionary races with hosts, infectious diseases select for three anticontagion behaviours: in-group assortative sociality; out-group avoidance; and limited dispersal. These behaviours, in turn, create intergroup boundaries that effectively fractionate, isolate and diversify an original culture leading to the genesis of two or more groups from one. Religion is one aspect of a group's culture that undergoes this process. If this argument is correct then, across the globe, religion diversity should correlate positively with infectious disease diversity, reflecting an evolutionary history of antagonistic coevolution between parasites and hosts and subsequent religion genesis. We present evidence that supports this model: for a global sample of traditional societies, societal range size is reduced in areas with more pathogens compared with areas with few pathogens, and in contemporary countries religion diversity is positively related to two measures of parasite stress. PMID:18664438

  18. Ultrasonic Vocalizations of Male Mice Differ among Species and Females Show Assortative Preferences for Male Calls

    Science.gov (United States)

    Musolf, Kerstin; Meindl, Stefanie; Larsen, Angela L.; Kalcounis-Rueppell, Matina C.; Penn, Dustin J.

    2015-01-01

    Male house mice (Mus musculus) emit ultrasonic vocalizations (USVs) during courtship, which attract females, and we aimed to test whether females use these vocalizations for species or subspecies recognition of potential mates. We recorded courtship USVs of males from different Mus species, Mus musculus subspecies, and populations (F1 offspring of wild-caught Mus musculus musculus, Mus musculus domesticus (and F1 hybrid crosses), and Mus spicilegus), and we conducted playback experiments to measure female preferences for male USVs. Male vocalizations contained at least seven distinct syllable types, whose frequency of occurrence varied among species, subspecies, and populations. Detailed analyses of multiple common syllable types indicated that Mus musculus and Mus spicilegus could be discriminated based on spectral and temporal characteristics of their vocalizations, and populations of Mus musculus were also distinctive regardless of the classification model used. Females were able to discriminate USVs from different species, and showed assortative preferences for conspecific males. We found no evidence that females discriminate USVs of males from a different subspecies or separate populations of the same species, even though our spectral analyses identified acoustic features that differ between species, subspecies, and populations of the same species. Our results provide the first comparison of USVs between Mus species or between Mus musculus subspecies, and the first evidence that male USVs potentially facilitate species recognition. PMID:26309246

  19. Intelligent, net or wireless enabled fluorosensors for high throughput monitoring of assorted crops

    Science.gov (United States)

    Barócsi, Attila

    2013-02-01

    Phenotypic characterization of assorted crops of different genotypes requires large data sets of diverse types for statistical reliability. Temporal monitoring of plant fluorescence is able to capture the dynamics of the photosynthesis process that is summarized in a number of parameters for which the genotypic heritability can be calculated. In this paper, an intelligent sensor system is presented that is capable of high-throughput production of baseline-corrected temporal fluorescence curves with many feature points. These are obtained by integrating several (direct and modulated) measurement methods applied at different wavelengths. Simultaneously, temporal change of the sample's emission and the ambient reference temperatures are recorded. Multiple sensors can be deployed easily in large span greenhouse environments with centralized data collection over wired or wireless infrastructure. The unique features of the sensors are a compact, embedded signal guiding fibre optic system, instrument-standard variable tubular detector and source modules, net or wireless enabling for remote control and fast, quasi real-time data collection. Along with the instrumentation, some representative phenotyping data are also presented that were taken on a subset of pepper recombinant inbred line population. It is also demonstrated that transient fluorescence feature points yield high heritability, offering a high confidence level for distinguishing the pepper genotypes.

  20. Moisture development behaviour and models applicable for pulpwood and round energywood assortments in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Hautamaeki, S.; Kilpelaeinen, H.; Sirkiae, S.; Verkasalo, E. (Finnish Forest Research Inst., Joensuu (Finland)), e-mail: erkki.verkasalo@metla.fi

    2010-07-01

    95775 truck loads of Scots pine, Norway spruce and birch pulpwood and round energywood from Finland were scaled for green density. For 27595 observations the storage time in the roadside was known. Fourth degree polynomial function was estimated to describe well the annual variation in moisture content. Later, partial linear regression analysis was applied to predict the annual variation in moisture content behaviour of zero to eight weeks stored Scots pine wood, the coefficient of determination being 0,52. The drying begins in March with a fast rate, and the moisture content reaches the bottom in June. Thereafter occurs a less steep rise in moisture content. This continues until November, when the moisture content is at ats highest level. The difference in green density between fresh and stored wood continues until November, when they reach a similar level. The models can be used in estimating the moisture content development of pulpwood and round energy wood, and developed further with more empirical data on energy wood assortments. In further research, predictor variables based on local weather data will be included into the models to estimate more efficiently the moisture content change during the storage. (orig.)

  1. International Migration and Educational Assortative Mating in Mexico and the United States

    Science.gov (United States)

    Mare, Robert D.

    2014-01-01

    This paper examines the relationship between migration and marriage by describing how the distributions of marital statuses and assortative mating patterns vary by individual and community experiences of migration. In Mexico, migrants and those living in areas with high levels of out-migration are more likely to be in heterogamous unions. This is because migration increases the relative attractiveness of single return migrants while disproportionately reducing the number of marriageable men in local marriage markets. In the United States, the odds of homogamy are lower for migrants compared with nonmigrants; however, they do not vary depending on the volume of migration in communities. Migrants are more likely than nonmigrants to “marry up” educationally because the relatively small size of this group compels them to expand their pool of potential spouses to include nonmigrants, who tend to be better educated than they are. Among migrants, the odds of marrying outside of one’s education group increase the most among the least educated. In Mexican communities with high rates of out-migration, the odds of marrying outside of one’s education group are highest among those with the highest level of education. These findings suggest that migration disrupts preferences and opportunities for homogamy by changing social arrangements and normative climates. PMID:22419447

  2. Ultrasonic Vocalizations of Male Mice Differ among Species and Females Show Assortative Preferences for Male Calls.

    Directory of Open Access Journals (Sweden)

    Kerstin Musolf

    Full Text Available Male house mice (Mus musculus emit ultrasonic vocalizations (USVs during courtship, which attract females, and we aimed to test whether females use these vocalizations for species or subspecies recognition of potential mates. We recorded courtship USVs of males from different Mus species, Mus musculus subspecies, and populations (F1 offspring of wild-caught Mus musculus musculus, Mus musculus domesticus (and F1 hybrid crosses, and Mus spicilegus, and we conducted playback experiments to measure female preferences for male USVs. Male vocalizations contained at least seven distinct syllable types, whose frequency of occurrence varied among species, subspecies, and populations. Detailed analyses of multiple common syllable types indicated that Mus musculus and Mus spicilegus could be discriminated based on spectral and temporal characteristics of their vocalizations, and populations of Mus musculus were also distinctive regardless of the classification model used. Females were able to discriminate USVs from different species, and showed assortative preferences for conspecific males. We found no evidence that females discriminate USVs of males from a different subspecies or separate populations of the same species, even though our spectral analyses identified acoustic features that differ between species, subspecies, and populations of the same species. Our results provide the first comparison of USVs between Mus species or between Mus musculus subspecies, and the first evidence that male USVs potentially facilitate species recognition.

  3. International migration and educational assortative mating in Mexico and the United States.

    Science.gov (United States)

    Choi, Kate H; Mare, Robert D

    2012-05-01

    This paper examines the relationship between migration and marriage by describing how the distributions of marital statuses and assortative mating patterns vary by individual and community experiences of migration. In Mexico, migrants and those living in areas with high levels of out-migration are more likely to be in heterogamous unions. This is because migration increases the relative attractiveness of single return migrants while disproportionately reducing the number of marriageable men in local marriage markets. In the United States, the odds of homogamy are lower for migrants compared with nonmigrants; however, they do not vary depending on the volume of migration in communities. Migrants are more likely than nonmigrants to "marry up" educationally because the relatively small size of this group compels them to expand their pool of potential spouses to include nonmigrants, who tend to be better educated than they are. Among migrants, the odds of marrying outside of one's education group increase the most among the least educated. In Mexican communities with high rates of out-migration, the odds of marrying outside of one's education group are highest among those with the highest level of education. These findings suggest that migration disrupts preferences and opportunities for homogamy by changing social arrangements and normative climates.

  4. How Do Different Ways of Measuring Individual Differences in Zero-Acquaintance Personality Judgment Accuracy Correlate With Each Other?

    Science.gov (United States)

    Hall, Judith A; Back, Mitja D; Nestler, Steffen; Frauendorfer, Denise; Schmid Mast, Marianne; Ruben, Mollie A

    2017-02-13

    This research compares two different approaches that are commonly used to measure accuracy of personality judgment: the trait accuracy approach wherein participants discriminate among targets on a given trait, thus making intertarget comparisons, and the profile accuracy approach wherein participants discriminate between traits for a given target, thus making intratarget comparisons. We examined correlations between these methods as well as correlations among accuracies for judging specific traits. The present article documents relations among these approaches based on meta-analysis of five studies of zero-acquaintance impressions of the Big Five traits. Trait accuracies correlated only weakly with overall and normative profile accuracy. Substantial convergence between the trait and profile accuracy methods was only found when an aggregate of all five trait accuracies was correlated with distinctive profile accuracy. Importantly, however, correlations between the trait and profile accuracy approaches were reduced to negligibility when statistical overlap was corrected by removing the respective trait from the profile correlations. Moreover, correlations of the separate trait accuracies with each other were very weak. Different ways of measuring individual differences in personality judgment accuracy are not conceptually and empirically the same, but rather represent distinct abilities that rely on different judgment processes. © 2017 Wiley Periodicals, Inc.

  5. Association between suicidal ideation and exposure to suicide in social relationships among family, friend, and acquaintance survivors in South Korea.

    Science.gov (United States)

    Song, In Han; Kwon, Se Won; Kim, Ji Eun

    2015-06-01

    Exposure to suicide in social relationships may be associated with suicidal ideation among survivors. In South Korea, which is known for having the highest suicide rate among OECD countries, exposure to suicide in social relationships can have serious consequences as social relationships are greatly emphasized in the society. The purpose of this study was to examine the association between survivors' suicidal ideation and their exposure to suicide in close relationships. Data collected through a telephone survey of a total of 1,000 men and women selected from across the nation using a stratified sampling method were analyzed. The results show that individuals who lost a family member, friend, or acquaintance in their lifetime are 4.5 times, 3.7 times, 2.2 times, respectively, more likely to have suicidal ideation in the past year compared to those without such experience. These findings suggest that special intervention for suicide survivors should be considered for those who experience suicide in close relationships. © 2015 The American Association of Suicidology.

  6. Predicting Romantic Interest at Zero Acquaintance: Evidence of Sex Differences in Trait Perception but Not in Predictors of Interest.

    Science.gov (United States)

    Olderbak, Sally G; Malter, Frederic; Wolf, Pedro Sofio Abril; Jones, Daniel N; Figueredo, Aurelio José

    2017-01-01

    We evaluated five competing hypotheses about what predicts romantic interest. Through a half-block quasi-experimental design, a large sample of young adults (i.e., responders; n = 335) viewed videos of opposite-sex persons (i.e., targets) talking about themselves and responders rated the targets' traits and their romantic interest in the target. We tested whether similarity, dissimilarity, or overall trait levels on mate value, physical attractiveness, life history strategy, and the Big-Five personality factors predicted romantic interest at zero acquaintance, and whether sex acted as a moderator. We tested the responders' individual perception of the targets' traits, in addition to the targets' own self-reported trait levels and a consensus rating of the targets made by the responders. We used polynomial regression with response surface analysis within multilevel modeling to test support for each of the hypotheses. Results suggest a large sex difference in trait perception; when women rated men, they agreed in their perception more often than when men rated women. However, as a predictor of romantic interest, there were no sex differences. Only the responders' perception of the targets' physical attractiveness predicted romantic interest; specifically, responders' who rated the targets' physical attractiveness as higher than themselves reported more romantic interest.

  7. Methodological Developments in Geophysical Assimilation Modeling

    Science.gov (United States)

    Christakos, George

    2005-06-01

    This work presents recent methodological developments in geophysical assimilation research. We revisit the meaning of the term "solution" of a mathematical model representing a geophysical system, and we examine its operational formulations. We argue that an assimilation solution based on epistemic cognition (which assumes that the model describes incomplete knowledge about nature and focuses on conceptual mechanisms of scientific thinking) could lead to more realistic representations of the geophysical situation than a conventional ontologic assimilation solution (which assumes that the model describes nature as is and focuses on form manipulations). Conceptually, the two approaches are fundamentally different. Unlike the reasoning structure of conventional assimilation modeling that is based mainly on ad hoc technical schemes, the epistemic cognition approach is based on teleologic criteria and stochastic adaptation principles. In this way some key ideas are introduced that could open new areas of geophysical assimilation to detailed understanding in an integrated manner. A knowledge synthesis framework can provide the rational means for assimilating a variety of knowledge bases (general and site specific) that are relevant to the geophysical system of interest. Epistemic cognition-based assimilation techniques can produce a realistic representation of the geophysical system, provide a rigorous assessment of the uncertainty sources, and generate informative predictions across space-time. The mathematics of epistemic assimilation involves a powerful and versatile spatiotemporal random field theory that imposes no restriction on the shape of the probability distributions or the form of the predictors (non-Gaussian distributions, multiple-point statistics, and nonlinear models are automatically incorporated) and accounts rigorously for the uncertainty features of the geophysical system. In the epistemic cognition context the assimilation concept may be used to

  8. On the sources of the height-intelligence correlation: new insights from a bivariate ACE model with assortative mating.

    Science.gov (United States)

    Beauchamp, Jonathan P; Cesarini, David; Johannesson, Magnus; Lindqvist, Erik; Apicella, Coren

    2011-03-01

    A robust positive correlation between height and intelligence, as measured by IQ tests, has been established in the literature. This paper makes several contributions toward establishing the causes of this association. First, we extend the standard bivariate ACE model to account for assortative mating. The more general theoretical framework provides several key insights, including formulas to decompose a cross-trait genetic correlation into components attributable to assortative mating and pleiotropy and to decompose a cross-trait within-family correlation. Second, we use a large dataset of male twins drawn from Swedish conscription records and examine how well genetic and environmental factors explain the association between (i) height and intelligence and (ii) height and military aptitude, a professional psychologist's assessment of a conscript's ability to deal with wartime stress. For both traits, we find suggestive evidence of a shared genetic architecture with height, but we demonstrate that point estimates are very sensitive to assumed degrees of assortative mating. Third, we report a significant within-family correlation between height and intelligence (p^ = 0.10), suggesting that pleiotropy might be at play.

  9. Temporal variation in size-assortative mating and male mate choice in a spider with amphisexual care

    Science.gov (United States)

    Moura, Rafael R.; Gonzaga, Marcelo O.

    2017-04-01

    Males should be more selective when they have a high investment in reproduction, especially in species with biparental or paternal care. In this context, male mate choice can promote size-assortative mating (SAM) when (1) large males win intrasexual disputes, (2) large females are more fecund, and (3) males prefer larger females to smaller ones. In the spider Manogea porracea, males exhibit high reproductive investment by building their webs above those of females and exhibiting extended care of offspring in the absence of females. Under these circumstances, we expect the occurrence of SAM and male preference for large females. Herein, we performed observations and experiments in the field to evaluate the hypotheses that (1) M. porracea mates assortatively by size and (2) SAM is influenced by male mate choice. Furthermore, we measured variables that could affect mating patterns, the sex ratios, and densities of both sexes. Pairing in M. porracea was positively size-assortative in 2012, but not in 2013. Large males won most disputes for mates and preferred larger females, which produced more eggs. The inconsistency in detection of SAM was due to population dynamics, namely variations in sex ratio and population density across the breeding season. Furthermore, we found that the significance of male mate choice on sexual selection of body size in M. porracea strongly depends on the competition intensity for mating opportunities. The traditional sexual selection hypothesis of SAM needs to be reviewed and must include measures of competition intensity.

  10. Assortativity and the Probability of Epidemic Extinction: A Case Study of Pandemic Influenza A (H1N1-2009

    Directory of Open Access Journals (Sweden)

    Hiroshi Nishiura

    2011-01-01

    Full Text Available Unlike local transmission of pandemic influenza A (H1N1-2009, which was frequently driven by school children, most cases identified in long-distance intranational and international travelers have been adults. The present study examines the relationship between the probability of temporary extinction and the age-dependent next-generation matrix, focusing on the impact of assortativity. Preferred mixing captures as a good approximation the assortativity of a heterogeneously mixing population. We show that the contribution of a nonmaintenance host (i.e., a host type which cannot sustain transmission on its own to the risk of a major epidemic is greatly diminished as mixing patterns become more assortative, and in such a scenario, a higher proportion of non-maintenance hosts among index cases elevates the probability of extinction. Despite the presence of various other epidemiological factors that undoubtedly influenced the delay between first importations and the subsequent epidemic, these results suggest that the dominance of adults among imported cases represents one of the possible factors explaining the delays in geographic spread observed during the recent pandemic.

  11. Assortativity and the Probability of Epidemic Extinction: A Case Study of Pandemic Influenza A (H1N1-2009).

    Science.gov (United States)

    Nishiura, Hiroshi; Cook, Alex R; Cowling, Benjamin J

    2011-01-01

    Unlike local transmission of pandemic influenza A (H1N1-2009), which was frequently driven by school children, most cases identified in long-distance intranational and international travelers have been adults. The present study examines the relationship between the probability of temporary extinction and the age-dependent next-generation matrix, focusing on the impact of assortativity. Preferred mixing captures as a good approximation the assortativity of a heterogeneously mixing population. We show that the contribution of a nonmaintenance host (i.e., a host type which cannot sustain transmission on its own) to the risk of a major epidemic is greatly diminished as mixing patterns become more assortative, and in such a scenario, a higher proportion of non-maintenance hosts among index cases elevates the probability of extinction. Despite the presence of various other epidemiological factors that undoubtedly influenced the delay between first importations and the subsequent epidemic, these results suggest that the dominance of adults among imported cases represents one of the possible factors explaining the delays in geographic spread observed during the recent pandemic.

  12. Clients' assimilation of experiences of their therapists.

    Science.gov (United States)

    Mosher, James K; Stiles, William B

    2009-12-01

    In this study, we examined how clients internalize their therapists, understanding this phenomenon through the lens of the assimilation model, a theory of psychological change. The assimilation model describes people as comprised of multiple voices, each voice being a representation of interrelated experiences organized around significant people or events. In this study, we interviewed five former psychotherapy clients and asked them to describe how they experienced, and continue to experience, their therapists internally. On the basis of these interviews, we extended the assimilation model by constructing an account of how clients' experiences of their therapists are internalized. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

  13. The importance of peers: assimilation patterns among second-generation Turkish immigrants in Western Europe

    NARCIS (Netherlands)

    Ali, S.; Fokkema, C.M.

    2011-01-01

    The two dominant approaches to immigrant assimilation, segmented assimilation and "new" assimilation theories, have been successful at reporting and analyzing between-group differences in assimilation patterns. However, studies of assimilation generally do not address differences at the individual

  14. Assimilative and non-assimilative color spreading in the watercolor configuration

    Directory of Open Access Journals (Sweden)

    Eiji eKimura

    2014-09-01

    Full Text Available A colored line flanking a darker contour will appear to spread its color onto an area enclosed by the line (watercolor effect. The watercolor effect has been characterized as an assimilative effect, but non-assimilative color spreading has also been demonstrated in the same spatial configuration; e.g., when a black inner contour (IC is paired with a blue outer contour (OC, yellow color spreading can be observed. To elucidate visual mechanisms underlying these different color spreading effects, this study investigated the effects of luminance ratio between the double contours on the induced color by systematically manipulating the IC and OC luminances (Experiment 1 as well as the background luminance (Experiment 2. The results showed that the luminance conditions suitable for assimilative and non-assimilative color spreading were nearly opposite. When the Weber contrast of the IC to the background luminances (IC contrast was smaller than that of the OC (OC contrast, the induced color became similar to the IC color (assimilative spreading. In contrast, when the OC contrast was smaller than or equal to the IC contrast, the induced color became yellow (non-assimilative spreading. Extending these findings, Experiment 3 showed that bilateral color spreading, e.g., assimilative spreading on one side and non-assimilative spreading on the other side, can also be observed in the watercolor configuration. These results suggest that the assimilative and non-assimilative spreading were mediated by different visual mechanisms. The properties of the assimilative spreading are consistent with the model proposed to account for neon color spreading [Grossberg, S. & Mingolla, E. (1985 Percept. Psychophys., 38, 141-171] and extended for the watercolor effect [Pinna, B., & Grossberg, S. (2005 J. Opt. Soc. Am. A, 22, 2207-2221]. However, the present results suggest that additional mechanisms are needed to account for the non-assimilative color spreading.

  15. THE SOCIAL CONTEXT OF ASSIMILATION: TESTING IMPLICATIONS OF SEGMENTED ASSIMILATION THEORY*

    OpenAIRE

    Xie, Yu; Greenman, Emily

    2011-01-01

    Segmented assimilation theory has been a popular explanation for the diverse experiences of assimilation among new waves of immigrants and their children. While the theory has been interpreted in many different ways, we emphasize its implications for the important role of social context: both processes and consequences of assimilation should depend on the local social context in which immigrants are embedded. We derive empirically falsifiable hypotheses about the interaction effects between s...

  16. IS ASSIMILATION THEORY DEAD? THE EFFECT OF ASSIMILATION ON ADOLESCENT WELL-BEING

    OpenAIRE

    Greenman, Emily; Xie, Yu

    2008-01-01

    The relationship between assimilation and the well-being of immigrant children has been the focus of debate in the recent sociological literature. Much of this work has questioned whether classical theories of immigrant adaptation, which assumed assimilation to be an integral part of the process of upward mobility for immigrants, are still applicable to today’s immigrant children. This study reevaluates the applicability of classical assimilation theory with a comprehensive empirical assessme...

  17. At first glance, transparency enhances assimilation

    NARCIS (Netherlands)

    Koning, A.R.; Weert, C.M.M. de; Lier, R.J. van

    2008-01-01

    We investigated the role of transparency, perceptual grouping, and presentation time on perceived lightness. Both transparency and perceptual grouping have been found to result in assimilation effects, but only for ambiguous stimulus displays and with specific attentional instructions. By varying

  18. ERP ASSIMILATION: AN END-USER APPROACH

    Directory of Open Access Journals (Sweden)

    Hurbean Luminita

    2013-07-01

    The paper discusses the ERP adoption based on the IT assimilation theory. The ERP lifecycle is associated with the IT assimilation steps. We propose a distribution of these steps along the lifecycle. Derived from the findings in the reviewed literature we will focus the cultural factors, in particular those related to the end-users (determined as a major impact factor in our previous study: Negovan et al., 2011. Our empirical study is centred on the end-users perspective and it tries to determine if and how their behaviour affects the achievement of the ERP assimilation steps. The paper reasons that organizations that understand the IT assimilation steps correlated to the ERP implementation critical factors are more likely to implement and use ERP successfully.

  19. Data assimilation in integrated hydrological modelling

    DEFF Research Database (Denmark)

    Rasmussen, Jørn

    Integrated hydrological models are useful tools for water resource management and research, and advances in computational power and the advent of new observation types has resulted in the models generally becoming more complex and distributed. However, the models are often characterized by a high...... using both synthetic data and real observations. Groundwater head and stream discharge observations are assimilated in an integrated hydrological model, with the aim of updating the groundwater head, stream discharge and water level, and model parameters. When synthetically generated observations......, two bias-aware data assimilation algorithms are tested and were shown to successfully estimate the bias of most observations. The data assimilation framework was applied to real observations and an improvement in stream discharge was obtained compared to a deterministic model without data assimilation...

  20. Multi-locus assortment (MLA for transgene dispersal and elimination in mosquito populations.

    Directory of Open Access Journals (Sweden)

    Jason L Rasgon

    Full Text Available BACKGROUND: Replacement of wild-type mosquito populations with genetically modified versions is being explored as a potential strategy to control vector-borne diseases. Due to lower expected relative fitness of transgenic individuals, transgenes must be driven into populations for these scenarios to be successful. Several gene drive mechanisms exist in a theoretical sense but none are currently workable in mosquitoes. Even if strategies were workable, it would be very difficult to recall released transgenes in the event of unforeseen consequences. What is needed is a way to test transgenes in the field for feasibility, efficacy and safety prior to releasing an active drive mechanism. METHODOLOGY/PRINCIPAL FINDINGS: We outline a method, termed Multi-locus assortment (MLA, to spread transgenes into vector populations by the release of genetically-modified mosquitoes carrying multiple stable transgene inserts. Simulations indicate that [1] insects do not have to carry transgenes at more than 4 loci, [2] transgenes can be maintained at high levels by sequential small releases, the frequency of which depends on the construct fitness cost, and [3] in the case of unforeseen negative non-target effects, transgenes can be eliminated from the population by halting transgenic releases and/or mass releases of wild-type insects. We also discuss potential methods to create MLA mosquito strains in the laboratory. CONCLUSIONS/SIGNIFICANCE: While not as efficient as active drive mechanisms, MLA has other advantages: [1] MLA strains can be constructed for some mosquito species with currently-available technology, [2] MLA will allow the ecological components of transgenic mosquito releases to be tested before actual gene drive mechanisms are ready to be deployed, [3] since MLA is not self-propagating, the risk of an accidental premature release into nature is minimized, and [4] in the case that active gene drive mechanisms prove impossible to develop, the MLA

  1. Multi-locus assortment (MLA) for transgene dispersal and elimination in mosquito populations.

    Science.gov (United States)

    Rasgon, Jason L

    2009-06-08

    Replacement of wild-type mosquito populations with genetically modified versions is being explored as a potential strategy to control vector-borne diseases. Due to lower expected relative fitness of transgenic individuals, transgenes must be driven into populations for these scenarios to be successful. Several gene drive mechanisms exist in a theoretical sense but none are currently workable in mosquitoes. Even if strategies were workable, it would be very difficult to recall released transgenes in the event of unforeseen consequences. What is needed is a way to test transgenes in the field for feasibility, efficacy and safety prior to releasing an active drive mechanism. We outline a method, termed Multi-locus assortment (MLA), to spread transgenes into vector populations by the release of genetically-modified mosquitoes carrying multiple stable transgene inserts. Simulations indicate that [1] insects do not have to carry transgenes at more than 4 loci, [2] transgenes can be maintained at high levels by sequential small releases, the frequency of which depends on the construct fitness cost, and [3] in the case of unforeseen negative non-target effects, transgenes can be eliminated from the population by halting transgenic releases and/or mass releases of wild-type insects. We also discuss potential methods to create MLA mosquito strains in the laboratory. While not as efficient as active drive mechanisms, MLA has other advantages: [1] MLA strains can be constructed for some mosquito species with currently-available technology, [2] MLA will allow the ecological components of transgenic mosquito releases to be tested before actual gene drive mechanisms are ready to be deployed, [3] since MLA is not self-propagating, the risk of an accidental premature release into nature is minimized, and [4] in the case that active gene drive mechanisms prove impossible to develop, the MLA approach can be used as a back-up transgene dispersal mechanism for disease control efforts

  2. Developmental effects of visual environment on species-assortative mating preferences in Lake Victoria cichlid fish.

    Science.gov (United States)

    Wright, D S; Demandt, N; Alkema, J T; Seehausen, O; Groothuis, T G G; Maan, M E

    2017-02-01

    Local adaptation can be a potent force in speciation, with environmental heterogeneity leading to niche specialization and population divergence. However, local adaption often requires nonrandom mating to generate reproductive isolation. Population divergence in sensory properties can be particularly consequential in speciation, affecting both ecological adaptation and sexual communication. Pundamilia pundamila and Pundamilia nyererei are two closely related African cichlid species that differ in male coloration, blue vs. red. They co-occur at rocky islands in southern Lake Victoria, but inhabit different depth ranges with different light environments. The species differ in colour vision properties, and females exert species-specific preferences for blue vs. red males. Here, we investigated the mechanistic link between colour vision and preference, which could provide a rapid route to reproductive isolation. We tested the behavioural components of this link by experimentally manipulating colour perception - we raised both species and their hybrids under light conditions mimicking shallow and deep habitats - and tested female preference for blue and red males under both conditions. We found that rearing light significantly affected female preference: shallow-reared females responded more strongly to P. pundamilia males and deep-reared females favoured P. nyererei males - implying that visual development causally affects mate choice. These results are consistent with sensory drive predictions, suggesting that the visual environment is key to behavioural isolation of these species. However, the observed plasticity could also make the species barrier vulnerable to environmental change: species-assortative preferences were weaker in females that were reared in the other species' light condition. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

  3. Molecular Assortment of Lens Species with Different Adaptations to Drought Conditions Using SSR Markers.

    Science.gov (United States)

    Singh, Dharmendra; Singh, Chandan Kumar; Tomar, Ram Sewak Singh; Taunk, Jyoti; Singh, Ranjeet; Maurya, Sadhana; Chaturvedi, Ashish Kumar; Pal, Madan; Singh, Rajendra; Dubey, Sarawan Kumar

    2016-01-01

    The success of drought tolerance breeding programs can be enhanced through molecular assortment of germplasm. This study was designed to characterize molecular diversity within and between Lens species with different adaptations to drought stress conditions using SSR markers. Drought stress was applied at seedling stage to study the effects on morpho-physiological traits under controlled condition, where tolerant cultivars and wilds showed 12.8-27.6% and 9.5-23.2% reduction in seed yield per plant respectively. When juxtaposed to field conditions, the tolerant cultivars (PDL-1 and PDL-2) and wild (ILWL-314 and ILWL-436) accessions showed 10.5-26.5% and 7.5%-15.6% reduction in seed yield per plant, respectively under rain-fed conditions. The reductions in seed yield in the two tolerant cultivars and wilds under severe drought condition were 48-49% and 30.5-45.3% respectively. A set of 258 alleles were identified among 278 genotypes using 35 SSR markers. Genetic diversity and polymorphism information contents varied between 0.321-0.854 and 0.299-0.836, with mean value of 0.682 and 0.643, respectively. All the genotypes were clustered into 11 groups based on SSR markers. Tolerant genotypes were grouped in cluster 6 while sensitive ones were mainly grouped into cluster 7. Wild accessions were separated from cultivars on the basis of both population structure and cluster analysis. Cluster analysis has further grouped the wild accessions on the basis of species and sub-species into 5 clusters. Physiological and morphological characters under drought stress were significantly (P = 0.05) different among microsatellite clusters. These findings suggest that drought adaptation is variable among wild and cultivated genotypes. Also, genotypes from contrasting clusters can be selected for hybridization which could help in evolution of better segregants for improving drought tolerance in lentil.

  4. Computational methods for data evaluation and assimilation

    CERN Document Server

    Cacuci, Dan Gabriel

    2013-01-01

    Data evaluation and data combination require the use of a wide range of probability theory concepts and tools, from deductive statistics mainly concerning frequencies and sample tallies to inductive inference for assimilating non-frequency data and a priori knowledge. Computational Methods for Data Evaluation and Assimilation presents interdisciplinary methods for integrating experimental and computational information. This self-contained book shows how the methods can be applied in many scientific and engineering areas. After presenting the fundamentals underlying the evaluation of experiment

  5. Applications of Constituent Data Assimilation Systems

    Science.gov (United States)

    Rood, Richard B.; Stajner, Ivanka

    1999-01-01

    Organizations in Europe, Australia, and the United States have recently broadened constituent assimilation activities beyond that water vapor, which has been assimilated for years in the numerical weather prediction community. Many of these activities have focused on ozone, with some efforts focused on the entire suite of reactive constituents that control the ozone distribution. This talk will draw from results from the near real-time ozone data assimilation system being run by NASA's Data Assimilation Office. This system utilizes ozone observations from both the TOMS and the SBUV instrument to generate global synoptic maps of ozone. The initial application of this product is to provide ozone fields to assist in the atmospheric corrections' that are necessary for the retrieval of information from other NASA instruments. The validation of the ozone assimilation system shows that the assimilated product agrees well with independent HALOE and ozonesonde observations. This suggests that the product is of sufficient quality to be extended to other applications. This talk will enumerate these other applications and present initial results from exploratory research. The applications being considered include estimates of tropospheric ozone, provision of ozone fields for interactive retrievals, use of analysis increments from the assimilation to evaluate model performance, and development of long-term consistent three-dimensional global ozone fields. The results from the exploratory studies are promising, and help demonstrate how assumptions made in the p development of the ozone assimilation impact the other applications. For instance, RMS errors in the current product are large near the tropopause, which is sensitive to the specification of vertical correlation functions, which in turns impacts the amount of ozone analyzed to be in the troposphere. How these sensitivities impact the different applications will also be discussed.

  6. Variational Data Assimilation in Shelf Circulation Models

    Science.gov (United States)

    2010-01-01

    circulation over shelf and in the adjacent interior ocean energized by coastal flows (a coastal transition zone, CTZ ). - Testing this data assimilation...2005c, Springer et al., 2009), jets in the CTZ (Koch et al., 2010), and internal tides in combination coastal upwelling (Kurapov et al., 2003, 2010a...the Oregon shelf and CTZ extending between 41-47N and 124-129W (Figure 1). In preparation to assimilation tests, a 3 km resolution ROMS model has

  7. Wage and occupational assimilation by skill level

    OpenAIRE

    Alcobendas, Miguel Angel; Rodríguez-Planas, Núria; Vegas, Raquel

    2012-01-01

    While much of the literature on immigrants' assimilation has focused on countries with a large tradition of receiving immigrants and with flexible labor markets, very little is known on how immigrants adjust to other types of host economies. With its severe dual labor market, and an unprecedented immigration boom, Spain presents a quite unique experience to analyze immigrations' assimilation process. Using alternative datasets and methodologies, this paper provides evidence of a differential ...

  8. Employment Assimilation of Immigrants in the Netherlands

    OpenAIRE

    Zorlu, Aslan; Hartog, Joop

    2008-01-01

    This discussion Paper led to a publication in International Journal of Population Research , Vol. 2012, article ID 634276. Using two Dutch labour force surveys, employment assimilation of immigrants is examined. We observe marked differences between immigrants by source country. Non-western immigrants never reach parity with native Dutch. Even second generation immigrants never fully catch up. Caribbean immigrants, who share a colonial history with the Dutch, assimilate relatively quick compa...

  9. Migration, Friendship Ties and Cultural Assimilation

    OpenAIRE

    Facchini, Giovanni; Patacchini, Eleonora; Steinhardt, Max F.

    2014-01-01

    In this paper we contribute to the analysis of the assimilation process of migrants by analyzing the extent to which friendship with natives can be seen as a measure of cultural assimilation and investigating the formation of social ties in the host country. Using novel information from the German Socio-Economic Panel, we find that migrants with a German friend are more similar to natives than those without a local companion along several important dimensions, including concerns about the eco...

  10. The effects of assortative mating on the genetic change due to linear index selection in Tribolium.

    Science.gov (United States)

    Campo, J L; Gil, M G

    1994-01-12

    The effectiveness of the assortative mating of selected individuals in increasing linear index selection response was tested in Tribolium castaneum. The experiment was designed to increase pupal length and adult weight, using selection and assortative mating with respect to a linear index of these traits. The experiment consisted of a randomly (R) and assortatively (A) mated line, with three replicates in each line. The proportion of selection was 25 %. Phenotypic correlations between mates in line A were not significantly different from 1. Average selection responses did not significantly differ in either line, although there was some indication of an effect of the mating system, since the response for the aggregate value was higher in line A (0.78 ± 0.15 as opposed to 0.57 ± 0.13). Average response for the selection goal and adult weight was statistically significant for both lines. ZUSAMMENFASSUNG: Die Auswirkungen assortativer Anpaarung auf genetischen Fortschritt bei Anwendung eines linearen Selektionsindex bei Tribolium Die Wirksamkeit assortativer Anpaarung selektionierter Individuen zur Verstärkung der Selektion mittels linearem Index wurde bei Tribolium castaneum untersucht. Selektion zielte auf längere Puppen und auf Gewichtssteigerung ausgewachsener Tiere. Das Experiment umfaßte eine zufällig angepaarte (R) und eine assortativ angepaarte (A) Linie mit je drei Wiederholungen. Die Remontierung betrug 25%. Die phänotypische Partner-Korrelation bei den in Linie A angepaarten Individuen wich nicht wesentlich von 1 ab. Die durchschnittliche Verbesserung war bei beiden Linien nicht significant verschieden, obwohl es Anzeichen einer Auswirkung des Paarungssystems gab. Die Koeffizienten der Linie A lagen höher (0.78 ± 0.15 gegenüber 0.57 ± 0.13 für Linie R). Die durchnittliche Veränderung des Selektionsziels und des Gewichts der ausgewachsenen Tiere waren statistisch significant. RÉSUMÉ: Les effets de l'accouplement classifié sur le changement g

  11. Conceptual Problems in Land Surface Data Assimilation

    Science.gov (United States)

    Reichle, Rolf

    2012-01-01

    A land data assimilation system (LDAS) merges observations (or satellite retrievals) of land surface hydrological conditions, including soil moisture, snow, and terrestrial water storage (TWS), into a numerical model of land surface processes. In theory, the output from such a system is superior to estimates based on the observations or the model alone, thereby enhancing our ability to understand, monitor, and predict key elements of the terrestrial water cycle. In practice, however, several conceptual problems can interfere with realizing the potential improvements from data assimilation. Of particular concern is the frequent mismatch between the assimilated observations and the land surface model variables of interest. The seminar will discuss recent research with the ensemble-based NASA GEOS-S LDAS to address various aspects of this mismatch. These aspects include (i) the assimilation of coarse-scale observations into higher-resolution land surface models, (ii) the partitioning of satellite observations (such as TWS retrievals) into their constituent water cycle components, (iii) the forward modeling of microwave brightness temperatures over land for radiance-based land surface data aSSimilation, and (iv) the selection of the most relevant types of observations for the analysis of a specific water cycle variable (such as root zone soil moisture). At its core, the solution to the above challenges involves the careful construction of an observation operator that maps from the land surface model variables of interest to the space of the assimilated observations.

  12. How acquainting shows verbally

    DEFF Research Database (Denmark)

    Hermann, Jesper

    2004-01-01

    A central tenet of the integrational view of language and communication is an anchoring in the acting and integrating behaviour of the communicants themselves. In this way the integrational approach has a certain phenomenological slant. What happens when this approach is combined with a ¿psychology...

  13. Getting Acquainted with OPML

    CERN Document Server

    Bellinger, Amy

    2006-01-01

    You've put off figuring out what Outline Processor Markup Language(OPML) is all about and what it can do, right? We'll bring you into the picture quickly with 14 wide-ranging uses forthe OPML format including: Reading lists and RSS subscription listsBloggingA wholly new sort of intranetProcess documentationInstant outlining and collaborationDistributed directories Included in this Short Cut are step-by-step how-to examples with illustrations to get you started using and remixing OPML right now. Let's get going.

  14. Getting Acquainted with AEJ

    Science.gov (United States)

    Community College Journalist, 1977

    1977-01-01

    Includes reports from three divisions of the Association for Education in Journalism: "Exchanging Teaching Ideas, Practices Major Aim of Photojournalism Division,""Secondary Education Division Promotes Journalism in Any Setting," and "Graphics Division Emphasis Shifting toward Development of Teaching Aids." (KS)

  15. THE SOCIAL CONTEXT OF ASSIMILATION: TESTING IMPLICATIONS OF SEGMENTED ASSIMILATION THEORY*

    Science.gov (United States)

    Xie, Yu; Greenman, Emily

    2011-01-01

    Segmented assimilation theory has been a popular explanation for the diverse experiences of assimilation among new waves of immigrants and their children. While the theory has been interpreted in many different ways, we emphasize its implications for the important role of social context: both processes and consequences of assimilation should depend on the local social context in which immigrants are embedded. We derive empirically falsifiable hypotheses about the interaction effects between social context and assimilation on immigrant children's well-being. We then test the hypotheses using data from the National Longitudinal Study of Adolescent Health. Our empirical analyses yield two main findings. First, for immigrant adolescents living in non-poverty neighborhoods, we find assimilation to be positively associated with educational achievement and psychological well-being but also positively associated with at-risk behavior. Second, there is little empirical evidence supporting our hypotheses derived from segmented assimilation theory. We interpret these results to mean that future research would be more fruitful focusing on differential processes of assimilation rather than differential consequences of assimilation. PMID:21572546

  16. The social context of assimilation: testing implications of segmented assimilation theory.

    Science.gov (United States)

    Xie, Yu; Greenman, Emily

    2011-05-01

    Segmented assimilation theory has been a popular explanation for the diverse experiences of assimilation among new waves of immigrants and their children. While the theory has been interpreted in many different ways, we emphasize its implications for the important role of social context: both processes and consequences of assimilation should depend on the local social context in which immigrants are embedded. We derive empirically falsifiable hypotheses about the interaction effects between social context and assimilation on immigrant children's well-being. We then test the hypotheses using data from the National Longitudinal Study of Adolescent Health. Our empirical analyses yield two main findings. First, for immigrant adolescents living in non-poverty neighborhoods, we find assimilation to be positively associated with educational achievement and psychological well-being but also positively associated with at-risk behavior. Second, there is little empirical evidence supporting our hypotheses derived from segmented assimilation theory. We interpret these results to mean that future research would be more fruitful focusing on differential processes of assimilation rather than differential consequences of assimilation.

  17. IS ASSIMILATION THEORY DEAD? THE EFFECT OF ASSIMILATION ON ADOLESCENT WELL-BEING.

    Science.gov (United States)

    Greenman, Emily; Xie, Yu

    2008-03-01

    The relationship between assimilation and the well-being of immigrant children has been the focus of debate in the recent sociological literature. Much of this work has questioned whether classical theories of immigrant adaptation, which assumed assimilation to be an integral part of the process of upward mobility for immigrants, are still applicable to today's immigrant children. This study reevaluates the applicability of classical assimilation theory with a comprehensive empirical assessment of the relationship between assimilation and the well-being of Hispanic and Asian immigrant adolescents. Using Add Health data, we examine the effect of different aspects of assimilation on educational achievement, psychological well-being, and at-risk behaviors. We find that the effect of assimilation varies greatly depending on the ethnic group and outcome under consideration, but that it is generally related to both greater academic achievement and more at-risk behavior. We conclude that assimilation theory is still relevant, but suggest an interpretation that emphasizes a process of decreasing differences between groups rather than either detrimental or beneficial effects of assimilation.

  18. Recent advances in land data assimilation at the NASA Global Modeling and Assimilation Office

    Science.gov (United States)

    Research in land surface data assimilation has grown rapidly over the last decade. We provide a brief overview of key research contributions by the NASA Global Modeling and Assimilation Office (GMAO). The GMAO contributions primarily include the continued development and application of the Ensembl...

  19. Green's Function-Based Tsunami Data Assimilation: A Fast Data Assimilation Approach Toward Tsunami Early Warning

    Science.gov (United States)

    Wang, Yuchen; Satake, Kenji; Maeda, Takuto; Gusman, Aditya Riadi

    2017-10-01

    We propose a new tsunami data assimilation approach based on Green's functions to reduce the computation time for tsunami early warning. Green's Function-based Tsunami Data Assimilation (GFTDA) forecasts the waveforms at points of interest (PoIs) by superposition of Green's functions between observation stations and PoIs. Unlike the previous assimilation approach, GFTDA does not require the calculation of the tsunami wavefield for the whole region during the assimilation process, because the Green's functions have been calculated in advance. The forecasted waveforms can be calculated by a simple matrix manipulation. The application to the tsunami waveforms recorded by the bottom pressure gauges of the Cascadia Initiative from the 2012 Haida Gwaii earthquake reveals that GFTDA achieves the same accuracy as the previous assimilation approach while reducing the time required to issue a valid tsunami warning.

  20. THE RAW MINERAL SALTS USE IN COSMETICS FORMULATIONS: ASSORTMENT, MINERAL RAW MATERIALS CHARACTERISTICS AND COSMETICS FORMULATION TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    S. B. Evseeva

    2016-01-01

    Full Text Available The application of mineral raw materials (brine lakes, thermal springs, sea water, bischofite in cosmetics is presented in this article. The assortment of cosmetics that contain mineral salts is presented. The technological characteristics of production of these cosmetic formulations, in particular the ability of mineral salts to influence the stability of formulation and the sensory properties of products are given. The main approaches of that formulation development are described.

  1. Healthy snacks at the checkout counter: a lab and field study on the impact of shelf arrangement and assortment structure on consumer choices.

    Science.gov (United States)

    van Kleef, Ellen; Otten, Kai; van Trijp, Hans C M

    2012-12-12

    The essence of nudging is to adapt the environment in which consumers make decisions to help them make better choices, without forcing certain outcomes upon them. To determine how consumers can effectively be guided to select healthier snacks, we examine the effect of manipulating the assortment structure and shelf layout of an impulse display including both healthy and unhealthy snacks near the checkout counter of a canteen. Both a lab and field study applied a two-factor experimental design manipulating snack offerings both in an on-screen choice environment and a natural environment (hospital staff restaurant). Shelf arrangement (i.e. accessibility) was altered by putting healthy snacks at higher shelves versus lower shelves. Assortment structure (i.e. availability) was altered by offering an assortment that either included 25% or 75% healthy snacks. Participants in the lab study (n = 158) made a choice from a shelf display. A brief survey following snack selection asked participants to evaluate the assortment and their choice. The field experiment took place in a hospital canteen. Daily sales data were collected for a period of four weeks. On completion of the field study, employees (n = 92) filled out a questionnaire about all four displays and rated their attractiveness, healthiness and perceived freedom of choice. The lab study showed a higher probability of healthy snack choice when 75% of the assortment consisted of healthy snacks compared to conditions with 25% healthy snack assortments, even though choices were not rated less satisfying or more restrictive. Regarding shelf display location of healthy snacks, no significant differences were observed. There was also no significant shelf arrangement by assortment structure interactive effect. The field study replicated these findings, in that this assortment structure led to higher sales of healthy snacks. Sales of unhealthy and total snacks were not impacted by manipulations (no main or interaction effects

  2. THE ASSORTMENT STRUCTURE AND THE PRICE LEVELS AS A FACTOR OF MARKETING CHANNEL COMPETITIVENESS–EMPIRICAL EVIDENCE FROM THE REPUBLIC OF SERBIA

    Directory of Open Access Journals (Sweden)

    Jelena Končar

    2016-12-01

    Full Text Available In this paper, the authors point out the differences in the structure of the product assortment of retailers who show their offers on the Web, with the aim of proving that the structure of the assortment may be a factor of marketing channel competitiveness that the consumers recognize and that makes them opt for a certain marketing channel. On the same basis we aim to compare the prices of representative product categories, in order to determine the impact of prices on marketing channel competitiveness, without taking other factors of channel competitiveness into consideration. Based on the conducted research, we can conclude that having a number of categories of products in the assortment presents a competitive advantage for the retailer in the traditional marketing channel since retailers with electronic sales have a more diverse assortment in their retail store than online. Compared to “pure play” electronic retailers, the structure of assortment measured in number of categories of products that are on offer in e-stores is not significantly different between “pure play” and “bricks and clicks” electronic retailers. On the other hand, if we look at the price levels, there is a difference in prices of product categories on websites of “brick and click” retailers since prices in retail stores are higher than prices in the traditional retail store of the same retailer. However, offers on the website of “pure play” electronic retailers are higher compared to “brick and click” retailers.

  3. The scale-of-choice effect and how estimates of assortative mating in the wild can be biased due to heterogeneous samples.

    Science.gov (United States)

    Rolán-Alvarez, Emilio; Carvajal-Rodríguez, Antonio; de Coo, Alicia; Cortés, Beatriz; Estévez, Daniel; Ferreira, Mar; González, Rubén; Briscoe, Adriana D

    2015-07-01

    The mode in which sexual organisms choose mates is a key evolutionary process, as it can have a profound impact on fitness and speciation. One way to study mate choice in the wild is by measuring trait correlation between mates. Positive assortative mating is inferred when individuals of a mating pair display traits that are more similar than those expected under random mating while negative assortative mating is the opposite. A recent review of 1134 trait correlations found that positive estimates of assortative mating were more frequent and larger in magnitude than negative estimates. Here, we describe the scale-of-choice effect (SCE), which occurs when mate choice exists at a smaller scale than that of the investigator's sampling, while simultaneously the trait is heterogeneously distributed at the true scale-of-choice. We demonstrate the SCE by Monte Carlo simulations and estimate it in two organisms showing positive (Littorina saxatilis) and negative (L. fabalis) assortative mating. Our results show that both positive and negative estimates are biased by the SCE by different magnitudes, typically toward positive values. Therefore, the low frequency of negative assortative mating observed in the literature may be due to the SCE's impact on correlation estimates, which demands new experimental evaluation. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  4. Data assimilation the ensemble Kalman filter

    CERN Document Server

    Evensen, Geir

    2007-01-01

    Data Assimilation comprehensively covers data assimilation and inverse methods, including both traditional state estimation and parameter estimation. This text and reference focuses on various popular data assimilation methods, such as weak and strong constraint variational methods and ensemble filters and smoothers. It is demonstrated how the different methods can be derived from a common theoretical basis, as well as how they differ and/or are related to each other, and which properties characterize them, using several examples. Rather than emphasize a particular discipline such as oceanography or meteorology, it presents the mathematical framework and derivations in a way which is common for any discipline where dynamics is merged with measurements. The mathematics level is modest, although it requires knowledge of basic spatial statistics, Bayesian statistics, and calculus of variations. Readers will also appreciate the introduction to the mathematical methods used and detailed derivations, which should b...

  5. The Acceleration of Immigrant Unhealthy Assimilation.

    Science.gov (United States)

    Giuntella, Osea; Stella, Luca

    2017-04-01

    It is well known that immigrants tend to be healthier than US natives and that this advantage erodes with time spent in the USA. However, we know less about the heterogeneity of these trajectories among arrival cohorts. Recent studies have shown that later arrival cohorts of immigrants have lower entry wages and experience less economic assimilation. In this paper, we investigate whether similar cohort effects can be observed in the weight assimilation of immigrants in the USA. Focusing on obesity, we show that more recent immigrant cohorts arrive with higher obesity rates and experience a faster 'unhealthy assimilation' in terms of weight gain. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  6. Optimal transport for variational data assimilation

    Directory of Open Access Journals (Sweden)

    N. Feyeux

    2018-01-01

    Full Text Available Usually data assimilation methods evaluate observation-model misfits using weighted L2 distances. However, it is not well suited when observed features are present in the model with position error. In this context, the Wasserstein distance stemming from optimal transport theory is more relevant.This paper proposes the adaptation of variational data assimilation for the use of such a measure. It provides a short introduction of optimal transport theory and discusses the importance of a proper choice of scalar product to compute the cost function gradient. It also extends the discussion to the way the descent is performed within the minimization process.These algorithmic changes are tested on a nonlinear shallow-water model, leading to the conclusion that optimal transport-based data assimilation seems to be promising to capture position errors in the model trajectory.

  7. Assimilation for Skin SST in the NASA GEOS Atmospheric Data Assimilation System

    Science.gov (United States)

    Akella, Santha; Todling, Ricardo; Suarez, Max

    2017-01-01

    The present article describes the sea surface temperature (SST) developments implemented in the Goddard Earth Observing System, Version 5 (GEOS) Atmospheric Data Assimilation System (ADAS). These are enhancements that contribute to the development of an atmosphere-ocean coupled data assimilation system using GEOS. In the current quasi-operational GEOS-ADAS, the SST is a boundary condition prescribed based on the OSTIA product, therefore SST and skin SST (Ts) are identical. This work modifies the GEOS-ADAS Ts by modelling and assimilating near sea surface sensitive satellite infrared (IR) observations. The atmosphere-ocean interface layer of the GEOS atmospheric general circulation model (AGCM) is updated to include near-surface diurnal warming and cool-skin effects. The GEOS analysis system is also updated to directly assimilate SST-relevant Advanced Very High Resolution Radiometer (AVHRR) radiance observations. Data assimilation experiments designed to evaluate the Ts modification in GEOS-ADAS show improvements in the assimilation of radiance observations that extend beyond the thermal infrared bands of AVHRR. In particular, many channels of hyperspectral sensors, such as those of the Atmospheric Infrared Sounder (AIRS), and Infrared Atmospheric Sounding Interferometer (IASI) are also better assimilated. We also obtained improved fit to withheld insitu buoy measurement of near-surface SST. Evaluation of forecast skill scores show neutral to marginal benefit from the modified Ts.

  8. Data assimilation approaches in the EURANOS project

    DEFF Research Database (Denmark)

    Kaiser, J.C.; Gering, F.; Astrup, Poul

    2010-01-01

    Within the EURANOS project data assimilation (DA) approaches have been successfully applied in two areas to improve the predictive power of simulation models used in the RODOS and ARGOS decision support systems. For the areas of atmospheric dispersion modelling and of modelling the fate of radio......-nuclides in urban areas the results of demonstration exercises are presented here. With the data assimilation module of the RIMPUFF dispersion code, predictions of the gamma dose rate are corrected with simulated readings of fixed detector stations. Using the DA capabilities of the IAMM package for mapping...

  9. Scalable and balanced dynamic hybrid data assimilation

    Science.gov (United States)

    Kauranne, Tuomo; Amour, Idrissa; Gunia, Martin; Kallio, Kari; Lepistö, Ahti; Koponen, Sampsa

    2017-04-01

    Scalability of complex weather forecasting suites is dependent on the technical tools available for implementing highly parallel computational kernels, but to an equally large extent also on the dependence patterns between various components of the suite, such as observation processing, data assimilation and the forecast model. Scalability is a particular challenge for 4D variational assimilation methods that necessarily couple the forecast model into the assimilation process and subject this combination to an inherently serial quasi-Newton minimization process. Ensemble based assimilation methods are naturally more parallel, but large models force ensemble sizes to be small and that results in poor assimilation accuracy, somewhat akin to shooting with a shotgun in a million-dimensional space. The Variational Ensemble Kalman Filter (VEnKF) is an ensemble method that can attain the accuracy of 4D variational data assimilation with a small ensemble size. It achieves this by processing a Gaussian approximation of the current error covariance distribution, instead of a set of ensemble members, analogously to the Extended Kalman Filter EKF. Ensemble members are re-sampled every time a new set of observations is processed from a new approximation of that Gaussian distribution which makes VEnKF a dynamic assimilation method. After this a smoothing step is applied that turns VEnKF into a dynamic Variational Ensemble Kalman Smoother VEnKS. In this smoothing step, the same process is iterated with frequent re-sampling of the ensemble but now using past iterations as surrogate observations until the end result is a smooth and balanced model trajectory. In principle, VEnKF could suffer from similar scalability issues as 4D-Var. However, this can be avoided by isolating the forecast model completely from the minimization process by implementing the latter as a wrapper code whose only link to the model is calling for many parallel and totally independent model runs, all of them

  10. Optimising assimilation of hydrographic profiles into isopycnal ocean models with ensemble data assimilation

    Science.gov (United States)

    Wang, Yiguo; Counillon, François; Bethke, Ingo; Keenlyside, Noel; Bocquet, Marc; Shen, Mao-lin

    2017-06-01

    Hydrographic profiles are crucial observational datasets for constraining ocean models and their vertical structure. In this study, we investigate a key implementation setup for optimising their assimilation into isopycnal ocean models. For this purpose, we use the Norwegian Climate Prediction Model (NorCPM), which is a fully-coupled climate prediction system based on the Norwegian Earth System Model and the ensemble Kalman filter. First, we revisit whether it is more accurate to assimilate observations in their original coordinate (z-level coordinate) or to transform them into isopycnal coordinates prior to assimilation. The analysis is performed with a single assimilation step using synthetic observations that mimic the characteristic properties of hydrographic profiles: varying vertical resolutions, profiles of only temperature and observations only in the top 1000 m. Assimilating profiles in their native coordinate (z-level coordinates) performs best because converting observations into isopycnal coordinates is strongly non-linear which reduces the efficiency of the assimilation. Secondly, we investigate how to set the horizontal localisation radius for our system. A radius that varies with latitude following a bimodal Gaussian function fits the system well. Thirdly, we estimate observation error, which consists of both instrumental error and representativeness error. In the proposed formulation only the instrumental error decreases with the number of observations during superobing, because the representativeness error is dominated by model limitation. Finally, we demonstrate the impact of assimilating hydrographic profiles from the observational EN4 dataset into NorCPM. An analysis of 10 years with monthly assimilation is performed with special focus on assessing the accuracy and the reliability of our analysis. The assimilation of hydrographic profiles into NorCPM is found to efficiently reduce the model bias and error, and the ensemble spread is found to be

  11. Differentiation between Trichophyton mentagrophytes and T. rubrum by sorbitol assimilation.

    OpenAIRE

    Rezusta, A; Rubio, M. C.; Alejandre, M C

    1991-01-01

    Trichophyton rubrum was easily differentiated from T. mentagrophytes by its ability to assimilate sorbitol with an API 20C AUX strip. One hundred percent of 36 T. rubrum strains and none of 147 T. mentagrophytes strains assimilated sorbitol.

  12. Altimeter data assimilation in the tropical Indian Ocean using water ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 121; Issue 1. Altimeter data assimilation in the tropical Indian Ocean using water property ... Keywords. Data assimilation; altimeter data; ocean general circulation model; thermocline depth; sea surface temperature; modeling; oceanography; remote sensing.

  13. Significance of Assimilation and Fractional Crystallization (AFC ...

    Indian Academy of Sciences (India)

    57

    Science. 323(5917):1017-8. Nicholson H, Condomines M, Fitton JG, Fallick Ae, Grönvold K And Rogers G 1991 Geochemical and isotopic evidence for crustal assimilation beneath krafla, Iceland. J Petrol. 32(5):1005-20. Paul D, White WM and Blichert‐Toft J 2005 Geochemistry of Mauritius and the origin of rejuvenescent.

  14. CH Waddington, Canalisation and Genetic Assimilation

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 6. C. H. Waddington, Canalisation and Genetic Assimilation. Vidyanand Nanjundiah. General Article Volume 15 Issue 6 June 2010 pp 503-513. Fulltext. Click here to view fulltext PDF. Permanent link:

  15. DIVERSE APPROACHES TO MODELLING THE ASSIMILATIVE ...

    African Journals Online (AJOL)

    This study evaluated the assimilative capacity of Ikpoba River using different approaches namely: homogeneous differential equation, ANOVA/Duncan Multiple rage test, first and second order differential equations, correlation analysis, Eigen values and eigenvectors, multiple linear regression, bootstrapping and far-field ...

  16. Radiance Data Assimilation for Binary Typhoon Cases

    Science.gov (United States)

    Choi, Y.; Snyder, C.; Cha, D. H.

    2015-12-01

    The predictability of track and intensity for binary tropical cyclones (TCs) is relatively low due to the interaction between two TCs. In this study, radiance data were assimilated using the Three Dimensional Variational (3D-Var) data assimilation method to improve track and intensity forecasts of binary TCs. In detail, a total of three binary TC cases over the Northwestern Pacific from 2010 to 2015, which affected the Korean Peninsula, were selected. Infrared and microwave radiance data from multiple instruments and satellites were assimilated with the appropriate treatments of quality control, channel selection, bias correction, and cloud detection. The Weather Research and Forecasting (WRF) model was used as a forecasting model, and the resolution of the innermost domain was high (2 km) to capture the structure and intensity of TCs. Background error covariance was calculated using the National Meteorological Center (NMC) method, where background error statistics were from the differences between 24-h and 12-h forecasts for a month-long period. Overall, track and intensity errors of three binary TCs are reduced through the assimilation of radiance data. Especially, track forecasts are improved significantly because large-scale environments such as the North Pacific High and mid-latitude trough/ridge are simulated well. Analysis increment and its evolution are investigated to reveal the reason for the improvement of each binary TC's forecast, focusing on TC's internal structure and its environment. Additionally, effects of other observational data (e.g. radiosonde, satellite wind) are analyzed through the sensitivity experiments.

  17. Lectin status, protein contents and ammonium assimilating ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-16

    Nov 16, 2009 ... Lectin status, protein contents and ammonium assimilating enzymatic activity of two indigenous cultivars of mulberry species, Morus alba and Morus nigra. Muhammad Zahoor*, Zakia Javaid, Muhammad Ali, Saleem Khan, Farhad Ali and Zahoor A. Swati. Institute of Biotechnology and Genetic Engineering, ...

  18. Development of a data assimilation algorithm

    DEFF Research Database (Denmark)

    Thomsen, Per Grove; Zlatev, Zahari

    2008-01-01

    efficiently observations in a large-scale model (for example, in order to obtain more reliable initial values). Variational data assimilation techniques are based on a combination of three very important components • numerical methods for solving differential equations, • splitting procedures...

  19. On the Linguistic Covariants of Cultural Assimilation

    Science.gov (United States)

    T'sou, Benjamin K.

    1975-01-01

    This paper discusses diverse sociolinguistic concepts such as borrowing, code-switching, bilingualism, and interference, and proposes a hypothesis concerning the progression of these linguistic developments in a contact situation and concerning the correlation of these developments with distinct phases of cultural assimilation. (Author/CLK)

  20. Assortive mating for personaltiy traits, educational level, religious affiliation, height, weight, adn body mass index in parents of Korean twin sample.

    Science.gov (United States)

    Hur, Yoon-Mi

    2003-12-01

    The degree of assortative mating for psychological and physical traits in Asian societies in relatively unknown. The present study examined assortative mating for educational level, personality traits, religious affiliation, height, weight, and body mass index in a korean sample. Age-adjusted spouse correlations were high for educational level (r = .63) and religious affiliation (r = .67), modest for most personality traits (rs = -.01 to .26), and trivial for height (r = .04), weight (r = .05)m and body mass index (r = .11). These results were remarkably similar to those found from the western samples. Implications of the present findings in behavior genetic studies and human mating patterns were briefly discussed.

  1. THE ASSORTMENT STRUCTURE AND THE PRICE LEVELS AS A FACTOR OF MARKETING CHANNEL COMPETITIVENESS–EMPIRICAL EVIDENCE FROM THE REPUBLIC OF SERBIA

    OpenAIRE

    Jelena Končar; Sonja Leković; Goran Vukmirović

    2016-01-01

    In this paper, the authors point out the differences in the structure of the product assortment of retailers who show their offers on the Web, with the aim of proving that the structure of the assortment may be a factor of marketing channel competitiveness that the consumers recognize and that makes them opt for a certain marketing channel. On the same basis we aim to compare the prices of representative product categories, in order to determine the impact of prices on marketing channel compe...

  2. Economic and Cultural Assimilation and Integration of Immigration in Europe

    OpenAIRE

    Mariya Aleksynska; Yann Algan

    2010-01-01

    This paper documents assimilation of immigrants in 16 European countries along cultural, civic, and economic dimensions, distinguishing by immigrants’ generation, duration of stay, and origin. It suggests that assimilation may have multiple facets, and take place at different speed depending on the outcome in question. While assimilation along some economic outcomes may be correlated with assimilation along some cultural outcomes, such correlations are not systematic, and imply that progress ...

  3. A flexible Open Data Assimilation framework

    Science.gov (United States)

    van Velzen, Nils; Ridler, Marc E.; Altaf, Umer; Madsen, Henrik; Heemink, Arnold; Dijkzeul, Johan

    2015-04-01

    Accurate and reliable real-time hydrological forecasts are essential for protection against water-related hazards, operation of infrastructure, and water resources management. Recent advances in radar rainfall estimation and forecasting, numerical weather predictions, satellite and in-situ monitoring, and faster computing facilities are opening up new opportunities in real-time hydrological forecasting. More effective use of the different information sources via data assimilation will provide the basis for producing more accurate and more reliable forecasts. In this regard, development and implementation of robust and computationally efficient data assimilation algorithms that are feasible for real-time applications remains one of the key challenges. The implementation of data assimilation techniques is traditionally in a model specific form. The disadvantage of this approach is the need to have in-depth knowledge of the numerical core computations and it does not allow to freely experiment with data assimilation algorithms and measurement sources without the need of additional programming. We present a more flexible approach to setup a forecasting system. The OpenDA data assimilation framework contains many state of the art data assimilation algorithms to easily set up a forecasting system. The setup of the framework allows users to select and experiment with various algorithms. OpenDA defines an interface between model and data assimilation algorithms. This interface only needs to be implemented once for a particular model. The OpenDA model interface is already implemented for various models. Besides these models it is very easy to couple models that are already implementing the Open Model Interface (OpenMI) to OpenDA using the generic OpenMI-OpenDA coupler. Using a synthetic test case we demonstrate the capabilities of the proposed approach using OpenMI and OpenDA. We use the MIKE SHE distributed and integrated hydrological modeling system to demonstrate how

  4. Bayesian Nonlinear Assimilation of Eulerian and Lagrangian Coastal Flow Data

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Bayesian Nonlinear Assimilation of Eulerian and...Develop and apply theory, schemes and computational systems for rigorous Bayesian nonlinear assimilation of Eulerian and Lagrangian coastal flow data...of coastal ocean fields by assimilation of Eulerian and Lagrangian flow data. - Apply our DO and GMM-DO schemes, as well as their theoretical

  5. Left or right? Sources of political orientation: the roles of genetic factors, cultural transmission, assortative mating, and personality.

    Science.gov (United States)

    Kandler, Christian; Bleidorn, Wiebke; Riemann, Rainer

    2012-03-01

    In this study, we used an extended twin family design to investigate the influences of genetic and cultural transmission as well as different sources of nonrandom mating on 2 core aspects of political orientation: acceptance of inequality and rejecting system change. In addition, we studied the sources of phenotypic links between Big Five personality traits and political beliefs using self- and other reports. Data of 1,992 individuals (224 monozygotic and 166 dizygotic twin pairs, 92 unmatched twins, 530 spouses of twins, 268 fathers, and 322 mothers) were analyzed. Genetically informative analyses showed that political attitudes are genetically but not environmentally transmitted from parents to offspring and that a substantial proportion of this genetic variance can be accounted for by genetic variance in personality traits. Beyond genetic effects and genotypic assortative mating, generation-specific environmental sources act to increase twins' and spouses' resemblance in political beliefs. The results suggest multiple sources of political orientations in a modern democracy.

  6. Assortative mating between two sympatric closely-related specialists: inferred from molecular phylogenetic analysis and behavioral data.

    Science.gov (United States)

    Xue, Huai-Jun; Li, Wen-Zhu; Yang, Xing-Ke

    2014-06-25

    Host plant shifting of phytophagous insects can lead to the formation of host associated differentiation and ultimately speciation. In some cases, host plant specificity alone acts as a nearly complete pre-mating isolating barrier among insect populations. We here test whether effective pre-mating isolation and host-independent behavioral isolation have evolved under the condition of extreme host specilization using two sympatric flea beetles with incomplete post-mating isolation under laboratory conditions. Phylogenetic analysis and coalescent simulation results showed that there is a limited interspecific gene flow, indicating effctive isolation between these species. Three types of mating tests in the absence of host plant cues showed that strong host-independent behavioral isolation has evolved between them. We conclude that almost perfect assortative mating between these two extreme host specialists results from a combination of reduced encounter rates due to differential host preference and strong sexual isolation.

  7. Transferring Fungi to a Deuterium-Enriched Medium Results in Assorted, Conditional Changes in Secondary Metabolite Production.

    Science.gov (United States)

    Wang, Bin; Park, Elizabeth M; King, Jarrod B; Mattes, Allison O; Nimmo, Susan L; Clendinen, Chaevien; Edison, Arthur S; Anklin, Clemens; Cichewicz, Robert H

    2015-06-26

    Deuterium is one of the few stable isotopes that have the capacity to significantly alter a compound's chemical and biological properties. The addition of a single neutron to a protium atom results in the near doubling of its mass, which gives rise to deuterium's characteristic isotope effects. Since the incorporation of deuterium into organic substrates is known to alter enzyme/protein-substrate interactions, we tested the extent to which deuterium enrichment would modify fungal secondary metabolite production. Several fungal cultures were tested, and in all cases their secondary metabolomes were marked by changes in natural product production. Workup of one Aspergillus sp. grown under deuterium-enrichment conditions resulted in the production of several secondary metabolites not previously detected from the fungus. Bioassay testing revealed that in comparison to the inactive crude fungal extract derived from growing the fungus under non-deuterium-enriched conditions, an extract derived from the same isolate cultured in a deuterium-enriched medium inhibited methicillin-resistant Staphylococcus aureus. Using an assortment of NMR and mass spectrometry experiments, we were able to identify the bacterial inhibitor as an isotope-labeled version of pigmentosin A (6). Five additional isotopically labeled metabolites were also obtained from the fungus including brevianamide F (1), stephacidin A (2), notoamide D (3), notoamide L (4), and notoamide C (5). Given the assorted changes observed in the secondary metabolite profiles of this and other fungi grown in deuterium-enriched environments, as well as the fact that 1 and 3-6 had not been previously observed from the Aspergillus sp. isolate used in this study, we propose that deuterium enrichment might offer an effective method for further expanding a fungus's chemical diversity potential.

  8. Assimilation of Gridded GRACE Terrestrial Water Storage Estimates in the North American Land Data Assimilation System

    Science.gov (United States)

    Kumar, Sujay V.; Zaitchik, Benjamin F.; Peters-Lidard, Christa D.; Rodell, Matthew; Reichle, Rolf; Li, Bailing; Jasinski, Michael; Mocko, David; Getirana, Augusto; De Lannoy, Gabrielle; hide

    2016-01-01

    The objective of the North American Land Data Assimilation System (NLDAS) is to provide best available estimates of near-surface meteorological conditions and soil hydrological status for the continental United States. To support the ongoing efforts to develop data assimilation (DA) capabilities for NLDAS, the results of Gravity Recovery and Climate Experiment (GRACE) DA implemented in a manner consistent with NLDAS development are presented. Following previous work, GRACE terrestrial water storage (TWS) anomaly estimates are assimilated into the NASA Catchment land surface model using an ensemble smoother. In contrast to many earlier GRACE DA studies, a gridded GRACE TWS product is assimilated, spatially distributed GRACE error estimates are accounted for, and the impact that GRACE scaling factors have on assimilation is evaluated. Comparisons with quality-controlled in situ observations indicate that GRACE DA has a positive impact on the simulation of unconfined groundwater variability across the majority of the eastern United States and on the simulation of surface and root zone soil moisture across the country. Smaller improvements are seen in the simulation of snow depth, and the impact of GRACE DA on simulated river discharge and evapotranspiration is regionally variable. The use of GRACE scaling factors during assimilation improved DA results in the western United States but led to small degradations in the eastern United States. The study also found comparable performance between the use of gridded and basin averaged GRACE observations in assimilation. Finally, the evaluations presented in the paper indicate that GRACE DA can be helpful in improving the representation of droughts.

  9. Probabilistic forecasting and Bayesian data assimilation

    CERN Document Server

    Reich, Sebastian

    2015-01-01

    In this book the authors describe the principles and methods behind probabilistic forecasting and Bayesian data assimilation. Instead of focusing on particular application areas, the authors adopt a general dynamical systems approach, with a profusion of low-dimensional, discrete-time numerical examples designed to build intuition about the subject. Part I explains the mathematical framework of ensemble-based probabilistic forecasting and uncertainty quantification. Part II is devoted to Bayesian filtering algorithms, from classical data assimilation algorithms such as the Kalman filter, variational techniques, and sequential Monte Carlo methods, through to more recent developments such as the ensemble Kalman filter and ensemble transform filters. The McKean approach to sequential filtering in combination with coupling of measures serves as a unifying mathematical framework throughout Part II. Assuming only some basic familiarity with probability, this book is an ideal introduction for graduate students in ap...

  10. The "textbook Gibson": The assimilation of dissidence.

    Science.gov (United States)

    Costall, Alan; Morris, Paul

    2015-02-01

    We examine how the textbooks have dealt with one of psychology's most eminent dissidents, James Gibson (1904-1979). Our review of more than a hundred textbooks, dating from the 1950s to the present, reveals fundamental and systematic misrepresentations of Gibson. Although Gibson continues to figure in most of the textbooks, his work is routinely assimilated to theoretical positions he emphatically rejected: cue theory, stimulus-response psychology, and nativism. As Gibson's one-time colleague, Ulric Neisser, pointed out, psychologists are especially prone to trying to understand new proposals "by mapping it on to some existing scheme," and warned that when "an idea is really new, that strategy fails" (Neisser, 1990, p. 749). The "Textbook Gibson" is an example of such a failure, and perhaps also of the more general importance of assimilation-"shadow history"-within the actual history of psychology. PsycINFO Database Record (c) 2015 APA, all rights reserved.

  11. Data assimilation for air quality models

    DEFF Research Database (Denmark)

    Silver, Jeremy David

    2014-01-01

    -dimensional optimal interpolation procedure (OI), an Ensemble Kalman Filter (EnKF), and a three-dimensional variational scheme (3D-var). The three assimilation procedures are described and tested. A multi-faceted approach is taken for the verification, using independent measurements from surface air......-quality monitoring stations, satellite retrievals of atmospheric chemical composition and comparison with idealised simulations. The 3D-var and EnKF schemes are capable of performing multi-species adjustments, meaning that observations of different chemical components can be assimilated simultaneously. Furthermore...... of the 3D-var and EnKF schemes are expanded to assess the potential benefits of joint multi-species adjustments (c.f. adjusting individual species independently) or direct adjustment of unobserved species....

  12. Hydrological data assimilation using Extreme Learning Machines

    Science.gov (United States)

    Boucher, Marie-Amélie; Quilty, John; Adamowski, Jan

    2017-04-01

    Data assimilation refers to any process that allows for updating state variables in a model to represent reality more accurately than the initial (open loop) simulation. In hydrology, data assimilation is often a pre-requisite for forecasting. In practice, many operational agencies rely on "manual" data assimilation: perturbations are added manually to meteorological inputs or directly to state variables based on "expert knowledge" until the simulated streamflow matches the observed streamflow closely. The corrected state variables are then considered as representative of the "true", unknown, state of the watershed just before the forecasting period. However, manual data assimilation raises concerns, mainly regarding reproducibility and high reliance on "expert knowledge". For those reasons, automatic data assimilation methods have been proposed in the literature. Automatic data assimilation also allows for the assessment and reduction of state variable uncertainty, which is predominant for short-term streamflow forecasts (e.g. Thiboult et al. 2016). The goal of this project is to explore the potential of Extreme Learning Machines (ELM, Zang and Liu 2015) for data assimilation. ELMs are an emerging type of neural network that does not require iterative optimisation of their weights and biases and therefore are much faster to calibrate than typical feed-forward backpropagation neural networks. We explore ELM for updating state variables of the lumped conceptual hydrological model GR4J. The GR4J model has two state variables: the level of water in the production and routing reservoirs. Although these two variables are sufficient to describe the state of a snow-free watershed, they are modelling artifices that are not measurable. Consequently, their "true" values can only be verified indirectly through a comparison of simulated and observed streamflow and their values are highly uncertain. GR4J can also be coupled with the snow model CemaNeige, which adds two other

  13. Data assimilation experiments within the POGEQA project

    Science.gov (United States)

    Peuch, V.; Attie, J. E.; Claeyman, M.; El Amroui, L.; Ricaud, P.; Semane, N.; Massart, S.; Piacentini, A.; Cariolle, D.; Flaud, J.; Bergametti, G.; Cantie, R.; Pasternak, F.; Lehors, L.; von Clarmann, T.; Hoepfner, M.; Orphal, J.

    2009-12-01

    The POGEQA (Observation of Air Quality from a Geostationary Platform) project is a French and German initiative currently funded by RTRA STAE (Midi-Pyrenees region). It links also with other international teams and initiatives sharing similar objectives, such as GEOCAPE. Using a sophisticated chemical data assimilation system, MOCAGE-PALM, POGEQA aims at defining optimal characteristics for a future instrument in geostationary orbit complementing orbiting instruments and surface observations for Air Quality monitoring and forecasting. POGEQA sits also in the context of the european initiative GMES (Global Monitoring for Environment and Security) and the project MACC, which aims at assembling operational atmospheric services ; MOCAGE-PALM is indeed one of the pre-operational systems upon which the production of regional Air Quality products is based. These experiments comprise both assimilation of currently existing sensors for tropospheric ozone and CO, such as IASI and MOPITT, and assimilation of synthetic data (OSSEs, Observing System Simulation Experiments) representative of possible geostationary instrumental concepts. These numerical experiments, though representing a very small fraction of the cost compared to the development of a real test instrument, will allow to justify quantitatively the requirements (geometry, sensitivity, errors,…). Differents aspects of operating such an instrument in real conditions (clouds, observations with representativeness errors, radiances…) can also be considered. We will show highlights from the first results obtained in the project. In particular, we will present the synthetic observations generating tool, which is based upon the KOPRA and KOPRAFIT models and 3D chemical scenes produced with chemical models CHIMERE and/or MOCAGE. We will discuss also findings from assimilation experiments and OSSEs.

  14. Immigrants and gender roles: Assimilation vs. culture

    OpenAIRE

    Francine D. Blau

    2015-01-01

    This paper examines evidence on the role of assimilation versus source country culture in influencing immigrant women's behavior in the United States – looking both over time with immigrants' residence in the United States and across immigrant generations. It focuses particularly on labor supply but, for the second generation, also examines fertility and education. We find considerable evidence that immigrant source country gender roles influence immigrant and second generation women's behavi...

  15. Assimilation and cohort effects for German immigrants

    OpenAIRE

    Gundel, Sebastian; Peters, Heiko

    2008-01-01

    Demographic change and the rising demand for highly qualified labor in Germany attracts notice to the analysis of immigration. In addition, the pattern of immigration changed markedly during the past decades. Therefore we use the latest data of the German Socioeconomic Panel up to the year 2006 in order to investigate the economic performance of immigrants. We perform regressions of three pooled cross sections (1986, 1996, 2006) to estimate assimilation and quality of immigrants as reflected ...

  16. Intermarriage and the Economic Assimilation of Immigrants

    OpenAIRE

    Xin Meng; Gregory, Robert G.

    2005-01-01

    This article investigates the assimilation role of intermarriage between immigrants and natives. Intermarried immigrants earn significantly higher incomes than endogamously married immigrants, even after we take account of human capital endowments and endogeneity of intermarriage. The premium does not appear to be a reward for unobservable individual characteristics. Natives who intermarry do not receive this premium, nor do immigrants who intermarry into another ethnic group. The premium is ...

  17. Variational Data Assimilation for the Global Ocean

    Science.gov (United States)

    2013-01-01

    profiles. One method is the Modular Ocean Data Assimilation System ( MODAS ) database, which models the time averaged co-variability of dynamic height...used in the MODAS method is derived from historical hydrographic data. Note that an upgrade to the MODAS synthetic profile capability, the Improved...ans real data constraints. MODAS does not suffer from these limitations, although MODAS may have marginal skill due to: (1) sampling limitations of

  18. SMAP Data Assimilation at the GMAO

    Science.gov (United States)

    Reichle, R.; De Lannoy, G.; Liu, Q.; Ardizzone, J.

    2016-01-01

    The NASA Soil Moisture Active Passive (SMAP) mission has been providing L-band (1.4 GHz) passive microwave brightness temperature (Tb) observations since April 2015. These observations are sensitive to surface(0-5 cm) soil moisture. Several of the key applications targeted by SMAP, however, require knowledge of deeper-layer, root zone (0-100 cm) soil moisture, which is not directly measured by SMAP. The NASA Global Modeling and Assimilation Office (GMAO) contributes to SMAP by providing Level 4 data, including the Level 4 Surface and Root Zone Soil Moisture(L4_SM) product, which is based on the assimilation of SMAP Tb observations in the ensemble-based NASA GEOS-5 land surface data assimilation system. The L4_SM product offers global data every three hours at 9 km resolution, thereby interpolating and extrapolating the coarser- scale (40 km) SMAP observations in time and in space (both horizontally and vertically). Since October 31, 2015, beta-version L4_SM data have been available to the public from the National Snow and Ice Data Center for the period March 31, 2015, to near present, with a mean latency of approx. 2.5 days.

  19. Solar Data Assimilation Engine for Ionospheric Forecasts

    Science.gov (United States)

    Fry, C. D.; Eccles, J. V.

    2007-12-01

    The Space Weather Modeling System (SWMS) is a Battlespace Environments Institute (BEI) project that couples space environment models together under the Earth System Modeling Framework, while ensuring that the component models are scalable and portable. BEI is sponsored by the High Performance Computing Modernization Office and managed by Air Force Weather Agency and Naval Research Laboratory. The Hakamada-Akasofu-Fry version 2 (HAFv2) solar wind model and the Global Assimilation of Ionospheric Measurements (GAIM) model are the first two coupled components in the SWMS. Serving as a data assimilation engine, the HAFv2 model uses solar observations to prepare its initial solar wind conditions. Then, the HAFv2 internal algorithms and the initial conditions determine the present and future states of the solar wind conditions at Earth. The outputs of HAFv2 are provided to GAIM to forecast the time-dependent energy input into the high- latitude ionosphere. This presentation describes how the HAFv2 model is being used as a solar data assimilation engine for producing forecasts of solar wind parameters, that then serve as inputs to drive GAIM and other near-Earth space environment models. The overarching goal is to extend the lead time and skill of forecasts of space weather conditions and their corresponding impacts on operational customers.

  20. Comparison of Sequential and Variational Data Assimilation

    Science.gov (United States)

    Alvarado Montero, Rodolfo; Schwanenberg, Dirk; Weerts, Albrecht

    2017-04-01

    Data assimilation is a valuable tool to improve model state estimates by combining measured observations with model simulations. It has recently gained significant attention due to its potential in using remote sensing products to improve operational hydrological forecasts and for reanalysis purposes. This has been supported by the application of sequential techniques such as the Ensemble Kalman Filter which require no additional features within the modeling process, i.e. it can use arbitrary black-box models. Alternatively, variational techniques rely on optimization algorithms to minimize a pre-defined objective function. This function describes the trade-off between the amount of noise introduced into the system and the mismatch between simulated and observed variables. While sequential techniques have been commonly applied to hydrological processes, variational techniques are seldom used. In our believe, this is mainly attributed to the required computation of first order sensitivities by algorithmic differentiation techniques and related model enhancements, but also to lack of comparison between both techniques. We contribute to filling this gap and present the results from the assimilation of streamflow data in two basins located in Germany and Canada. The assimilation introduces noise to precipitation and temperature to produce better initial estimates of an HBV model. The results are computed for a hindcast period and assessed using lead time performance metrics. The study concludes with a discussion of the main features of each technique and their advantages/disadvantages in hydrological applications.

  1. Ionospheric data assimilation and forecasting during storms

    Science.gov (United States)

    Chartier, A.; Matsuo, T.; Anderson, J. L.; Collins, N.; Hoar, T.; Lu, G.; Mitchell, C. N.; Coster, A. J.; Bust, G. S.; Paxton, L. J.

    2016-12-01

    Ionospheric storms can have important effects on radio communications and navigation systems. Storm time ionospheric predictions have the potential to form part of effective mitigation strategies to these problems. Ionospheric storms are caused by strong forcing from the solar wind. Electron density enhancements are driven by penetration electric fields, as well as by thermosphere-ionosphere behavior including Traveling Atmospheric Disturbances and Traveling Ionospheric Disturbances and changes to the neutral composition. This study assesses the effect on 1 h predictions of specifying initial ionospheric and thermospheric conditions using total electron content (TEC) observations under a fixed set of solar and high-latitude drivers. Prediction performance is assessed against TEC observations, incoherent scatter radar, and in situ electron density observations. Corotated TEC data provide a benchmark of forecast accuracy. The primary case study is the storm of 10 September 2005, while the anomalous storm of 21 January 2005 provides a secondary comparison. The study uses an ensemble Kalman filter constructed with the Data Assimilation Research Testbed and the Thermosphere Ionosphere Electrodynamics General Circulation Model. Maps of preprocessed, verticalized GPS TEC are assimilated, while high-latitude specifications from the Assimilative Mapping of Ionospheric Electrodynamics and solar flux observations from the Solar Extreme Ultraviolet Experiment are used to drive the model. The filter adjusts ionospheric and thermospheric parameters, making use of time-evolving covariance estimates. The approach is effective in correcting model biases.

  2. The Importance of Peers: Assimilation Patterns among Second-generation Turkish Immigrants in Western Europe

    OpenAIRE

    Ali, S.; Fokkema, T.

    2015-01-01

    The two dominant approaches to immigrant assimilation, segmented assimilation and "new" assimilation theories, have been successful at reporting and analyzing between-group differences in assimilation patterns. However, studies of assimilation generally do not address differences at the individual level. Current theories of assimilation cannot answer the simple question that gets to the heart of individual-level differences: how do you account for siblings in the same family assimilating in d...

  3. Ensemble-Based Assimilation of Aerosol Observations in GEOS-5

    Science.gov (United States)

    Buchard, V.; Da Silva, A.

    2016-01-01

    MERRA-2 is the latest Aerosol Reanalysis produced at NASA's Global Modeling Assimilation Office (GMAO) from 1979 to present. This reanalysis is based on a version of the GEOS-5 model radiatively coupled to GOCART aerosols and includes assimilation of bias corrected Aerosol Optical Depth (AOD) from AVHRR over ocean, MODIS sensors on both Terra and Aqua satellites, MISR over bright surfaces and AERONET data. In order to assimilate lidar profiles of aerosols, we are updating the aerosol component of our assimilation system to an Ensemble Kalman Filter (EnKF) type of scheme using ensembles generated routinely by the meteorological assimilation. Following the work performed with the first NASA's aerosol reanalysis (MERRAero), we first validate the vertical structure of MERRA-2 aerosol assimilated fields using CALIOP data over regions of particular interest during 2008.

  4. Segmented assimilation, neighborhood disadvantage, and Hispanic immigrant health.

    Science.gov (United States)

    Akresh, Ilana Redstone; Do, D Phuong; Frank, Reanne

    2016-01-01

    We use a subset of Hispanics from the New Immigrant Survey, a nationally representative data set on immigrants recently granted legal permanent residency (n = 2245), to examine whether the relationship between assimilation and health is modified by neighborhood disadvantage and, in doing so, carry out an empirical test of the segmented assimilation hypothesis. Results indicate that assimilation in the least disadvantaged neighborhoods can be protective against poor health. Specifically, more assimilated men and women in the lowest disadvantage neighborhoods have a lower likelihood of self-reported poorer health and being overweight, respectively; no link was found in higher disadvantage neighborhoods. Assimilation was not found to be associated with self-reported health for women or BMI for men, regardless of neighborhood disadvantage level. Overall, we find some evidence supporting the hypothesis that the effects of assimilation on health depend on the context in which immigrants experience it. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Morphodynamic data assimilation used to understand changing coasts

    Science.gov (United States)

    Plant, Nathaniel G.; Long, Joseph W.

    2015-01-01

    Morphodynamic data assimilation blends observations with model predictions and comes in many forms, including linear regression, Kalman filter, brute-force parameter estimation, variational assimilation, and Bayesian analysis. Importantly, data assimilation can be used to identify sources of prediction errors that lead to improved fundamental understanding. Overall, models incorporating data assimilation yield better information to the people who must make decisions impacting safety and wellbeing in coastal regions that experience hazards due to storms, sea-level rise, and erosion. We present examples of data assimilation associated with morphologic change. We conclude that enough morphodynamic predictive capability is available now to be useful to people, and that we will increase our understanding and the level of detail of our predictions through assimilation of observations and numerical-statistical models.

  6. Data assimilation for the monitoring of continental surfaces

    OpenAIRE

    Jarlan, L.; Boulet, Gilles

    2014-01-01

    This chapter presents the basis of data assimilation by limiting the mathematical developments as much as possible. It emphasizes the data assimilation of remote sensing observations in land surface models, although the assimilation techniques presented can be applied to different kinds of dynamical models. The chapter considers three documents to be benchmarks in their respective fields for anyone who wishes to study them in greater depth. They are as follows: dynamic modeling of natural lan...

  7. Data Assimilation Cycling for Weather Analysis

    Science.gov (United States)

    Tran, Nam; Li, Yongzuo; Fitzpatrick, Patrick

    2008-01-01

    This software package runs the atmospheric model MM5 in data assimilation cycling mode to produce an optimized weather analysis, including the ability to insert or adjust a hurricane vortex. The program runs MM5 through a cycle of short forecasts every three hours where the vortex is adjusted to match the observed hurricane location and storm intensity. This technique adjusts the surrounding environment so that the proper steering current and environmental shear are achieved. MM5cycle uses a Cressman analysis to blend observation into model fields to get a more accurate weather analysis. Quality control of observations is also done in every cycle to remove bad data that may contaminate the analysis. This technique can assimilate and propagate data in time from intermittent and infrequent observations while maintaining the atmospheric field in a dynamically balanced state. The software consists of a C-shell script (MM5cycle.driver) and three FORTRAN programs (splitMM5files.F, comRegrid.F, and insert_vortex.F), and are contained in the pre-processor component of MM5 called "Regridder." The model is first initialized with data from a global model such as the Global Forecast System (GFS), which also provides lateral boundary conditions. These data are separated into single-time files using splitMM5.F. The hurricane vortex is then bogussed in the correct location and with the correct wind field using insert_vortex.F. The modified initial and boundary conditions are then recombined into the model fields using comRegrid.F. The model then makes a three-hour forecast. The three-hour forecast data from MM5 now become the analysis for the next short forecast run, where the vortex will again be adjusted. The process repeats itself until the desired time of analysis is achieved. This code can also assimilate observations if desired.

  8. Variational data assimilation using targetted random walks

    KAUST Repository

    Cotter, S. L.

    2011-02-15

    The variational approach to data assimilation is a widely used methodology for both online prediction and for reanalysis. In either of these scenarios, it can be important to assess uncertainties in the assimilated state. Ideally, it is desirable to have complete information concerning the Bayesian posterior distribution for unknown state given data. We show that complete computational probing of this posterior distribution is now within the reach in the offline situation. We introduce a Markov chain-Monte Carlo (MCMC) method which enables us to directly sample from the Bayesian posterior distribution on the unknown functions of interest given observations. Since we are aware that these methods are currently too computationally expensive to consider using in an online filtering scenario, we frame this in the context of offline reanalysis. Using a simple random walk-type MCMC method, we are able to characterize the posterior distribution using only evaluations of the forward model of the problem, and of the model and data mismatch. No adjoint model is required for the method we use; however, more sophisticated MCMC methods are available which exploit derivative information. For simplicity of exposition, we consider the problem of assimilating data, either Eulerian or Lagrangian, into a low Reynolds number flow in a two-dimensional periodic geometry. We will show that in many cases it is possible to recover the initial condition and model error (which we describe as unknown forcing to the model) from data, and that with increasing amounts of informative data, the uncertainty in our estimations reduces. © 2011 John Wiley & Sons, Ltd.

  9. Boundary Conditions, Data Assimilation, and Predictability in Coastal Ocean Models

    National Research Council Canada - National Science Library

    Samelson, Roger M; Allen, John S; Egbert, Gary D; Kindle, John C; Snyder, Chris

    2007-01-01

    ...: The specific objectives of this research are to determine the impact on coastal ocean circulation models of open ocean boundary conditions from Global Ocean Data Assimilation Experiment (GODAE...

  10. An Ensemble Algorithm Based Component for Geomagnetic Data Assimilation

    Directory of Open Access Journals (Sweden)

    Zhibin Sun and Weijia Kuang

    2015-01-01

    Full Text Available Geomagnetic data assimilation is one of the most recent developments in geomagnetic studies. It combines geodynamo model outputs and surface geomagnetic observations to provide more accurate estimates of the core dynamic state and provide accurate geomagnetic secular variation forecasting. To facilitate geomagnetic data assimilation studies, we develop a stand-alone data assimilation component for the geomagnetic community. This component is used to calculate the forecast error covariance matrices and the gain matrix from a given geodynamo solution, which can then be used for sequential geomagnetic data assimilation. This component is very flexible and can be executed independently. It can also be easily integrated with arbitrary dynamo models.

  11. Aerodynamic Modeling with Heterogeneous Data Assimilation and Uncertainty Quantification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Clear Science Corp. proposes to develop an aerodynamic modeling tool that assimilates data from different sources and facilitates uncertainty quantification. The...

  12. Conundrum of an Immigrant: Assimilation versus Cultural Preservation

    National Research Council Canada - National Science Library

    Joanna Diane Caytas

    2012-01-01

    .... The fundamental polarity remains between the traditional model of assimilation as compared to the cultural preservation under various models of multiculturalism - aside, of course, from hybrid forms...

  13. Brightness contrast-contrast induction model predicts assimilation and inverted assimilation effects.

    Science.gov (United States)

    Barkan, Yuval; Spitzer, Hedva; Einav, Shmuel

    2008-10-17

    In classical assimilation effects, intermediate luminance patches appear lighter when their immediate surround is comprised of white patches and appear darker when their immediate surround is comprised of dark patches. With patches either darker or lighter than both inducing patches, the direction of the brightness effect is reversed and termed as "inverted assimilation effect." Several explanations and models have been suggested, some are relevant to specific stimulus geometry, anchoring theory, and models that involve high level cortical processing (such as scission, etc.). None of these studies predicted the various types of assimilation effects and their inverted effects. We suggest here a compound brightness model, which is based on contrast-contrast induction (second-order adaptation mechanism). The suggested model predicts the various types of brightness assimilation effects and their inverted effects. The model is composed of three main stages: (1) composing post-retinal second-order opponent receptive fields, (2) calculations of local and remote contrast, and (3) adaptation of the second-order (contrast-contrast induction). We also utilize a variation of the Jacobi iteration process to enable elegant edge integration in order to evaluate the model is performance.

  14. First assimilations of COSMIC radio occultation data into the Electron Density Assimilative Model (EDAM

    Directory of Open Access Journals (Sweden)

    M. J. Angling

    2008-02-01

    Full Text Available Ground based measurements of slant total electron content (TEC can be assimilated into ionospheric models to produce 3-D representations of ionospheric electron density. The Electron Density Assimilative Model (EDAM has been developed for this purpose. Previous tests using EDAM and ground based data have demonstrated that the information on the vertical structure of the ionosphere is limited in this type of data. The launch of the COSMIC satellite constellation provides the opportunity to use radio occultation data which has more vertical information. EDAM assimilations have been run for three time periods representing quiet, moderate and disturbed geomagnetic conditions. For each run, three data sets have been ingested – only ground based data, only COSMIC data and both ground based and COSMIC data. The results from this preliminary study show that both ground and space based data are capable of improving the representation of the vertical structure of the ionosphere. However, the analysis is limited by the incomplete deployment of the COSMIC constellation and the use of auto-scaled ionosonde data. The first of these can be addressed by repeating this type of study once full deployment has been achieved. The latter requires the manual scaling of ionosonde data; ideally an agreed data set would be scaled and made available to the community to facilitate comparative testing of assimilative models.

  15. Heterozygosity-based assortative mating in blue tits (Cyanistes caeruleus): implications for the evolution of mate choice

    Science.gov (United States)

    García-Navas, Vicente; Ortego, Joaquín; Sanz, Juan José

    2009-01-01

    The general hypothesis of mate choice based on non-additive genetic traits suggests that individuals would gain important benefits by choosing genetically dissimilar mates (compatible mate hypothesis) and/or more heterozygous mates (heterozygous mate hypothesis). In this study, we test these hypotheses in a socially monogamous bird, the blue tit (Cyanistes caeruleus). We found no evidence for a relatedness-based mating pattern, but heterozygosity was positively correlated between social mates, suggesting that blue tits may base their mating preferences on partner's heterozygosity. We found evidence that the observed heterozygosity-based assortative mating could be maintained by both direct and indirect benefits. Heterozygosity reflected individual quality in both sexes: egg production and quality increased with female heterozygosity while more heterozygous males showed higher feeding rates during the brood-rearing period. Further, estimated offspring heterozygosity correlated with both paternal and maternal heterozygosity, suggesting that mating with heterozygous individuals can increase offspring genetic quality. Finally, plumage crown coloration was associated with male heterozygosity, and this could explain unanimous mate preferences for highly heterozygous and more ornamented individuals. Overall, this study suggests that non-additive genetic traits may play an important role in the evolution of mating preferences and offers empirical support to the resolution of the lek paradox from the perspective of the heterozygous mate hypothesis. PMID:19474042

  16. I. V. Michurin’S Work on Expansion of the Plant Horticulture Assortment and Improvement of Food Quality

    Directory of Open Access Journals (Sweden)

    Sokolov Viktor V.

    2015-09-01

    Full Text Available October 2015 marks the 160th anniversary of the birth of Ivan V. Michurin. As a scientist and plant breeder, he made a significant improvement of many fruit and berry plants, and flowers. He developed methods of plant breeding, especially regarding long-distance hybridisation of fruit plants, and promoted gardening to the north and east of Russia. He introduced some new berry species, such as Actinidia and black chokeberry, and was the first in Russia to use dwarf and semi dwarf stocks of apples. Michurin initiated the mass movement of gardeners and horticulture experimenters in USSR who changed and significantly extended the assortment and areas of fruit and berries cultivation in the country. He not only brought together a representative collection of species and varieties of fruit, berry and flower plants from around the world, but also used them in breeding by hybridization, including interspecific. He created some new artificial interspecific hybrids such as Cerapadus (cherry and bird cherry tree hybrid, and others. Michurin created 132 cultivars. Eleven of them are not only cultivated, but are also included in “The State Register of Protected Plant Breeding of the Russian Federation”.

  17. Non-Mendelian assortment of homologous autosomes of different sizes in males is the ancestral state in the Caenorhabditis lineage.

    Science.gov (United States)

    Le, Tho Son; Yang, Fang-Jung; Lo, Yun-Hua; Chang, Tiffany C; Hsu, Jung-Chen; Kao, Chia-Yi; Wang, John

    2017-10-09

    Organismal genome sizes vary by six orders of magnitude and appear positively correlated with organismal size and complexity. Neutral models have been proposed to explain the broad patterns of genome size variation based on organism population sizes. In the Caenorhabditis genus, hermaphrodite genomes are smaller than those of gonochoristic species. One possible driving force for this genome size difference could be non-random chromosome segregation. In Caenorhabditis elegans, chromosome assortment is non-independent and violates Mendel's second law. In males, the shorter homologue of a heterozygous autosome pair preferentially co-segregates with the X chromosome while the longer one preferentially co-segregates with the nullo-X (O) chromosome in a process we call "skew". Since hermaphrodites preferentially receive the shorter chromosomes and can start populations independently, their genome size would be predicted to decrease over evolutionary time. If skew is an important driver for genome size reduction in hermaphroditic Caenorhabditis species, then it should be present in all congeneric species. In this study, we tested this hypothesis and found that skew is present in all eight examined species. Our results suggest that skew is likely the ancestral state in this genus. More speculatively, skew may drive genome size patterns in hermaphroditic species in other nematodes.

  18. Dissortative From the Outside, Assortative From the Inside: Social Structure and Behavior in the Industrial Trade Network

    CERN Document Server

    Kelman, Guy; Manes, Eran; Lamieri, Marco; Golo, Natasa; Solomon, Sorin

    2014-01-01

    It is generally accepted that neighboring nodes in financial networks are negatively assorted with respect to the correlation between their degrees. This feature would play an important 'damping' role in the market during downturns (periods of distress) since this connectivity pattern between firms lowers the chances of auto-amplifying (the propagation of) distress. In this paper we explore a trade-network of industrial firms where the nodes are suppliers or buyers, and the links are those invoices that the suppliers send out to their buyers and then go on to present to their bank for discounting. The network was collected by a large Italian bank in 2007, from their intermediation of the sales on credit made by their clients. The network also shows dissortative behavior as seen in other studies on financial networks. However, when looking at the credit rating of the firms, an important attribute internal to each node, we find that firms that trade with one another share overwhelming similarity. We know that m...

  19. Modeling and Assimilating Ocean Color Radiances

    Science.gov (United States)

    Gregg, Watson

    2012-01-01

    Radiances are the source of information from ocean color sensors to produce estimates of biological and geochemical constituents. They potentially provide information on various other aspects of global biological and chemical systems, and there is considerable work involved in deriving new information from these signals. Each derived product, however, contains errors that are derived from the application of the radiances, above and beyond the radiance errors. A global biogeochemical model with an explicit spectral radiative transfer model is used to investigate the potential of assimilating radiances. The results indicate gaps in our understanding of radiative processes in the oceans and their relationships with biogeochemical variables. Most important, detritus optical properties are not well characterized and produce important effects of the simulated radiances. Specifically, there does not appear to be a relationship between detrital biomass and its optical properties, as there is for chlorophyll. Approximations are necessary to get beyond this problem. In this reprt we will discuss the challenges in modeling and assimilation water-leaving radiances and the prospects for improving our understanding of biogeochemical process by utilizing these signals.

  20. Hispanic Assimilation and Fertility in New Destinations.

    Science.gov (United States)

    Lichter, Daniel T; Johnson, Kenneth M; Turner, Richard N; Churilla, Allison

    2012-01-01

    This paper evaluates comparative patterns of fertility in new Hispanic destinations and established gateways using pooled cross-sectional data from the 2005-2009 microdata files of the American Community Survey. Changing Hispanic fertility provides a useful indicator of cultural incorporation. Analyses show that high fertility among Hispanics has been driven in part by the Mexican-origin and other new immigrant populations (e.g., noncitizens, those with poor English language skills, etc.). However, high fertility rates among Hispanics - and Mexican-origin Hispanics in particular - cannot be explained entirely by socio-demographic characteristics that place them at higher risk of fertility. For 2005-2009, Hispanic fertility rates were 48 percent higher than fertility among whites; they were roughly 25 percent higher after accounting for differences in key social characteristics, such as age, nativity, county of origin, and education. Contrary to most previous findings of spatial assimilation among in-migrants, fertility rates among Hispanics in new destinations exceeded fertility in established gateways by 18 percent. In the multivariate analyses, Hispanics in new destinations were roughly 10 percent more likely to have had a child in the past year than those living in established gateways. Results are consistent with sub-cultural explanations of Hispanic fertility and raise new questions about the spatial patterning of assimilation and the formation of ethnic enclaves outside traditional settlement areas.

  1. Adding Four- Dimensional Data Assimilation (aka grid ...

    Science.gov (United States)

    Adding four-dimensional data assimilation (a.k.a. grid nudging) to MPAS.The U.S. Environmental Protection Agency is investigating the use of MPAS as the meteorological driver for its next-generation air quality model. To function as such, MPAS needs to operate in a diagnostic mode in much the same manner as the current meteorological driver, the Weather Research and Forecasting (WRF) model. The WRF operates in diagnostic mode using Four-Dimensional Data Assimilation, also known as "grid nudging". MPAS version 4.0 has been modified with the addition of an FDDA routine to the standard physics drivers to nudge the state variables for wind, temperature and water vapor towards MPAS initialization fields defined at 6-hour intervals from GFS-derived data. The results to be shown demonstrate the ability to constrain MPAS simulations to known historical conditions and thus provide the U.S. EPA with a practical meteorological driver for global-scale air quality simulations. The National Exposure Research Laboratory (NERL) Computational Exposure Division (CED) develops and evaluates data, decision-support tools, and models to be applied to media-specific or receptor-specific problem areas. CED uses modeling-based approaches to characterize exposures, evaluate fate and transport, and support environmental diagnostics/forensics with input from multiple data sources. It also develops media- and receptor-specific models, process models, and decision support tools for use bo

  2. Genetic and Environmental Factors Associated with Laboratory Rearing Affect Survival and Assortative Mating but Not Overall Mating Success in Anopheles gambiae Sensu Stricto

    OpenAIRE

    Paton, D.; Touré, M.; Sacko, A.; Coulibaly, MB; Traoré, SF; Tripet, F

    2013-01-01

    Anopheles gambiae sensu stricto, the main vector of malaria in Africa, is characterized by its vast geographical range and complex population structure. Assortative mating amongst the reproductively isolated cryptic forms that co-occur in many areas poses unique challenges for programs aiming to decrease malaria incidence via the release of sterile or genetically-modified mosquitoes. Importantly, whether laboratory-rearing affects the ability of An. gambiae individuals of a given cryptic taxa...

  3. Genetic and environmental factors associated with laboratory rearing affect survival and assortative mating but not overall mating success in Anopheles gambiae sensu stricto.

    Directory of Open Access Journals (Sweden)

    Doug Paton

    Full Text Available Anopheles gambiae sensu stricto, the main vector of malaria in Africa, is characterized by its vast geographical range and complex population structure. Assortative mating amongst the reproductively isolated cryptic forms that co-occur in many areas poses unique challenges for programs aiming to decrease malaria incidence via the release of sterile or genetically-modified mosquitoes. Importantly, whether laboratory-rearing affects the ability of An. gambiae individuals of a given cryptic taxa to successfully mate with individuals of their own form in field conditions is still unknown and yet crucial for mosquito-releases. Here, the independent effects of genetic and environmental factors associated with laboratory rearing on male and female survival, mating success and assortative mating were evaluated in the Mopti form of An. gambiae over 2010 and 2011. In semi-field enclosures experiments and despite strong variation between years, the overall survival and mating success of male and female progeny from a laboratory strain was not found to be significantly lower than those of the progeny of field females from the same population. Adult progeny from field-caught females reared at the larval stage in the laboratory and from laboratory females reared outdoors exhibited a significant decrease in survival but not in mating success. Importantly, laboratory individuals reared as larvae indoors were unable to mate assortatively as adults, whilst field progeny reared either outdoors or in the laboratory, as well as laboratory progeny reared outdoors all mated significantly assortatively. These results highlight the importance of genetic and environment interactions for the development of An. gambiae's full mating behavioral repertoire and the challenges this creates for mosquito rearing and release-based control strategies.

  4. Assortative mating and directional or stabilizing selection for a non-linear function of traits in Tribolium.

    Science.gov (United States)

    Campo, J L; Gil, M G

    1993-01-12

    Assortative or random mating following selection in either direction on a non-linear index (experiment 1) or stabilizing selection for pupal length (experiment 2) were carried out for five generations in two lines of Tribolium castaneum (A and R, respectively), with three replicates each. The selected proportion was 25% in all lines. In experiment 1, the selection criterion was designed to increase the aggregate value of adult weight and the first- and second-order powers of pupal length. The A and R lines gave significant responses for the aggregate value (184 ± 6 and 161 ± 14, respectively), pupal length (0.74 ± 0.02 and 0.64 ± 0.05, respectively), and adult weight (0.79 ± 0.03 and 0.78 ± 0.12, respectively). Although the A line was not significantly better than the R line, there was a consistent advantage for assortative mating over random mating, the mean response for aggregate value and pupal length being approximately 1.15 times greater for the A line. In experiment 2 the selection criterion was the square of the deviation from the mean pupal length (stabilizing selection); both lines did not show any change for pupal length. The phenotypic variance showed a significant decrease in the A and R lines, due to a decrease in between-family variance. The assortatively and randomly mated lines were similar for these changes in phenotypic variation. RESUMEN: Aparemiento clasificado y selección direccional o estabilizante para una función no lineal en Tribolium. Dos líneas de Tribolium castaneum fueron seleccionadas direccionalmente para un índice no lineal (experimento 1) o estabilizantemente para longitud de pupa (experimento 2), apareando los animales seleccionados clasificadamente (A) o aleatoriamente (R). Había tres repeticiones por experimento y línea, siendo la proporción de selección el 25%. En el experimento 1, el objetivo de selección incluía el peso adulto así como la longitud de pupa y su cuadrado. Ambas líneas dieron respuesta

  5. Narcissism Guides Mate Selection: Humans Mate Assortatively, as Revealed by Facial Resemblance, following an Algorithm of “Self Seeking Like”

    Directory of Open Access Journals (Sweden)

    Liliana Alvarez

    2004-01-01

    Full Text Available Theoretical studies suggest that mating and pair formation is not likely to be random. Computer simulations suggested that sex among genetically complex organisms requires mate choice strategies for its evolutionary maintenance, to reduce excessive genetic variance produced by out-crossing. One strategy achieving this aim efficiently in computer simulations is assortative mating modeled as “self seeking like”. Another one is selection of “good genes”. Assortative mating increases the probability of finding a genetically similar mate, without fomenting inbreeding, achieving assortative mating without hindering the working of other mate selection strategies which aim to maximize the search for “good genes”, optimizing the working of sex in evolutionary terms. Here we present indirect evidence that in a significant proportion of human reproductive couples, the partners show much higher facial resemblances than can be expected by random pair formation, or as the outcome of “matching for attractiveness” or the outcome of competition for the most attractive partner accessible, as had been previously assumed. The data presented is compatible with the hypothesis derived from computer simulations, that human mate selection strategies achieve various aims: “self seeking like” (including matching for attractiveness and mating with the best available genes.

  6. Digestive parameters and energy assimilation of Cape porcupine on ...

    African Journals Online (AJOL)

    Digestive parameters and energy assimilation of Cape porcupine on ... body mass on all three experimental diets and energy intake ranged from 3 002.36 kJ kg−1 ... Keywords: agricultural pest, assimilation, digestion, human–wildlife conflict, ...

  7. Altimeter data assimilation in the tropical Indian Ocean using water ...

    Indian Academy of Sciences (India)

    Altimeter data have been assimilated in an ocean general circulation model using the water property conserving scheme. ... 2003). Keywords. Data assimilation; altimeter data; ocean general circulation model; thermocline depth; sea surface temperature; .... converting wind to wind stress using bulk aero- dynamic formula.

  8. Mid vowel assimilation in siSwati | Malambe | Southern African ...

    African Journals Online (AJOL)

    [ibola] 'football'), suggesting that siSwati has a vowel height assimilation and/or ATR assimilation. However, Kockaert, in his acoustic analysis of the same vowels in the same environments, disputes this description. He concludes that there is no significant difference in the F1, F2, and F3 frequency values of these vowels.

  9. The effects of drought stress on assimilate availability and ...

    African Journals Online (AJOL)

    Changes in carbohydrate status and metabolism in the source and sink organs determine rate of growth and yield of plants subjected to drought stress. The objective of this study was to assess the effect of lost-flowering drought stress on assimilate synthesis at source level and availability of the assimilates for metabolism in ...

  10. Consonant assimilation in isiNdebele: A distinctive feature approach ...

    African Journals Online (AJOL)

    The article discusses consonant assimilation on isiNdebele nouns, and examines that within the parameters of the Distinctive Feature approach. The main submission in this study is that consonant assimilation is local, homorganic and that it is found in the construction of class 9 and class 10 nouns. The terminal alveolar ...

  11. Phyto-agglutinin, total proteins and amino assimilating enzymatic ...

    African Journals Online (AJOL)

    ... the amino assimilating (glutamine synthetase) enzymatic activity. Both of KK-1 and Hassan-2K cultivars extract showed highly phyto-agglutination of human erythrocytes with reproductive organs and other tissues, which represents the presence of potent lectins (phyto-agglutinin). The amino assimilating enzymatic activity ...

  12. Auxanographic Carbohydrate Assimilation Method for Large Scale Yeast Identification.

    Science.gov (United States)

    Devadas, Suganthi Martena; Ballal, Mamatha; Prakash, Peralam Yegneswaran; Hande, Manjunath H; Bhat, Geetha V; Mohandas, Vinitha

    2017-04-01

    The auxanographic carbohydrate assimilation had been an important method for differentiation of yeasts. Prevailing methods described in the literature for carbohydrate assimilation has limited scope for use in large scale yeast identification. To optimize the large scale auxanographic carbohydrate assimilation method for yeast identification. A modified auxanographic carbohydrate assimilation method was developed and a total of 35 isolates of Candida species comprising of four ATCC (American Type Culture Collection) Candida strains ( Candida albicans ATCC 90028, Candida tropicalis ATCC 90018, Candida parapsilosis ATCC 750, Candida krusei ATCC 6258) and 31 clinical isolates of Candida tropicalis (n=13), Candida krusei (n=7), Candida glabrata (n=3), Candida kefyr (n=3), Candida albicans (n=5) were validated. The carbohydrates tested were Glucose, Sucrose, Maltose, Lactose, Cellubiose, Raffinose, Trehalose, Xylose, Galactose and Dulcitol. A total of 35 Candida species were tested for their carbohydrate assimilative property and the results were consistent with the existing standard protocols. A well circumscribed opaque yeast growth indicated assimilation of the test carbohydrate and translucent to opalescent growth with the outline of initial inoculum alone indicated lack of assimilation. The control plate indicated no growth of the Candida species. The carbohydrate assimilation tests finds utility for yeast diversity studies exploring novel ecological niches. The technique described here facilitates testing of an extended range of carbohydrates and yeasts in a cost effective manner.

  13. Perceptual assimilation and discrimination of non-native vowel contrasts

    Science.gov (United States)

    Tyler, Michael D.; Best, Catherine T.; Faber, Alice; Levitt, Andrea G.

    2014-01-01

    Research on language-specific tuning in speech perception has focused mainly on consonants, while that on non-native vowel perception has failed to address whether the same principles apply. Therefore, non-native vowel perception was investigated here in light of relevant theoretical models: The Perceptual Assimilation Model (PAM) and the Natural Referent Vowel (NRV) framework. American-English speakers completed discrimination and L1-assimilation (categorization and goodness rating) tests on six non-native vowel contrasts. Discrimination was consistent with PAM assimilation types, but asymmetries predicted by NRV were only observed for single-category assimilations, suggesting that perceptual assimilation might modulate the effects of vowel peripherality on non-native vowel perception. PMID:24923313

  14. Data assimilation in integrated hydrological modeling using ensemble Kalman filtering

    DEFF Research Database (Denmark)

    Rasmussen, Jørn; Madsen, H.; Jensen, Karsten Høgh

    2015-01-01

    Groundwater head and stream discharge is assimilated using the ensemble transform Kalman filter in an integrated hydrological model with the aim of studying the relationship between the filter performance and the ensemble size. In an attempt to reduce the required number of ensemble members...... numbers and spatial distributions of groundwater head observations and with or without discharge assimilation and parameter estimation. The study shows that (1) more ensemble members are needed when fewer groundwater head observations are assimilated, and (2) assimilating discharge observations...... and estimating parameters requires a much larger ensemble size than just assimilating groundwater head observations. However, the required ensemble size can be greatly reduced with the use of adaptive localization, which by far outperforms distance-based localization. The study is conducted using synthetic data...

  15. Perceptual assimilation and discrimination of non-native vowel contrasts.

    Science.gov (United States)

    Tyler, Michael D; Best, Catherine T; Faber, Alice; Levitt, Andrea G

    2014-01-01

    Research on language-specific tuning in speech perception has focused mainly on consonants, while that on non-native vowel perception has failed to address whether the same principles apply. Therefore, non-native vowel perception was investigated here in light of relevant theoretical models: the Perceptual Assimilation Model (PAM) and the Natural Referent Vowel (NRV) framework. American-English speakers completed discrimination and native language assimilation (categorization and goodness rating) tests on six nonnative vowel contrasts. Discrimination was consistent with PAM assimilation types, but asymmetries predicted by NRV were only observed for single-category assimilations, suggesting that perceptual assimilation might modulate the effects of vowel peripherality on non-native vowel perception. © 2014 S. Karger AG, Basel.

  16. Assimilating Eulerian and Lagrangian data in traffic-flow models

    Science.gov (United States)

    Xia, Chao; Cochrane, Courtney; DeGuire, Joseph; Fan, Gaoyang; Holmes, Emma; McGuirl, Melissa; Murphy, Patrick; Palmer, Jenna; Carter, Paul; Slivinski, Laura; Sandstede, Björn

    2017-05-01

    Data assimilation of traffic flow remains a challenging problem. One difficulty is that data come from different sources ranging from stationary sensors and camera data to GPS and cell phone data from moving cars. Sensors and cameras give information about traffic density, while GPS data provide information about the positions and velocities of individual cars. Previous methods for assimilating Lagrangian data collected from individual cars relied on specific properties of the underlying computational model or its reformulation in Lagrangian coordinates. These approaches make it hard to assimilate both Eulerian density and Lagrangian positional data simultaneously. In this paper, we propose an alternative approach that allows us to assimilate both Eulerian and Lagrangian data. We show that the proposed algorithm is accurate and works well in different traffic scenarios and regardless of whether ensemble Kalman or particle filters are used. We also show that the algorithm is capable of estimating parameters and assimilating real traffic observations and synthetic observations obtained from microscopic models.

  17. Ensemble data assimilation in the Whole Atmosphere Community Climate Model

    Science.gov (United States)

    Pedatella, N. M.; Raeder, K.; Anderson, J. L.; Liu, H.-L.

    2014-08-01

    We present results pertaining to the assimilation of real lower, middle, and upper atmosphere observations in the Whole Atmosphere Community Climate Model (WACCM) using the Data Assimilation Research Testbed (DART) ensemble adjustment Kalman filter. The ability to assimilate lower atmosphere observations of aircraft and radiosonde temperature and winds, satellite drift winds, and Constellation Observing System for Meteorology, Ionosphere, and Climate refractivity along with middle/upper atmosphere temperature observations from SABER and Aura MLS is demonstrated. The WACCM+DART data assimilation system is shown to be able to reproduce the salient features, and variability, of the troposphere present in the National Centers for Environmental Prediction/National Center for Atmospheric Research Re-Analysis. In the mesosphere, the fit of WACCM+DART to observations is found to be slightly worse when only lower atmosphere observations are assimilated compared to a control experiment that is reflective of the model climatological variability. This differs from previous results which found that assimilation of lower atmosphere observations improves the fit to mesospheric observations. This discrepancy is attributed to the fact that due to the gravity wave drag parameterizations, the model climatology differs significantly from the observations in the mesosphere, and this is not corrected by the assimilation of lower atmosphere observations. The fit of WACCM+DART to mesospheric observations is, however, significantly improved compared to the control experiment when middle/upper atmosphere observations are assimilated. We find that assimilating SABER observations reduces the root-mean-square error and bias of WACCM+DART relative to the independent Aura MLS observations by ˜50%, demonstrating that assimilation of middle/upper atmosphere observations is essential for accurate specification of the mesosphere and lower thermosphere region in WACCM+DART. Last, we demonstrate that

  18. [Thermophilic and thermotolerant bacteria that assimilate methane].

    Science.gov (United States)

    Malashenko, Iu R; Romanovskaia, V A; Bogachenko, V N; Shved, A D

    1975-01-01

    Microorganisms assimilating methane at temperatures above 40 degrees C were isolated from various natural sources: ooze, mud, waste water of coal pits. The bacteria are obligate methylotrophs and are represented by two groups: (a) thermotolerant, growing at 37 to 45 degrees C; and (b) thermophilic, growing at 50 to 62 degrees C. The selective factor used to isolate various physiological forms of methylotrophs is corresponding temperatures of growth which allow to isolate from the same substrate meso-, thermotolerant, and thermophilic forms. Morphological and physiological properties of the strains are described. The thermotolerant cultures of methylotrophs are similar to Methylobacter vinelandii, though differ from it by some characteristics. The thermophilic microorganisms should be classed as a separate species Methylococcus thermophilus.

  19. Merging particle filter for sequential data assimilation

    Directory of Open Access Journals (Sweden)

    S. Nakano

    2007-07-01

    Full Text Available A new filtering technique for sequential data assimilation, the merging particle filter (MPF, is proposed. The MPF is devised to avoid the degeneration problem, which is inevitable in the particle filter (PF, without prohibitive computational cost. In addition, it is applicable to cases in which a nonlinear relationship exists between a state and observed data where the application of the ensemble Kalman filter (EnKF is not effectual. In the MPF, the filtering procedure is performed based on sampling of a forecast ensemble as in the PF. However, unlike the PF, each member of a filtered ensemble is generated by merging multiple samples from the forecast ensemble such that the mean and covariance of the filtered distribution are approximately preserved. This merging of multiple samples allows the degeneration problem to be avoided. In the present study, the newly proposed MPF technique is introduced, and its performance is demonstrated experimentally.

  20. Face-to-Face Sharing with Strangers and Altruistic Punishment of Acquaintances for Strangers: Young Adolescents Exhibit Greater Altruism than Adults

    Science.gov (United States)

    Hao, Jian; Yang, Yue; Wang, Zhiwen

    2016-01-01

    Young adolescents are generally considered to be self-absorbed. Studies indicate that they lack relevant general cognitive abilities, such as impulse control, that mature in early adulthood. However, their idealism may cause them to be more intolerant of unfair treatment to others and thus result in their engaging in more altruistic behavior. The present study aimed to clarify whether young adolescents are more altruistic than adults and thus indicate whether altruistic competence is domain-specific. One hundred 22 young adolescents and adults participated in a face-to-face, two-round, third-party punishment experiment. In each interaction group, a participant served as an allocator who could share money units with a stranger; another participant who knew the allocator could punish the acquaintance for the stranger. Participants reported their emotions after the first round, and at the end of the experiment, the participants justified their behavior in each round. The results indicated that the young adolescents both shared more and punished more than did the adults. Sharing was associated with a reference to fairness in the justifications, but altruistic punishment was associated with subsequent positive emotion. In sum, greater altruism in young adolescents compared to adults with mature cognitive abilities provides evidence of domain-specificity of altruistic competence. Moreover, sharing and altruistic punishment are related to specific cognitive and emotional mechanisms, respectively. PMID:27752246

  1. Face-to-Face Sharing with Strangers and Altruistic Punishment of Acquaintances for Strangers: Young Adolescents Exhibit Greater Altruism than Adults.

    Science.gov (United States)

    Hao, Jian; Yang, Yue; Wang, Zhiwen

    2016-01-01

    Young adolescents are generally considered to be self-absorbed. Studies indicate that they lack relevant general cognitive abilities, such as impulse control, that mature in early adulthood. However, their idealism may cause them to be more intolerant of unfair treatment to others and thus result in their engaging in more altruistic behavior. The present study aimed to clarify whether young adolescents are more altruistic than adults and thus indicate whether altruistic competence is domain-specific. One hundred 22 young adolescents and adults participated in a face-to-face, two-round, third-party punishment experiment. In each interaction group, a participant served as an allocator who could share money units with a stranger; another participant who knew the allocator could punish the acquaintance for the stranger. Participants reported their emotions after the first round, and at the end of the experiment, the participants justified their behavior in each round. The results indicated that the young adolescents both shared more and punished more than did the adults. Sharing was associated with a reference to fairness in the justifications, but altruistic punishment was associated with subsequent positive emotion. In sum, greater altruism in young adolescents compared to adults with mature cognitive abilities provides evidence of domain-specificity of altruistic competence. Moreover, sharing and altruistic punishment are related to specific cognitive and emotional mechanisms, respectively.

  2. Face-to-face sharing with strangers and altruistic punishment of acquaintances for strangers: Young adolescents exhibit greater altruism than adults

    Directory of Open Access Journals (Sweden)

    Jian Hao

    2016-10-01

    Full Text Available Young adolescents are generally considered to be self-absorbed. Studies indicate that they lack relevant general cognitive abilities, such as impulse control, that mature in early adulthood. However, their idealism may cause them to be more intolerant of unfair treatment to others and thus result in their engaging in more altruistic behavior. The present study aimed to clarify whether young adolescents are more altruistic than adults and thus indicate whether altruistic competence is domain-specific. One hundred twenty-two young adolescents and adults participated in a face-to-face, two-round, third-party punishment experiment. In each interaction group, a participant served as an allocator who could share money units with a stranger; another participant who knew the allocator could punish the acquaintance for the stranger. Participants reported their emotions after the first round, and at the end of the experiment, the participants justified their behavior in each round. The results indicated that the young adolescents both shared more and punished more than did the adults. Sharing was associated with a reference to fairness in the justifications, but altruistic punishment was associated with subsequent positive emotion. In sum, greater altruism in young adolescents compared to adults with mature cognitive abilities provides evidence of domain-specificity of altruistic competence. Moreover, sharing and altruistic punishment is related to specific cognitive and emotional mechanisms respectively.

  3. GST M1-T1 null allele frequency patterns in geographically assorted human populations: a phylogenetic approach.

    Directory of Open Access Journals (Sweden)

    Senthilkumar Pitchalu Kasthurinaidu

    Full Text Available Genetic diversity in drug metabolism and disposition is mainly considered as the outcome of the inter-individual genetic variation in polymorphism of drug-xenobiotic metabolizing enzyme (XME. Among the XMEs, glutathione-S-transferases (GST gene loci are an important candidate for the investigation of diversity in allele frequency, as the deletion mutations in GST M1 and T1 genotypes are associated with various cancers and genetic disorders of all major Population Affiliations (PAs. Therefore, the present population based phylogenetic study was focused to uncover the frequency distribution pattern in GST M1 and T1 null genotypes among 45 Geographically Assorted Human Populations (GAHPs. The frequency distribution pattern for GST M1 and T1 null alleles have been detected in this study using the data derived from literatures representing 44 populations affiliated to Africa, Asia, Europe, South America and the genome of PA from Gujarat, a region in western India. Allele frequency counting for Gujarat PA and scattered plot analysis for geographical distribution among the PAs were performed in SPSS-21. The GST M1 and GST T1 null allele frequencies patterns of the PAs were computed in Seqboot, Gendist program of Phylip software package (3.69 versions and Unweighted Pair Group method with Arithmetic Mean in Mega-6 software. Allele frequencies from South African Xhosa tribe, East African Zimbabwe, East African Ethiopia, North African Egypt, Caucasian, South Asian Afghanistan and South Indian Andhra Pradesh have been identified as the probable seven patterns among the 45 GAHPs investigated in this study for GST M1-T1 null genotypes. The patternized null allele frequencies demonstrated in this study for the first time addresses the missing link in GST M1-T1 null allele frequencies among GAHPs.

  4. Bos taurus genome sequence reveals the assortment of immunoglobulin and surrogate light chain genes in domestic cattle

    Directory of Open Access Journals (Sweden)

    Liljavirta Jenni

    2009-04-01

    Full Text Available Abstract Background The assortment of cattle immunoglobulin and surrogate light chain genes has been extracted from the version 3.1 of Bos taurus genome sequence as a part of an international effort to sequence and annotate the bovine genome. Results 63 variable lambda chain and 22 variable kappa chain genes were identified and phylogenetically assigned to 8 and 4 subgroups, respectively. The specified phylogenetic relationships are compatible with the established ruminant light chain variable gene families or subgroups. Because of gaps and uncertainties in the assembled genome sequence, the number of genes might change in the future versions of the genome sequence. In addition, three bovine surrogate light chain genes were identified. The corresponding cDNAs were cloned and the expression of the surrogate light chain genes was demonstrated from fetal material. Conclusion The bovine kappa gene locus is compact and simple which may reflect the preferential use of the lambda chain in cattle. The relative orientation of variable and joining genes in both loci are consistent with a deletion mechanism in VJ joining. The orientation of some variable genes cannot be determined from the data available. The number of functional variable genes is moderate when compared to man or mouse. Thus, post-recombinatorial mechanisms might contribute to the generation of the bovine pre-immune antibody repertoire. The heavy chains probably contribute more to recombinational immunoglobulin repertoire diversity than the light chains but the heavy chain locus could not be annotated from the version 3.1 of Bos taurus genome.

  5. Assimilation efficiency of PBDE congeners in Chinook salmon.

    Science.gov (United States)

    Dietrich, Joseph P; Strickland, Stacy A; Hutchinson, Greg P; Van Gaest, Ahna L; Krupkin, Alex B; Ylitalo, Gina M; Arkoosh, Mary R

    2015-03-17

    Polybrominated diphenyl ether (PBDE) flame retardants are environmental contaminants that can accumulate in biota. PBDE accumulation in an organism depends on exposure, assimilation efficiency, and elimination/metabolism. Net assimilation efficiency represents the fraction of the contaminant that is retained in the organism after exposure. In the present study, congener-specific estimates of net PBDE assimilation efficiencies were calculated from dietary exposures of juvenile Chinook salmon. The fish were exposed to one to eight PBDE congeners up to 1500 ng total PBDEs/g food. Mean assimilation efficiencies varied from 0.32 to 0.50 for BDE congeners 28, 47, 99, 100, 153, and 154. The assimilation efficiency of BDE49 was significantly greater than 100%, suggesting biotransformation from higher brominated congeners. Whole body concentrations of BDE49 significantly increased with both exposure to increasing concentrations of BDE99 and decreasing fish lipid levels, implying lipid-influenced debromination of BDE99 to BDE49. Excluding BDE49, PBDE assimilation efficiency was not significantly related to the numbers of congeners in the diets, or congener hydrophobicity, but was greater in foods with higher lipid levels. Estimates of PBDE assimilation efficiency can be used in bioaccumulation models to assess threats from PBDE exposure to Chinook salmon health and recovery efforts, as well as to their predators.

  6. SMOS brightness temperature assimilation into the Community Land Model

    Directory of Open Access Journals (Sweden)

    D. Rains

    2017-11-01

    Full Text Available SMOS (Soil Moisture and Ocean Salinity mission brightness temperatures at a single incident angle are assimilated into the Community Land Model (CLM across Australia to improve soil moisture simulations. Therefore, the data assimilation system DasPy is coupled to the local ensemble transform Kalman filter (LETKF as well as to the Community Microwave Emission Model (CMEM. Brightness temperature climatologies are precomputed to enable the assimilation of brightness temperature anomalies, making use of 6 years of SMOS data (2010–2015. Mean correlation R with in situ measurements increases moderately from 0.61 to 0.68 (11 % for upper soil layers if the root zone is included in the updates. A reduced improvement of 5 % is achieved if the assimilation is restricted to the upper soil layers. Root-zone simulations improve by 7 % when updating both the top layers and root zone, and by 4 % when only updating the top layers. Mean increments and increment standard deviations are compared for the experiments. The long-term assimilation impact is analysed by looking at a set of quantiles computed for soil moisture at each grid cell. Within hydrological monitoring systems, extreme dry or wet conditions are often defined via their relative occurrence, adding great importance to assimilation-induced quantile changes. Although still being limited now, longer L-band radiometer time series will become available and make model output improved by assimilating such data that are more usable for extreme event statistics.

  7. Data Assimilation to Estimate the Water Level of River

    Science.gov (United States)

    Apriliani, Erna; Hanafi, Lukman; Imron, Chairul

    2017-09-01

    Data assimilation is an estimation method for stochastic dynamic system by combining the mathematical model with measurement data. Water level and velocity of river are stochastic dynamic system, and it is important to estimate the water level and velocity of river flow to reduce flood risk disaster. Here, we estimate the water level and velocity of river flow by using data assimilation specially Kalman filter and Ensemble Kalman filter. We define mathematical model of river flow, discretize and do simulation by Kalman filter and Ensemble Kalman filter. In data assimilation, we forecast the water level and velocity by using mathematical model and based on the measurement data, the correction of forecasting is made.

  8. [Carbohydrate assimilation by clinical and environmental Rhodotorula glutinis strains].

    Science.gov (United States)

    García-Martos, Pedro; García-Agudo, Lidia; Ruiz-Aragón, Jesús; Saldarreaga, Abel; Marín, Pilar

    2004-06-01

    This study was carried to determine the carbohydrate assimilation patterns of Rhodotorula strains isolated from clinical and environmental specimens. We have tested the commercial system ID 32C (bioMerieux, France) on 80 different strains of Rhodotorula glutinis: 47 strains from clinical samples and 33 strains from environmental samples. The assimilation percentages obtained in our study for galactose, cellobiose, gluconate and sorbose were lower than those showed in the identification table of the method. However, the assimilation percentages for mannitol and esculin were higher. According to our results, we conclude that the numerical profiles and the identification software of the commercial system present limitations for the characterization of some R. glutinis strains.

  9. Data assimilation in the early phase: Kalman filtering RIMPUFF

    DEFF Research Database (Denmark)

    Astrup, P.; Turcanu, C.; Puch, R.O.

    2004-01-01

    In the framework of the DAONEM project (Data Assimilation for Off-site Nuclear Emergency Management), a data assimilation module, ADUM (Atmospheric Dispersion Updating Module), for the mesoscale atmospheric dispersion program RIMPUFF (Risø Mesoscale Puffmodel) – part of the early-phase programs...... of RODOS (Realtime Online DecisiOn Support system for nuclear emergencies) – has been developed. It is built on the Kalman filtering algorithm and it assimilates 10-minute averaged gamma dose rates measured atground level stations. Since the gamma rates are non-linear functions of the state vector...

  10. Application of Bred Vectors To Data Assimilation

    Science.gov (United States)

    Corazza, M.; Kalnay, E.; Patil, Dj

    We introduced a statistic, the BV-dimension, to measure the effective local finite-time dimensionality of the atmosphere. We show that this dimension is often quite low, and suggest that this finding has important implications for data assimilation and the accuracy of weather forecasting (Patil et al, 2001). The original database for this study was the forecasts of the NCEP global ensemble forecasting system. The initial differences between the control forecast and the per- turbed forecasts are called bred vectors. The control and perturbed initial conditions valid at time t=n(t are evolved using the forecast model until time t=(n+1) (t. The differences between the perturbed and the control forecasts are scaled down to their initial amplitude, and constitute the bred vectors valid at (n+1) (t. Their growth rate is typically about 1.5/day. The bred vectors are similar by construction to leading Lya- punov vectors except that they have small but finite amplitude, and they are valid at finite times. The original NCEP ensemble data set has 5 independent bred vectors. We define a local bred vector at each grid point by choosing the 5 by 5 grid points centered at the grid point (a region of about 1100km by 1100km), and using the north-south and east- west velocity components at 500mb pressure level to form a 50 dimensional column vector. Since we have k=5 global bred vectors, we also have k local bred vectors at each grid point. We estimate the effective dimensionality of the subspace spanned by the local bred vectors by performing a singular value decomposition (EOF analysis). The k local bred vector columns form a 50xk matrix M. The singular values s(i) of M measure the extent to which the k column unit vectors making up the matrix M point in the direction of v(i). We define the bred vector dimension as BVDIM={Sum[s(i)]}^2/{Sum[s(i)]^2} For example, if 4 out of the 5 vectors lie along v, and one lies along v, the BV- dimension would be BVDIM[sqrt(4), 1, 0

  11. Assimilation of MODIS Snow Cover Through the Data Assimilation Research Testbed and the Community Land Model Version 4

    Science.gov (United States)

    Zhang, Yong-Fei; Hoar, Tim J.; Yang, Zong-Liang; Anderson, Jeffrey L.; Toure, Ally M.; Rodell, Matthew

    2014-01-01

    To improve snowpack estimates in Community Land Model version 4 (CLM4), the Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover fraction (SCF) was assimilated into the Community Land Model version 4 (CLM4) via the Data Assimilation Research Testbed (DART). The interface between CLM4 and DART is a flexible, extensible approach to land surface data assimilation. This data assimilation system has a large ensemble (80-member) atmospheric forcing that facilitates ensemble-based land data assimilation. We use 40 randomly chosen forcing members to drive 40 CLM members as a compromise between computational cost and the data assimilation performance. The localization distance, a parameter in DART, was tuned to optimize the data assimilation performance at the global scale. Snow water equivalent (SWE) and snow depth are adjusted via the ensemble adjustment Kalman filter, particularly in regions with large SCF variability. The root-mean-square error of the forecast SCF against MODIS SCF is largely reduced. In DJF (December-January-February), the discrepancy between MODIS and CLM4 is broadly ameliorated in the lower-middle latitudes (2345N). Only minimal modifications are made in the higher-middle (4566N) and high latitudes, part of which is due to the agreement between model and observation when snow cover is nearly 100. In some regions it also reveals that CLM4-modeled snow cover lacks heterogeneous features compared to MODIS. In MAM (March-April-May), adjustments to snowmove poleward mainly due to the northward movement of the snowline (i.e., where largest SCF uncertainty is and SCF assimilation has the greatest impact). The effectiveness of data assimilation also varies with vegetation types, with mixed performance over forest regions and consistently good performance over grass, which can partly be explained by the linearity of the relationship between SCF and SWE in the model ensembles. The updated snow depth was compared to the Canadian Meteorological

  12. Towards a Comprehensive Dynamic-chemistry Assimilation for Eos-Chem: Plans and Status in NASA's Data Assimilation Office

    Science.gov (United States)

    Pawson, Steven; Lin, Shian-Jiann; Rood, Richard B.; Stajner, Ivanka; Nebuda, Sharon; Nielsen, J. Eric; Douglass, Anne R.

    2000-01-01

    In order to support the EOS-Chem project, a comprehensive assimilation package for the coupled chemical-dynamical system is being developed by the Data Assimilation Office at NASA GSFC. This involves development of a coupled chemistry/meteorology model and of data assimilation techniques for trace species and meteorology. The model is being developed using the flux-form semi-Lagrangian dynamical core of Lin and Rood, the physical parameterizations from the NCAR Community Climate Model, and atmospheric chemistry modules from the Atmospheric Chemistry and Dynamics branch at NASA GSFC. To date the following results have been obtained: (i) multi-annual simulations with the dynamics-radiation model show the credibility of the package for atmospheric simulations; (ii) initial simulations including a limited number of middle atmospheric trace gases reveal the realistic nature of transport mechanisms, although there is still a need for some improvements. Samples of these results will be shown. A meteorological assimilation system is currently being constructed using the model; this will form the basis for the proposed meteorological/chemical assimilation package. The latter part of the presentation will focus on areas targeted for development in the near and far terms, with the objective of Providing a comprehensive assimilation package for the EOS-Chem science experiment. The first stage will target ozone assimilation. The plans also encompass a reanalysis (ReSTS) for the 1991-1995 period, which includes the Mt. Pinatubo eruption and the time when a large number of UARS observations were available. One of the most challenging aspects of future developments will be to couple theoretical advances in tracer assimilation with the practical considerations of a real environment and eventually a near-real-time assimilation system.

  13. User acquaintance with mobile interfaces.

    Science.gov (United States)

    Ehrler, Frederic; Walesa, Magali; Sarrey, Evelyne; Wipfli, Rolf; Lovis, Christian

    2013-01-01

    Handheld technology finds slowly its place in the healthcare world. Some clinicians already use intensively dedicated mobile applications to consult clinical references. However, handheld technology hasn't still broadly embraced to the core of the healthcare business, the hospitals. The weak penetration of handheld technology in the hospitals can be partly explained by the caution of stakeholders that must be convinced about the efficiency of these tools before going forward. In a domain where temporal constraints are increasingly strong, caregivers cannot loose time on playing with gadgets. All users are not comfortable with tactile manipulations and the lack of dedicated peripheral complicates entering data for novices. Stakeholders must be convinced that caregivers will be able to master handheld devices. In this paper, we make the assumption that the proper design of an interface may influence users' performances to record information. We are also interested to find out whether users increase their efficiency when using handheld tools repeatedly. To answer these questions, we have set up a field study to compare users' performances on three different user interfaces while recording vital signs. Some user interfaces were familiar to users, and others were totally innovative. Results showed that users' familiarity with smartphone influences their performances and that users improve their performances by repeating a task.

  14. Getting Acquainted with the Dandelion.

    Science.gov (United States)

    Knapp, Vera; Knapp, Clifford

    1980-01-01

    Presented is a discussion of the natural history of the dandelion. Three activities involving study of dandelions are presented. Each activity includes discussion of purpose, skills, and materials needed. (RE)

  15. Epigenetic inheritance, genetic assimilation and speciation.

    Science.gov (United States)

    Pál, C; Miklós, I

    1999-09-07

    Epigenetic inheritance systems enable the environmentally induced phenotypes to be transmitted between generations. Jablonka and Lamb (1991, 1995) proposed that these systems have a substantial role during speciation. They argued that divergence of isolated populations may be first triggered by the accumulation of (heritable) phenotypic differences that are later followed and strengthened by genetic changes. The plausibility of this idea is examined in this paper. At first, we discuss the "exploratory" behaviour of an epigenetic inheritance system on a one peak adaptive landscape. If a quantitative trait is far from the optimum, then it is advantageous to induce heritable phenotypic variation. Conversely, if the genotypes get closer to the peak, it is more favorable to canalize the phenotypic expression of the character. This process would lead to genetic assimilation. Next we show that the divergence of heritable epigenetic marks acts to reduce or to eliminate the genetic barrier between two adaptive peaks. Therefore, an epigenetic inheritance system can increase the probability of transition from one adaptive state to another. Peak shift might be initiated by (i) slight changes in the inducing environment or by (ii) genetic drift of the genes controlling epigenetic variability. Remarkably, drift-induced transition is facilitated even if phenotypic variation is not heritable. A corollary of our thesis is that evolution can proceed through suboptimal phenotypic states, without passing through a deep adaptive valley of the genotype. We also consider the consequences of this finding on the dynamics and mode of reproductive isolation. Copyright 1999 Academic Press.

  16. Assimilate partitioning in avocado, Persea americana

    Energy Technology Data Exchange (ETDEWEB)

    Finazzo, S.; Davenport, T.L.

    1986-04-01

    Assimilate partitioning is being studied in avocado, Persea americana cv. Millborrow in relation to fruit set. Single leaves on girdled branches of 10 year old trees were radiolabeled for 1 hr with 13..mu..Ci of /sup 14/CO/sub 2/. The source leaves were sampled during the experiment to measure translocation rates. At harvest the sink tissues were dissected and the incorporated radioactivity was measured. The translocation of /sup 14/C-labelled compounds to other leaves was minimal. Incorporation of label into fruitlets varied with the tissue and the stage of development. Sink (fruitlets) nearest to the labelled leaf and sharing the same phyllotaxy incorporated the most /sup 14/C. Source leaves for single non-abscising fruitlets retained 3X more /sup 14/C-labelled compounds than did source leaves for 2 or more fruitlets at 31 hrs. post-labelling. Export of label decreased appreciably when fruitlets abscised. If fruitlets abscised within 4 days of labeling then the translocation pattern was similar to the pattern for single fruitlets. If the fruitlet abscised later, the translocation pattern was intermediate between the single and double fruitlet pattern.

  17. Efficient Data Assimilation Algorithms for Bathymetry Applications

    Science.gov (United States)

    Ghorbanidehno, H.; Kokkinaki, A.; Lee, J. H.; Farthing, M.; Hesser, T.; Kitanidis, P. K.; Darve, E. F.

    2016-12-01

    Information on the evolving state of the nearshore zone bathymetry is crucial to shoreline management, recreational safety, and naval operations. The high cost and complex logistics of using ship-based surveys for bathymetry estimation have encouraged the use of remote sensing monitoring. Data assimilation methods combine monitoring data and models of nearshore dynamics to estimate the unknown bathymetry and the corresponding uncertainties. Existing applications have been limited to the basic Kalman Filter (KF) and the Ensemble Kalman Filter (EnKF). The former can only be applied to low-dimensional problems due to its computational cost; the latter often suffers from ensemble collapse and uncertainty underestimation. This work explores the use of different variants of the Kalman Filter for bathymetry applications. In particular, we compare the performance of the EnKF to the Unscented Kalman Filter and the Hierarchical Kalman Filter, both of which are KF variants for non-linear problems. The objective is to identify which method can better handle the nonlinearities of nearshore physics, while also having a reasonable computational cost. We present two applications; first, the bathymetry of a synthetic one-dimensional cross section normal to the shore is estimated from wave speed measurements. Second, real remote measurements with unknown error statistics are used and compared to in situ bathymetric survey data collected at the USACE Field Research Facility in Duck, NC. We evaluate the information content of different data sets and explore the impact of measurement error and nonlinearities.

  18. Satellite Sounder Data Assimilation for Improving Alaska Region Weather Forecast

    Science.gov (United States)

    Zhu, Jiang; Stevens, E.; Zavodsky, B. T.; Zhang, X.; Heinrichs, T.; Broderson, D.

    2014-01-01

    Data assimilation has been demonstrated very useful in improving both global and regional numerical weather prediction. Alaska has very coarser surface observation sites. On the other hand, it gets much more satellite overpass than lower 48 states. How to utilize satellite data to improve numerical prediction is one of hot topics among weather forecast community in Alaska. The Geographic Information Network of Alaska (GINA) at University of Alaska is conducting study on satellite data assimilation for WRF model. AIRS/CRIS sounder profile data are used to assimilate the initial condition for the customized regional WRF model (GINA-WRF model). Normalized standard deviation, RMSE, and correlation statistic analysis methods are applied to analyze one case of 48 hours forecasts and one month of 24-hour forecasts in order to evaluate the improvement of regional numerical model from Data assimilation. The final goal of the research is to provide improved real-time short-time forecast for Alaska regions.

  19. ASSIMILATION CHOICES AMONG IMMIGRANT FAMILIES: DOES SCHOOL CONTEXT MATTER?

    Science.gov (United States)

    Greenman, Emily

    2015-01-01

    This paper explores the relationship between social context, measured in terms of school characteristics, and the assimilation of immigrant adolescents. First, it develops a measure of assimilation based on comparing immigrant adolescents to native peers within the same school. Second, it investigates whether immigrant adolescents’ degree of assimilation varies systematically according to school SES. Third, it explores the role of parental and adolescent behavior in creating such variation. Results show that both Asian and Hispanic immigrant youth are less assimilated to native youths’ substance use and delinquency patterns in lower-SES schools. This association can be explained by parenting behaviors and adolescent friendship choices for Asian youth, but not Hispanic youth. PMID:26478649

  20. Air Quality Activities in the Global Modeling and Assimilation Office

    Science.gov (United States)

    Pawson, Steven

    2016-01-01

    GMAO's mission is to enhance the use of NASA's satellite observations in weather and climate modeling. This presentation will be discussing GMAO's mission, value of data assimilation, and some relevant (available) GMAO data products.

  1. Understanding nitrate assimilation and its regulation in microalgae.

    Science.gov (United States)

    Sanz-Luque, Emanuel; Chamizo-Ampudia, Alejandro; Llamas, Angel; Galvan, Aurora; Fernandez, Emilio

    2015-01-01

    Nitrate assimilation is a key process for nitrogen (N) acquisition in green microalgae. Among Chlorophyte algae, Chlamydomonas reinhardtii has resulted to be a good model system to unravel important facts of this process, and has provided important insights for agriculturally relevant plants. In this work, the recent findings on nitrate transport, nitrate reduction and the regulation of nitrate assimilation are presented in this and several other algae. Latest data have shown nitric oxide (NO) as an important signal molecule in the transcriptional and posttranslational regulation of nitrate reductase and inorganic N transport. Participation of regulatory genes and proteins in positive and negative signaling of the pathway and the mechanisms involved in the regulation of nitrate assimilation, as well as those involved in Molybdenum cofactor synthesis required to nitrate assimilation, are critically reviewed.

  2. Regional Ocean Modeling System (ROMS): Samoa: Data Assimilating

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Regional Ocean Modeling System (ROMS) 3-day, 3-hourly data assimilating hindcast for the region surrounding the islands of Samoa at approximately 3-km resolution....

  3. A simple lightning assimilation technique for improving retrospective WRF simulations.

    Science.gov (United States)

    Convective rainfall is often a large source of error in retrospective modeling applications. In particular, positive rainfall biases commonly exist during summer months due to overactive convective parameterizations. In this study, lightning assimilation was applied in the Kain-F...

  4. UARS Correlative UKMO Daily Gridded Stratospheric Assimilated Data V001

    Data.gov (United States)

    National Aeronautics and Space Administration — The UARS Correlative assimilation data from the U.K. Meteorological Office (UKMO) consists of daily model runs at 12:00 GMT as a means of providing an independent...

  5. Regional Ocean Modeling System (ROMS): Main Hawaiian Islands: Data Assimilating

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Regional Ocean Modeling System (ROMS) 3-day, 3-hourly data assimilating hindcast for the region surrounding the main Hawaiian islands at approximately 4-km...

  6. Regional Ocean Modeling System (ROMS): CNMI: Data Assimilating

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Regional Ocean Modeling System (ROMS) 3-day, 3-hourly data assimilating hindcast for the region surrounding the Commonwealth of the Northern Mariana Islands (CNMI)...

  7. Regional Ocean Modeling System (ROMS): Oahu: Data Assimilating

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Regional Ocean Modeling System (ROMS) 2-day, 3-hourly data assimilating hindcast for the region surrounding the island of Oahu at approximately 1-km resolution....

  8. Assimilation of freshwater salmonid aquaculture waste by native aquatic biota

    National Research Council Canada - National Science Library

    Kullman, M.A

    2006-01-01

    .... Assimilation of aquaculture-derived carbon was evident in the minnows, as well as in the pelagic and profundal invertebrates. These studies showed that aquaculture waste was an important nutrient source for native organisms, and that mortality impacts were localized.

  9. Implicit particle methods and their connection with variational data assimilation

    CERN Document Server

    Atkins, Ethan; Chorin, Alexandre J

    2012-01-01

    The implicit particle filter is a sequential Monte Carlo method for data assimilation that guides the particles to the high-probability regions via a sequence of steps that includes minimizations. We present a new and more general derivation of this approach and extend the method to particle smoothing as well as to data assimilation for perfect models. We show that the minimizations required by implicit particle methods are similar to the ones one encounters in variational data assimilation and explore the connection of implicit particle methods with variational data assimilation. In particular, we argue that existing variational codes can be converted into implicit particle methods at a low cost, often yielding better estimates, that are also equipped with quantitative measures of the uncertainty. A detailed example is presented.

  10. North American Land Data Assimilation System Phase 2

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The goal of the North American Land Data Assimilation System (NLDAS) is to construct quality-controlled, and spatially and temporally consistent, land-surface model...

  11. Ionospheric radio occultation inversion constrained with the data assimillation

    Science.gov (United States)

    Wu, X.; Hu, X.; Zhang, Y.

    2015-12-01

    Ionospheric radio occultation inversion constrained with the data assimillation Wu Xiaocheng, Hu Xiong, Zhang Yanan National Space Science Center, Chinese Academy of Sciences The assumption that electron density distribution is spherically symmetric, is usually used in the traditional ionospheric radio occultation (IRO) inversion, and it is the main error source of IRO inversion. In order to improve the IRO inversion, many methods were studied. One of them uses known ionosphere background to constrain the inversion of IRO, but it has not been used in the routine processing of observation data, due to that it is difficult to get the proper ionosphere background. Data assimilation can provide accurate electron density on the three dimensional grid, which may be used to constrain the IRO inversion and improve the inversion result. This article assimilates the TEC of ground GPS and IRO observation, and the constrains the IRO inversion. The inversion result is greatly improved. Key Words: Ionospheric radio occultation, Data assimilation, Inversion, GPS

  12. Sea level ECV quality assessment via global ocean model assimilation

    Science.gov (United States)

    Scharffenberg, Martin; Köhl, Armin; Stammer, Detlef

    2015-04-01

    In the ocean modeling community satellite data, especially SSH fields, are assimilated on a regular basis. SSH fields are very important in this context because of their dynamical relevance for constraining the ocean's flow field. However, assimilating SSH data into an ocean model does not only improve the quality of model but in addition, can also help testing the quality and the consistency of the input data as well. In our work we aim to quantify improvements in Sea Level (SL) data through the ESA - Climate Change Initiative (cci) effort and we aim to test the consistency of the Essential Climate Variable (ECV) of Sea Level (SL_ECV) with other ECVs through the assimilation process and to investigate where remaining inconsistencies exist and why. For this purpose the GECCO2 assimilation approach assimilates SSH jointly with in situ data over the ocean. The dynamically consistent ocean state estimation adjusts only uncertain model parameters to bring the model into consistency with ocean observations. Improvements in data products can be investigated by studying the residuals between the different data products and the constrained model. PHASE 1: With this approach we could demonstrate, that in many regions the SL_ECV has been improved from version V0 (AVISO product) to version V1 (SL_cci product). However, there are regions where SL_ECV_V1 is further away from the model "truth". In that sense it is important to understand that the model assimilated SL_ECV_V0 (origianl AVISO product) and therefore has tried to adapt to the SL_ECV_V0. Therefore, inconsistencies existed when comparing the synthesis results to the updated version SL_ECV_V1! These deviations between the model "truth" and the improved data product (SL_ECV_V1) increased mostly in low energetic areas. PHASE 2: Two GECCO2-assimilation-runs (5 additional iterations) have been performed to date: 1) assimilating the original AVISO SL-product (V0) and 2) assimilating the updated-improved sea level estimate

  13. Multi-parametric variational data assimilation for hydrological forecasting

    Science.gov (United States)

    Alvarado-Montero, R.; Schwanenberg, D.; Krahe, P.; Helmke, P.; Klein, B.

    2017-12-01

    Ensemble forecasting is increasingly applied in flow forecasting systems to provide users with a better understanding of forecast uncertainty and consequently to take better-informed decisions. A common practice in probabilistic streamflow forecasting is to force deterministic hydrological model with an ensemble of numerical weather predictions. This approach aims at the representation of meteorological uncertainty but neglects uncertainty of the hydrological model as well as its initial conditions. Complementary approaches use probabilistic data assimilation techniques to receive a variety of initial states or represent model uncertainty by model pools instead of single deterministic models. This paper introduces a novel approach that extends a variational data assimilation based on Moving Horizon Estimation to enable the assimilation of observations into multi-parametric model pools. It results in a probabilistic estimate of initial model states that takes into account the parametric model uncertainty in the data assimilation. The assimilation technique is applied to the uppermost area of River Main in Germany. We use different parametric pools, each of them with five parameter sets, to assimilate streamflow data, as well as remotely sensed data from the H-SAF project. We assess the impact of the assimilation in the lead time performance of perfect forecasts (i.e. observed data as forcing variables) as well as deterministic and probabilistic forecasts from ECMWF. The multi-parametric assimilation shows an improvement of up to 23% for CRPS performance and approximately 20% in Brier Skill Scores with respect to the deterministic approach. It also improves the skill of the forecast in terms of rank histogram and produces a narrower ensemble spread.

  14. Perceptual assimilation and discrimination of non-native vowel contrasts

    OpenAIRE

    Michael D Tyler; Best, Catherine T.; Faber, Alice; Levitt, Andrea G.

    2014-01-01

    Research on language-specific tuning in speech perception has focused mainly on consonants, while that on non-native vowel perception has failed to address whether the same principles apply. Therefore, non-native vowel perception was investigated here in light of relevant theoretical models: The Perceptual Assimilation Model (PAM) and the Natural Referent Vowel (NRV) framework. American-English speakers completed discrimination and L1-assimilation (categorization and goodnes...

  15. Assimilative Learning with the Aid of Cognitive Maps

    OpenAIRE

    D. Läge; Oberholzer, R; Egli, S.; R. Streule

    2008-01-01

    Assimilative learning is understood as integrating new information into existing knowledge or cognitive structures without restructuring the current schema. If new information causes inconsistencies, cognitive efforts are necessary to reorganize or to accommodate the old knowledge. Thus, assimilative learning is more efficient and economic. Nonetheless a stable and most notably a correct memory representation which “spans” the knowledge space is essential. The current article highlights the l...

  16. Immigrants' Assimilation Process In A Segmented Labor Market

    OpenAIRE

    Rodríguez-Planas, Núria; Alcobendas, Miguel Angel

    2010-01-01

    While much of the literature on immigrants' assimilation has focused on countries with a large tradition of receiving immigrants and with flexible labor markets, very little is known on how immigrants adjust to other types of host economies. With its severe dual labor market, and an unprecedented immigration boom, Spain presents a quite unique experience to analyze immigrations' assimilation process. Using data from the 2000 to 2008 Labor Force Survey, we find that immigrants are more occupat...

  17. Data Assimilation to Extract Soil Moisture Information from SMAP Observations

    OpenAIRE

    Jana Kolassa; Rolf H. Reichle; Qing Liu; Michael Cosh; David D. Bosch; Todd G. Caldwell; Andreas Colliander; Chandra Holifield Collins; Thomas J. Jackson; Stan J. Livingston; Mahta Moghaddam; Patrick J. Starks

    2017-01-01

    This study compares different methods to extract soil moisture information through the assimilation of Soil Moisture Active Passive (SMAP) observations. Neural network (NN) and physically-based SMAP soil moisture retrievals were assimilated into the National Aeronautics and Space Administration (NASA) Catchment model over the contiguous United States for April 2015 to March 2017. By construction, the NN retrievals are consistent with the global climatology of the Catchment model soil moisture...

  18. All-Sky Microwave Imager Data Assimilation at NASA GMAO

    Science.gov (United States)

    Kim, Min-Jeong; Jin, Jianjun; El Akkraoui, Amal; McCarty, Will; Todling, Ricardo; Gu, Wei; Gelaro, Ron

    2017-01-01

    Efforts in all-sky satellite data assimilation at the Global Modeling and Assimilation Office (GMAO) at NASA Goddard Space Flight Center have been focused on the development of GSI configurations to assimilate all-sky data from microwave imagers such as the GPM Microwave Imager (GMI) and Global Change Observation Mission-Water (GCOM-W) Advanced Microwave Scanning Radiometer 2 (AMSR-2). Electromagnetic characteristics associated with their wavelengths allow microwave imager data to be relatively transparent to atmospheric gases and thin ice clouds, and highly sensitive to precipitation. Therefore, GMAOs all-sky data assimilation efforts are primarily focused on utilizing these data in precipitating regions. The all-sky framework being tested at GMAO employs the GSI in a hybrid 4D-EnVar configuration of the Goddard Earth Observing System (GEOS) data assimilation system, which will be included in the next formal update of GEOS. This article provides an overview of the development of all-sky radiance assimilation in GEOS, including some performance metrics. In addition, various projects underway at GMAO designed to enhance the all-sky implementation will be introduced.

  19. IASI Radiance Data Assimilation in Local Ensemble Transform Kalman Filter

    Science.gov (United States)

    Cho, K.; Hyoung-Wook, C.; Jo, Y.

    2016-12-01

    Korea institute of Atmospheric Prediction Systems (KIAPS) is developing NWP model with data assimilation systems. Local Ensemble Transform Kalman Filter (LETKF) system, one of the data assimilation systems, has been developed for KIAPS Integrated Model (KIM) based on cubed-sphere grid and has successfully assimilated real data. LETKF data assimilation system has been extended to 4D- LETKF which considers time-evolving error covariance within assimilation window and IASI radiance data assimilation using KPOP (KIAPS package for observation processing) with RTTOV (Radiative Transfer for TOVS). The LETKF system is implementing semi operational prediction including conventional (sonde, aircraft) observation and AMSU-A (Advanced Microwave Sounding Unit-A) radiance data from April. Recently, the semi operational prediction system updated radiance observations including GPS-RO, AMV, IASI (Infrared Atmospheric Sounding Interferometer) data at July. A set of simulation of KIM with ne30np4 and 50 vertical levels (of top 0.3hPa) were carried out for short range forecast (10days) within semi operation prediction LETKF system with ensemble forecast 50 members. In order to only IASI impact, our experiments used only conventional and IAIS radiance data to same semi operational prediction set. We carried out sensitivity test for IAIS thinning method (3D and 4D). IASI observation number was increased by temporal (4D) thinning and the improvement of IASI radiance data impact on the forecast skill of model will expect.

  20. Results From Global Land-surface Data Assimilation Methods

    Science.gov (United States)

    Radakovich, J. D.; Houser, P. R.; da Silva, A.; Bosilovich, M. G.

    2001-05-01

    Realistic representation of the land surface is crucial in global climate modeling (GCM). Recently, the Mosaic land-surface Model (LSM) has been driven off-line using GEOS DAS (Goddard Earth Observing System Data Assimilation System) atmospheric forcing, forming the Off-line Land-surface Global Assimilation (OLGA) system. This system provides a computationally efficient test bed for land surface data assimilation. Here, we validate the OLGA simulation of surface processes and the assimilation of ISCCP surface temperatures. Another component of this study was the incorporation of the Physical-space Statistical Analysis System (PSAS) into OLGA, in order to assimilate surface temperature observations from the International Satellite Cloud Climatology Project (ISCCP). To counteract the subsequent forcing of the analyzed skin temperature back to the initial state following the analysis, incremental bias correction (IBC) was included in the assimilation. The IBC scheme effectively removed the time mean bias, but did not remove bias in the mean diurnal cycle. Therefore, a diurnal bias correction (DBC) scheme was developed, where the time-dependent bias was modeled with a sine wave parameterization. In addition, quality control of the ISCCP data and anisotropic temperature correction were implemented in PSAS. Preliminary results showed a substantial impact from the inclusion of PSAS and DBC that was visible in the surface meteorology fields and energy budget. Also, the monthly mean diurnal cycle from the experiment closely matched the diurnal cycle from the observations.

  1. Cholesterol assimilation by Lactobacillus probiotic bacteria: an in vitro investigation.

    Science.gov (United States)

    Tomaro-Duchesneau, Catherine; Jones, Mitchell L; Shah, Divya; Jain, Poonam; Saha, Shyamali; Prakash, Satya

    2014-01-01

    Excess cholesterol is associated with cardiovascular diseases (CVD), an important cause of mortality worldwide. Current CVD therapeutic measures, lifestyle and dietary interventions, and pharmaceutical agents for regulating cholesterol levels are inadequate. Probiotic bacteria have demonstrated potential to lower cholesterol levels by different mechanisms, including bile salt hydrolase activity, production of compounds that inhibit enzymes such as 3-hydroxy-3-methylglutaryl coenzyme A, and cholesterol assimilation. This work investigates 11 Lactobacillus strains for cholesterol assimilation. Probiotic strains for investigation were selected from the literature: Lactobacillus reuteri NCIMB 11951, L. reuteri NCIMB 701359, L. reuteri NCIMB 702655, L. reuteri NCIMB 701089, L. reuteri NCIMB 702656, Lactobacillus fermentum NCIMB 5221, L. fermentum NCIMB 8829, L. fermentum NCIMB 2797, Lactobacillus rhamnosus ATCC 53103 GG, Lactobacillus acidophilus ATCC 314, and Lactobacillus plantarum ATCC 14917. Cholesterol assimilation was investigated in culture media and under simulated intestinal conditions. The best cholesterol assimilator was L. plantarum ATCC 14917 (15.18±0.55 mg/10(10) cfu) in MRS broth. L. reuteri NCIMB 701089 assimilated over 67% (2254.70±63.33 mg/10(10) cfu) of cholesterol, the most of all the strains, under intestinal conditions. This work demonstrates that probiotic bacteria can assimilate cholesterol under intestinal conditions, with L. reuteri NCIMB 701089 showing great potential as a CVD therapeutic.

  2. Estimating Model Evidence Using Data Assimilation

    Science.gov (United States)

    Carrassi, Alberto; Bocquet, Marc; Hannart, Alexis; Ghil, Michael

    2017-04-01

    We review the field of data assimilation (DA) from a Bayesian perspective and show that, in addition to its by now common application to state estimation, DA may be used for model selection. An important special case of the latter is the discrimination between a factual model - which corresponds, to the best of the modeller's knowledge, to the situation in the actual world in which a sequence of events has occurred-and a counterfactual model, in which a particular forcing or process might be absent or just quantitatively different from the actual world. Three different ensemble-DA methods are reviewed for this purpose: the ensemble Kalman filter (EnKF), the ensemble four-dimensional variational smoother (En-4D-Var), and the iterative ensemble Kalman smoother (IEnKS). An original contextual formulation of model evidence (CME) is introduced. It is shown how to apply these three methods to compute CME, using the approximated time-dependent probability distribution functions (pdfs) each of them provide in the process of state estimation. The theoretical formulae so derived are applied to two simplified nonlinear and chaotic models: (i) the Lorenz three-variable convection model (L63), and (ii) the Lorenz 40- variable midlatitude atmospheric dynamics model (L95). The numerical results of these three DA-based methods and those of an integration based on importance sampling are compared. It is found that better CME estimates are obtained by using DA, and the IEnKS method appears to be best among the DA methods. Differences among the performance of the three DA-based methods are discussed as a function of model properties. Finally, the methodology is implemented for parameter estimation and for event attribution.

  3. Improving Weather Forecasts Through Reduced Precision Data Assimilation

    Science.gov (United States)

    Hatfield, Samuel; Düben, Peter; Palmer, Tim

    2017-04-01

    We present a new approach for improving the efficiency of data assimilation, by trading numerical precision for computational speed. Future supercomputers will allow a greater choice of precision, so that models can use a level of precision that is commensurate with the model uncertainty. Previous studies have already indicated that the quality of climate and weather forecasts is not significantly degraded when using a precision less than double precision [1,2], but so far these studies have not considered data assimilation. Data assimilation is inherently uncertain due to the use of relatively long assimilation windows, noisy observations and imperfect models. Thus, the larger rounding errors incurred from reducing precision may be within the tolerance of the system. Lower precision arithmetic is cheaper, and so by reducing precision in ensemble data assimilation, we can redistribute computational resources towards, for example, a larger ensemble size. Because larger ensembles provide a better estimate of the underlying distribution and are less reliant on covariance inflation and localisation, lowering precision could actually allow us to improve the accuracy of weather forecasts. We will present results on how lowering numerical precision affects the performance of an ensemble data assimilation system, consisting of the Lorenz '96 toy atmospheric model and the ensemble square root filter. We run the system at half precision (using an emulation tool), and compare the results with simulations at single and double precision. We estimate that half precision assimilation with a larger ensemble can reduce assimilation error by 30%, with respect to double precision assimilation with a smaller ensemble, for no extra computational cost. This results in around half a day extra of skillful weather forecasts, if the error-doubling characteristics of the Lorenz '96 model are mapped to those of the real atmosphere. Additionally, we investigate the sensitivity of these results

  4. Gradient Evolution of Body Colouration in Surface- and Cave-Dwelling Poecilia mexicana and the Role of Phenotype-Assortative Female Mate Choice

    Directory of Open Access Journals (Sweden)

    David Bierbach

    2013-01-01

    Full Text Available Ecological speciation assumes reproductive isolation to be the product of ecologically based divergent selection. Beside natural selection, sexual selection via phenotype-assortative mating is thought to promote reproductive isolation. Using the neotropical fish Poecilia mexicana from a system that has been described to undergo incipient ecological speciation in adjacent, but ecologically divergent habitats characterized by the presence or absence of toxic H2S and darkness in cave habitats, we demonstrate a gradual change in male body colouration along the gradient of light/darkness, including a reduction of ornaments that are under both inter- and intrasexual selection in surface populations. In dichotomous choice tests using video-animated stimuli, we found surface females to prefer males from their own population over the cave phenotype. However, female cave fish, observed on site via infrared techniques, preferred to associate with surface males rather than size-matched cave males, likely reflecting the female preference for better-nourished (in this case: surface males. Hence, divergent selection on body colouration indeed translates into phenotype-assortative mating in the surface ecotype, by selecting against potential migrant males. Female cave fish, by contrast, do not have a preference for the resident male phenotype, identifying natural selection against migrants imposed by the cave environment as the major driver of the observed reproductive isolation.

  5. The relationship of height and body fat to gender-assortative weight gain in children. A longitudinal cohort study (EarlyBird 44).

    Science.gov (United States)

    Ajala, Olubukola; Fr Meaux, Alissa E; Hosking, Joanne; Metcalf, Brad S; Jeffery, Alison N; Voss, Linda D; Wilkin, Terence J

    2011-08-01

    Height, body fat and body mass index (BMI) are correlated in children, so we hypothesized that the gender-assortative associations in BMI recently reported in contemporary children might extend to their height and body fat. Prospective longitudinal cohort study. A total of 226 healthy trios (mother, father and child) from a 1995?1996 birth cohort randomly recruited in the city of Plymouth, UK. Height, weight, and BMI (kg/m(2)) were measured in each of the parents and, in addition, sum of five skin-folds (SF) in their children at 5, 6, 7 and 8 y. BMI and SF were strongly height-dependent in the children by 8 y (r = 0.41-0.56). SF was gender-assortative insofar as the mean SF was significantly greater in the daughters (but not the sons) of obese mothers (obese vs. normal weight: +2.5 cm p obese fathers (obese vs. normal: +1.3 cm p obese children were systematically taller than normal weight children (boys: +1.02 SDS, girls: +1.14 SDS, p obese children largely by the same-sex parent, but the extra height associated with more fat in the child is unrelated to the height or weight of either parent. The secular trend in height among contemporary children may simply reflect their rising body fat. Excess fat is unhealthy, so the trend in height may not be healthy either.

  6. Assimilation of GPM GMI Rainfall Product with WRF GSI

    Science.gov (United States)

    Li, Xuanli; Mecikalski, John; Zavodsky, Bradley

    2015-01-01

    The Global Precipitation Measurement (GPM) is an international mission to provide next-generation observations of rain and snow worldwide. The GPM built on Tropical Rainfall Measuring Mission (TRMM) legacy, while the core observatory will extend the observations to higher latitudes. The GPM observations can help advance our understanding of precipitation microphysics and storm structures. Launched on February 27th, 2014, the GPM core observatory is carrying advanced instruments that can be used to quantify when, where, and how much it rains or snows around the world. Therefore, the use of GPM data in numerical modeling work is a new area and will have a broad impact in both research and operational communities. The goal of this research is to examine the methodology of assimilation of the GPM retrieved products. The data assimilation system used in this study is the community Gridpoint Statistical Interpolation (GSI) system for the Weather Research and Forecasting (WRF) model developed by the Development Testbed Center (DTC). The community GSI system runs in independently environment, yet works functionally equivalent to operational centers. With collaboration with the NASA Short-term Prediction Research and Transition (SPoRT) Center, this research explores regional assimilation of the GPM products with case studies. Our presentation will highlight our recent effort on the assimilation of the GPM product 2AGPROFGMI, the retrieved Microwave Imager (GMI) rainfall rate data for initializing a real convective storm. WRF model simulations and storm scale data assimilation experiments will be examined, emphasizing both model initialization and short-term forecast of precipitation fields and processes. In addition, discussion will be provided on the development of enhanced assimilation procedures in the GSI system with respect to other GPM products. Further details of the methodology of data assimilation, preliminary result and test on the impact of GPM data and the

  7. Data Assimilation in Forest Inventory: First Empirical Results

    Directory of Open Access Journals (Sweden)

    Mattias Nyström

    2015-12-01

    Full Text Available Data assimilation techniques were used to estimate forest stand data in 2011 by sequentially combining remote sensing based estimates of forest variables with predictions from growth models. Estimates of stand data, based on canopy height models obtained from image matching of digital aerial images at six different time-points between 2003 and 2011, served as input to the data assimilation. The assimilation routines were built on the extended Kalman filter. The study was conducted in hemi-boreal forest at the Remningstorp test site in southern Sweden (lat. 13°37′ N; long. 58°28′ E. The assimilation results were compared with two other methods used in practice for estimation of forest variables: the first was to use only the most recent estimate obtained from remotely sensed data (2011 and the second was to forecast the first estimate (2003 to the endpoint (2011. All three approaches were validated using nine 40 m radius validation plots, which were carefully measured in the field. The results showed that the data assimilation approach provided better results than the two alternative methods. Data assimilation of remote sensing time series has been used previously for calibrating forest ecosystem models, but, to our knowledge, this is the first study with real data where data assimilation has been used for estimating forest inventory data. The study constitutes a starting point for the development of a framework useful for sequentially utilizing all types of remote sensing data in order to provide precise and up-to-date estimates of forest stand parameters.

  8. Assimilative domain proficiency and performance in chemistry coursework

    Science.gov (United States)

    Byrnes, Scott William

    The assimilation and synthesis of knowledge is essential for students to be successful in chemistry, yet not all students synthesize knowledge as intended. The study used the Learning Preference Checklist to classify students into one of three learning modalities -- visual, auditory, or kinesthetic (VAK). It also used the Kolb Learning Style Inventory (KLSI), which utilizes four learning domains - Converging, Accommodating, Diverging, and Assimilating - to explain the students' maturation process by showing shift from any domain towards the Assimilating domain. A shift approaching this domain was considered as improvement in the assimilation and synthesis of knowledge. This pre-experimental one-group pretest-posttest study was used to test the hypothesis that modifying a high school chemistry curriculum to accentuate a student's learning preference would result in a shift towards the Assimilative domain on the KLSI and if there was a correlation between the improvement in student learning and a shift towards the KLSI Assimilating domain. Forty-two high school students were issued the VAK and provided with differentiated instruction via homologous cooperative learning groups. Pre- and post-KLSI and chemistry concepts tests were administered. T test analyses showed no significant shift towards the Assimilating domain. Further Pearson's r analyses showed no significant correlation between the KLSI and exam scores. This study contributes to social change by providing empirical evidence related to the effectiveness infusing learning styles into the science curriculum and the integration of the KLSI to monitor cognitive development as tools in raising standardized test scores and enhancing academic achievement. Results from the study can also inform future research into learning styles through their incorporation into the science curriculum.

  9. DART: A Community Facility for Ensemble Data Assimilation

    Science.gov (United States)

    Hoar, T. J.; Raeder, K.; Anderson, J. L.; Collins, N.; Liu, H.; Romine, G.; Arellano, A. F.; Lawson, G.

    2009-12-01

    The Data Assimilation Research Testbed (DART) is a mature community software facility providing researchers access to state-of-the-art ensemble data assimilation tools. The freely-available DART distribution includes fully functional low-order and high-order models, support for commonly available observations, hooks to easily add both new models and observation types, diagnostic programs to interpret the results, and a full tutorial suitable for self-study or teaching data assimilation concepts, including exercises using the models distributed with DART. DART is used regularly with a number of geophysical models including NCAR's WRF and CAM atmospheric models. DART/WRF is being used for tropical storm analysis and prediction in the Pacific and Atlantic and was used to produce real-time predictions during the 2009 Atlantic hurricane season. DART/CAM has played an integral part in the development of the new CAM version 4 that will be used for NCAR's contribution to the next IPCC. DART/CAM has been run for many model configurations to evaluate CAM systematic errors and parameterization options. DART is also in use for chemical assimilation in the WRF-CHEM and CAM-CHEM versions of these models. New models, both small and large continue to be added to the set compatible with DART. During 2009, DART assimilation was developed for the POP (Parallel Ocean Program) ocean general circulation model that is being used for decadal coupled atmosphere/ocean predictions at NCAR. The newest version of the Planet WRF model, configured for Martian data assimilation, is also now in use with DART. Novel observation types also continue to be added to DART. For instance, assimilation capabilities for radiance observations from the COSMIC and MOPITT instruments on earth and from TES on Mars have been added in 2009.

  10. Gravity changes, soil moisture and data assimilation

    Science.gov (United States)

    Walker, J.; Grayson, R.; Rodell, M.; Ellet, K.

    2003-04-01

    Remote sensing holds promise for near-surface soil moisture and snow mapping, but current techniques do not directly resolve the deeper soil moisture or groundwater. The benefits that would arise from improved monitoring of variations in terrestrial water storage are numerous. The year 2002 saw the launch of NASA's Gravity Recovery And Climate Experiment (GRACE) satellites, which are mapping the Earth's gravity field at such a high level of precision that we expect to be able to infer changes in terrestrial water storage (soil moisture, groundwater, snow, ice, lake, river and vegetation). The project described here has three distinct yet inter-linked components that all leverage off the same ground-based monitoring and land surface modelling framework. These components are: (i) field validation of a relationship between soil moisture and changes in the Earth's gravity field, from ground- and satellite-based measurements of changes in gravity; (ii) development of a modelling framework for the assimilation of gravity data to constrain land surface model predictions of soil moisture content (such a framework enables the downscaling and disaggregation of low spatial (500 km) and temporal (monthly) resolution measurements of gravity change to finer spatial and temporal resolutions); and (iii) further refining the downscaling and disaggregation of space-borne gravity measurements by making use of other remotely sensed information, such as the higher spatial (25 km) and temporal (daily) resolution remotely sensed near-surface soil moisture measurements from the Advanced Microwave Scanning Radiometer (AMSR) instruments on Aqua and ADEOS II. The important field work required by this project will be in the Murrumbidgee Catchment, Australia, where an extensive soil moisture monitoring program by the University of Melbourne is already in place. We will further enhance the current monitoring network by the addition of groundwater wells and additional soil moisture sites. Ground

  11. DART: New Research Using Ensemble Data Assimilation in Geophysical Models

    Science.gov (United States)

    Hoar, T. J.; Raeder, K.

    2015-12-01

    The Data Assimilation Research Testbed (DART) is a community facilityfor ensemble data assimilation developed and supported by the NationalCenter for Atmospheric Research. DART provides a comprehensive suite of software, documentation, and tutorials that can be used for ensemble data assimilation research, operations, and education. Scientists and software engineers at NCAR are available to support DART users who want to use existing DART products or develop their own applications. Current DART users range from university professors teaching data assimilation, to individual graduate students working with simple models, through national laboratories doing operational prediction with large state-of-the-art models. DART runs efficiently on many computational platforms ranging from laptops through thousands of cores on the newest supercomputers.This poster focuses on several recent research activities using DART with geophysical models.Using CAM/DART to understand whether OCO-2 Total Precipitable Water observations can be useful in numerical weather prediction.Impacts of the synergistic use of Infra-red CO retrievals (MOPITT, IASI) in CAM-CHEM/DART assimilations.Assimilation and Analysis of Observations of Amazonian Biomass Burning Emissions by MOPITT (aerosol optical depth), MODIS (carbon monoxide) and MISR (plume height).Long term evaluation of the chemical response of MOPITT-CO assimilation in CAM-CHEM/DART OSSEs for satellite planning and emission inversion capabilities.Improved forward observation operators for land models that have multiple land use/land cover segments in a single grid cell,Simulating mesoscale convective systems (MCSs) using a variable resolution, unstructured grid in the Model for Prediction Across Scales (MPAS) and DART.The mesoscale WRF+DART system generated an ensemble of year-long, real-time initializations of a convection allowing model over the United States.Constraining WACCM with observations in the tropical band (30S-30N) using DART

  12. Nitrogen assimilation in denitrifier Bacillus azotoformans LMG 9581T.

    Science.gov (United States)

    Sun, Yihua; De Vos, Paul; Willems, Anne

    2017-12-01

    Until recently, it has not been generally known that some bacteria can contain the gene inventory for both denitrification and dissimilatory nitrate (NO3-)/nitrite (NO2-) reduction to ammonium (NH4+) (DNRA). Detailed studies of these microorganisms could shed light on the differentiating environmental drivers of both processes without interference of organism-specific variation. Genome analysis of Bacillus azotoformans LMG 9581T shows a remarkable redundancy of dissimilatory nitrogen reduction, with multiple copies of each denitrification gene as well as DNRA genes nrfAH, but a reduced capacity for nitrogen assimilation, with no nas operon nor amtB gene. Here, we explored nitrogen assimilation in detail using growth experiments in media with different organic and inorganic nitrogen sources at different concentrations. Monitoring of growth, NO3- NO2-, NH4+ concentration and N2O production revealed that B. azotoformans LMG 9581T could not grow with NH4+ as sole nitrogen source and confirmed the hypothesis of reduced nitrogen assimilation pathways. However, NH4+ could be assimilated and contributed up to 50% of biomass if yeast extract was also provided. NH4+ also had a significant but concentration-dependent influence on growth rate. The mechanisms behind these observations remain to be resolved but hypotheses for this deficiency in nitrogen assimilation are discussed. In addition, in all growth conditions tested a denitrification phenotype was observed, with all supplied NO3- converted to nitrous oxide (N2O).

  13. An approach to localization for ensemble-based data assimilation.

    Science.gov (United States)

    Wang, Bin; Liu, Juanjuan; Liu, Li; Xu, Shiming; Huang, Wenyu

    2018-01-01

    Localization techniques are commonly used in ensemble-based data assimilation (e.g., the Ensemble Kalman Filter (EnKF) method) because of insufficient ensemble samples. They can effectively ameliorate the spurious long-range correlations between the background and observations. However, localization is very expensive when the problem to be solved is of high dimension (say 106 or higher) for assimilating observations simultaneously. To reduce the cost of localization for high-dimension problems, an approach is proposed in this paper, which approximately expands the correlation function of the localization matrix using a limited number of principal eigenvectors so that the Schür product between the localization matrix and a high-dimension covariance matrix is reduced to the sum of a series of Schür products between two simple vectors. These eigenvectors are actually the sine functions with different periods and phases. Numerical experiments show that when the number of principal eigenvectors used reaches 20, the approximate expansion of the correlation function is very close to the exact one in the one-dimensional (1D) and two-dimensional (2D) cases. The new approach is then applied to localization in the EnKF method, and its performance is evaluated in assimilation-cycle experiments with the Lorenz-96 model and single assimilation experiments using a barotropic shallow water model. The results suggest that the approach is feasible in providing comparable assimilation analysis with far less cost.

  14. Data Assimilation to Extract Soil Moisture Information From SMAP Observations

    Science.gov (United States)

    Kolassa, J.; Reichle, R. H.; Liu, Q.; Alemohammad, S. H.; Gentine, P.

    2017-01-01

    Statistical techniques permit the retrieval of soil moisture estimates in a model climatology while retaining the spatial and temporal signatures of the satellite observations. As a consequence, they can be used to reduce the need for localized bias correction techniques typically implemented in data assimilation (DA) systems that tend to remove some of the independent information provided by satellite observations. Here, we use a statistical neural network (NN) algorithm to retrieve SMAP (Soil Moisture Active Passive) surface soil moisture estimates in the climatology of the NASA Catchment land surface model. Assimilating these estimates without additional bias correction is found to significantly reduce the model error and increase the temporal correlation against SMAP CalVal in situ observations over the contiguous United States. A comparison with assimilation experiments using traditional bias correction techniques shows that the NN approach better retains the independent information provided by the SMAP observations and thus leads to larger model skill improvements during the assimilation. A comparison with the SMAP Level 4 product shows that the NN approach is able to provide comparable skill improvements and thus represents a viable assimilation approach.

  15. Assimilation of GNSS radio occultation observations in GRAPES

    Science.gov (United States)

    Liu, Y.; Xue, J.

    2014-11-01

    This paper reviews the development of the global navigation satellite system (GNSS) radio occultation (RO) observations assimilation in the Global/Regional Assimilation and PrEdiction System (GRAPES) of China Meteorological Administration, including the choice of data to assimilate, the data quality control, the observation operator, the tuning of observation error, and the results of the observation impact experiments. The results indicate that RO data have a significantly positive effect on analysis and forecast at all ranges in GRAPES, not only in the Southern Hemisphere where conventional observations are lacking but also in the Northern Hemisphere where data are rich. It is noted that a relatively simple assimilation and forecast system in which only the conventional and RO observation are assimilated still has analysis and forecast skill even after nine months integration, and the analysis difference between both hemispheres is gradually reduced with height when compared with NCEP (National Centers for Environmental Prediction) analyses. Finally, as a result of the new on-board payload of the Chinese FengYun-3 (FY-3) satellites, the research status of the RO of FY-3 satellites is also presented.

  16. Data Assimilation in Hydrodynamic Models of Continental Shelf Seas

    DEFF Research Database (Denmark)

    Sørensen, Jacob Viborg Tornfeldt

    2004-01-01

    of a stochastic state propagation step using a numerical hydrodynamic model and an update step based on a best linear unbiased estimator when new measurements are available. The main challenge is to construct a stochastic model of the high dimensional ocean state that provides su cient skill for a proper update....... Assimilation of sea surface temperature and parameter estimation in hydrodynamic models are also considered. The main focus has been on the development of robust and efficient techniques applicable in real operational settings. The applied assimilation techniques all use a Kalman filter approach. They consist...... and forecast skill in the Inner Danish Waters. The framework for combining data assimilation and off-line error correction techniques is discussed and presented. Early results show a potential for such an approach, but a more elaborate investigation is needed to further develop the idea. Finally, work has been...

  17. Data assimilation on atmospheric dispersion of radioactive materials

    DEFF Research Database (Denmark)

    Drews, Martin

    , radiological observations, e.g. dose rate measurements, can be used to improve these model predictions and to obtain real-time estimates of the atmospheric dispersion parameters. This thesis examines data assimilation in the context of atmospheric dispersion of radioactive materials. In particular, it presents...... assimilation methods in a realistic setting. New experimental studies of atmospheric dispersion of radioactive material was carried out in October 2001 at the SCK"CEN in Mol, Belgium. In the Mol experiment, the radiation field from routine releases of 41 Ar is recorded by an array of gamma detectors along...... for evaluation of gamma dose rate models and for development and testing of data assimilation methods for atmospheric dispersion of radioactive materials. The Mol dataset has been used for experimental evaluation of the Gaussian plume model and the RIMPUFF model; the results of these studies are presented...

  18. Storm surge model based on variational data assimilation method

    Directory of Open Access Journals (Sweden)

    Shi-li Huang

    2010-06-01

    Full Text Available By combining computation and observation information, the variational data assimilation method has the ability to eliminate errors caused by the uncertainty of parameters in practical forecasting. It was applied to a storm surge model based on unstructured grids with high spatial resolution meant for improving the forecasting accuracy of the storm surge. By controlling the wind stress drag coefficient, the variation-based model was developed and validated through data assimilation tests in an actual storm surge induced by a typhoon. In the data assimilation tests, the model accurately identified the wind stress drag coefficient and obtained results close to the true state. Then, the actual storm surge induced by Typhoon 0515 was forecast by the developed model, and the results demonstrate its efficiency in practical application.

  19. Assimilating models and data to enhance predictions of shoreline evolution

    Science.gov (United States)

    Long, Joseph W.; Plant, Nathaniel G.; Smith, Jane McKee; Lynett, Patrick

    2010-01-01

    A modeling system that considers both long- and short-term process-driven shoreline change is presented. The modeling system is integrated into a data assimilation framework that uses sparse observations of shoreline change to correct a model forecast and to determine unobserved model variables and free parameters. Application of the assimilation algorithm also provides quantitative statistical estimates of uncertainty that can be applied to coastal hazard and vulnerability assessments. Significant attention is given to the estimation of four non-observable quantities using the data assimilation framework that utilizes only one observable process (i.e. ,shoreline change). The general framework discussed here can be applied to many other geophysical processes by simply changing the model component to one applicable to the processes of interest.

  20. Data assimilation in the decision support system RODOS

    DEFF Research Database (Denmark)

    Rojas-Palma, C.; Madsen, H.; Gering, F.

    2003-01-01

    . The process of combining model predictions and observations, usually referred to as data assimilation, is described in this article within the framework of the real time on-line decision support system (RODOS) for off-site nuclear emergency management in Europe. Data assimilation capabilities, based on Kalman...... filters, are under development for several modules of the RODOS system, including the atmospheric dispersion, deposition, food chain and hydrological models. The use of such a generic data assimilation methodology enables the propagation of uncertainties throughout the various modules of the system....... This would in turn provide decision makers with uncertainty estimates taking into account both model and observation errors. This paper describes the methodology employed as well as results of some preliminary studies based on simulated data....

  1. The Impact of the Assimilation of Aquarius Sea Surface Salinity Data in the GEOS Ocean Data Assimilation System

    Science.gov (United States)

    Vernieres, Guillaume Rene Jean; Kovach, Robin M.; Keppenne, Christian L.; Akella, Santharam; Brucker, Ludovic; Dinnat, Emmanuel Phillippe

    2014-01-01

    Ocean salinity and temperature differences drive thermohaline circulations. These properties also play a key role in the ocean-atmosphere coupling. With the availability of L-band space-borne observations, it becomes possible to provide global scale sea surface salinity (SSS) distribution. This study analyzes globally the along-track (Level 2) Aquarius SSS retrievals obtained using both passive and active L-band observations. Aquarius alongtrack retrieved SSS are assimilated into the ocean data assimilation component of Version 5 of the Goddard Earth Observing System (GEOS-5) assimilation and forecast model. We present a methodology to correct the large biases and errors apparent in Version 2.0 of the Aquarius SSS retrieval algorithm and map the observed Aquarius SSS retrieval into the ocean models bulk salinity in the topmost layer. The impact of the assimilation of the corrected SSS on the salinity analysis is evaluated by comparisons with insitu salinity observations from Argo. The results show a significant reduction of the global biases and RMS of observations-minus-forecast differences at in-situ locations. The most striking results are found in the tropics and southern latitudes. Our results highlight the complementary role and problems that arise during the assimilation of salinity information from in-situ (Argo) and space-borne surface (SSS) observations

  2. Assimilation scheme of the Mediterranean Forecasting System: operational implementation

    Directory of Open Access Journals (Sweden)

    E. Demirov

    2003-01-01

    Full Text Available This paper describes the operational implementation of the data assimilation scheme for the Mediterranean Forecasting System Pilot Project (MFSPP. The assimilation scheme, System for Ocean Forecast and Analysis (SOFA, is a reduced order Optimal Interpolation (OI scheme. The order reduction is achieved by projection of the state vector into vertical Empirical Orthogonal Functions (EOF. The data assimilated are Sea Level Anomaly (SLA and temperature profiles from Expandable Bathy Termographs (XBT. The data collection, quality control, assimilation and forecast procedures are all done in Near Real Time (NRT. The OI is used intermittently with an assimilation cycle of one week so that an analysis is produced once a week. The forecast is then done for ten days following the analysis day. The root mean square (RMS between the model forecast and the analysis (the forecast RMS is below 0.7°C in the surface layers and below 0.2°C in the layers deeper than 200 m for all the ten forecast days. The RMS between forecast and initial condition (persistence RMS is higher than forecast RMS after the first day. This means that the model improves forecast with respect to persistence. The calculation of the misfit between the forecast and the satellite data suggests that the model solution represents well the main space and time variability of the SLA except for a relatively short period of three – four weeks during the summer when the data show a fast transition between the cyclonic winter and anti-cyclonic summer regimes. This occurs in the surface layers that are not corrected by our assimilation scheme hypothesis. On the basis of the forecast skill scores analysis, conclusions are drawn about future improvements. Key words. Oceanography; general (marginal and semi-enclosed seas; numerical modeling; ocean prediction

  3. Assimilation scheme of the Mediterranean Forecasting System: operational implementation

    Directory of Open Access Journals (Sweden)

    E. Demirov

    Full Text Available This paper describes the operational implementation of the data assimilation scheme for the Mediterranean Forecasting System Pilot Project (MFSPP. The assimilation scheme, System for Ocean Forecast and Analysis (SOFA, is a reduced order Optimal Interpolation (OI scheme. The order reduction is achieved by projection of the state vector into vertical Empirical Orthogonal Functions (EOF. The data assimilated are Sea Level Anomaly (SLA and temperature profiles from Expandable Bathy Termographs (XBT. The data collection, quality control, assimilation and forecast procedures are all done in Near Real Time (NRT. The OI is used intermittently with an assimilation cycle of one week so that an analysis is produced once a week. The forecast is then done for ten days following the analysis day. The root mean square (RMS between the model forecast and the analysis (the forecast RMS is below 0.7°C in the surface layers and below 0.2°C in the layers deeper than 200 m for all the ten forecast days. The RMS between forecast and initial condition (persistence RMS is higher than forecast RMS after the first day. This means that the model improves forecast with respect to persistence. The calculation of the misfit between the forecast and the satellite data suggests that the model solution represents well the main space and time variability of the SLA except for a relatively short period of three – four weeks during the summer when the data show a fast transition between the cyclonic winter and anti-cyclonic summer regimes. This occurs in the surface layers that are not corrected by our assimilation scheme hypothesis. On the basis of the forecast skill scores analysis, conclusions are drawn about future improvements.

    Key words. Oceanography; general (marginal and semi-enclosed seas; numerical modeling; ocean prediction

  4. SMAP Data Assimilation at NASA SPoRT

    Science.gov (United States)

    Blankenship, Clay B.; Case, Jonathan L.; Zavodsky, Bradley T.

    2016-01-01

    The NASA Short-Term Prediction Research and Transition (SPoRT) Center maintains a near-real- time run of the Noah Land Surface Model within the Land Information System (LIS) at 3-km resolution. Soil moisture products from this model are used by several NOAA/National Weather Service Weather Forecast Offices for flood and drought situational awareness. We have implemented assimilation of soil moisture retrievals from the Soil Moisture Ocean Salinity (SMOS) and Soil Moisture Active/ Passive (SMAP) satellites, and are now evaluating the SMAP assimilation. The SMAP-enhanced LIS product is planned for public release by October 2016.

  5. Multivariate and Multiscale Data Assimilation in Terrestrial Systems: A Review

    Directory of Open Access Journals (Sweden)

    Harry Vereecken

    2012-11-01

    Full Text Available More and more terrestrial observational networks are being established to monitor climatic, hydrological and land-use changes in different regions of the World. In these networks, time series of states and fluxes are recorded in an automated manner, often with a high temporal resolution. These data are important for the understanding of water, energy, and/or matter fluxes, as well as their biological and physical drivers and interactions with and within the terrestrial system. Similarly, the number and accuracy of variables, which can be observed by spaceborne sensors, are increasing. Data assimilation (DA methods utilize these observations in terrestrial models in order to increase process knowledge as well as to improve forecasts for the system being studied. The widely implemented automation in observing environmental states and fluxes makes an operational computation more and more feasible, and it opens the perspective of short-time forecasts of the state of terrestrial systems. In this paper, we review the state of the art with respect to DA focusing on the joint assimilation of observational data precedents from different spatial scales and different data types. An introduction is given to different DA methods, such as the Ensemble Kalman Filter (EnKF, Particle Filter (PF and variational methods (3/4D-VAR. In this review, we distinguish between four major DA approaches: (1 univariate single-scale DA (UVSS, which is the approach used in the majority of published DA applications, (2 univariate multiscale DA (UVMS referring to a methodology which acknowledges that at least some of the assimilated data are measured at a different scale than the computational grid scale, (3 multivariate single-scale DA (MVSS dealing with the assimilation of at least two different data types, and (4 combined multivariate multiscale DA (MVMS. Finally, we conclude with a discussion on the advantages and disadvantages of the assimilation of multiple data types in a

  6. Multivariate and multiscale data assimilation in terrestrial systems: a review.

    Science.gov (United States)

    Montzka, Carsten; Pauwels, Valentijn R N; Franssen, Harrie-Jan Hendricks; Han, Xujun; Vereecken, Harry

    2012-11-26

    More and more terrestrial observational networks are being established to monitor climatic, hydrological and land-use changes in different regions of the World. In these networks, time series of states and fluxes are recorded in an automated manner, often with a high temporal resolution. These data are important for the understanding of water, energy, and/or matter fluxes, as well as their biological and physical drivers and interactions with and within the terrestrial system. Similarly, the number and accuracy of variables, which can be observed by spaceborne sensors, are increasing. Data assimilation (DA) methods utilize these observations in terrestrial models in order to increase process knowledge as well as to improve forecasts for the system being studied. The widely implemented automation in observing environmental states and fluxes makes an operational computation more and more feasible, and it opens the perspective of short-time forecasts of the state of terrestrial systems. In this paper, we review the state of the art with respect to DA focusing on the joint assimilation of observational data precedents from different spatial scales and different data types. An introduction is given to different DA methods, such as the Ensemble Kalman Filter (EnKF), Particle Filter (PF) and variational methods (3/4D-VAR). In this review, we distinguish between four major DA approaches: (1) univariate single-scale DA (UVSS), which is the approach used in the majority of published DA applications, (2) univariate multiscale DA (UVMS) referring to a methodology which acknowledges that at least some of the assimilated data are measured at a different scale than the computational grid scale, (3) multivariate single-scale DA (MVSS) dealing with the assimilation of at least two different data types, and (4) combined multivariate multiscale DA (MVMS). Finally, we conclude with a discussion on the advantages and disadvantages of the assimilation of multiple data types in a

  7. HOW DO IMMIGRANTS SPEND THEIR TIME?: THE PROCESS OF ASSIMILATION.

    Science.gov (United States)

    Hamermesh, Daniel S; Trejo, Stephen J

    2013-04-01

    Sharp differences in time use by nativity emerge when activities are distinguished by incidence and intensity in recent U.S. data. A model with daily fixed costs for assimilating activities predicts immigrants are less likely than natives to undertake such activities on a given day; but those who do will spend relatively more time on them. Activities such as purchasing, education, and market work conform to the model. Other results suggest that fixed costs for assimilating activities are higher for immigrants with poor English proficiency or who originate in less developed countries. An analysis of comparable Australian data yields similar results.

  8. Fundamentals of Modeling, Data Assimilation, and High-performance Computing

    Science.gov (United States)

    Rood, Richard B.

    2005-01-01

    This lecture will introduce the concepts of modeling, data assimilation and high- performance computing as it relates to the study of atmospheric composition. The lecture will work from basic definitions and will strive to provide a framework for thinking about development and application of models and data assimilation systems. It will not provide technical or algorithmic information, leaving that to textbooks, technical reports, and ultimately scientific journals. References to a number of textbooks and papers will be provided as a gateway to the literature.

  9. Assimilation of radar-based nowcast into HIRLAM NWP model

    DEFF Research Database (Denmark)

    Jensen, David Getreuer; Petersen, Claus; Rasmussen, Michael R.

    2015-01-01

    . A selection criterion based on spatial coverage and temporal duration is applied to identify rain events for evaluation. Eight events from August 2010 comply with the criteria and additionally, an extreme event on 2 July 2011 is also evaluated. The RED assimilated NWP model is verified against a non...... by correlation) methodology and are generated from cleaned radar mosaics from the Danish weather radar network. The assimilation technique is a newly developed method that increases model precipitation by increasing low-level convergence and decreasing convergence aloft in order to increase the vertical velocity....... The level of improved predictability relies on the RED quality, which again relies on the type of event....

  10. Gaia Assorted Mass Binaries Long Excluded from SLoWPoKES (GAMBLES): Identifying Ultra-wide Binary Pairs with Components of Diverse Mass

    Science.gov (United States)

    Oelkers, Ryan J.; Stassun, Keivan G.; Dhital, Saurav

    2017-06-01

    The formation and evolution of binary star systems are some of the remaining key questions in modern astronomy. Wide binary pairs (separations >103 au) are particularly intriguing because their low binding energies make it difficult for the stars to stay gravitationally bound over extended timescales, and thus to probe the dynamics of binary formation and dissolution. Our previous SLoWPoKES catalogs, I and II, provided the largest and most complete sample of wide-binary pairs of low masses. Here we present an extension of these catalogs to a broad range of stellar masses: the Gaia Assorted Mass Binaries Long Excluded from SloWPoKES (GAMBLES), comprising 8660 statistically significant wide pairs that we make available in a living online database. Within this catalog we identify a subset of 543 long-lived (dissipation timescale >1.5 Gyr) candidate binary pairs, of assorted mass, with typical separations between 103 and 105.5 au (0.002-1.5 pc), using the published distances and proper motions from the Tycho-Gaia Astrometric Solution and Sloan Digital Sky Survey photometry. Each pair has at most a false positive probability of 0.05; the total expectation is 2.44 false binaries in our sample. Among these, we find 22 systems with 3 components, 1 system with 4 components, and 15 pairs consisting of at least 1 possible red giant. We find the largest long-lived binary separation to be nearly 3.2 pc even so, >76% of GAMBLES long-lived binaries have large binding energies and dissipation lifetimes longer than 1.5 Gyr. Finally, we find that the distribution of binary separations is clearly bimodal, corroborating the findings from SloWPoKES and suggesting multiple pathways for the formation and dissipation of the widest binaries in the Galaxy.

  11. A primer for data assimilation with ecological models using Markov Chain Monte Carlo (MCMC).

    Science.gov (United States)

    Zobitz, J M; Desai, A R; Moore, D J P; Chadwick, M A

    2011-11-01

    Data assimilation, or the fusion of a mathematical model with ecological data, is rapidly expanding knowledge of ecological systems across multiple spatial and temporal scales. As the amount of ecological data available to a broader audience increases, quantitative proficiency with data assimilation tools and techniques will be an essential skill for ecological analysis in this data-rich era. We provide a data assimilation primer for the novice user by (1) reviewing data assimilation terminology and methodology, (2) showcasing a variety of data assimilation studies across the ecological, environmental, and atmospheric sciences with the aim of gaining an understanding of potential applications of data assimilation, and (3) applying data assimilation in specific ecological examples to determine the components of net ecosystem carbon uptake in a forest and also the population dynamics of the mayfly (Hexagenia limbata, Serville). The review and examples are then used to provide guiding principles to newly proficient data assimilation practitioners.

  12. Does assimilation of problematic experiences predict a decrease in symptom intensity?

    Science.gov (United States)

    Basto, Isabel Morais; Stiles, William B; Rijo, Daniel; Salgado, João

    2017-09-10

    The assimilation model describes therapeutic change as an integration of experiences that had previously been problematic, distressing, avoided, or warded off. This study assessed whether assimilation was associated with treatment outcome in a sample of psychotherapeutic treatments for depression. Further, it assessed the direction of the association-whether increasing assimilation predicted decreases in symptom intensity or decreasing symptom intensity predicted increases in assimilation. Participants were 22 clients with mild to moderate depression drawn from a clinical trial comparing cognitive behavioral therapy with emotion-focused therapy. The direction of prediction between assimilation progress and changes in self-reported symptom intensity was assessed. The assimilation progress was shown to be a better predictor of decreases in symptom intensity than the reverse. The results supported the assimilation model's suggestion that assimilation progress promotes decreases in symptom intensity in the treatment of clients with major depressive disorder. Copyright © 2017 The Authors. Clinical Psychology & Psychotherapy Published by John Wiley & Sons Ltd.

  13. Effect of assimilate availability on flower characteristics and plant height of cut chrysanthemum: an integrated study

    NARCIS (Netherlands)

    Carvalho, S.M.P.; Heuvelink, E.

    2003-01-01

    The influence of assimilate availability on the number of flowers per plant, individual flower size and plant height of chrysanthemum was investigated in different seasons, integrating the results from eight greenhouse experiments. Increased assimilate availability was obtained by higher light

  14. Sensitivity of Satellite Altimetry Data Assimilation on a Weapon Acoustic Preset Using MODAS

    National Research Council Canada - National Science Library

    Chu, Peter; Mancini, Steven; Gottshall, Eric; Cwalina, David; Barron, Charlie N

    2007-01-01

    ...) is analyzed with SSP derived from the modular ocean data assimilation system (MODAS). The MODAS fields differ in that one uses altimeter data assimilated from three satellites while the other uses no altimeter data...

  15. "Arab Americans and Segmented Assimilation: Looking Beyond the Theory to the Reality in the Detroit Metro Area"

    OpenAIRE

    Weaver, Kristin

    2010-01-01

    This thesis aims to apply Segmented Assimilation Theory to the Arab-American community in Metropolitan Detroit. Segmented assimilation theory relates to second-generation immigrants, and proposes three possible assimilation-trajectories. The findings of this thesis show that Detroit's Arab Americans are most likely to follow what segmented assimilation scholars call "selective assimilation." Selective assimilation is the process where the second generation is able to use resources and network...

  16. Maternal effects and beta-carotene assimilation in Canary chicks.

    Science.gov (United States)

    Tanvez, Aurélie; Amy, Mathieu; Chastel, Olivier; Leboucher, Gérard

    2009-03-02

    Carotenoids are pigments responsible for the red, orange and yellow coloration of plants and animals. They may be beneficial in two ways; they have a powerful antioxidant activity, and they can behave as an immunostimulant. Animals however cannot synthesize carotenoids de novo, they must obtain them through their diet. In our experiments on Canaries, we investigated how mothers transfer their dietary carotenoid-related benefits to their offspring; either through the egg, or through the diet (during chicks' feeding). Female Canaries were allowed to access beta-carotene enriched food during egg formation and/or chicks' feeding. We sorted the chicks into four groups using the period when they assimilated the beta-carotene as a variable. The four groups were: (i) before hatching (from yolk), (ii) after hatching (from maternal feeding), (iii) before and after hatching, or (iv) never. Colorimetry and HPLC analysis from sub-samples of yolks confirmed the maternal transfer of dietary carotenoids to the yolk. Our results show that benefits from maternal dietary carotenoids are transferred to the chicks, but according to the period when they are assimilated by the chicks, the physiological effects are different. It was found that the chicks' growth was enhanced when carotenoids were assimilated both before and after hatching. However an increase in cellular immunity efficiency only occurs when the assimilation takes place after hatching.

  17. Probability Maps for the Visualization of Assimilation Ensemble Flow Data

    KAUST Repository

    Hollt, Thomas

    2015-05-25

    Ocean forecasts nowadays are created by running ensemble simulations in combination with data assimilation techniques. Most of these techniques resample the ensemble members after each assimilation cycle. This means that in a time series, after resampling, every member can follow up on any of the members before resampling. Tracking behavior over time, such as all possible paths of a particle in an ensemble vector field, becomes very difficult, as the number of combinations rises exponentially with the number of assimilation cycles. In general a single possible path is not of interest but only the probabilities that any point in space might be reached by a particle at some point in time. In this work we present an approach using probability-weighted piecewise particle trajectories to allow such a mapping interactively, instead of tracing quadrillions of individual particles. We achieve interactive rates by binning the domain and splitting up the tracing process into the individual assimilation cycles, so that particles that fall into the same bin after a cycle can be treated as a single particle with a larger probability as input for the next time step. As a result we loose the possibility to track individual particles, but can create probability maps for any desired seed at interactive rates.

  18. Sulfide assimilation by ectosymbionts of the sessile ciliate, Zoothamnium niveum

    DEFF Research Database (Denmark)

    Røy, Hans; Vopel, Kay; Huettel, Marcus

    2009-01-01

    was the free-flowing water although the size of the colonies suggests that they live partly submerged in the diffusive boundary layer. We showed that the filtered volume allows Z. niveum to assimilate sufficient sulfide to sustain the symbiosis at a few micromoles per liter in ambient concentration. Numerical...

  19. Voicing and Devoicing Assimilation of French /s/ and /z/

    Science.gov (United States)

    Abdelli-Beruh, Nassima B.

    2012-01-01

    The present acoustic-phonetic study explores whether voicing and devoicing assimilations of French fricatives are equivalent in magnitude and whether they operate similarly (i.e., complete vs. gradient, obligatory vs. optional, regressive vs. progressive). It concurrently assesses the contribution of speakers' articulation rate to the proportion…

  20. Growth, assimilate partitioning and grain yield response of soybean ...

    African Journals Online (AJOL)

    This investigation tested variation in the growth components, assimilate partitioning and grain yield of soybean (Glycine max L. Merrrill) varieties established in CO2 enriched atmosphere when inoculated with mixtures of Arbuscular mycorrhizal fungi (AMF) species in the humid rainforest of Nigeria. A pot and a field ...

  1. Information Flow in an Atmospheric Model and Data Assimilation

    Science.gov (United States)

    Yoon, Young-noh

    2011-01-01

    Weather forecasting consists of two processes, model integration and analysis (data assimilation). During the model integration, the state estimate produced by the analysis evolves to the next cycle time according to the atmospheric model to become the background estimate. The analysis then produces a new state estimate by combining the background…

  2. assimilation efficiency in two herbivores, oreochromis niloticus and ...

    African Journals Online (AJOL)

    Preferred Customer

    that acid lyses of phytoplankton is the means for breaking down and releasing the contents of the cells. Fig. 3. Stomach fullness and stomach pH in O. niloticus at different times of the day (modified from Getachew. Teferra and Fernando, 1989). The best-fit line drawn through all assimilation efficiency values for both fish and ...

  3. Thr translocation of C-14-assimilates in Eragrostis curvula: an ...

    African Journals Online (AJOL)

    In intact plants C-14-assimilates were translocated from the treated leaf on the primary tiller to young leaves on that tiller, to secondary tillers, and also to the roots. Plants defoliated after labeling revealed movement of materials from the storage organs to all the new leaves. Here these materials were used as a respiratory ...

  4. Anterior Cingulate Cortex in Schema Assimilation and Expression

    Science.gov (United States)

    Wang, Szu-Han; Tse, Dorothy; Morris, Richard G. M.

    2012-01-01

    In humans and in animals, mental schemas can store information within an associative framework that enables rapid and efficient assimilation of new information. Using a hippocampal-dependent paired-associate task, we now report that the anterior cingulate cortex is part of a neocortical network of schema storage with NMDA receptor-mediated…

  5. Normalization: Integration or Assimilation? A Response to Miquel Strubell.

    Science.gov (United States)

    Atkinson, David

    1998-01-01

    Responds to an article by Strubell, "Language, Democracy, and Devolution in Catalonia," focusing on the position of Castilian-speaking individuals resident and working in Catalonia. The paper notes that the policy of assimilating migrants is no longer accepted without question, and it suggests diglossia as the only way to provide…

  6. Economic Assimilation and Outmigration of Immigrants in West-Germany

    NARCIS (Netherlands)

    Bellemare, C.

    2003-01-01

    By analyzing earnings of observed immigrants workers, the literature on the economic assimilation of immigrants has generally overlooked two potentially important selectivity issues.First, earnings of immigrant workers may di¿er substantially from those of non-workers.Second, earnings of immigrants

  7. Catchment-scale hydrological modeling and data assimilation

    NARCIS (Netherlands)

    Troch, P.A.A.; Paniconi, C.; McLaughlin, D.

    2003-01-01

    This special issue of Advances in Water Resources presents recent progress in the application of DA (data assimilation) for distributed hydrological modeling and in the use of in situ and remote sensing datasets for hydrological analysis and parameter estimation. The papers were presented at the De

  8. Homophily and assimilation among sportactive adolescent substance users

    NARCIS (Netherlands)

    Pearson, M; Steglich, Ch.; Snijders, T.A.B.

    2006-01-01

    We analyse the co-evolution of social networks and substance use behaviour of adolescents and address the problem of separating the effects of homophily and assimilation. Adolescents who prefer friends with the same substance-use behaviour exhibit the homophily principle. Adolescents who adapt their

  9. modification has been assimilated contain only genes which were ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 85; Issue 2. The Genetic Basis of the `Assimilated Bithorax' Stock (Published on 1957 J. Genet. 55, 241-245). C. H. Waddington. J. Genet. Classic Volume 85 Issue 2 August 2006 pp 101-105. Fulltext. Click here to view fulltext PDF. Permanent link:

  10. Assimilation of Doppler weather radar observations in a mesoscale ...

    Indian Academy of Sciences (India)

    ral and spatial resolution for determining the ini- tial conditions. ... rized as an iterative solution of equation (1) to find an analysis state x that ... satellites. Table 2. Summary of MM5 forecast experiments. Experiment. Initialization and assimilation. CTRL−GSFC. Using global analysis of NCMRWF T80 model without data ...

  11. Modelling nitrogen assimilation of Escherichia coli at low ammonium concentration.

    NARCIS (Netherlands)

    Ma, H.; Boogerd, F.C.; Goryanin, I.

    2009-01-01

    Modelling is an important methodology in systems biology research. In this paper, we presented a kinetic model for the complex ammonium assimilation regulation system of Escherichia coli. Based on a previously published model, the new model included AmtB mediated ammonium transport and AmtB

  12. Phenological model of bird cherry Padus racemosa with data assimilation

    Science.gov (United States)

    Kalvāns, Andis; Sīle, Tija; Kalvāne, Gunta

    2017-12-01

    The accuracy of the operational models can be improved by using observational data to shift the model state in a process called data assimilation. Here, a data assimilation approach using the temperature similarity to control the extent of extrapolation of point-like phenological observations is explored. A degree-day model is used to describe the spring phenology of the bird cherry Padus racemosa in the Baltic region in 2014. The model results are compared to phenological observations that are expressed on a continuous scale based on the BBCH code. The air temperature data are derived from a numerical weather prediction (NWP) model. It is assumed that the phenology at two points with a similar temperature pattern should be similar. The root mean squared difference (RMSD) between the time series of hourly temperature data over a selected time interval are used to measure the temperature similarity of any two points. A sigmoidal function is used to scale the RMSD into a weight factor that determines how the modelled and observed phenophases are combined in the data assimilation. The parameter space for determining the weight of observations is explored. It is found that data assimilation improved the accuracy of the phenological model and that the value of the point-like observations can be increased through using a weighting function based on environmental parameters, such as temperature.

  13. Opinion Dynamics with Heterogeneous Interactions and Information Assimilation

    Science.gov (United States)

    Mir Tabatabaei, Seydeh Anahita

    2013-01-01

    In any modern society, individuals interact to form opinions on various topics, including economic, political, and social aspects. Opinions evolve as the result of the continuous exchange of information among individuals and of the assimilation of information distributed by media. The impact of individuals' opinions on each other forms a network,…

  14. Local ensemble assimilation scheme with global constraints and conservation

    Science.gov (United States)

    Barth, Alexander; Yan, Yajing; Alvera-Azcárate, Aida; Beckers, Jean-Marie

    2016-12-01

    Ensemble assimilation schemes applied in their original, global formulation respect linear conservation properties if the ensemble perturbations are set up accordingly. For realistic ocean systems, only a relatively small number of ensemble members can be calculated. A localization of the ensemble increment is therefore necessary to filter out spurious long-range correlations. The conservation of the global properties will be lost if the assimilation is performed locally, since the conservation requires a coupling between all model grid points which is removed by the localization. The distribution of ocean observations is often highly inhomogeneous. Systematic errors of the observed parts of the ocean state can lead to spurious adjustment of the non-observed parts via data assimilation and thus to a spurious increase or decrease in long-term simulations of global properties which should be conserved. In this paper, we propose a local assimilation scheme (with different variants and assumptions) which can satisfy global conservation properties. The proposed scheme can also be used for non-local observation operators. Different variants of the proposed scheme are tested in an idealized model and compared to the traditional covariance localization with an ad-hoc step enforcing conservation. It is shown that the inclusion of the conservation property reduces the total RMS error and that the presented stochastic and deterministic schemes avoiding error space rotation provide better results than the traditional covariance localization.

  15. Parameter estimation for subsurface flow using ensemble data assimilation

    NARCIS (Netherlands)

    S. Ruchi (Sangeetika); S. Dubinkina (Svetlana)

    2017-01-01

    textabstractOver the years, different data assimilation methods have been implemented to acquire improved estimations of model parameters by adjusting the uncertain parameter values in such a way that the mathematical model approximates the observed data as closely and consistently as possible.

  16. Lexical frequency and voice assimilation in complex words in Dutch

    Science.gov (United States)

    Ernestus, Mirjam; Lahey, Mybeth; Verhees, Femke; Baayen, Harald

    2004-05-01

    Words with higher token frequencies tend to have more reduced acoustic realizations than lower frequency words (e.g., Hay, 2000; Bybee, 2001; Jurafsky et al., 2001). This study documents frequency effects for regressive voice assimilation (obstruents are voiced before voiced plosives) in Dutch morphologically complex words in the subcorpus of read-aloud novels in the corpus of spoken Dutch (Oostdijk et al., 2002). As expected, the initial obstruent of the cluster tends to be absent more often as lexical frequency increases. More importantly, as frequency increases, the duration of vocal-fold vibration in the cluster decreases, and the duration of the bursts in the cluster increases, after partialing out cluster duration. This suggests that there is less voicing for higher-frequency words. In fact, phonetic transcriptions show regressive voice assimilation for only half of the words and progressive voice assimilation for one third. Interestingly, the progressive voice assimilation observed for higher-frequency complex words renders these complex words more similar to monomorphemic words: Dutch monomorphemic words typically contain voiceless obstruent clusters (Zonneveld, 1983). Such high-frequency complex words may therefore be less easily parsed into their constituent morphemes (cf. Hay, 2000), favoring whole word lexical access (Bertram et al., 2000).

  17. Naming game with biased assimilation over adaptive networks

    Science.gov (United States)

    Fu, Guiyuan; Zhang, Weidong

    2018-01-01

    The dynamics of two-word naming game incorporating the influence of biased assimilation over adaptive network is investigated in this paper. Firstly an extended naming game with biased assimilation (NGBA) is proposed. The hearer in NGBA accepts the received information in a biased manner, where he may refuse to accept the conveyed word from the speaker with a predefined probability, if the conveyed word is different from his current memory. Secondly, the adaptive network is formulated by rewiring the links. Theoretical analysis is developed to show that the population in NGBA will eventually reach global consensus on either A or B. Numerical simulation results show that the larger strength of biased assimilation on both words, the slower convergence speed, while larger strength of biased assimilation on only one word can slightly accelerate the convergence; larger population size can make the rate of convergence slower to a large extent when it increases from a relatively small size, while such effect becomes minor when the population size is large; the behavior of adaptively reconnecting the existing links can greatly accelerate the rate of convergence especially on the sparse connected network.

  18. Assimilation (in vitro) of cholesterol by yogurt bacteria.

    Science.gov (United States)

    Dilmi-Bouras, Abdelkader

    2006-01-01

    A considerable variation is noticed between the different species studied and even between the strains of the same species, in the assimilation of cholesterol in synthetic media, in presence of different concentrations of bile salts and under anaerobiosis conditions. The obtained results show that certain strains of Streptococcus thermophilus and Lactobacillus bulgaricus resist bile salts and assimilate appreciable cholesterol quantities in their presence. The study of associations shows that only strains assimilating cholesterol in a pure state remain active when they are put in associations, but there is no additional effect. However, the symbiotic effect between Streptococcus thermophilus and Lactobacillus bulgaricus of yogurt, with regard to bile salts, is confirmed. The lactic fermenters of yogurt (Y2) reduce the levels of total cholesterol, HDL-cholesterol and LDL-cholesterol, in a well-balanced way. In all cases, the assimilated quantity of HDL-cholesterol is lower than that of LDL-cholesterol. Moreover, yogurt Y2 keeps a significant number of bacteria, superior to 10(8) cells ml(-1), and has a good taste 10 days after its production.

  19. Satellite Data Assimilation within KIAPS-LETKF system

    Science.gov (United States)

    Jo, Y.; Lee, S., Sr.; Cho, K.

    2016-12-01

    Korea Institute of Atmospheric Prediction Systems (KIAPS) has been developing an ensemble data assimilation system using four-dimensional local ensemble transform kalman filter (LETKF; Hunt et al., 2007) within KIAPS Integrated Model (KIM), referred to as "KIAPS-LETKF". KIAPS-LETKF system was successfully evaluated with various Observing System Simulation Experiments (OSSEs) with NCAR Community Atmospheric Model - Spectral Element (Kang et al., 2013), which has fully unstructured quadrilateral meshes based on the cubed-sphere grid as the same grid system of KIM. Recently, assimilation of real observations has been conducted within the KIAPS-LETKF system with four-dimensional covariance functions over the 6-hr assimilation window. Then, conventional (e.g., sonde, aircraft, and surface) and satellite (e.g., AMSU-A, IASI, GPS-RO, and AMV) observations have been provided by the KIAPS Package for Observation Processing (KPOP). Wind speed prediction was found most beneficial due to ingestion of AMV and for the temperature prediction the improvement in assimilation is mostly due to ingestion of AMSU-A and IASI. However, some degradation in the simulation of the GPS-RO is presented in the upper stratosphere, even though GPS-RO leads positive impacts on the analysis and forecasts. We plan to test the bias correction method and several vertical localization strategies for radiance observations to improve analysis and forecast impacts.

  20. Multi-instrumental Analysis and Assimilation of Carbon Monoxide Data

    Science.gov (United States)

    Yudin, V.

    2008-12-01

    Challenges and perspectives of data fusion studies with the space-borne CO retrievals in the troposphere and lower stratosphere are discussed in this paper. The combined chemical data assimilation and inverse modeling scheme that analyze the MOPITT CO retrievals with assumption of the bias-free data are outlined and year-to-year variations of analyzed regional CO concentrations and optimized surface CO emissions are presented. Uncertainties of CO and quantification of the NH boreal fire emissions (May-September) in chemical transport model forecasts and analysis are examined employing data from three thermal infrared CO sensors (AIRS, TES, MOPITT). Paper evaluates and discusses differences between the multi- instrumental CO products characterized by resolution kernels and a priori. For chemical data assimilation studies the perspectives to combine the multi-sensor information from the CO sensitive radiances (microwave, MLS, near-infrared, SCIAMACHY, and thermal channels, MOPITT, AIRS, TES) to optimize the partial CO sub-columns between the surface and the tropopause are considered. The possible data quality controls, model and data bias correction schemes, along with scale-dependent retrieval/assimilation algorithms are proposed to unify analysis of the multi-sensor CO measurements (radiances and/or retrievals) in the single data assimilation (CO concentrations) and inverse modeling (CO sources) system.

  1. Music playlist generation by assimilating GMMs into SOMs

    NARCIS (Netherlands)

    Balkema, Wietse; van der Heijden, Ferdinand

    A method for music playlist generation, using assimilated Gaussian mixture models (GMMs) in self organizing maps (SOMs) is presented. Traditionally, the neurons in a SOM are represented by vectors, but in this paper we propose to use GMMs instead. To this end, we introduce a method to adapt a GMM

  2. Assimilation of Doppler weather radar observations in a mesoscale ...

    Indian Academy of Sciences (India)

    The simulated rainfall has also been compared with that derived from the Tropical Rainfall Measuring Mission (TRMM) satellite. The encouraging result from this study can be the basis for further investigation of the direct assimilation of radar reflectivity data in 3DVAR system. The present study indicates that Doppler radar ...

  3. Screening of oleaginous yeast with xylose assimilating capacity for ...

    African Journals Online (AJOL)

    ... in industrial-scale production. In our preliminary study, 57 oleaginous yeast with xylose assimilating capacity were isolated from 13 soil samples, 16 strains were identified as potential lipid biomass producer. Four strains which showed higher lipid content were used for further ethanol fermentation at different conditions.

  4. A reduced adjoint approach to variational data assimilation

    KAUST Repository

    Altaf, Muhammad

    2013-02-01

    The adjoint method has been used very often for variational data assimilation. The computational cost to run the adjoint model often exceeds several original model runs and the method needs significant programming efforts to implement the adjoint model code. The work proposed here is variational data assimilation based on proper orthogonal decomposition (POD) which avoids the implementation of the adjoint of the tangent linear approximation of the original nonlinear model. An ensemble of the forward model simulations is used to determine the approximation of the covariance matrix and only the dominant eigenvectors of this matrix are used to define a model subspace. The adjoint of the tangent linear model is replaced by the reduced adjoint based on this reduced space. Thus the adjoint model is run in reduced space with negligible computational cost. Once the gradient is obtained in reduced space it is projected back in full space and the minimization process is carried in full space. In the paper the reduced adjoint approach to variational data assimilation is introduced. The characteristics and performance of the method are illustrated with a number of data assimilation experiments in a ground water subsurface contaminant model. © 2012 Elsevier B.V.

  5. Satellite Sounder Data Assimilation for Improving Alaska Region Weather Forecast

    Science.gov (United States)

    Zhu, Jiang; Stevens, E.; Zhang, X.; Zavodsky, B. T.; Heinrichs, T.; Broderson, D.

    2014-01-01

    A case study and monthly statistical analysis using sounder data assimilation to improve the Alaska regional weather forecast model are presented. Weather forecast in Alaska faces challenges as well as opportunities. Alaska has a large land with multiple types of topography and coastal area. Weather forecast models must be finely tuned in order to accurately predict weather in Alaska. Being in the high-latitudes provides Alaska greater coverage of polar orbiting satellites for integration into forecasting models than the lower 48. Forecasting marine low stratus clouds is critical to the Alaska aviation and oil industry and is the current focus of the case study. NASA AIRS/CrIS sounder profiles data are used to do data assimilation for the Alaska regional weather forecast model to improve Arctic marine stratus clouds forecast. Choosing physical options for the WRF model is discussed. Preprocess of AIRS/CrIS sounder data for data assimilation is described. Local observation data, satellite data, and global data assimilation data are used to verify and/or evaluate the forecast results by the MET tools Model Evaluation Tools (MET).

  6. Abscisic acid and assimilate partitioning during seed development

    NARCIS (Netherlands)

    Bruijn, de S.M.

    1993-01-01

    This thesis describes the influence of abscisic acid (ABA) on the transport of assimilates to seeds and the deposition of reserves in seeds. It is well-known from literature that ABA accumulates in seeds during development, and that ABA concentrations in seeds correlate rather well with

  7. Assimilative Domain Proficiency and Performance in Chemistry Coursework

    Science.gov (United States)

    Byrnes, Scott William

    2010-01-01

    The assimilation and synthesis of knowledge is essential for students to be successful in chemistry, yet not all students synthesize knowledge as intended. The study used the Learning Preference Checklist to classify students into one of three learning modalities--visual, auditory, or kinesthetic (VAK). It also used the Kolb Learning Style…

  8. Improving Forecast Skill by Assimilation of AIRS Temperature Soundings

    Science.gov (United States)

    Susskind, Joel; Reale, Oreste

    2010-01-01

    AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU-A are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. The AIRS Version 5 retrieval algorithm, is now being used operationally at the Goddard DISC in the routine generation of geophysical parameters derived from AIRS/AMSU data. A major innovation in Version 5 is the ability to generate case-by-case level-by-level error estimates delta T(p) for retrieved quantities and the use of these error estimates for Quality Control. We conducted a number of data assimilation experiments using the NASA GEOS-5 Data Assimilation System as a step toward finding an optimum balance of spatial coverage and sounding accuracy with regard to improving forecast skill. The model was run at a horizontal resolution of 0.5 deg. latitude X 0.67 deg longitude with 72 vertical levels. These experiments were run during four different seasons, each using a different year. The AIRS temperature profiles were presented to the GEOS-5 analysis as rawinsonde profiles, and the profile error estimates delta (p) were used as the uncertainty for each measurement in the data assimilation process. We compared forecasts analyses generated from the analyses done by assimilation of AIRS temperature profiles with three different sets of thresholds; Standard, Medium, and Tight. Assimilation of Quality Controlled AIRS temperature profiles significantly improve 5-7 day forecast skill compared to that obtained without the benefit of AIRS data in all of the cases studied. In addition, assimilation of Quality Controlled AIRS temperature soundings performs better than assimilation of AIRS observed radiances. Based on the experiments shown, Tight Quality Control of AIRS temperature profile performs best

  9. Data Assimilation to Extract Soil Moisture Information from SMAP Observations

    Directory of Open Access Journals (Sweden)

    Jana Kolassa

    2017-11-01

    Full Text Available This study compares different methods to extract soil moisture information through the assimilation of Soil Moisture Active Passive (SMAP observations. Neural network (NN and physically-based SMAP soil moisture retrievals were assimilated into the National Aeronautics and Space Administration (NASA Catchment model over the contiguous United States for April 2015 to March 2017. By construction, the NN retrievals are consistent with the global climatology of the Catchment model soil moisture. Assimilating the NN retrievals without further bias correction improved the surface and root zone correlations against in situ measurements from 14 SMAP core validation sites (CVS by 0.12 and 0.16, respectively, over the model-only skill, and reduced the surface and root zone unbiased root-mean-square error (ubRMSE by 0.005 m 3 m − 3 and 0.001 m 3 m − 3 , respectively. The assimilation reduced the average absolute surface bias against the CVS measurements by 0.009 m 3 m − 3 , but increased the root zone bias by 0.014 m 3 m − 3 . Assimilating the NN retrievals after a localized bias correction yielded slightly lower surface correlation and ubRMSE improvements, but generally the skill differences were small. The assimilation of the physically-based SMAP Level-2 passive soil moisture retrievals using a global bias correction yielded similar skill improvements, as did the direct assimilation of locally bias-corrected SMAP brightness temperatures within the SMAP Level-4 soil moisture algorithm. The results show that global bias correction methods may be able to extract more independent information from SMAP observations compared to local bias correction methods, but without accurate quality control and observation error characterization they are also more vulnerable to adverse effects from retrieval errors related to uncertainties in the retrieval inputs and algorithm. Furthermore, the results show that using global bias correction approaches without a

  10. Lidar data assimilation for improved analyses of volcanic aerosol events

    Science.gov (United States)

    Lange, Anne Caroline; Elbern, Hendrik

    2014-05-01

    Observations of hazardous events with release of aerosols are hardly analyzable by today's data assimilation algorithms, without producing an attenuating bias. Skillful forecasts of unexpected aerosol events are essential for human health and to prevent an exposure of infirm persons and aircraft with possibly catastrophic outcome. Typical cases include mineral dust outbreaks, mostly from large desert regions, wild fires, and sea salt uplifts, while the focus aims for volcanic eruptions. In general, numerical chemistry and aerosol transport models cannot simulate such events without manual adjustments. The concept of data assimilation is able to correct the analysis, as long it is operationally implemented in the model system. Though, the tangent-linear approximation, which describes a substantial precondition for today's cutting edge data assimilation algorithms, is not valid during unexpected aerosol events. As part of the European COPERNICUS (earth observation) project MACC II and the national ESKP (Earth System Knowledge Platform) initiative, we developed a module that enables the assimilation of aerosol lidar observations, even during unforeseeable incidences of extreme emissions of particulate matter. Thereby, the influence of the background information has to be reduced adequately. Advanced lidar instruments comprise on the one hand the aspect of radiative transfer within the atmosphere and on the other hand they can deliver a detailed quantification of the detected aerosols. For the assimilation of maximal exploited lidar data, an appropriate lidar observation operator is constructed, compatible with the EURAD-IM (European Air Pollution and Dispersion - Inverse Model) system. The observation operator is able to map the modeled chemical and physical state on lidar attenuated backscatter, transmission, aerosol optical depth, as well as on the extinction and backscatter coefficients. Further, it has the ability to process the observed discrepancies with lidar

  11. A problem-solving environment for data assimilation in air quality modelling

    NARCIS (Netherlands)

    Velzen, N. van; Segers, A.J.

    2010-01-01

    A generic toolbox for data assimilation called COSTA (COmmon Set of Tools for the Assimilation of data) makes it possible to simplify the application of data assimilation to models and to try out various methods for a particular model. Concepts of object oriented programming are used to define

  12. Assimilating Tropospheric Airborne Meteorological Data Reporting (TAMDAR) Observations and the Relative Value of Other Observation Types

    Science.gov (United States)

    2014-08-01

    Assimilating Tropospheric Airborne Meteorological Data Reporting (TAMDAR) Observations and the Relative Value of Other Observation Types by...Army Research Laboratory Adelphi, MD 20783-1197 ARL-TR-7022 August 2014 Assimilating Tropospheric Airborne Meteorological Data...From - To) 15 August 2012–30 September 2013 4. TITLE AND SUBTITLE Assimilating Tropospheric Airborne Meteorological Data Reporting (TAMDAR

  13. Impact of high-resolution data assimilation of GPS zenith delay on Mediterranean heavy rainfall forecasting

    Directory of Open Access Journals (Sweden)

    K. Boniface

    2009-07-01

    Full Text Available Impact of GPS (Global Positioning System data assimilation is assessed here using a high-resolution numerical weather prediction system at 2.5 km horizontal resolution. The Zenithal Tropospheric Delay (ZTD GPS data from mesoscale networks are assimilated with the 3DVAR AROME data assimilation scheme. Data from more than 280 stations over the model domain have been assimilated during 15-day long assimilation cycles prior each of the two studied events. The results of these assimilation cycles show that the assimilation of GPS ZTD with the AROME system performs well in producing analyses closer to the ZTD observations in average. Then the impacts of assimilating GPS data on the precipitation forecast have been evaluated. For the first case, only the AROME runs starting a few hours prior the triggering of the convective system are able to simulate the convective precipitation. The assimilation of GPS ZTD observations improves the simulation of the spatial extent of the precipitation, but slightly underestimates the heaviest precipitation in that case compared with the experiment without GPS. The accuracy of the precipitation forecast for the second case is much better. The analyses from the control assimilation cycle provide already a good description of the atmosphere state that cannot be further improved by the assimilation of GPS observations. Only for the latest day (22 November 2007, significant differences have been found between the two parallel cycles. In that case, the assimilation of GPS ZTD allows to improve the first 6 to 12 h of the precipitation forecast.

  14. Impact of high-resolution data assimilation of GPS zenith delay on Mediterranean heavy rainfall forecasting

    Energy Technology Data Exchange (ETDEWEB)

    Boniface, K.; Champollion, C.; Chery, J.; Doerflinger, E. [Geosciences Montpellier, UMR 5243 CNRS-UM2 (France); Ducrocq, V.; Jaubert, G.; Yan, X.; Brousseau, P. [GAME-CNRM, CNRS-Meteo-France, Toulouse (France); Masson, F. [UMR 7516-IPGS-CNRS-EOST, Strasbourg (France)

    2009-07-01

    Impact of GPS (Global Positioning System) data assimilation is assessed here using a high-resolution numerical weather prediction system at 2.5 km horizontal resolution. The Zenithal Tropospheric Delay (ZTD) GPS data from mesoscale networks are assimilated with the 3DVAR AROME data assimilation scheme. Data from more than 280 stations over the model domain have been assimilated during 15-day long assimilation cycles prior each of the two studied events. The results of these assimilation cycles show that the assimilation of GPS ZTD with the AROME system performs well in producing analyses closer to the ZTD observations in average. Then the impacts of assimilating GPS data on the precipitation forecast have been evaluated. For the first case, only the AROME runs starting a few hours prior the triggering of the convective system are able to simulate the convective precipitation. The assimilation of GPS ZTD observations improves the simulation of the spatial extent of the precipitation, but slightly underestimates the heaviest precipitation in that case compared with the experiment without GPS. The accuracy of the precipitation forecast for the second case is much better. The analyses from the control assimilation cycle provide already a good description of the atmosphere state that cannot be further improved by the assimilation of GPS observations. Only for the latest day (22 November 2007), significant differences have been found between the two parallel cycles. In that case, the assimilation of GPS ZTD allows to improve the first 6 to 12 h of the precipitation forecast. (orig.)

  15. Assimilation of SMOS Retrievals in the Land Information System

    Science.gov (United States)

    Blankenship, Clay B.; Case, Jonathan L.; Zavodsky, Bradley T.; Crosson, William L.

    2016-01-01

    The Soil Moisture and Ocean Salinity (SMOS) satellite provides retrievals of soil moisture in the upper 5 cm with a 30-50 km resolution and a mission accuracy requirement of 0.04 cm(sub 3 cm(sub -3). These observations can be used to improve land surface model soil moisture states through data assimilation. In this paper, SMOS soil moisture retrievals are assimilated into the Noah land surface model via an Ensemble Kalman Filter within the NASA Land Information System. Bias correction is implemented using Cumulative Distribution Function (CDF) matching, with points aggregated by either land cover or soil type to reduce sampling error in generating the CDFs. An experiment was run for the warm season of 2011 to test SMOS data assimilation and to compare assimilation methods. Verification of soil moisture analyses in the 0-10 cm upper layer and root zone (0-1 m) was conducted using in situ measurements from several observing networks in the central and southeastern United States. This experiment showed that SMOS data assimilation significantly increased the anomaly correlation of Noah soil moisture with station measurements from 0.45 to 0.57 in the 0-10 cm layer. Time series at specific stations demonstrate the ability of SMOS DA to increase the dynamic range of soil moisture in a manner consistent with station measurements. Among the bias correction methods, the correction based on soil type performed best at bias reduction but also reduced correlations. The vegetation-based correction did not produce any significant differences compared to using a simple uniform correction curve.

  16. Personalized glucose forecasting for type 2 diabetes using data assimilation.

    Science.gov (United States)

    Albers, David J; Levine, Matthew; Gluckman, Bruce; Ginsberg, Henry; Hripcsak, George; Mamykina, Lena

    2017-04-01

    Type 2 diabetes leads to premature death and reduced quality of life for 8% of Americans. Nutrition management is critical to maintaining glycemic control, yet it is difficult to achieve due to the high individual differences in glycemic response to nutrition. Anticipating glycemic impact of different meals can be challenging not only for individuals with diabetes, but also for expert diabetes educators. Personalized computational models that can accurately forecast an impact of a given meal on an individual's blood glucose levels can serve as the engine for a new generation of decision support tools for individuals with diabetes. However, to be useful in practice, these computational engines need to generate accurate forecasts based on limited datasets consistent with typical self-monitoring practices of individuals with type 2 diabetes. This paper uses three forecasting machines: (i) data assimilation, a technique borrowed from atmospheric physics and engineering that uses Bayesian modeling to infuse data with human knowledge represented in a mechanistic model, to generate real-time, personalized, adaptable glucose forecasts; (ii) model averaging of data assimilation output; and (iii) dynamical Gaussian process model regression. The proposed data assimilation machine, the primary focus of the paper, uses a modified dual unscented Kalman filter to estimate states and parameters, personalizing the mechanistic models. Model selection is used to make a personalized model selection for the individual and their measurement characteristics. The data assimilation forecasts are empirically evaluated against actual postprandial glucose measurements captured by individuals with type 2 diabetes, and against predictions generated by experienced diabetes educators after reviewing a set of historical nutritional records and glucose measurements for the same individual. The evaluation suggests that the data assimilation forecasts compare well with specific glucose measurements

  17. Assimilation of diazotrophic nitrogen into pelagic food webs.

    Science.gov (United States)

    Woodland, Ryan J; Holland, Daryl P; Beardall, John; Smith, Jonathan; Scicluna, Todd; Cook, Perran L M

    2013-01-01

    The fate of diazotrophic nitrogen (N(D)) fixed by planktonic cyanobacteria in pelagic food webs remains unresolved, particularly for toxic cyanophytes that are selectively avoided by most herbivorous zooplankton. Current theory suggests that N(D) fixed during cyanobacterial blooms can enter planktonic food webs contemporaneously with peak bloom biomass via direct grazing of zooplankton on cyanobacteria or via the uptake of bioavailable N(D) (exuded from viable cyanobacterial cells) by palatable phytoplankton or microbial consortia. Alternatively, N(D) can enter planktonic food webs post-bloom following the remineralization of bloom detritus. Although the relative contribution of these processes to planktonic nutrient cycles is unknown, we hypothesized that assimilation of bioavailable N(D) (e.g., nitrate, ammonium) by palatable phytoplankton and subsequent grazing by zooplankton (either during or after the cyanobacterial bloom) would be the primary pathway by which N(D) was incorporated into the planktonic food web. Instead, in situ stable isotope measurements and grazing experiments clearly documented that the assimilation of N(D) by zooplankton outpaced assimilation by palatable phytoplankton during a bloom of toxic Nodularia spumigena Mertens. We identified two distinct temporal phases in the trophic transfer of N(D) from N. spumigena to the plankton community. The first phase was a highly dynamic transfer of N(D) to zooplankton with rates that covaried with bloom biomass while bypassing other phytoplankton taxa; a trophic transfer that we infer was routed through bloom-associated bacteria. The second phase was a slowly accelerating assimilation of the dissolved-N(D) pool by phytoplankton that was decoupled from contemporaneous variability in N. spumigena concentrations. These findings provide empirical evidence that N(D) can be assimilated and transferred rapidly throughout natural plankton communities and yield insights into the specific processes underlying

  18. Development of KIAPS Observation Processing Package for Data Assimilation System

    Science.gov (United States)

    Kang, Jeon-Ho; Chun, Hyoung-Wook; Lee, Sihye; Han, Hyun-Jun; Ha, Su-Jin

    2015-04-01

    The Korea Institute of Atmospheric Prediction Systems (KIAPS) was founded in 2011 by the Korea Meteorological Administration (KMA) to develop Korea's own global Numerical Weather Prediction (NWP) system as nine year (2011-2019) project. Data assimilation team at KIAPS has been developing the observation processing system (KIAPS Package for Observation Processing: KPOP) to provide optimal observations to the data assimilation system for the KIAPS Global Model (KIAPS Integrated Model - Spectral Element method based on HOMME: KIM-SH). Currently, the KPOP is capable of processing the satellite radiance data (AMSU-A, IASI), GPS Radio Occultation (GPS-RO), AIRCRAFT (AMDAR, AIREP, and etc…), and synoptic observation (SONDE and SURFACE). KPOP adopted Radiative Transfer for TOVS version 10 (RTTOV_v10) to get brightness temperature (TB) for each channel at top of the atmosphere (TOA), and Radio Occultation Processing Package (ROPP) 1-dimensional forward module to get bending angle (BA) at each tangent point. The observation data are obtained from the KMA which has been composited with BUFR format to be converted with ODB that are used for operational data assimilation and monitoring at the KMA. The Unified Model (UM), Community Atmosphere - Spectral Element (CAM-SE) and KIM-SH model outputs are used for the bias correction (BC) and quality control (QC) of the observations, respectively. KPOP provides radiance and RO data for Local Ensemble Transform Kalman Filter (LETKF) and also provides SONDE, SURFACE and AIRCRAFT data for Three-Dimensional Variational Assimilation (3DVAR). We are expecting all of the observation type which processed in KPOP could be combined with both of the data assimilation method as soon as possible. The preliminary results from each observation type will be introduced with the current development status of the KPOP.

  19. Assimilating soil moisture into an Earth System Model

    Science.gov (United States)

    Stacke, Tobias; Hagemann, Stefan

    2017-04-01

    Several modelling studies reported potential impacts of soil moisture anomalies on regional climate. In particular for short prediction periods, perturbations of the soil moisture state may result in significant alteration of surface temperature in the following season. However, it is not clear yet whether or not soil moisture anomalies affect climate also on larger temporal and spatial scales. In an earlier study, we showed that soil moisture anomalies can persist for several seasons in the deeper soil layers of a land surface model. Additionally, those anomalies can influence root zone moisture, in particular during explicitly dry or wet periods. Thus, one prerequisite for predictability, namely the existence of long term memory, is evident for simulated soil moisture and might be exploited to improve climate predictions. The second prerequisite is the sensitivity of the climate system to soil moisture. In order to investigate this sensitivity for decadal simulations, we implemented a soil moisture assimilation scheme into the Max-Planck Institute for Meteorology's Earth System Model (MPI-ESM). The assimilation scheme is based on a simple nudging algorithm and updates the surface soil moisture state once per day. In our experiments, the MPI-ESM is used which includes model components for the interactive simulation of atmosphere, land and ocean. Artificial assimilation data is created from a control simulation to nudge the MPI-ESM towards predominantly dry and wet states. First analyses are focused on the impact of the assimilation on land surface variables and reveal distinct differences in the long-term mean values between wet and dry state simulations. Precipitation, evapotranspiration and runoff are larger in the wet state compared to the dry state, resulting in an increased moisture transport from the land to atmosphere and ocean. Consequently, surface temperatures are lower in the wet state simulations by more than one Kelvin. In terms of spatial pattern

  20. ASSIMILATION OF COARSE-SCALEDATAUSINGTHE ENSEMBLE KALMAN FILTER

    KAUST Repository

    Efendiev, Yalchin

    2011-01-01

    Reservoir data is usually scale dependent and exhibits multiscale features. In this paper we use the ensemble Kalman filter (EnKF) to integrate data at different spatial scales for estimating reservoir fine-scale characteristics. Relationships between the various scales is modeled via upscaling techniques. We propose two versions of the EnKF to assimilate the multiscale data, (i) where all the data are assimilated together and (ii) the data are assimilated sequentially in batches. Ensemble members obtained after assimilating one set of data are used as a prior to assimilate the next set of data. Both of these versions are easily implementable with any other upscaling which links the fine to the coarse scales. The numerical results with different methods are presented in a twin experiment setup using a two-dimensional, two-phase (oil and water) flow model. Results are shown with coarse-scale permeability and coarse-scale saturation data. They indicate that additional data provides better fine-scale estimates and fractional flow predictions. We observed that the two versions of the EnKF differed in their estimates when coarse-scale permeability is provided, whereas their results are similar when coarse-scale saturation is used. This behavior is thought to be due to the nonlinearity of the upscaling operator in the case of the former data. We also tested our procedures with various precisions of the coarse-scale data to account for the inexact relationship between the fine and coarse scale data. As expected, the results show that higher precision in the coarse-scale data yielded improved estimates. With better coarse-scale modeling and inversion techniques as more data at multiple coarse scales is made available, the proposed modification to the EnKF could be relevant in future studies.

  1. Sequential Data Assimilation for Seismicity: a Proof of Concept

    Science.gov (United States)

    van Dinther, Ylona; Kuensch, Hans Rudolf; Fichtner, Andreas

    2017-04-01

    Integrating geological and geophysical observations, laboratory results and physics-based numerical modeling is crucial to improve our understanding of the occurrence of large subduction earthquakes. How to do this integration is less obvious, especially in light of the scarcity and uncertainty of natural and laboratory data and the difficulty of modeling the physics governing earthquakes. One way to efficiently combine information from these sources in order to estimate states and/or parameters is data assimilation, a mathematically sound framework extensively developed for weather forecasting purposes. We demonstrate the potential of using data assimilation by applying an Ensemble Kalman Filter to recover the current and forecast the future state of stress and strength on the megathrust based on data from a single borehole. Data and its errors are for the first time assimilated to - using the least-squares solution of Bayes theorem - update a Partial Differential Equation-driven seismic cycle model. This visco-elasto-plastic continuum forward model solves Navier-Stokes equations with a rate-dependent friction coefficient. To prove this concept we perform a perfect model test in an analogue subduction zone setting. Synthetic numerical data from a single analogue borehole are assimilated into 150 ensemble models. Since we know the true state of the numerical data model, a quantitative and qualitative evaluation shows that meaningful information on the stress and strength is available, even when only data from a single borehole is assimilated over only a part of a seismic cycle. This is possible, since the sampled error covariance matrix contains prior information on the physics that relates velocities, stresses, and pressures at the surface to those at the fault. During the analysis step, stress and strength distributions are thus reconstructed in such a way that fault coupling can be updated to either inhibit or trigger events. In the subsequent forward

  2. Lifetime segmented assimilation trajectories and health outcomes in Latino and other community residents.

    Science.gov (United States)

    Castro, Felipe González; Marsiglia, Flavio F; Kulis, Stephen; Kellison, Joshua G

    2010-04-01

    Under an ecodevelopmental framework, we examined lifetime segmented assimilation trajectories (diverging assimilation pathways influenced by prior life conditions) and related them to quality-of-life indicators in a diverse sample of 258 men in the Phoenix, AZ, metropolitan area. We used a growth mixture model analysis of lifetime changes in socioeconomic status, and used acculturation to identify distinct lifetime segmented assimilation trajectory groups, which we compared on life satisfaction, exercise, and dietary behaviors. We hypothesized that lifetime assimilation change toward mainstream American culture (upward assimilation) would be associated with favorable health outcomes, and downward assimilation change with unfavorable health outcomes. A growth mixture model latent class analysis identified 4 distinct assimilation trajectory groups. In partial support of the study hypotheses, the extreme upward assimilation trajectory group (the most successful of the assimilation pathways) exhibited the highest life satisfaction and the lowest frequency of unhealthy food consumption. Upward segmented assimilation is associated in adulthood with certain positive health outcomes. This may be the first study to model upward and downward lifetime segmented assimilation trajectories, and to associate these with life satisfaction, exercise, and dietary behaviors.

  3. Narrative evolution and assimilation of problematic experiences in a case of pharmacotherapy for schizophrenia.

    Science.gov (United States)

    Osatuke, Katerine; Reid, Mary; Stiles, William B; Kasckow, John W; Zisook, Sidney; Mohamed, Somaia

    2011-01-01

    This case study applied the assimilation model to examine the changing narrative of an outpatient with schizophrenia and symptoms of depression across a successful pharmacotherapy. The assimilation model describes how clients assimilate painful, problematic experiences. Therapeutic progress is understood to reflect increasing assimilation, measured by the Assimilation of Problematic Experiences Scale (APES). The authors used a 15-min semistructured interview (Problematic Experiences Questionnaire) to elicit narrative descriptions of the patient's problems and coping across five interviews throughout his 12-week treatment. They describe how the patient's narrative and APES ratings of his main problems by two clinicians changed in concert through treatment, explain these developments using assimilation concepts, and interpret the results in relation to assimilation and insight in schizophrenia.

  4. Joint Sentinel-1 and SMAP data assimilation to improve soil moisture estimates

    Science.gov (United States)

    Lievens, H.; Reichle, R. H.; Liu, Q.; De Lannoy, G. J. M.; Dunbar, R. S.; Kim, S. B.; Das, N. N.; Cosh, M.; Walker, J. P.; Wagner, W.

    2017-06-01

    SMAP (Soil Moisture Active and Passive) radiometer observations at ˜40 km resolution are routinely assimilated into the NASA Catchment Land Surface Model to generate the 9 km SMAP Level-4 Soil Moisture product. This study demonstrates that adding high-resolution radar observations from Sentinel-1 to the SMAP assimilation can increase the spatiotemporal accuracy of soil moisture estimates. Radar observations were assimilated either separately from or simultaneously with radiometer observations. Assimilation impact was assessed by comparing 3-hourly, 9 km surface and root-zone soil moisture simulations with in situ measurements from 9 km SMAP core validation sites and sparse networks, from May 2015 to December 2016. The Sentinel-1 assimilation consistently improved surface soil moisture, whereas root-zone impacts were mostly neutral. Relatively larger improvements were obtained from SMAP assimilation. The joint assimilation of SMAP and Sentinel-1 observations performed best, demonstrating the complementary value of radar and radiometer observations.

  5. Data Assimilation by Conditioning of Driving Noise on Future Observations

    KAUST Repository

    Lee, Wonjung

    2014-08-01

    Conventional recursive filtering approaches, designed for quantifying the state of an evolving stochastic dynamical system with intermittent observations, use a sequence of i) an uncertainty propagation step followed by ii) a step where the associated data is assimilated using Bayes\\' rule. Alternatively, the order of the steps can be switched to i) one step ahead data assimilation followed by ii) uncertainty propagation. In this paper, we apply this smoothing-based sequential filter to systems driven by random noise, however with the conditioning on future observation not only to the system variable but to the driving noise. Our research reveals that, for the nonlinear filtering problem, the conditioned driving noise is biased by a nonzero mean and in turn pushes forward the filtering solution in time closer to the true state when it drives the system. As a result our proposed method can yield a more accurate approximate solution for the state estimation problem. © 1991-2012 IEEE.

  6. Regulation of assimilate partitioning by daylength and spectral quality

    Energy Technology Data Exchange (ETDEWEB)

    Britz, S.J. [USDA-Climate Stress Lab., Beltsville, MD (United States)

    1994-12-31

    Photosynthesis is the process by which plants utilize light energy to assimilate and transform carbon dioxide into products that support growth and development. The preceding review provides an excellent summary of photosynthetic mechanisms and diurnal patterns of carbon metabolism with emphasis on the importance of gradual changes in photosynthetically-active radiation at dawn and dusk. In addition to these direct effects of irradiance, there are indirect effects of light period duration and spectral quality on carbohydrate metabolism and assimilate partitioning. Both daylength and spectral quality trigger developmental phenomena such as flowering (e.g., photoperiodism) and shade avoidance responses, but their effects on partitioning of photoassimilates in leaves are less well known. Moreover, the adaptive significance to the plants of such effects is sometimes not clear.

  7. Predicting flow reversals in chaotic natural convection using data assimilation

    Directory of Open Access Journals (Sweden)

    Kameron Decker Harris

    2012-04-01

    Full Text Available A simplified model of natural convection, similar to the Lorenz system, is compared to computational fluid dynamics simulations of a thermosyphon in order to test data assimilation (DA methods and better understand the dynamics of convection. The thermosyphon is represented by a long time flow simulation, which serves as a reference ‘truth’. Forecasts are then made using the Lorenz-like model and synchronised to noisy and limited observations of the truth using DA. The resulting analysis is observed to infer dynamics absent from the model when using short assimilation windows. Furthermore, chaotic flow reversal occurrence and residency times in each rotational state are forecast using analysis data. Flow reversals have been successfully forecast in the related Lorenz system, as part of a perfect model experiment, but never in the presence of significant model error or unobserved variables. Finally, we provide new details concerning the fluid dynamical processes present in the thermosyphon during these flow reversals.

  8. Mathematical foundations of hybrid data assimilation from a synchronization perspective

    Science.gov (United States)

    Penny, Stephen G.

    2017-12-01

    The state-of-the-art data assimilation methods used today in operational weather prediction centers around the world can be classified as generalized one-way coupled impulsive synchronization. This classification permits the investigation of hybrid data assimilation methods, which combine dynamic error estimates of the system state with long time-averaged (climatological) error estimates, from a synchronization perspective. Illustrative results show how dynamically informed formulations of the coupling matrix (via an Ensemble Kalman Filter, EnKF) can lead to synchronization when observing networks are sparse and how hybrid methods can lead to synchronization when those dynamic formulations are inadequate (due to small ensemble sizes). A large-scale application with a global ocean general circulation model is also presented. Results indicate that the hybrid methods also have useful applications in generalized synchronization, in particular, for correcting systematic model errors.

  9. Bimodal magmatism produced by progressively inhibited crustal assimilation.

    Science.gov (United States)

    Meade, F C; Troll, V R; Ellam, R M; Freda, C; Font, L; Donaldson, C H; Klonowska, I

    2014-06-20

    The origin of bimodal (mafic-felsic) rock suites is a fundamental question in volcanology. Here we use major and trace elements, high-resolution Sr, Nd and Pb isotope analyses, experimental petrology and thermodynamic modelling to investigate bimodal magmatism at the iconic Carlingford Igneous Centre, Ireland. We show that early microgranites are the result of extensive assimilation of trace element-enriched partial melts of local metasiltstones into mafic parent magmas. Melting experiments reveal the crust is very fusible, but thermodynamic modelling indicates repeated heating events rapidly lower its melt-production capacity. Granite generation ceased once enriched partial melts could no longer form and subsequent magmatism incorporated less fertile restite compositions only, producing mafic intrusions and a pronounced compositional gap. Considering the frequency of bimodal magma suites in the North Atlantic Igneous Province, and the ubiquity of suitable crustal compositions, we propose 'progressively inhibited crustal assimilation' (PICA) as a major cause of bimodality in continental volcanism.

  10. Ensemble-Based Data Assimilation in Reservoir Characterization: A Review

    Directory of Open Access Journals (Sweden)

    Seungpil Jung

    2018-02-01

    Full Text Available This paper presents a review of ensemble-based data assimilation for strongly nonlinear problems on the characterization of heterogeneous reservoirs with different production histories. It concentrates on ensemble Kalman filter (EnKF and ensemble smoother (ES as representative frameworks, discusses their pros and cons, and investigates recent progress to overcome their drawbacks. The typical weaknesses of ensemble-based methods are non-Gaussian parameters, improper prior ensembles and finite population size. Three categorized approaches, to mitigate these limitations, are reviewed with recent accomplishments; improvement of Kalman gains, add-on of transformation functions, and independent evaluation of observed data. The data assimilation in heterogeneous reservoirs, applying the improved ensemble methods, is discussed on predicting unknown dynamic data in reservoir characterization.

  11. Atlas Assimilation Patterns in Different Types of Adult Craniocervical Junction Malformations.

    Science.gov (United States)

    Ferreira, Edson Dener Zandonadi; Botelho, Ricardo Vieira

    2015-11-01

    This is a cross-sectional analysis of resonance magnetic images of 111 patients with craniocervical malformations and those of normal subjects. To test the hypothesis that atlas assimilation is associated with basilar invagination (BI) and atlas's anterior arch assimilation is associated with craniocervical instability and type I BI. Atlas assimilation is the most common malformation in the craniocervical junction. This condition has been associated with craniocervical instability and BI in isolated cases. We evaluated midline Magnetic Resonance Images (MRIs) (and/or CT scans) from patients with craniocervical junction malformation and normal subjects. The patients were separated into 3 groups: Chiari type I malformation, BI type I, and type II. The atlas assimilations were classified according to their embryological origins as follows: posterior, anterior, and both arches assimilation. We studied the craniometric values of 111 subjects, 78 with craniocervical junction malformation and 33 without malformations. Of the 78 malformations, 51 patients had Chiari type I and 27 had BI, of whom 10 presented with type I and 17 with type II BI. In the Chiari group, 41 showed no assimilation of the atlas. In the type I BI group, all patients presented with anterior arch assimilation, either in isolation or associated with assimilation of the posterior arch. 63% of the patients with type II BI presented with posterior arch assimilation, either in isolation or associated with anterior arch assimilation. In the control group, no patients had atlas assimilation. Anterior atlas assimilation leads to type I BI. Posterior atlas assimilation more frequently leads to type II BI. Separation in terms of anterior versus posterior atlas assimilation reflects a more accurate understanding of the clinical and embryological differences in craniocervical junction malformations. N/A.

  12. AMSR2 all-sky radiance assimilation and its impact on the analysis and forecast of Hurricane Sandy with a limited-area data assimilation system

    Directory of Open Access Journals (Sweden)

    Chun Yang

    2016-06-01

    Full Text Available A method to assimilate all-sky radiances from the Advanced Microwave Scanning Radiometer 2 (AMSR2 was developed within the Weather Research and Forecasting (WRF model's data assimilation (WRFDA system. The four essential elements are: (1 extending the community radiative transform model's (CRTM interface to include hydrometeor profiles; (2 using total water Qt as the moisture control variable; (3 using a warm-rain physics scheme for partitioning the Qt increment into individual increments of water vapour, cloud liquid water and rain; and (4 adopting a symmetric observation error model for all-sky radiance assimilation.Compared to a benchmark experiment with no AMSR2 data, the impact of assimilating clear-sky or all-sky AMSR2 radiances on the analysis and forecast of Hurricane Sandy (2012 was assessed through analysis/forecast cycling experiments using WRF and WRFDA's three-dimensional variational (3DVAR data assimilation scheme. With more cloud/precipitation-affected data being assimilated around tropical cyclone (TC core areas in the all-sky AMSR2 assimilation experiment, better analyses were obtained in terms of the TC's central sea level pressure (CSLP, warm-core structure and cloud distribution. Substantial (>20 % error reduction in track and CSLP forecasts was achieved from both clear-sky and all-sky AMSR2 assimilation experiments, and this improvement was consistent from the analysis time to 72-h forecasts. Moreover, the all-sky assimilation experiment consistently yielded better track and CSLP forecasts than the clear-sky did for all forecast lead times, due to a better analysis in the TC core areas. Positive forecast impact from assimilating AMSR2 radiances is also seen when verified against the European Center for Medium-Range Weather Forecasts (ECMWF analysis and the Stage IV precipitation analysis, with an overall larger positive impact from the all-sky assimilation experiment.

  13. An accelerated data assimilation approach for volcanic ash forecast

    Science.gov (United States)

    Fu, Guangliang; Lin, Haixiang; Heemink, Arnold; Segers, Arjo; Lu, Sha

    2016-04-01

    The 2010 Eyjafjallajökull volcano eruption had serious consequences to civil aviation. This has initiated a lot of research on volcanic ash forecast in recent years. Ensemble-based data assimilation uses the observation data to improve the parameter and state estimation and subsequently the volcanic ash forecast accuracy. Due to the computational complexity of ensemble-based algorithms and the large scale of real-life applications, application of these methods usually introduces a large computational cost, particularly in the analysis step of assimilation processes. Because the other time-consuming part in the single CPU case, the forecast step, can be efficiently and easily parallelized. In this study, we focus on speeding up of the analysis step. For volcanic ash assimilation of aircraft-based measurements, the most time-consuming part in the analysis step has been shown to be the computation of the Kalman gain matrix. After a careful study on the characteristics of ensemble ash states, we propose a model-reduced Kalman gain (MR-Gain) approach which transforms the ensemble state matrix into a low-rank matrix by a multiplication with an index matrix which recorded the sparsity information of the ensemble state matrix, and thus the computational cost of all the ensemble-related matrix multiplications are reduced. After the computation of Kalman gain, using the previously recorded state index, the full analyzed ensemble states are reconstructed. The result shows the MR-Gain approach is exact, which can be used to replace the original full matrix with a much low computation cost. Computer experiments show that the computing time for the analysis step with the new approach is a factor of ten times faster than the conventional analysis step. The result also shows that with the accelerated analysis step in volcanic ash assimilation system, the total amount of computing time for volcanic ash forecast can be significantly reduced by up to a factor of 5.

  14. Climate seasonality limits carbon assimilation and storage in tropical forests

    OpenAIRE

    Wagner, FH; Hérault, B.; D. Bonal; Stahl, C.; Anderson, LO; Baker, TR; Sebastian Becker, G; Beeckman, H.; D. Boanerges Souza; Cesar Botosso, P; Bowman, DMJS; Bräuning, A.; Brede, B; Irving Brown, F; Julio Camarero, J.

    2016-01-01

    The seasonal climate drivers of the carbon cycle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combination of seasonal pan-tropical data sets from 89 experimental sites (68 include aboveground wood productivity measurements and 35 litter productivity measurements), their associated canopy photosynthetic capacity (enhanced vegetation index, EVI) and clima...

  15. Variational Assimilation of Glider Data in Monterey Bay

    Science.gov (United States)

    2011-01-01

    gliders and ten Slocum gliders were deployed in the Monterey Bay region, collecting temperature and salinity profiles (Ramp et al., 2008). Since the... Glider Data in the Monterey Bay 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 0601153N 6. AUTHOR(S) Chudong Pan, Max...observed by gliders in the Monterey Bay in August 2003 are assimilated into NCOM model in the framework of a 3dVar scheme with a hybrid background error

  16. Data Assimilation in Integrated and Distributed Hydrological Models

    DEFF Research Database (Denmark)

    Zhang, Donghua

    Integrated hydrological models are frequently used in water-related environmental resource management. With our better understanding of the hydrological processes and the improved computational power, hydrological models are becoming increasingly more complex as they integrate multiple hydrological...... processes and provide simulations in refined temporal and spatial resolutions. Recent developments in measurement and sensor technologies have significantly improved the coverage, quality, frequency and diversity of hydrological observations. Data assimilation provides a great potential in relation...

  17. Remote sensing data assimilation for a prognostic phenology model

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, Peter E [ORNL; Stockli, Reto [Colorado State University, Fort Collins

    2008-01-01

    Predicting the global carbon and water cycle requires a realistic representation of vegetation phenology in climate models. However most prognostic phenology models are not yet suited for global applications, and diagnostic satellite data can be uncertain and lack predictive power. We present a framework for data assimilation of Fraction of Photosynthetically Active Radiation absorbed by vegetation (FPAR) and Leaf Area Index (LAI) from the MODerate Resolution Imaging Spectroradiometer (MODIS) to constrain empirical temperature, light, moisture and structural vegetation parameters of a prognostic phenology model. We find that data assimilation better constrains structural vegetation parameters than climate control parameters. Improvements are largest for drought-deciduous ecosystems where correlation of predicted versus satellite-observed FPAR and LAI increases from negative to 0.7-0.8. Data assimilation effectively overcomes the cloud- and aerosol-related deficiencies of satellite data sets in tropical areas. Validation with a 49-year-long phenology data set reveals that the temperature-driven start of season (SOS) is light limited in warm years. The model has substantial skill (R = 0.73) to reproduce SOS inter-annual and decadal variability. Predicted SOS shows a higher inter-annual variability with a negative bias of 5-20 days compared to species-level SOS. It is however accurate to within 1-2 days compared to SOS derived from net ecosystem exchange (NEE) measurements at a FLUXNET tower. The model only has weak skill to predict end of season (EOS). Use of remote sensing data assimilation for phenology model development is encouraged but validation should be extended with phenology data sets covering mediterranean, tropical and arctic ecosystems.

  18. Life Satisfaction of Immigrants: Does Cultural Assimilation Matter?

    OpenAIRE

    Viola Angelini; Laura Casi; Luca Corazzini

    2014-01-01

    We empirically assess the relationship between cultural assimilation and subjective well-being of immigrants by using the German Socio-Economic Panel, a longitudinal dataset including information on both the economic and non economic conditions of the respondents. We find that the more immigrants identify with the German culture and fluently speak the national language, the more they report to be satisfied with their lives. This result is robust to several potential confounding factors, inclu...

  19. The Assimilation of Astrology in the Tibetan Bon Religion

    OpenAIRE

    Ramble, Charles

    2013-01-01

    International audience; The sciences subsumed within the Tibetan category tsi (rtsis), "calculation," include calendrical reckoning and astrology (kartsi; dkar rtsis) and, secondly, elemental divination (naktsi; nag rtsis). The former is essentially based on the Kālacakra, a late tantra that was introduced from India in the twelfth century, and the latter on Chinese precedents. Although scholarly literature concerning the Tibetans' assimilation of these sciences is steadily growing, there has...

  20. Data Assimilation using an Ensemble of Models: A hierarchical approach

    OpenAIRE

    Rayner, Peter

    2017-01-01

    One characteristic of biogeochemical models is uncertainty about their formulation. Data assimilation should take this uncertainty into account. A common approach is to use an ensemble of models. We must assign probabilities not only to the parameters of the models but the models themselves. The method of hierarchical modelling allows us to calculate these probabilities. This paper describes the approach, develops the algebra for the most common case then applies it to the TRANSCO...

  1. A modified iterative ensemble Kalman filter data assimilation method

    Science.gov (United States)

    Xu, Baoxiong; Bai, Yulong; Wang, Yizhao; Li, Zhe; Ma, Boyang

    2017-08-01

    High nonlinearity is a typical characteristic associated with data assimilation systems. Additionally, iterative ensemble based methods have attracted a large amount of research attention, which has been focused on dealing with nonlinearity problems. To solve the local convergence problem of the iterative ensemble Kalman filter, a modified iterative ensemble Kalman filter algorithm was put forward, which was based on a global convergence strategy from the perspective of a Gauss-Newton iteration. Through self-adaption, the step factor was adjusted to enable every iteration to approach expected values during the process of the data assimilation. A sensitivity experiment was carried out in a low dimensional Lorenz-63 chaotic system, as well as a Lorenz-96 model. The new method was tested via ensemble size, observation variance, and inflation factor changes, along with other aspects. Meanwhile, comparative research was conducted with both a traditional ensemble Kalman filter and an iterative ensemble Kalman filter. The results showed that the modified iterative ensemble Kalman filter algorithm was a data assimilation method that was able to effectively estimate a strongly nonlinear system state.

  2. Accounting for observation errors in image data assimilation

    Directory of Open Access Journals (Sweden)

    Vincent Chabot

    2015-02-01

    Full Text Available This paper deals with the assimilation of image-type data. Such kinds of data, such as satellite images, have good properties (dense coverage in space and time, but also one crucial problem for data assimilation: they are affected by spatially correlated errors. Classical approaches in data assimilation assume uncorrelated noise, because the proper description and numerical manipulation of non-diagonal error covariance matrices is complex. This paper proposes a simple way to provide observation error covariance matrices adapted to spatially correlated errors. This is done using various image transformations: multiscale (Wavelets, Fourier, Curvelets, gradients, and gradient orientations. These transformations are described and compared to classical approaches, such as pixel-to-pixel comparison and observation thinning. We provide simple yet effective covariance matrices for each of these transformations, which take into account the observation error correlations and improve the results. The effectiveness of the proposed approach is demonstrated on twin experiments performed on a 2-D shallow-water model.

  3. Formulation of scale transformation in a stochastic data assimilation framework

    Science.gov (United States)

    Liu, Feng; Li, Xin

    2017-06-01

    Understanding the errors caused by spatial-scale transformation in Earth observations and simulations requires a rigorous definition of scale. These errors are also an important component of representativeness errors in data assimilation. Several relevant studies have been conducted, but the theory of the scale associated with representativeness errors is still not well developed. We addressed these problems by reformulating the data assimilation framework using measure theory and stochastic calculus. First, measure theory is used to propose that the spatial scale is a Lebesgue measure with respect to the observation footprint or model unit, and the Lebesgue integration by substitution is used to describe the scale transformation. Second, a scale-dependent geophysical variable is defined to consider the heterogeneities and dynamic processes. Finally, the structures of the scale-dependent errors are studied in the Bayesian framework of data assimilation based on stochastic calculus. All the results were presented on the condition that the scale is one-dimensional, and the variations in these errors depend on the differences between scales. This new formulation provides a more general framework to understand the representativeness error in a non-linear and stochastic sense and is a promising way to address the spatial-scale issue.

  4. Data assimilation with state alignment using the EnKF

    Science.gov (United States)

    Makris, A.; Papadakis, N.

    2012-12-01

    Sequential assimilation methods allow tracking physical states using dynamic priors and external observations of the studied system. However, when dense image satellite observations are available, such approaches realize a correction of the amplitude of the different state values but do not incorporate the spatial errors of structure positions. In the case of the position of a vortex, for example, when there is misfit between state and observation, the processes can be long to converge and even diverge when high dimensional state spaces are treated with few iterations of the assimilation methods as it is the case in operational algorithms. In this paper, we tackle this issue by decomposing the state of the system to displacement and amplitude varibales. We then propose an alignment method based on object detection methods that uses visual correspondences between the physical state model and the structural information given by a sequence of images observing the phenomena. The ensemble Kalman filter (EnKF) is modified in order to perform sequentially the alignment followed by the amplitude correction. The experimental evaluation of the method using both simulated and real data shows accurate structure detection and a faster convergence rate of the assimilation method.

  5. Decadal Prediction Efforts in GMAO (Global Modeling and Assimilation Office)

    Science.gov (United States)

    Rienecker, Michele M.; Suarez, Max; Schubert, Siegfried

    2010-01-01

    The Global Modeling and Assimilation Office (GMAO) plans to use our GEOS-5 atmosphere-ocean general circulation model (AOGCM) to explore issues associated with predictability on decadal time scales and to contribute to the decadal prediction project that is part ofCMIP5. The GEOS-5 AOGCM is comprised of the GEOS-5 AGCM with the Catchment Land Surface Model, coupled to GFDL's MOM, version 4. We have assimilation systems for both the atmosphere and ocean. For our climate prediction efforts, the atmosphere will be initialized from the GEOS-5 Modem Era Retrospective-analysis for Research and Applications (MERRA), available from 1979 to present at 112 resolution, and from 1948 to present at 2 resolution. The ocean assimilation is conducted within the coupled model framework, using the MERRA as a constraint for both the atmosphere and the ocean. The decadal prediction experiments will be conducted with a 1 atmosphere and a 112 ocean. Some initial results will be presented, focusing on initialization aspects of the GEOS-5 system.

  6. Uncertainty of Flood Forecasting Based on Radar Rainfall Data Assimilation

    Directory of Open Access Journals (Sweden)

    Xinchi Chen

    2016-01-01

    Full Text Available Precipitation is the core data input to hydrological forecasting. The uncertainty in precipitation forecast data can lead to poor performance of predictive hydrological models. Radar-based precipitation measurement offers advantages over ground-based measurement in the quantitative estimation of temporal and spatial aspects of precipitation, but errors inherent in this method will still act to reduce the performance. Using data from White Lotus River of Hubei Province, China, five methods were used to assimilate radar rainfall data transformed from the classified Z-R relationship, and the postassimilation data were compared with precipitation measured by rain gauges. The five sets of assimilated rainfall data were then used as input to the Xinanjiang model. The effect of precipitation data input error on runoff simulation was analyzed quantitatively by disturbing the input data using the Breeding of Growing Modes method. The results of practical application demonstrated that the statistical weight integration and variational assimilation methods were superior. The corresponding performance in flood hydrograph prediction was also better using the statistical weight integration and variational methods compared to the others. It was found that the errors of radar rainfall data disturbed by the Breeding of Growing Modes had a tendency to accumulate through the hydrological model.

  7. Ensemble Kalman filter data assimilation for the MPAS system

    Science.gov (United States)

    Ha, Soyoung; Snyder, Chris

    2015-04-01

    The Model for Prediction Across Scales (MPAS; http://mpas-dev.github.io/) is a global non-hydrostatic numerical atmospheric model based on unstructured centroidal Voronoi meshes that allow both uniform and variable resolutions. The variable resolution allows locally high-resolution meshes that transition smoothly to coarser resolution over the rest of the globe, avoiding the need to drive a limited-area model with lateral boundary conditions from a separate global model. The nonhydrostatic MPAS solver (for both atmospheric and oceanic components) is now coupled to the Data Assimilation Research Testbed (DART; http://www.image.ucar.edu/ DAReS/DART) system with a full capability of ensemble Kalman filter data assimilation. The analysis/forecast cycling experiments using MPAS/DART is successfully tested with real observations for different retrospective cases. Assimilated observations are all conventional data as well as satellite winds and GPS radio occultation refractivity data. Testing on different grid mesh, we examine issues specific to the MPAS grid, such as smoothing in the interpolation and the update of horizontal wind fields, and show their impact on the Ensemble Kalman Filter (EnKF) analysis and the following short-range forecast. Up to 5-day forecasts for a month-long cycle period are verified against observations and compared to the NCEP GFS (Global Forecast System) forecasts.

  8. Using Data Assimilation Methods of Prediction of Solar Activity

    Science.gov (United States)

    Kitiashvili, Irina N.; Collins, Nancy S.

    2017-01-01

    The variable solar magnetic activity known as the 11-year solar cycle has the longest history of solar observations. These cycles dramatically affect conditions in the heliosphere and the Earth's space environment. Our current understanding of the physical processes that make up global solar dynamics and the dynamo that generates the magnetic fields is sketchy, resulting in unrealistic descriptions in theoretical and numerical models of the solar cycles. The absence of long-term observations of solar interior dynamics and photospheric magnetic fields hinders development of accurate dynamo models and their calibration. In such situations, mathematical data assimilation methods provide an optimal approach for combining the available observational data and their uncertainties with theoretical models in order to estimate the state of the solar dynamo and predict future cycles. In this presentation, we will discuss the implementation and performance of an Ensemble Kalman Filter data assimilation method based on the Parker migratory dynamo model, complemented by the equation of magnetic helicity conservation and long-term sunspot data series. This approach has allowed us to reproduce the general properties of solar cycles and has already demonstrated a good predictive capability for the current cycle, 24. We will discuss further development of this approach, which includes a more sophisticated dynamo model, synoptic magnetogram data, and employs the DART Data Assimilation Research Testbed.

  9. Flexible digestion strategies and trace metal assimilation in marine bivalves

    Science.gov (United States)

    Decho, Alan W.; Luoma, Samuel N.

    1996-01-01

    Pulse-chase experiments show that two marine bivalves take optimal advantage of different types of particulate food by varying food retention time in a flexible two-phase digestive system. For example, carbon is efficiently assimilated from bacteria by subjecting nearly all the ingested bacteria to prolonged digestion. Prolonging digestion also enhances assimilation of metals, many of which are toxic in minute quantities if they are biologically available. Detritus-feeding aquatic organisms have always lived in environments naturally rich in particle-reactive metals. We suggest that avoiding excess assimilation of metals could be a factor in the evolution of digestion strategies. We tested that suggestion by studying digestion of particles containing different Cr concentrations. We show that bivalves are capable of modifying the digestive processing of food to reduce exposure to high, biologically available, Cr concentrations. The evolution of a mechanism in some species to avoid high concentrations of metals in food could influence how effects of modern metal pollution are manifested in marine ecosystems.

  10. Forecasts and assimilation experiments of the Antarctic ozone hole 2008

    Science.gov (United States)

    Flemming, J.; Inness, A.; Jones, L.; Eskes, H. J.; Huijnen, V.; Schultz, M. G.; Stein, O.; Cariolle, D.; Kinnison, D.; Brasseur, G.

    2011-03-01

    The 2008 Antarctic ozone hole was one of the largest and most long-lived in recent years. Predictions of the ozone hole were made in near-real time (NRT) and hindcast mode with the Integrated Forecast System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). The forecasts were carried out both with and without assimilation of satellite observations from multiple instruments to provide more realistic initial conditions. Three different chemistry schemes were applied for the description of stratospheric ozone chemistry: (i) a linearization of the ozone chemistry, (ii) the stratospheric chemical mechanism of the Model of Ozone and Related Chemical Tracers, version 3, (MOZART-3) and (iii) the relaxation to climatology as implemented in the Transport Model, version 5, (TM5). The IFS uses the latter two schemes by means of a two-way coupled system. Without assimilation, the forecasts showed model-specific shortcomings in predicting start time, extent and duration of the ozone hole. The assimilation of satellite observations from the Microwave Limb Sounder (MLS), the Ozone Monitoring Instrument (OMI), the Solar Backscattering Ultraviolet radiometer (SBUV-2) and the SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY) led to a significant improvement of the forecasts when compared with total columns and vertical profiles from ozone sondes. The combined assimilation of observations from multiple instruments helped to overcome limitations of the ultraviolet (UV) sensors at low solar elevation over Antarctica. The assimilation of data from MLS was crucial to obtain a good agreement with the observed ozone profiles both in the polar stratosphere and troposphere. The ozone analyses by the three model configurations were very similar despite the different underlying chemistry schemes. Using ozone analyses as initial conditions had a very beneficial but variable effect on the predictability of the ozone hole over 15 days. The

  11. Key aspects of stratospheric tracer modeling using assimilated winds

    Directory of Open Access Journals (Sweden)

    B. Bregman

    2006-01-01

    Full Text Available This study describes key aspects of global chemistry-transport models and their impact on stratospheric tracer transport. We concentrate on global models that use assimilated winds from numerical weather predictions, but the results also apply to tracer transport in general circulation models. We examined grid resolution, numerical diffusion, air parcel dispersion, the wind or mass flux update frequency, and time interpolation. The evaluation is performed with assimilated meteorology from the "operational analyses or operational data" (OD from the European Centre for Medium-Range Weather Forecasts (ECMWF. We also show the effect of the mass flux update frequency using the ECMWF 40-year re-analyses (ERA40. We applied the three-dimensional chemistry-transport Tracer Model version 5 (TM5 and a trajectory model and performed several diagnoses focusing on different transport regimes. Covering different time and spatial scales, we examined (1 polar vortex dynamics during the Arctic winter, (2 the large-scale stratospheric meridional circulation, and (3 air parcel dispersion in the tropical lower stratosphere. Tracer distributions inside the Arctic polar vortex show considerably worse agreement with observations when the model grid resolution in the polar region is reduced to avoid numerical instability. The results are sensitive to the diffusivity of the advection. Nevertheless, the use of a computational cheaper but diffusive advection scheme is feasible for tracer transport when the horizontal grid resolution is equal or smaller than 1 degree. The use of time interpolated winds improves the tracer distributions, particularly in the middle and upper stratosphere. Considerable improvement is found both in the large-scale tracer distribution and in the polar regions when the update frequency of the assimilated winds is increased from 6 to 3 h. It considerably reduces the vertical dispersion of air parcels in the tropical lower stratosphere. Strong

  12. Predicting Stem Total and Assortment Volumes in an Industrial Pinus taeda L. Forest Plantation Using Airborne Laser Scanning Data and Random Forest

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Silva

    2017-07-01

    Full Text Available Improvements in the management of pine plantations result in multiple industrial and environmental benefits. Remote sensing techniques can dramatically increase the efficiency of plantation management by reducing or replacing time-consuming field sampling. We tested the utility and accuracy of combining field and airborne lidar data with Random Forest, a supervised machine learning algorithm, to estimate stem total and assortment (commercial and pulpwood volumes in an industrial Pinus taeda L. forest plantation in southern Brazil. Random Forest was populated using field and lidar-derived forest metrics from 50 sample plots with trees ranging from three to nine years old. We found that a model defined as a function of only two metrics (height of the top of the canopy and the skewness of the vertical distribution of lidar points has a very strong and unbiased predictive power. We found that predictions of total, commercial, and pulp volume, respectively, showed an adjusted R2 equal to 0.98, 0.98 and 0.96, with unbiased predictions of −0.17%, −0.12% and −0.23%, and Root Mean Square Error (RMSE values of 7.83%, 7.71% and 8.63%. Our methodology makes use of commercially available airborne lidar and widely used mathematical tools to provide solutions for increasing the industry efficiency in monitoring and managing wood volume.

  13. On the assimilation of ice velocity and concentration data into large-scale sea ice models

    Directory of Open Access Journals (Sweden)

    V. Dulière

    2007-06-01

    Full Text Available Data assimilation into sea ice models designed for climate studies has started about 15 years ago. In most of the studies conducted so far, it is assumed that the improvement brought by the assimilation is straightforward. However, some studies suggest this might not be true. In order to elucidate this question and to find an appropriate way to further assimilate sea ice concentration and velocity observations into a global sea ice-ocean model, we analyze here results from a number of twin experiments (i.e. experiments in which the assimilated data are model outputs carried out with a simplified model of the Arctic sea ice pack. Our objective is to determine to what degree the assimilation of ice velocity and/or concentration data improves the global performance of the model and, more specifically, reduces the error in the computed ice thickness. A simple optimal interpolation scheme is used, and outputs from a control run and from perturbed experiments without and with data assimilation are thoroughly compared. Our results indicate that, under certain conditions depending on the assimilation weights and the type of model error, the assimilation of ice velocity data enhances the model performance. The assimilation of ice concentration data can also help in improving the model behavior, but it has to be handled with care because of the strong connection between ice concentration and ice thickness. This study is first step towards real data assimilation into NEMO-LIM, a global sea ice-ocean model.

  14. Lightning Forecasts and Data Assimilation into Numerical Weather Prediction Models

    Science.gov (United States)

    MacGorman, D. R.; Mansell, E. R.; Fierro, A.; Ziegler, C.

    2012-12-01

    This presentation reviews two aspects of lightning in numerical weather prediction (NWP) models: forecasting lightning and assimilating lightning data into NWP models to improve weather forecasts. One of the earliest routine forecasts of lightning was developed for fire weather operations. This approach used a multi-parameter regression analysis of archived cloud-to-ground (CG) lightning data and archived NWP data to optimize the combination of model state variables to use in forecast equations for various CG rates. Since then, understanding of how storms produce lightning has improved greatly. As the treatment of ice in microphysics packages used by NWP models has improved and the horizontal resolution of models has begun approaching convection-permitting scales (with convection-resolving scales on the horizon), it is becoming possible to use this improved understanding in NWP models to predict lightning more directly. An important role for data assimilation in NWP models is to depict the location, timing, and spatial extent of thunderstorms during model spin-up so that the effects of prior convection that can strongly influence future thunderstorm activity, such as updrafts and outflow boundaries, can be included in the initial state of a NWP model run. Radar data have traditionally been used, but systems that map lightning activity with varying degrees of coverage, detail, and detection efficiency are now available routinely over large regions and reveal information about storms that is complementary to the information provided by radar. Because data from lightning mapping systems are compact, easily handled, and reliably indicate the location and timing of thunderstorms, even in regions with little or no radar coverage, several groups have investigated techniques for assimilating these data into NWP models. This application will become even more valuable with the launch of the Geostationary Lightning Mapper on the GOES-R satellite, which will extend routine

  15. Sub-dialectal Coronal and Non-coronal Assimilation in Yemeni Arabic

    Directory of Open Access Journals (Sweden)

    Nadhim Abdulamalek Aldubai

    2015-09-01

    Full Text Available This is an investigation of the assimilation process across word boundaries of the four main dialects of Yemeni Arabic. Twenty native speakers of these dialects have been asked to read the collected data, five from each dialect. The reading of the phrases has been transcribed for the analysis. The data under investigation uncovers the fact that assimilation in the four Yemeni dialects can be classified into symmetrical and asymmetrical categories. Symmetrical assimilation does not lead to irregularity. However, asymmetrical assimilation can cause irregularity among the four Yemeni dialects. The asymmetrical category of assimilation is investigated in terms of place, voicing, and emphasis. These irregularities are analogous to earlier typological work undertaken by Lehn (1963, Mohanon (1993, Watson (2002, Zuraiq and Zhang (2006, and Zuraiq and Abu Joudeh (2013. The study provides informative phonetic data useful for the foundation of a cross-dialectal study of assimilation in YA consonants.

  16. Assimilation of NUCAPS Retrieved Profiles in GSI for Unique Forecasting Applications

    Science.gov (United States)

    Berndt, Emily Beth; Zavodsky, Bradley; Srikishen, Jayanthi; Blankenship, Clay

    2015-01-01

    Hyperspectral IR profiles can be assimilated in GSI as a separate observation other than radiosondes with only changes to tables in the fix directory. Assimilation of profiles does produce changes to analysis fields and evidenced by: Innovations larger than +/-2.0 K are present and represent where individual profiles impact the final temperature analysis.The updated temperature analysis is colder behind the cold front and warmer in the warm sector. The updated moisture analysis is modified more in the low levels and tends to be drier than the original model background Analysis of model output shows: Differences relative to 13-km RAP analyses are smaller when profiles are assimilated with NUCAPS errors. CAPE is under-forecasted when assimilating NUCAPS profiles, which could be problematic for severe weather forecasting Refining the assimilation technique to incorporate an error covariance matrix and creating a separate GSI module to assimilate satellite profiles may improve results.

  17. Assimilation of neural network soil moisture in land surface models

    Science.gov (United States)

    Rodriguez-Fernandez, Nemesio; de Rosnay, Patricia; Albergel, Clement; Aires, Filipe; Prigent, Catherine; Kerr, Yann; Richaume, Philippe; Muñoz-Sabater, Joaquin; Drusch, Matthias

    2017-04-01

    In this study a set of land surface data assimilation (DA) experiments making use of satellite derived soil moisture (SM) are presented. These experiments have two objectives: (1) to test the information content of satellite remote sensing of soil moisture for numerical weather prediction (NWP) models, and (2) to test a simplified assimilation of these data through the use of a Neural Network (NN) retrieval. Advanced Scatterometer (ASCAT) and Soil Moisture and Ocean Salinity (SMOS) data were used. The SMOS soil moisture dataset was obtained specifically for this project training a NN using SMOS brightness temperatures as input and using as reference for the training European Centre for Medium-Range Weather Forecasts (ECMWF) H-TESSEL SM fields. In this way, the SMOS NN SM dataset has a similar climatology to that of the model and it does not present a global bias with respect to the model. The DA experiments are computed using a surface-only Land Data Assimilation System (so-LDAS) based on the HTESSEL land surface model. This system is very computationally efficient and allows to perform long surface assimilation experiments (one whole year, 2012). SMOS NN SM DA experiments are compared to ASCAT SM DA experiments. In both cases, experiments with and without 2 m air temperature and relative humidity DA are discussed using different observation errors for the ASCAT and SMOS datasets. Seasonal, geographical and soil-depth-related differences between the results of those experiments are presented and discussed. The different SM analysed fields are evaluated against a large number of in situ measurements of SM. On average, the SM analysis gives in general similar results to the model open loop with no assimilation even if significant differences can be seen for specific sites with in situ measurements. The sensitivity to observation errors to the SM dataset slightly differs depending on the networks of in situ measurements, however it is relatively low for the tests

  18. Impact of high-resolution data assimilation of GPS zenith delay on Mediterranean heavy rainfall forecasting

    Directory of Open Access Journals (Sweden)

    K. Boniface

    2009-07-01

    Full Text Available Impact of GPS (Global Positioning System data assimilation is assessed here using a high-resolution numerical weather prediction system at 2.5 km horizontal resolution. The Zenithal Tropospheric Delay (ZTD GPS data from mesoscale networks are assimilated with the 3DVAR AROME data assimilation scheme. Data from more than 280 stations over the model domain have been assimilated during 15-day long assimilation cycles prior each of the two studied events. The results of these assimilation cycles show that the assimilation of GPS ZTD with the AROME system performs well in producing analyses closer to the ZTD observations in average.

    Then the impacts of assimilating GPS data on the precipitation forecast have been evaluated. For the first case, only the AROME runs starting a few hours prior the triggering of the convective system are able to simulate the convective precipitation. The assimilation of GPS ZTD observations improves the simulation of the spatial extent of the precipitation, but slightly underestimates the heaviest precipitation in that case compared with the experiment without GPS. The accuracy of the precipitation forecast for the second case is much better. The analyses from the control assimilation cycle provide already a good description of the atmosphere state that cannot be further improved by the assimilation of GPS observations. Only for the latest day (22 November 2007, significant differences have been found between the two parallel cycles. In that case, the assimilation of GPS ZTD allows to improve the first 6 to 12 h of the precipitation forecast.

  19. Employment and Wage assimilation of Male First Generation Immigrants in Denmark

    DEFF Research Database (Denmark)

    Husted, Leif; Nielsen, Helena Skyt; Rosholm, Michael

    Labour market assimilation of Danish first generation male immigrants is analysed based on two panel data sets covering the population of immigrants and 10% of the Danish population during 1984-1995. Wages and employment probabilities are estimated jointly in a random effects model which corrects...... for unobserved cohort and individual effects and panel selectivity due to missing wage information. The results show that immigrants assimilate partially to Danes, but the assimilation process differs between refugees and non-refugees....

  20. Employment and Wage Assimilation of Male First Generation Immigrants in Denmark

    DEFF Research Database (Denmark)

    Husted, Leif; Nielsen, Helena Skyt; Rosholm, Michael

    2000-01-01

    Labour market assimilation of Danish first generation male immigrants is analysed based on two panel data sets covering the population of immigrants and 10% of the Danish population during 1984-1995. Wages and employment probabilities are estimated jointly in a random effects model which corrects...... for unobserved cohort and individual effects and panel selectivity due to missing wage information. The results show that immigrants assimilate partially to Danes, but the assimilation process differs between refugees and non-refugees....

  1. Factors Related to the Global Assimilation of Collaborative Information Technologies: An Exploratory Investigation in Five Regions

    OpenAIRE

    Bajwa, Deepinder S; Lewis, L Floyd; Pervan, Graham; Lai, Vincent S; Munkvold, Bjorn E; Schwabe, Gerhard

    2008-01-01

    The diffusion of innovation theory is deployed to investigate the global assimilation of collaborative information technologies (cIts). Based on the concepts of It acquisition and utilization, an assimilation framework is presented to highlight four states (limited, focused, lagging, and pervasive) that capture the assimilation of conferencing and groupware cIts. Data collected from 538 organizations in the united States, australia, hong kong, Norway, and Switzerland are aggregated and analyz...

  2. Factors in the global assimilation of collaborative information technologies: an exploratory investigation in five regions

    OpenAIRE

    Bajwa, D S; Lewis, L F; Pervan, G; Lai, V S; Munkvold, B E; Schwabe, G

    2008-01-01

    The diffusion of innovation theory is deployed to investigate the global assimilation of collaborative information technologies (CITs). Based on the concepts of IT acquisition and utilization, an assimilation framework is presented to highlight four states (limited, focused, lagging, and pervasive) that capture the assimilation of conferencing and groupware CITs. Data collected from 538 organizations in the United States, Australia, Hong Kong, Norway, and Switzerland are aggregated and analyz...

  3. Employment and Wage Assimilation of Male First Generation Immigrants in Denmark

    OpenAIRE

    Husted, Leif; Nielsen, Helena Skyt; Rosholm, Michael; Smith, Nina

    2000-01-01

    Labour market assimilation of Danish first generation male immigrants is analysed based on two panel data sets covering the population of immigrants and 10% of the Danish population during 1984-1995. Wages and employment probabilities are estimated jointly in a random effects model which corrects for unobserved cohort and individual effects and panel selectivity due to missing wage information. The results show that immigrants assimilate partially to Danes, but the assimilation process differ...

  4. Employment and Wage Assimilation of Male First-generation immigrants in Denmark

    DEFF Research Database (Denmark)

    Husted, Leif; Nielsen, Helena Skyt; Rosholm, Michael

    2001-01-01

    Labour market assimilation of Danish first generation male immigrants is analysed based on two panel data sets covering the population of immigrants and 10% of the Danish population during 1984-1995. Wages and employment probabilities are estimated jointly in a random effects model which corrects...... for unobserved cohort and individual effects and panel selectivity due to missing wage information. The results show that immigrants assimilate partially to Danes, but the assimilation process differs between refugees and non-refugees....

  5. Sulfate assimilation in eukaryotes: fusions, relocations and lateral transfers

    Directory of Open Access Journals (Sweden)

    Durnford Dion G

    2008-02-01

    Full Text Available Abstract Background The sulfate assimilation pathway is present in photosynthetic organisms, fungi, and many bacteria, providing reduced sulfur for the synthesis of cysteine and methionine and a range of other metabolites. In photosynthetic eukaryotes sulfate is reduced in the plastids whereas in aplastidic eukaryotes the pathway is cytosolic. The only known exception is Euglena gracilis, where the pathway is localized in mitochondria. To obtain an insight into the evolution of the sulfate assimilation pathway in eukaryotes and relationships of the differently compartmentalized isoforms we determined the locations of the pathway in lineages for which this was unknown and performed detailed phylogenetic analyses of three enzymes involved in sulfate reduction: ATP sulfurylase (ATPS, adenosine 5'-phosphosulfate reductase (APR and sulfite reductase (SiR. Results The inheritance of ATPS, APR and the related 3'-phosphoadenosine 5'-phosphosulfate reductase (PAPR are remarkable, with multiple origins in the lineages that comprise the opisthokonts, different isoforms in chlorophytes and streptophytes, gene fusions with other enzymes of the pathway, evidence a eukaryote to prokaryote lateral gene transfer, changes in substrate specificity and two reversals of cellular location of host- and endosymbiont-originating enzymes. We also found that the ATPS and APR active in the mitochondria of Euglena were inherited from its secondary, green algal plastid. Conclusion Our results reveal a complex history for the enzymes of the sulfate assimilation pathway. Whilst they shed light on the origin of some characterised novelties, such as a recently described novel isoform of APR from Bryophytes and the origin of the pathway active in the mitochondria of Euglenids, the many distinct and novel isoforms identified here represent an excellent resource for detailed biochemical studies of the enzyme structure/function relationships.

  6. Assimilation of thermospheric measurements for ionosphere-thermosphere state estimation

    Science.gov (United States)

    Miladinovich, Daniel S.; Datta-Barua, Seebany; Bust, Gary S.; Makela, Jonathan J.

    2016-12-01

    We develop a method that uses data assimilation to estimate ionospheric-thermospheric (IT) states during midlatitude nighttime storm conditions. The algorithm Estimating Model Parameters from Ionospheric Reverse Engineering (EMPIRE) uses time-varying electron densities in the F region, derived primarily from total electron content data, to estimate two drivers of the IT: neutral winds and electric potential. A Kalman filter is used to update background models based on ingested plasma densities and neutral wind measurements. This is the first time a Kalman filtering technique is used with the EMPIRE algorithm and the first time neutral wind measurements from 630.0 nm Fabry-Perot interferometers (FPIs) are ingested to improve estimates of storm time ion drifts and neutral winds. The effects of assimilating remotely sensed neutral winds from FPI observations are studied by comparing results of ingesting: electron densities (N) only, N plus half the measurements from a single FPI, and then N plus all of the FPI data. While estimates of ion drifts and neutral winds based on N give estimates similar to the background models, this study's results show that ingestion of the FPI data can significantly change neutral wind and ion drift estimation away from background models. In particular, once neutral winds are ingested, estimated neutral winds agree more with validation wind data, and estimated ion drifts in the magnetic field-parallel direction are more sensitive to ingestion than the field-perpendicular zonal and meridional directions. Also, data assimilation with FPI measurements helps provide insight into the effects of contamination on 630.0 nm emissions experienced during geomagnetic storms.

  7. [Al3+ Absorption and Assimilation by Four Ectomycorrhizal Fungi].

    Science.gov (United States)

    Wang, Ming-xia; Yuan, Ling; Huang, Jian-guo; Zhou, Zhi-feng

    2015-09-01

    The present experiment was carried out in order to know the resistance mechanism of the ectomycorrhizal (ECM) fungi under Al stress, to establish the theoretical foundation to alleviate the Al toxicity of trees, to guide the selection of Al-resisted ECM fungi and preserve forest health. The absorption and assimilation of Al3+ by four ECM fungi [Pisolithus tinctorius (Pt 715), Suillus luteus (Sl 08 and Sl 14), Gyroporus cyanescens (Gc 99)], which were isolated from different forest soils, were investigated in pure culture in liquid media. The growths of Pt 715 and Sl 08 were less affected by Al3+, but growths of S114 and Gc 99 were obviously inhibited by Al3+. With the increasing of Al3+ concentration in culture, the absorption and assimilation of Al3+ by four ECM fungi increased. It indicated that the concentration of Al3+ in environments might be the primary factor determining the Al3+ content in the cell of each tested fungi. Amounts of Al3+ absorbed (in total or calculated in unit hyphae) by the Al3+ tolerant strains (Pt 715 and Sl 08) were significantly lower than those by the Al3+ sensitive strains (S1 14 and Gc 99), which illustrated that reducing the absorption of Al3+ under Al3+ stress environment might be an effective approach to alleviate the Al3+ poison for these Al3+ tolerant strains. Furthermore, Al3+ stress could stimulate the ECM fungi to assimilate more N, P, and K, which might indicate that increasing requirement of the nutrients also could be helpful for ECM fungi to fight against the harmful effects caused by Al3+ stress.

  8. Microbial lipids reveal carbon assimilation patterns on hydrothermal sulfide chimneys.

    Science.gov (United States)

    Reeves, Eoghan P; Yoshinaga, Marcos Y; Pjevac, Petra; Goldenstein, Nadine I; Peplies, Jörg; Meyerdierks, Anke; Amann, Rudolf; Bach, Wolfgang; Hinrichs, Kai-Uwe

    2014-11-01

    Sulfide 'chimneys' characteristic of seafloor hydrothermal venting are diverse microbial habitats. ¹³C/¹²C ratios of microbial lipids have rarely been used to assess carbon assimilation pathways on these structures, despite complementing gene- and culture-based approaches. Here, we integrate analyses of the diversity of intact polar lipids (IPL) and their side-chain δ¹³C values (δ¹³ C(lipid)) with 16S rRNA gene-based phylogeny to examine microbial carbon flow on active and inactive sulfide structures from the Manus Basin. Surficial crusts of active structures, dominated by Epsilonproteobacteria, yield bacterial δ¹³C(lipid) values higher than biomass δ¹³C (total organic carbon), implicating autotrophy via the reverse tricarboxylic acid cycle. Our data also suggest δ¹³C(lipid) values vary on individual active structures without accompanying microbial diversity changes. Temperature and/or dissolved substrate effects - likely relating to variable advective-diffusive fluxes to chimney exteriors - may be responsible for differing ¹³C fractionation during assimilation. In an inactive structure, δ¹³C(lipid) values lower than biomass δ¹³C and a distinctive IPL and 16S rRNA gene diversity suggest a shift to a more diverse community and an alternate carbon assimilation pathway after venting ceases. We discuss here the potential of IPL and δ¹³C(lipid) analyses to elucidate carbon flow in hydrothermal structures when combined with other molecular tools. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  9. Towards an Operational Nearshore Wave Data Assimilation System

    Science.gov (United States)

    Veeramony, J.; Orzech, M.; Ngodock, H. E.; Flampouris, S.

    2012-12-01

    For Navy operations, the model used for wave predictions in the nearshore is SWAN, which solves the spectral action balance equation to estimate the wave state. Boundary conditions for local (nearshore) model domains are generally obtained from regional model simulations that use either SWAN or WAVEWATCH III, which in turn gets boundary conditions from global simulations with WAVEWATCH III forced by the meteorological models. Inaccuracies in meteorological forcing and the coarse grid resolutions for the global model can lead to significant errors in SWAN's spectral estimates, particularly in shallow water. To improve the model's performance, especially for the small nearshore domains, we have developed a 4DVAR data assimilation system based on a tangent linear code and the corresponding adjoint from the numerical SWAN model. The system utilizes point measurements of 2D wave spectra, such as from a wave buoy, to improve the solution in the whole domain. Given a set of observations measured at different times and locations in the model domain, the assimilation system minimizes a cost function (representing overall error between the model and observations) and generates corrected boundary and initial conditions that optimize the fit of SWAN's output to the measurements. In addition to time dependence, the system accounts for nonlinear triad and quadruplet interactions, depth-limited breaking, wind forcing, bottom friction, and whitecapping as well as the influence of currents on waves. This presentation will review the current status of the system using simulations with data from Duck, North Carolina and the 2012 RIMPAC exercises held by the Commander, US Pacific Fleet in and around the Hawaiian Islands. Examples shown will include analysis of effects of using different background fields, and of assimilating different instruments simultaneously. Adjoint-generated sensitivity maps, which can be generated using the adjoint, will be used to demonstrate the optimal

  10. Terrestrial cross-calibrated assimilation of various datasources

    Science.gov (United States)

    Groß, André; Müller, Richard; Schömer, Elmar; Trentmann, Jörg

    2014-05-01

    We introduce a novel software tool, ANACLIM, for the efficient assimilation of multiple two-dimensional data sets using a variational approach. We consider a single objective function in two spatial coordinates with higher derivatives. This function measures the deviation of the input data from the target data set. By using the Euler-Lagrange formalism the minimization of this objective function can be transformed into a sparse system of linear equations, which can be efficiently solved by a conjugate gradient solver on a desktop workstation. The objective function allows for a series of physically-motivated constraints. The user can control the relative global weights, as well as the individual weight of each constraint on a per-grid-point level. The different constraints are realized as separate terms of the objective function: One similarity term for each input data set and two additional smoothness terms, penalizing high gradient and curvature values. ANACLIM is designed to combine similarity and smoothness operators easily and to choose different solvers. We performed a series of benchmarks to calibrate and verify our solution. We use, for example, terrestrial stations of BSRN and GEBA for the solar incoming flux and AERONET stations for aerosol optical depth. First results show that the combination of these data sources gain a significant benefit against the input datasets with our approach. ANACLIM also includes a region growing algorithm for the assimilation of ground based data. The region growing algorithm computes the maximum area around a station that represents the station data. The regions are grown under several constraints like the homogeneity of the area. The resulting dataset is then used within the assimilation process. Verification is performed by cross-validation. The method and validation results will be presented and discussed.

  11. Hydrologic Remote Sensing and Land Surface Data Assimilation

    Directory of Open Access Journals (Sweden)

    Hamid Moradkhani

    2008-05-01

    Full Text Available Accurate, reliable and skillful forecasting of key environmental variables such as soil moisture and snow are of paramount importance due to their strong influence on many water resources applications including flood control, agricultural production and effective water resources management which collectively control the behavior of the climate system. Soil moisture is a key state variable in land surface–atmosphere interactions affecting surface energy fluxes, runoff and the radiation balance. Snow processes also have a large influence on land-atmosphere energy exchanges due to snow high albedo, low thermal conductivity and considerable spatial and temporal variability resulting in the dramatic change on surface and ground temperature. Measurement of these two variables is possible through variety of methods using ground-based and remote sensing procedures. Remote sensing, however, holds great promise for soil moisture and snow measurements which have considerable spatial and temporal variability. Merging these measurements with hydrologic model outputs in a systematic and effective way results in an improvement of land surface model prediction. Data Assimilation provides a mechanism to combine these two sources of estimation. Much success has been attained in recent years in using data from passive microwave sensors and assimilating them into the models. This paper provides an overview of the remote sensing measurement techniques for soil moisture and snow data and describes the advances in data assimilation techniques through the ensemble filtering, mainly Ensemble Kalman filter (EnKF and Particle filter (PF, for improving the model prediction and reducing the uncertainties involved in prediction process. It is believed that PF provides a complete representation of the probability distribution of state variables of interests (according to sequential Bayes law and could be a strong alternative to EnKF which is subject to some

  12. Representativeness Uncertainty in Chemical Data Assimilation Highlight Mixing Barriers

    Science.gov (United States)

    Lary, David John

    2003-01-01

    When performing chemical data assimilation the observational, representativeness, and theoretical uncertainties have very different characteristics. In this study we have accurately characterized the representativeness uncertainty by studying the probability distribution function (PDF) of the observations. The average deviation has been used as a measure of the width of the PDF and of the variability (representativeness uncertainty) for the grid cell. It turns out that for long-lived tracers such as N2O and CH4 the representativeness uncertainty is markedly different from the observational uncertainty and clearly delineates mixing barriers such as the polar vortex edge, the tropical pipe and the tropopause.

  13. Experimenting with the GMAO 4D Data Assimilation

    Science.gov (United States)

    Todling, R.; El Akkraoui, A.; Errico, R. M.; Guo, J.; Kim, J.; Kliest, D.; Parrish, D. F.; Suarez, M.; Trayanov, A.; Tremolet, Yannick; hide

    2012-01-01

    The Global Modeling and Assimilation Office (GMAO) has been working to promote its prototype four-dimensional variational (4DVAR) system to a version that can be exercised at operationally desirable configurations. Beyond a general circulation model (GeM) and an analysis system, traditional 4DV AR requires availability of tangent linear (TL) and adjoint (AD) models of the corresponding GeM. The GMAO prototype 4DVAR uses the finite-volume-based GEOS GeM and the Grid-point Statistical Interpolation (GSI) system for the first two, and TL and AD models derived ITom an early version of the finite-volume hydrodynamics that is scientifically equivalent to the present GEOS nonlinear GeM but computationally rather outdated. Specifically, the TL and AD models hydrodynamics uses a simple (I-dimensional) latitudinal MPI domain decomposition, which has consequent low scalability and prevents the prototype 4DV AR ITom being used in realistic applications. In the near future, GMAO will be upgrading its operational GEOS GCM (and assimilation system) to use a cubed-sphere-based hydrodynamics. This versions of the dynamics scales to thousands of processes and has led to a decision to re-derive the TL and AD models for this more modern dynamics, thus taking advantage of a two-dimensional MPI decomposition and improved scalability properties. With the aid of the Transformation of Algorithms in FORTRAN (l'AF) automatic adjoint generation tool and some hand-coding, a version of the cubed-sphere-based TL and AD models, with a simplified vertical diffusion scheme, is now available, enabling multiple configurations of standard implementations of 4DV AR in GEOS. Concurrent to this development, collaboration with the National Centers for Environmental Prediction (NCEP) and the Earth System Research Laboratory (ESRL) has allowed GMAO to implement a hybrid-ensemble capability within the GEOS data assimilation system. Both 3Dand 4D-ensemble capabilities are presently available thus allowing

  14. (14C)acetate assimilation by a type I obligate methylotroph, Methylococcus capsulatus.

    Science.gov (United States)

    Patel, R N; Hoare, S L; Hoare, D S; Taylor, B F

    1977-01-01

    Methanol and formate oxidation supported the assimilation of [14C]acetate by cell suspensions of Methylococcus capsulatus; oxidation of other primary alcohols, except ethanol, did not. The extent of [1-14C]acetate assimilation supported by methanol oxidation was decreased in the presence of primary alcohols, except ethanol. Potassium cyanide (0.33 mM) completely inhibited the oxidation of formate and its stimulation of [1-14C]acetate assimilation. The amount of [1-14C]acetate assimilation supported by methanol oxidation was significantly inhibited by cyanide. PMID:412469

  15. Simulation of wheat growth and development based on organ-level photosynthesis and assimilate allocation

    National Research Council Canada - National Science Library

    J. B. Evers; J. Vos; X. Yin; P. Romero; P. E. L. van der Putten; P. C. Struik

    2010-01-01

    .... An existing spatially explicit 3D architectural model of wheat development was extended with routines for organ-level microclimate, photosynthesis, assimilate distribution within the plant structure...

  16. Rapid differentiation of Candida dubliniensis from Candida albicans by early D-xylose assimilation.

    Science.gov (United States)

    Ellepola, A N B; Khan, Z U

    2012-01-01

    To determine if D-xylose (XYL) and/or α-methyl-D-glucoside (MDG) assimilation can be used reliably as a rapid test to differentiate Candida dubliniensis from Candida albicans at an earlier time point such as 2 h after inoculation. Thirty isolates of C. albicans and C. dubliniensis recovered from anatomical sites and clinical specimens were used. Isolates were inoculated into the API 20C AUX yeast identification system, and incubated at 30°C. XYL and MDG assimilations were read at 2-hour intervals beginning 2 h after the initial inoculation and up to 24 h of incubation; thereafter, results were read after 48 and 72 h. Twenty-nine (97%) C. albicans isolates had assimilated XYL at 16 h and, by 24 h, all isolates were positive for XYL assimilation. None of the C. dubliniensis isolates assimilated XYL. The MDG assimilation revealed that 24, 40, 92 and 100% of C. albicans isolates became positive after 16, 24, 48 and 72 h of incubation, respectively, whereas only 3% of C. dubliniensis isolates assimilated MDG after 72 h. The findings showed that it is possible to rapidly differentiate C. albicans from C. dubliniensis isolates using the API 20C AUX carbohydrate assimilation kits after 16 h of incubation at 30°C based on the XYL assimilation. Copyright © 2012 S. Karger AG, Basel.

  17. Assortative weight gain in mother-daughter and father-son pairs: an emerging source of childhood obesity. Longitudinal study of trios (EarlyBird 43).

    Science.gov (United States)

    Perez-Pastor, E M; Metcalf, B S; Hosking, J; Jeffery, A N; Voss, L D; Wilkin, T J

    2009-07-01

    To look for same-sex (gender assortative) association of body mass index (BMI) in healthy trios (mother, father and child) from a contemporary birth cohort, which might imply shared environment rather than shared genes because selective mother-daughter and father-son gene transmission is not a common Mendelian trait. Prospective (longitudinal) cohort study with four annual time points, from 5 to 8 years. 226 healthy trios from a 1995 to 1996 birth cohort randomly selected in the city of Plymouth, UK. Average BMI of the two parents and maternal/paternal BMI separately related to the BMI-SDS (standard deviation score) of all offspring and to the BMI-SDS of the sons and the daughters separately. There were big differences in BMI-SDS among the daughters grouped according to mothers' category of BMI (effect size 1.37 SDS), but not their sons (effect size 0.16 SDS, gender interaction Pfathers' BMI (effect size 1.28 SDS), but not their daughters (effect size 0.17, gender interaction P=0.02). Children whose same-sex parents were of normal weight, weighed either close to (girls+0.20 BMI-SDS) or less than (boys,-0.34 BMI-SDS) children of 20 years ago, and did not change from 5 to 8 years. In contrast, the risks of obesity at 8 years were 10-fold greater (girls 41%, Pobese. Longitudinal linear mixed effects (multilevel) modelling showed a marked influence of maternal and paternal BMI on the rate of weight gain, which was unaffected by birth weight of the child. We report perhaps the largest effect sizes so far recorded in childhood obesity. Childhood obesity today seems to be largely confined to those whose same-sex parents are obese, and the link does not seem to be genetic. Parental obesity, like smoking, might be targeted in the interests of the child.

  18. Remote sensing data assimilation using coupled radiative transfer models

    Science.gov (United States)

    Verhoef, Wout; Bach, Heike

    This paper discusses data assimilation of biophysical parameters retrieved from optical remote sensing images in land surface process models by means of image simulation and model inversion. Two different approaches are presented. The first is based on model inversion of atmospherically corrected Landsat TM surface reflectance images and assimilation of the retrieved parameters in a crop growth model. In the second approach top-of-atmosphere (TOA) hyperspectral radiance images have been simulated for the future ESA mission SPECTRA. In this case only the simulation of the images has been executed in order to demonstrate the feasibility of this task with existing software running on a PC. The radiative transfer models that have been used are PROSPECT (leaf level), GeoSAIL (canopy level) and MODTRAN4 (atmosphere). Coupling of this chain of models to land use information of the area can be used to generate TOA radiance images. Comparison of simulated images with actual remote sensing data can be applied to retrieve biophysical parameters and in turn these can be employed to update process models of crop growth.

  19. Sequential Data Assimilation for Seismicity: a Proof of Concept

    Science.gov (United States)

    van Dinther, Y.; Fichtner, A.; Kuensch, H. R.

    2015-12-01

    Our physical understanding and probabilistic forecasting ability of earthquakes is significantly hampered by limited indications of the state of stress and strength on faults and their governing parameters. Using the sequential data assimilation framework developed in meteorology and oceanography (e.g., Evensen, JGR, 1994) and a seismic cycle forward model based on Navier-Stokes Partial Differential Equations (van Dinther et al., JGR, 2013), we show that such information with its uncertainties is within reach, at least for laboratory setups. We aim to provide the first, thorough proof of concept for seismicity related PDE applications via a perfect model test of seismic cycles in a simplified wedge-like subduction setup. By evaluating the performance with respect to known numerical input and output, we aim to answer wether there is any probabilistic forecast value for this laboratory-like setup, which and how many parameters can be constrained, and how much data in both space and time would be needed to do so. Thus far our implementation of an Ensemble Kalman Filter demonstrated that probabilistic estimates of both the state of stress and strength on a megathrust fault can be obtained and utilized even when assimilating surface velocity data at a single point in time and space. An ensemble-based error covariance matrix containing velocities, stresses and pressure links surface velocity observations to fault stresses and strengths well enough to update fault coupling accordingly. Depending on what synthetic data show, coseismic events can then be triggered or inhibited.

  20. Data assimilation on the exponentially accurate slow manifold.

    Science.gov (United States)

    Cotter, Colin

    2013-05-28

    I describe an approach to data assimilation making use of an explicit map that defines a coordinate system on the slow manifold in the semi-geostrophic scaling in Lagrangian coordinates, and apply the approach to a simple toy system that has previously been proposed as a low-dimensional model for the semi-geostrophic scaling. The method can be extended to Lagrangian particle methods such as Hamiltonian particle-mesh and smooth-particle hydrodynamics applied to the rotating shallow-water equations, and many of the properties will remain for more general Eulerian methods. Making use of Hamiltonian normal-form theory, it has previously been shown that, if initial conditions for the system are chosen as image points of the map, then the fast components of the system have exponentially small magnitude for exponentially long times as ε→0, and this property is preserved if one uses a symplectic integrator for the numerical time stepping. The map may then be used to parametrize initial conditions near the slow manifold, allowing data assimilation to be performed without introducing any fast degrees of motion (more generally, the precise amount of fast motion can be selected).