WorldWideScience

Sample records for assimilating assorted acquaintance

  1. VirusPKT: A Search Tool For Assimilating Assorted Acquaintance For Viruses

    CERN Document Server

    Manicassamy, Jayanthi

    2009-01-01

    Viruses utilize various means to circumvent the immune detection in the biological systems. Several mathematical models have been investigated for the description of viral dynamics in the biological system of human and various other species. One common strategy for evasion and recognition of viruses is, through acquaintance in the systems by means of search engines. In this perspective a search tool have been developed to provide a wider comprehension about the structure and other details on viruses which have been narrated in this paper. This provides an adequate knowledge in evolution and building of viruses, its functions through information extraction from various websites. Apart from this, tool aim to automate the activities associated with it in a self-maintainable, self-sustainable, proactive one which has been evaluated through analysis made and have been discussed in this paper.

  2. VirusPKT: A Search Tool For Assimilating Assorted Acquaintance For Viruses

    Directory of Open Access Journals (Sweden)

    Jayanthi Manicassamy

    2009-11-01

    Full Text Available Viruses utilize various means to circumvent the immune detection in the biological systems. Several mathematical models have been investigated for the description of viral dynamics in the biological system of human and various other species. One common strategy for evasion and recognition of viruses is, through acquaintance in the systems by means of search engines. In this perspective a search tool have been developed to provide a wider comprehension about the structure and other details on viruses which have been narrated in this paper. This provides an adequate knowledge in evolution and building of viruses, its functions through information extraction from various websites. Apart from this, tool aim to automate the activities associated with it in a self-maintainable, self-sustainable, proactive one which has been evaluated through analysis made and have been discussed in this paper.

  3. Leveling the Playing Field: Longer Acquaintance Predicts Reduced Assortative Mating on Attractiveness.

    Science.gov (United States)

    Hunt, Lucy L; Eastwick, Paul W; Finkel, Eli J

    2015-07-01

    Clear empirical demonstrations of the theoretical principles underlying assortative mating remain elusive. This article examines a moderator of assortative mating--how well couple members knew each other before dating--suggested by recent findings related to market-based (i.e., competition) theories. Specifically, competition is pervasive to the extent that people achieve consensus about who possesses desirable qualities (e.g., attractiveness) and who does not. Because consensus is stronger earlier in the acquaintance process, assortative mating based on attractiveness should be stronger among couples who formed a relationship after a short period rather than a long period of acquaintance. A study of 167 couples included measures of how long partners had known each other before dating and whether they had been friends before dating, as well as coders' ratings of physical attractiveness. As predicted, couples revealed stronger evidence of assortative mating to the extent that they knew each other for a short time and were not friends before initiating a romantic relationship. PMID:26068893

  4. Acquaintance Rape: Effective Avoidance Strategies.

    Science.gov (United States)

    Levine-MacCombie, Joyce; Koss, Mary P.

    1986-01-01

    Determined that acknowledged and unacknowledged acquaintance rape victims and rape avoiders could be discriminated by situational variables and response strategies. Avoiders were less likely to have experienced passive or internalizing emotions at the time of the assault, perceived the assault as less violent, and were more likely to have utilized…

  5. Product Assortment in a Triopoly

    OpenAIRE

    Steven M. Shugan

    1989-01-01

    Producers of super-premium ice cream, such as Häagen-Dazs, offer a smaller assortment of flavors than the producers of lesser quality ice cream. Examples of this phenomenon can be found in other industries as well. In many industries, the producers of higher-quality products offer a smaller assortment of flavors, colors, sizes, patterns, textures, fragrances, tones, styles, models, designs, types or other options. This paper explores when and why producers of super-premium products should fin...

  6. Assortment Variety: Attribute versus Product-Based

    OpenAIRE

    van Herpen, H.W.I.; Pieters, R.

    2000-01-01

    Retailers need to decide on the content and structure of their product assortments, and thereby on the degree of variety that they offer to their customers.This paper compares measures of assortment variety and relates them to underlying variety components.We conceptualize assortment variety from a product and an attribute perspective, compare extant measures of assortment variety, and examine the appropriateness of these measures in capturing assortment variety as perceived by consumers.Rece...

  7. Risk Appraisal in Scripted Acquaintance Rape Scenarios.

    Science.gov (United States)

    Wright, Doris J.

    Cognitive appraisals are believed to influence how women judge or appraise risk in acquaintance interactions which lead to sexual assault. Ways in which men and women judge the presence of risk factors in scripted acquaintance rape scenarios, and whether alcohol was a significant factor in assessing risk, are examined in this paper. Participants…

  8. Campus Acquaintance Rape: An Ethical Analysis.

    Science.gov (United States)

    Haggard, William K.

    1992-01-01

    Introduces idea of including ethics in acquaintance rape prevention programming. Applies education model for ethical analysis of sexual behavior to problem of acquaintance rape among college and university students to provide practitioners with new insights which will motivate inclusion of moral and ethical objectives in future prevention…

  9. Reactions to Stranger and Acquaintance Rape.

    Science.gov (United States)

    Tetreault, Patricia A.; Barnett, Mark A.

    1987-01-01

    Investigated reactions to a woman who presumably had been raped by a stranger or an acquaintance. Undergraduates read one of two rape descriptions prior to watching a videotape of the woman who (they were led to believe) had been the victim of the rape. Females and males showed markedly different reactions to stranger and acquaintance rape and…

  10. Assortment Variety : Attribute versus Product-Based

    NARCIS (Netherlands)

    van Herpen, H.W.I.; Pieters, R.

    2000-01-01

    Retailers need to decide on the content and structure of their product assortments, and thereby on the degree of variety that they offer to their customers.This paper compares measures of assortment variety and relates them to underlying variety components.We conceptualize assortment variety from a

  11. Acquaintance Rape on Campus: A Literature Review.

    Science.gov (United States)

    Benson, Dennis; And Others

    1992-01-01

    Examines issues related to acquaintance rape: cultural context, legal issues, adolescent attitudes and development, alcohol and sexual assault, the assailants, the victims, and the institutional response, and makes recommendations for a system that all colleges should have in place. (SM)

  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. Acquaintance Rape on College and University Campuses

    Science.gov (United States)

    Romeo, Felicia F.

    2004-01-01

    While a university experience offers young women many rewards, unfortunately, there are also significant dangers, and one of these dangers is men who are sexual predators. Acquaintance rape is a sexual assault perpetrated by someone who is known to the victim. It is a violent and serious crime that is far too common an occurrence at our…

  15. Attitudes toward Acquaintance Rape and Risk Appraisal.

    Science.gov (United States)

    Wright, Doris J.

    1999-01-01

    Examines how men and women judge the presence of risk factors in a scripted acquaintance rape scenario and if alcohol was a significant factor in assessing risk. Significant differences were found in African American and Caucasian participants' attitudes toward rape and risk appraisal. There was a negative correlation between risk appraisal and…

  16. Acquaintance Rape and the College Social Scene.

    Science.gov (United States)

    Ward, Sally K.; And Others

    1991-01-01

    Estimated incidence of unwanted sexual experiences on one college campus. Based on self-administered survey, estimated that 34 percent of women had experienced contact; 20 percent experienced attempted intercourse; and 10 percent experienced completed intercourse. Argues that stranger-acquaintance dichotomy be abandoned in favor of typology…

  17. Acquaintance Rape: A Case Study Approach.

    Science.gov (United States)

    Marinelli, Rosalie D.

    1994-01-01

    Describes a case study approach to acquaintance rape used in a Personal Health and Lifestyles course at the University of Nevada in Reno that allows students to discuss the characters in a scenario, an instructional process seen as less threatening than describing personal experiences. (MDM)

  18. Acquaintance Rape on Campus: A Model for Institutional Response.

    Science.gov (United States)

    Burling, Philip

    This booklet explains the actions that college or university administrators should take to prevent or respond to incidents of acquaintance rape ("date rape") on campus. It outlines specific preventive measures, risk management procedures, and internal disciplinary procedures for acquaintance rape cases. Institutions should define acquaintance rape…

  19. Happiness is assortative in online social networks

    OpenAIRE

    Bollen, Johan; Goncalves, Bruno; Ruan, Guangchen; Mao, Huina

    2011-01-01

    Social networks tend to disproportionally favor connections between individuals with either similar or dissimilar characteristics. This propensity, referred to as assortative mixing or homophily, is expressed as the correlation between attribute values of nearest neighbour vertices in a graph. Recent results indicate that beyond demographic features such as age, sex and race, even psychological states such as "loneliness" can be assortative in a social network. In spite of the increasing soci...

  20. Higher order assortativity in complex networks

    CERN Document Server

    Arcagni, Alberto; Stefani, Silvana; Torriero, Anna

    2016-01-01

    Assortativity was first introduced by Newman and has been extensively studied and applied to many real world networked systems since then. Assortativity is a graph metrics and describes the tendency of high degree nodes to be directly connected to high degree nodes and low degree nodes to low degree nodes. It can be interpreted as a first order measure of the connection between nodes, i.e. the first autocorrelation of the degree-degree vector. Even though assortativity has been used so extensively, to the author's knowledge, no attempt has been made to extend it theoretically. This is the scope of our paper. We will introduce higher order assortativity by extending the Newman index based on a suitable choice of the matrix driving the connections. Higher order assortativity will be defined for paths, shortest paths, random walks of a given time length, connecting any couple of nodes. The Newman assortativity is achieved for each of these measures when the matrix is the adjacency matrix, or, in other words, the...

  1. Enhancing neural-network performance via assortativity

    International Nuclear Information System (INIS)

    The performance of attractor neural networks has been shown to depend crucially on the heterogeneity of the underlying topology. We take this analysis a step further by examining the effect of degree-degree correlations - assortativity - on neural-network behavior. We make use of a method recently put forward for studying correlated networks and dynamics thereon, both analytically and computationally, which is independent of how the topology may have evolved. We show how the robustness to noise is greatly enhanced in assortative (positively correlated) neural networks, especially if it is the hub neurons that store the information.

  2. Happiness is assortative in online social networks.

    Science.gov (United States)

    Bollen, Johan; Gonçalves, Bruno; Ruan, Guangchen; Mao, Huina

    2011-01-01

    Online social networking communities may exhibit highly complex and adaptive collective behaviors. Since emotions play such an important role in human decision making, how online networks modulate human collective mood states has become a matter of considerable interest. In spite of the increasing societal importance of online social networks, it is unknown whether assortative mixing of psychological states takes place in situations where social ties are mediated solely by online networking services in the absence of physical contact. Here, we show that the general happiness, or subjective well-being (SWB), of Twitter users, as measured from a 6-month record of their individual tweets, is indeed assortative across the Twitter social network. Our results imply that online social networks may be equally subject to the social mechanisms that cause assortative mixing in real social networks and that such assortative mixing takes place at the level of SWB. Given the increasing prevalence of online social networks, their propensity to connect users with similar levels of SWB may be an important factor in how positive and negative sentiments are maintained and spread through human society. Future research may focus on how event-specific mood states can propagate and influence user behavior in "real life." PMID:21554117

  3. 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. PMID:24860081

  4. Consensus in personality judgments at zero acquaintance.

    Science.gov (United States)

    Albright, L; Kenny, D A; Malloy, T E

    1988-09-01

    This research focused on the target effect on a perceiver's judgments of personality when the perceiver and the target are unacquainted. The perceiver was given no opportunity to interact with the target, a condition we refer to as zero acquaintance. We reasoned that in order to make personality judgments, perceivers would use the information available to them (physical appearance). Consensus in personality judgments would result, then, from shared stereotypes about particular physical appearance characteristics. Results from three separate studies with 259 subjects supported this hypothesis. On two of the five dimensions (extraversion and conscientiousness) on which subjects rated each other, a significant proportion of variance was due to the stimulus target. Consensus on judgments of extraversion appears to have been largely mediated by judgments of physical attractiveness. Across the three studies there was also evidence that the consensus in judgments on these two dimensions had some validity, in that they correlated with self-judgments on those two dimensions. PMID:3171912

  5. Date and Acquaintance Rape: Perceptions and Attitude Change Strategies.

    Science.gov (United States)

    Harrison, Patrick J.; And Others

    1991-01-01

    Investigated the dimensions of university students' (n=96) attitudes toward date and acquaintance rape. Examined the effects of a program designed to change those attitudes. Found college men had substantially greater tendencies to blame the victim for date and acquaintance rape than did women. (Author/ABL)

  6. Assortativity Decreases the Robustness of Interdependent Networks

    CERN Document Server

    Zhou, Di; Scala, Antonio; Stanley, H Eugene

    2012-01-01

    The protection of critical infrastructures is one of the highest priorities in our technological society. It was recently recognized that interdependencies among different networks can play a crucial role in triggering cascading failures and hence system-wide disasters. A recent model shows how pairs of interdependent networks can exhibit an abrupt percolation transition as failures accumulate. We report on the effects of topology on failure propagation for a model system consisting of two interdependent networks. We find that the internal node correlations in each of the two interdependent networks significantly changes the critical density of failures that triggers the total disruption of the two-network system. We find, in particular, that the assortativity within a single network decreases the robustness of the entire system. The results of this study on the influence of assortativity may provide insights into ways of improving the robustness of network architecture, and thus enhance the level of protecti...

  7. Marriage and Assortative Matching in Rural Ethiopia

    OpenAIRE

    Marcel Fafchamps; Agnes Quisumbing

    2002-01-01

    This paper examines the determinants of human and physical capital at marriage. Using detailed data from rural Ethiopia, we find ample evidence of assortative matching at marriage. Assets brought to marriage are distributed in a highly unequal manner. Sorting operates at a variety of levels – wealth, schooling, and work experience – that cannot be summarized into a single additive index. For first unions, assets brought to marriage are positively associated with parents’ wealth, indicating th...

  8. The factors affecting sexual assaults committed by strangers and acquaintances.

    Science.gov (United States)

    Pazzani, Lynn M

    2007-07-01

    Research on the causes of sexual assault typically analyzes rape committed by acquaintances and strangers together, despite the fact that the characteristics of the assault in these two circumstances are very different. Thus, this work examines whether the causes of each type of sexual assault--stranger and acquaintance rape--differ. The results of the analyses reveal that variables that describe a culture of gender equality, prior child abuse, and prior sexual assaults are associated with acquaintance assaults. In contrast, a culture of "hypermasculinity" is associated with stranger rape. The implications of these findings are discussed. PMID:17600307

  9. 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

  10. Geo-Social Group Queries with Minimum Acquaintance Constraint

    OpenAIRE

    Zhu, Qijun; Hu, Haibo; Xu, Jianliang; Lee, Wang-Chien

    2014-01-01

    The prosperity of location-based social networking services enables geo-social group queries for group-based activity planning and marketing. This paper proposes a new family of geo-social group queries with minimum acquaintance constraint (GSGQs), which are more appealing than existing geo-social group queries in terms of producing a cohesive group that guarantees the worst-case acquaintance level. GSGQs, also specified with various spatial constraints, are more complex than conventional spa...

  11. 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. 

  12. The internet and family and acquaintance sexual abuse.

    Science.gov (United States)

    Mitchell, Kimberly J; Finkelhor, David; Wolak, Janis

    2005-02-01

    This article explores the dynamics of cases involving family and acquaintance sexual offenders who used the Internet to commit sex crimes against minors. Although the stereotype of Internet crimes involves unknown adults meeting juvenile victims online, Internet use can also play a role in sexual crimes against minors by family members and acquaintances. Data were collected from a national sample of law enforcement agencies about arrests for Internet-related sex crimes against minors. Family and acquaintance offenders were nearly as numerous as offenders who used the Internet to meet victims online. They used the Internet in various ways to further their crimes including as a tool to seduce or groom, store or disseminate sexual images of victims, arrange meetings and communicate, reward victims, or advertise or sell victims. Prevention messages and investigation approaches should be revised to incorporate awareness of such cases and their dynamics. PMID:15611326

  13. Assortment structure in beech coppice stands in Boljevac region

    Directory of Open Access Journals (Sweden)

    Danilović Milorad

    2004-01-01

    Full Text Available Assortment structure in beech coppice stands was studied in the area of Boljevac. Assortment structure was evaluated according to the articles of the valid standard (JUS. The assortments represented in the assortment structure, based on the stemwood quality are: Logs for matches, sawlogs I II and III classes, mine timber, technical roundwood, pulpwood, wood for excelsior and fuelwood, I and II classes. The results of the analyses show that the value assortment structure (sum of the values of assortments produced from one tree grows significantly with the increase of tree diameter and this dependence is presented by a degree function. The value percentage of logs for matches, sawlogs of the I and II classes, technical roundwood, mine timber, fuelwood and pulpwood, grows with the increase of the tree diameter. The occurrence of better quality logs (sawlogs in these stands, in contrast to the beech coppice stand in the area of Crni Vrh results from the more favourable diameter structure. There are no statistically significant differences between the value assortment structure on the established sample plot series within the same locality, consequently the data ere united. Because of the differences in stand age, the data are not unified for the localities, although there are no statistically significant differences between value assortment structure for diameter degrees represented in them. False heart (red heart is one of very significant defects of beech wood, and its incidence, inter alia, depends on tree age. The low effect of this defect of wood resulted in a significant percentage of logs for matches. Along with the value assortment structure this paper also presents the percentage of assortments depending on tree diameter.

  14. Evolution of assortative mating in a population expressing dominance.

    Directory of Open Access Journals (Sweden)

    Kristan A Schneider

    Full Text Available In this article, we study the influence of dominance on the evolution of assortative mating. We perform a population-genetic analysis of a two-locus two-allele model. We consider a quantitative trait that is under a mixture of frequency-independent stabilizing selection and density- and frequency-dependent selection caused by intraspecific competition for a continuum of resources. The trait is determined by a single (ecological locus and expresses intermediate dominance. The second (modifier locus determines the degree of assortative mating, which is expressed in females only. Assortative mating is based on similarities in the quantitative trait ('magic trait' model. Analytical conditions for the invasion of assortment modifiers are derived in the limit of weak selection and weak assortment. For the full model, extensive numerical iterations are performed to study the global dynamics. This allows us to gain a better understanding of the interaction of the different selective forces. Remarkably, depending on the size of modifier effects, dominance can have different effects on the evolution of assortment. We show that dominance hinders the evolution of assortment if modifier effects are small, but promotes it if modifier effects are large. These findings differ from those in previous work based on adaptive dynamics.

  15. How Newly Acquainted Dyads Develop Shared Stereotypic Impressions through Conversation

    OpenAIRE

    Ruscher, Janet B.; Cralley, Elizabeth L.; O’Farrell, Kimberly J.

    2005-01-01

    Abstract This study investigated how feelings of closeness at initial acquaintance encourage the development of shared stereotypic impressions of others through conversation. At least early in a relationship, closer dyads may be especially inclined to get along with one another. In order to satisfy this goal, they should focus their conversations around easily agreed upon stereotypic attributes and spontane...

  16. Young Children's Collaboration on the Computer with Friends and Acquaintances

    Science.gov (United States)

    Chen, Yi-Jeng

    2016-01-01

    The processes and patterns of strategies used by children when drawing on the computer with friends and acquaintances were investigated in a case study. The participants were five-and-six-year-old children and the study took place in their home settings. The data collection methods consisted of interviews, observations, audio recordings, video…

  17. 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…

  18. Hidden, Unacknowledged, Acquaintance, and Date Rape: Looking Back, Looking Forward

    Science.gov (United States)

    Koss, Mary P.

    2011-01-01

    In this commentary, the author reflects on two articles that have been among the most highly cited publications in "Psychology of Women Quarterly" ("PWQ") over its first 35 years, "The Hidden Rape Victim: Personality, Attitudinal, and Situational Characteristics" (Koss, 1985) and "Stranger and Acquaintance Rape: Are There Differences in the…

  19. A Model Acquaintance Rape Prevention Program for Men.

    Science.gov (United States)

    Berkowitz, Alan D.

    1994-01-01

    Describes the underlying philosophy, content and evaluation issues, and selection and training of facilitators for a model acquaintance rape prevention program for male students conducted at Hobart College. Provides guidelines to help other colleges and universities implement a model rape prevention program for men that uses small-group discussion…

  20. Date and Acquaintance Rape among a Sample of College Students.

    Science.gov (United States)

    Mills, Crystal S.; Granoff, Barbara J.

    1992-01-01

    Conducted date and acquaintance rape needs-assessment survey on 106 male and 113 female college students. Thirty-two women acknowledged that they were victims of rape or attempted rape, and majority reported multiple victimizations. Eighteen men admitted to committing acts that met legal definition of sexual assault in Hawaii. (Author/NB)

  1. Acquaintance Rape on College Campuses: A Review of the Literature.

    Science.gov (United States)

    Kier, Frederick J.

    Although research on acquaintance, or date rape, dates back to the late 1950's, only recently has the literature in this area focused on prevention. In addition, although research has shown that, conservatively, 1 out of 10 women on university campuses has been raped by someone with whom she is familiar, little appears to have been done about the…

  2. 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…

  3. Assortative mixing in functional brain networks during epileptic seizures

    CERN Document Server

    Bialonski, Stephan

    2013-01-01

    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.

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

    CERN Document Server

    Yang, Dan; Zhou, Tao

    2016-01-01

    The degree-degree correlation is important in understanding the structural organization of a network and the dynamics upon a network. Such correlation is usually measured by the assortativity coefficient $r$, with natural bounds $r \\in [-1,1]$. For scale-free networks with power-law degree distribution $p(k) \\sim k^{-\\gamma}$, 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 $\\gamma$. This work challenges the validation of 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.

  5. Changes in educational assortative mating in contemporary Spain

    OpenAIRE

    Clara Cortina; Albert Esteve

    2006-01-01

    This article analyses patterns and trends in educational assortative mating of the Spanish women born between 1920 and 1969 using data from the 2001 Spanish Census. By means of loglinear models we examine the following issues: i) intensity and changes in educational assortative mating patterns; ii) crossing barriers across educational thresholds and iii) degree of symmetry between male and female patterns. Results show that education matters in the composition of unions: people tend to mar...

  6. The Algebra of Assortative Encounters and the Evolution of Cooperation

    OpenAIRE

    Bergstrom, Ted

    2001-01-01

    This paper explores the quantitative relation between non random, assortative matching and the maintenance of cooperative behavior under evolutionary dynamics. We consider a population of individuals who are \\hardwired" to play either cooperate or defect. They meet other individuals according to some random process and play their programmed strategy in a game of Prisoners' Dilemma. The type that gets the higher expected payoff reproduces more rapidly. We de¯ne an index of assortativity of en...

  7. Stranger and Acquaintance Rape: Are There Differences in the Victim's Experience?

    Science.gov (United States)

    Koss, Mary P.; And Others

    1988-01-01

    Examined rape by strangers and by acquaintances, including nonromantic acquaintances, casual dates, steady dates, and family members in 489 rape victims. Acquaintance rape typically involved single offender and multiple episodes, was less often perceived as rape or revealed to anyone, and, except for rapes by family members, was rated less…

  8. Managing assortment in terms of foreign economic activity of the enterprise trade

    Directory of Open Access Journals (Sweden)

    Sergei Udin

    2015-02-01

    Full Text Available Assortment management is the main task of trade enterprises. Assortment is a basic tool in the marketing mix, it affects the sales and distribution costs. Management of assortment is an important issue for interna-tional companies, because they have a high cost of export-import operations, and this fact influences the financial result. The article considers the information technology assortment management aimed at increas-ing turnover and reducing distribution costs by forming a balanced assortment structure.

  9. Degree distribution and assortativity in line graphs of complex networks

    Science.gov (United States)

    Wang, Xiangrong; Trajanovski, Stojan; Kooij, Robert E.; Van Mieghem, Piet

    2016-03-01

    Topological characteristics of links of complex networks influence the dynamical processes executed on networks triggered by links, such as cascading failures triggered by links in power grids and epidemic spread due to link infection. The line graph transforms links in the original graph into nodes. In this paper, we investigate how graph metrics in the original graph are mapped into those for its line graph. In particular, we study the degree distribution and the assortativity of a graph and its line graph. Specifically, we show, both analytically and numerically, the degree distribution of the line graph of an Erdős-Rényi graph follows the same distribution as its original graph. We derive a formula for the assortativity of line graphs and indicate that the assortativity of a line graph is not linearly related to its original graph. Additionally, line graphs of various graphs, e.g. Erdős-Rényi graphs, scale-free graphs, show positive assortativity. In contrast, we find certain types of trees and non-trees whose line graphs have negative assortativity.

  10. Changes in educational assortative mating in contemporary Spain

    Directory of Open Access Journals (Sweden)

    Clara Cortina

    2006-05-01

    Full Text Available This article analyses patterns and trends in educational assortative mating of the Spanish women born between 1920 and 1969 using data from the 2001 Spanish Census. By means of loglinear models we examine the following issues: i intensity and changes in educational assortative mating patterns; ii crossing barriers across educational thresholds and iii degree of symmetry between male and female patterns. Results show that education matters in the composition of unions: people tend to marry assortatively according to their education. However this pattern clearly differs across cohorts and between educational groups, being higher for the extreme categories. The most notable trends are 1 the increasing intensity of homogamy among the more educated and 2 the incipient extinction of the traditional female hypergamic pattern.

  11. The Theory of Assortative Matching Based on Costly Signals

    OpenAIRE

    Hoppe, Heidrun C.; Moldovanu, Benny; Sela, Aner

    2005-01-01

    We study two-sided markets with a finite numbers of agents on each side, and with two-sided incomplete information. Agents are matched assortatively on the basis of costly signals. A main goal is to identify conditions under which the potential increase in expected output due to assortative matching (relative to random matching) is completely offset by the costs of signalling. We also study how the signalling activity and welfare on each side of the market change when we vary the number of ag...

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

    OpenAIRE

    Yang, Dan; Pan, Liming; Zhou, Tao

    2016-01-01

    The degree-degree correlation is important in understanding the structural organization of a network and the dynamics upon a network. Such correlation is usually measured by the assortativity coefficient $r$, with natural bounds $r \\in [-1,1]$. For scale-free networks with power-law degree distribution $p(k) \\sim k^{-\\gamma}$, 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 $\\gamma$...

  13. 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.

  14. Emergence of clustering in an acquaintance model without homophily

    International Nuclear Information System (INIS)

    We introduce an agent-based acquaintance model in which social links are created by processes in which there is no explicit homophily. In spite of the homogeneous nature of the social interactions, highly-clustered social networks can arise. The crucial feature of our model is that of variable transitive interactions. Namely, when an agent introduces two unconnected friends, the rate at which a connection actually occurs between them depends on the number of their mutual acquaintances. As this transitive interaction rate is varied, the social network undergoes a dramatic clustering transition. Close to the transition, the network consists of a collection of well-defined communities. As a function of time, the network can also undergo an incomplete gelation transition, in which the gel, or giant cluster, does not constitute the entire network, even at infinite time. Some of the clustering properties of our model also arise, but in a more gradual manner, in Facebook networks. Finally, we discuss a more realistic variant of our original model in which network realizations can be constructed that quantitatively match Facebook networks. (paper)

  15. 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

  16. Assortativity Effects on Diffusion-like Processes in Scale-free Networks

    CERN Document Server

    D'Agostino, Gregorio; Zlatić, Vinko; Caldarelli, Guido

    2011-01-01

    We study the variation in epidemic thresholds in complex networks with different assortativity properties. We determine the thresholds by applying spectral analysis to the matrices associated to the graphs. In order to produce graphs with a specific assortativity we introduce a procedure to sample the space of all the possible networks with a given degree sequence. Our analysis shows that while disassortative networks have an higher epidemiological threshold, assortative networks have a slower diffusion time for diseases. We also used these networks for evaluating the effects of assortativity in a specific dynamic model of sandpile. We show that immunization procedures give different results according to the assortativity of the network considered.

  17. A Review of Acquaintance/Date Rape Research: Implications for the University Campus.

    Science.gov (United States)

    Drapeau, Robert F.

    1992-01-01

    Reviews literature on incidence and ramifications of acquaintance rape and discusses specific gender-related factors. Identifies four areas that require proactive college response: access and intrusion, nonnegligent hiring and training, alcohol and drugs, and awareness education. Concludes that effective response to acquaintance rape requires…

  18. Preventing Alcohol-Related Problems on Campus: Acquaintance Rape. A Guide for Program Coordinators.

    Science.gov (United States)

    Finn, Peter

    This is a guide for college and university program coordinators and planning committees on how to establish, expand, or improve a program on the prevention of acquaintance rape. Information is given for Presidents, Vice Presidents, and Deans on the relationship between acquaintance rape and alcohol, reasons for top administrators to become…

  19. College Women's Fears and Precautionary Behaviors Relating to Acquaintance Rape and Stranger Rape.

    Science.gov (United States)

    Hickman, Susan E.; Muehlenhard, Charlene L.

    1997-01-01

    Studied the fears, beliefs, and behaviors of 139 college women about acquaintance and stranger rape. Women were more afraid of stranger rape and took more precautions against it but paradoxically believed that acquaintance rape was more common. Precautionary behaviors were best predicted by level of fear. Theoretical and educational implications…

  20. 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…

  1. A Comparison of Strategies for Changing College Students' Attitudes toward Acquaintance Rape.

    Science.gov (United States)

    Nelson, Eileen S.; Torgler, Cyndee C.

    1990-01-01

    Compared effects of strategies for informing college students about date rape. Assigned students to either experimental group that viewed videotape on acquaintance rape (n=33), experimental group that read brochure on acquaintance rape (n=31), or control group (n=25). Findings revealed no significant difference between effects of videotape and…

  2. Interdisciplinary Matchmaking: Choosing Collaborators by Skill, Acquaintance and Trust

    Science.gov (United States)

    Hupa, Albert; Rzadca, Krzysztof; Wierzbicki, Adam; Datta, Anwitaman

    Social networks are commonly used to enhance recommender systems. Most of such systems recommend a single resource or a person. However, complex problems or projects usually require a team of experts that must work together on a solution. Team recommendation is much more challenging, mostly because of the complex interpersonal relations between members. This chapter presents fundamental concepts on how to score a team based on members' social context and their suitability for a particular project. We represent the social context of an individual as a three-dimensional social network (3DSN) composed of a knowledge dimension expressing skills, a trust dimension and an acquaintance dimension. Dimensions of a 3DSN are used to mathematically formalize the criteria for prediction of the team's performance. We use these criteria to formulate the team recommendation problem as a multi-criteria optimization problem. We demonstrate our approach on empirical data crawled from two web2.0 sites: onephoto.net and a social networking site. We construct 3DSNs and analyze properties of team's performance criteria.

  3. Bridging across nations. The social capital of diversity, brokerage and closure in transnational migrant networks: a study on assimilation patterns in Milan and Barcelona

    OpenAIRE

    Vacca,, C.

    2013-01-01

    This dissertation deals with the network effects on immigrant assimilation: how the composition and structure of migrants' personal networks affect patterns of assimilation in host societies. A personal network is the set of all current and active social contacts that a focal individual (Ego) has, including family, friends and acquaintances. It is operationalized here as the list of 45 alters who were mentioned by Ego (the migrant) as people with whom he had some kind of contact in the las...

  4. When Granny Is the Wolf: Understanding and Approaching College-aged Female Victims of Acquaintance Rape

    OpenAIRE

    Lam, Charlene; Roman, Brenda

    2009-01-01

    College is generally felt to be an exciting time in the lives of young people; however, some college-aged students find themselves in difficult situations. For young women especially, acquaintance rape in the college years is a risk. While men can also be victims of sexual assault, it is far more common for women to be victimized. This article reviews the literature of acquaintance rape, including situational risk factors, perpetrator characteristics, and victim characteristics, as well as st...

  5. Explosive Synchronization and Emergence of Assortativity on Adaptive Networks

    Institute of Scientific and Technical Information of China (English)

    JIANG Hui-Jun; WU Hao; HOU Zhong-Huai

    2011-01-01

    @@ We report an explosive transition from incoherence to synchronization of coupled phase oscillators on adaptive networks,following an Achlioptas process based on dynamic clustering information.During each adaptive step of the network topology,a portion of the links is randomly removed and the same amount of new links is generated following the so-called product rules(PRs) applied to the dynamic clusters.Particularly,two types of PRs are considered,namely,the min-PR and max-PR.We demonstrate that the synchronization transition becomes explosive in both cases.Interestingly,we find that the min-PR rule can lead to disassortativity of the network topology,while the max-PR rule leads to assortativity.%We report an explosive transition from incoherence to synchronization of coupled phase oscillators on adaptive networks, following an Achlioptas process based on dynamic clustering information. During each adaptive step of the network topology, a portion of the links is randomly removed and the same amount of new links is generated following the so-called product rules (PRs) applied to the dynamic clusters. Particularly, two types of PRs are considered, namely, the min-PR and max-PR. We demonstrate that the synchronization transition becomes explosive in both cases. Interestingly, we find that the min-PR rule can lead to disassortativity of the network topology, while the max-PR rule leads to assortativity.

  6. 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

  7. Assimilation of Images

    OpenAIRE

    Vidard, Arthur; Titaud, Olivier

    2014-01-01

    International audience Data assimilation aims at determining as accurately as possible the state of a dynamical system by combining heterogeneous sources of information in an optimal way. Generally speaking, the mathematical methods of data assimilation describe algorithms for forming optimal combinations of observations of a system, a numerical model that describes its evolution, and appropriate prior information. Data assimilation has a long history of application to high-dimensional geo...

  8. Assimilation in multilingual cities

    OpenAIRE

    Ortega, Javier

    2011-01-01

    Using the Public Use Microdata Files of the 2001 and 2006 Canadian Censuses, we study the determinants of the assimilation of language minorities into the city majority language. We show that official minority members (i.e. francophones in English-speaking cities and anglophones in French-speaking cities) assimilate less than the "allophones" (the individuals with a mother tongue other than English or French), and that immigrants generally assimilate less than natives. In addition, the langua...

  9. 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.

  10. Innovative approaches to the prices management within the framework of product assortment

    Directory of Open Access Journals (Sweden)

    O.I. Laburtseva

    2011-03-01

    Full Text Available The article is devoted to the development of methodical recommendations on a products prices management with presence of substitution or complementation connections in the product assortment. The variants of product intercommunications in the assortment of enterprise are systematized, the proper methodical approaches to pricing are recommended and the results of business-approbation of recommendations are presented.

  11. 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…

  12. Inducing Self-Organized Criticality in a network toy model by neighborhood assortativity

    CERN Document Server

    Allen-Perkins, Alfonso; Pastor, Juan Manuel

    2016-01-01

    Complex networks are a recent type of frameworks used to study complex systems with many interacting elements, such as Self-Organized Criticality (SOC). The network node's tendency to link to other nodes of similar type is characterized by assortative mixing. Real networks exhibit assortative mixing by vertex degree, however typical random network models, such as Erdos-Renyi or Barabasi-Albert, show no assortative arrangements. In this paper we introduce the neighborhood assortativity notion, as the tendency of a node to belong to a community (its neighborhood) showing an average property similar to its own. Imposing neighborhood assortative mixing by degree in a network toy model, SOC dynamics can be found. The long-range correlations resulting from the criticality have been characterized by means of fluctuation analysis and show an anticorrelation in the node's activity. The model contains only one parameter and its statistics plots for different values of the parameter can be collapsed into a single curve....

  13. 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

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

    Science.gov (United States)

    Pechenick, Dov A; Payne, Joshua L; Moore, Jason H

    2014-08-01

    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 components of the

  15. When Granny Is the Wolf: Understanding and Approaching College-aged Female Victims of Acquaintance Rape.

    Science.gov (United States)

    Lam, Charlene; Roman, Brenda

    2009-08-01

    College is generally felt to be an exciting time in the lives of young people; however, some college-aged students find themselves in difficult situations. For young women especially, acquaintance rape in the college years is a risk. While men can also be victims of sexual assault, it is far more common for women to be victimized. This article reviews the literature of acquaintance rape, including situational risk factors, perpetrator characteristics, and victim characteristics, as well as strategies to prevent revictimization, utilizing a female victim as the composite case. PMID:19763203

  16. Displacement Data Assimilation

    CERN Document Server

    Rosenthal, W Steven; Mariano, Arthur J; Restrepo, Juan M

    2016-01-01

    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 important. While the displacement transformation is not tied to any particular assimilation scheme, here we implement it within an ensemble Kalman Filter and demonstrate its effectiveness in tracking stochastically perturbed vortices.

  17. Assimilative Capacity Revisited

    OpenAIRE

    Cairns, John

    2008-01-01

    Assimilative capacity is the ability of natural systems to assimilate humankind's wastes. Wastes (output) of some species in natural systems are the resources (input) of other species. Before the Industrial Revolution, this concept of input and output held true for human activity, but industrialization created wastes that were qualitatively and quantitatively different from those of natural systems. The unique nature of some persistent wastes that accumulate in organisms over long periods of ...

  18. "Nobody Told Me It Was Rape": A Parent's Guide for Talking with Teenagers about Acquaintance Rape and Sexual Exploitation.

    Science.gov (United States)

    Adams, Caren; Fay, Jennifer

    This book was written to help parents talk to their adolescent children about acquaintance rape and sexual exploitation. It may also be useful to family life educators presenting units on rape and sexual exploitation. Acquaintance rape and sexual exploitation are explained in the first section. The second section discusses talking with teenagers…

  19. Differential Characteristics of Intimate Partner, Acquaintance, and Stranger Rape Survivors Examined by a Sexual Assault Nurse Examiner (SANE)

    Science.gov (United States)

    Logan, TK; Cole, Jennifer; Capillo, Anita

    2007-01-01

    Relatively little is known about characteristics of sexual assault survivors who present to the emergency room. Examination of differences in survivor, assault, and exam characteristics by type of offender (intimate partner, acquaintance, acquaintance-just-met, and stranger) was conducted using intake data collected from 331 women who presented to…

  20. An Acquaintance Rape Prevention Program: Effects on Attitudes Toward Women, Rape-Related Attitudes, and Perceptions of Rape Scenarios.

    Science.gov (United States)

    Pinzone-Glover, Holly A.; Gidycz, Christine A.; Jacobs, Cecilia Dine

    1998-01-01

    Studied the effects of an acquaintance-rape prevention program on college students' attitudes (n=152) toward rape and attitudes toward women, perceptions of acquaintance rape scenarios, and rape empathy. Positive attitude change was stronger among men, who became more certain of rape definitions. Contains 53 references. (SLD)

  1. The Effectiveness of Personalizing Acquaintance Rape Prevention: Programs on Perception of Vulnerability and on Reducing Risk-Taking Behavior.

    Science.gov (United States)

    Gray, Michael D.; And Others

    1990-01-01

    Tested hypothesis that a personalized acquaintance rape prevention program reduces risk-taking behavior and increases perception of vulnerability. Seventy female college students were exposed to Acquaintance Rape Prevention Program with experimentals and controls receiving personalized or nonpersonalized instruction, respectively. Findings showed…

  2. Acquaintance with international and Iranian organizations responsible to replacement of the destroying materials of ozone layer

    International Nuclear Information System (INIS)

    Acquaintance with international and Iranian organizations responsible to replacement of the depletion materials of ozone layer is discussed. Vienna Convection for depletion is briefly reviewed and then Montreal Protocol is described. Finally,Islamic Republic of Iran programs in this respect are represented

  3. Acquaintance Rape Workshops: Their Effectiveness in Changing the Attitudes of First Year College Men

    Science.gov (United States)

    Earle, James P.

    2009-01-01

    The statistics on acquaintance rape and sexual assault against women are a clear indication that this is a problem that needs to be confronted. An increasing number of articles address the problems that rape survivors face and examine methods mental health professionals can use to assist survivors in dealing with these problems. Articles that…

  4. An Acquaintance Rape Education Program for Students Transitioning to High School

    Science.gov (United States)

    Fay, Karen E.; Medway, Frederic J.

    2006-01-01

    Based on Parrot's work with college students, a six-activity acquaintance rape prevention program for first-year high school students living in a rural South Carolina community was implemented and evaluated. The program decreased students' acceptance of rape myths compared with non-participating students both on a scale developed by Burt and on…

  5. Date and Acquaintance Rape: The Legal Point of View. Part 1. The Traditional Law of Rape.

    Science.gov (United States)

    Julian, Frank H.

    1993-01-01

    First article in two-part series on date and acquaintance rape explains unique circumstances of rape trials and looks at development of traditional rape law. Examines judicial history of rape, and reviews elements of rape (penetration, intent, force, and consent). (Author/NB)

  6. Five Year Campus Acquaintance Rape Education: Evaluating the Impact of a Mandatory Intervention.

    Science.gov (United States)

    Lonsway, Kimberly A.; Kothari, Chevon

    2000-01-01

    Evaluated the impact of a mandatory acquaintance rape education program for college freshmen. Surveys of participating and nonparticipating students immediately and several months following the program indicated a positive impact of participation on attitudes and judgements immediately following participation. Increases in knowledge were…

  7. 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)

  8. Acquaintance Rape of College Students. Problem-Oriented Guides for Police Series.

    Science.gov (United States)

    Sampson, Rana

    Guides in this series summarize knowledge about how police can reduce the harm caused by specific crime and disorder problems. They are guides to prevention, not to investigating offenses of handling incidents. This guide focuses on rape of college students by acquaintances. It is estimated that almost 25% of college women have been victims of…

  9. Suggested Acquaintance/Date Rape Education & Prevention Strategies for School Health Instruction.

    Science.gov (United States)

    Weiler, Robert M.; Walls, Nicole A.

    Data suggest that acquaintance and date rape may account for 50-70 percent of all reported rapes in the United States. Recent findings also indicate that one in four college women have been raped or a victim of attempted rape. As most rape victims are between 15 and 24 years of age, high school-based education programs must be provided if society…

  10. The Impact of Acquaintance Rape Stories and Case-Specific Pretrial Publicity on Juror Decision Making.

    Science.gov (United States)

    Mullin, Charles; And Others

    1996-01-01

    Reports on a trial simulation in which exposure to publicity regarding the defendant and general stories about acquaintance rape were manipulated; participants then viewed an enacted rape trial. Finds that male subjects exposed to predatory rape publicity were pro-defendant, whereas women were unaffected. Discusses male reaction to information…

  11. Gender, Sex-Role Stereotypes, and the Attribution of Responsibility for Date and Acquaintance Rape.

    Science.gov (United States)

    Proite, Rosanne; And Others

    1993-01-01

    Examined college student attitudes toward women and attribution of responsibility for acquaintance rape. Findings from 417 students revealed that, in situations described in scenarios, male college students were more likely to assign responsibility to the woman. They more strongly believed that the woman wanted to have sexual intercourse and that…

  12. 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....

  13. 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.

  14. 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...

  15. Reconsidering the Heritability of Intelligence in Adulthood: Taking Assortative Mating and Cultural Transmission into Account

    OpenAIRE

    Vinkhuyzen, Anna A E; van der Sluis, Sophie; Maes, Hermine H. M.; Posthuma, Danielle

    2011-01-01

    Heritability estimates of general intelligence in adulthood generally range from 75 to 85%, with all heritability due to additive genetic influences, while genetic dominance and shared environmental factors are absent, or too small to be detected. These estimates are derived from studies based on the classical twin design and are based on the assumption of random mating. Yet, considerable positive assortative mating has been reported for general intelligence. Unmodeled assortative mating may ...

  16. Linking intra- and interspecific assortative mating: Consequences for asymmetric sexual isolation.

    Science.gov (United States)

    Svensson, Erik I; Nordén, Anna; Waller, John T; Runemark, Anna

    2016-06-01

    Assortative mating is of interest because of its role in speciation and the maintenance of species boundaries. However, we know little about how within-species assortment is related to interspecific sexual isolation. Most previous studies of assortative mating have focused on a single trait in males and females, rather than utilizing multivariate trait information. Here, we investigate how intraspecific assortative mating relates to sexual isolation in two sympatric and congeneric damselfly species (genus Calopteryx). We connect intraspecific assortment to interspecific sexual isolation by combining field observations, mate preference experiments, and enforced copulation experiments. Using canonical correlation analysis, we demonstrate multivariate intraspecific assortment for body size and body shape. Males of the smaller species mate more frequently with heterospecific females than males of the larger species, which showed less attraction to small heterospecific females. Field experiments suggest that sexual isolation asymmetry is caused by male preferences for large heterospecific females, rather than by mechanical isolation due to interspecific size differences or female preferences for large males. Male preferences for large females and male-male competition for high quality females can therefore counteract sexual isolation. This sexual isolation asymmetry indicates that sexual selection currently opposes a species boundary. PMID:27151764

  17. 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

  18. 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

  19. On Assimilation of English Sounds

    Institute of Scientific and Technical Information of China (English)

    刘恩华

    2015-01-01

    This paper makes a careful study of assimilation in English speaking, meanwhile a systematic knowledge of assimilation wil be helpful for the pronunciations of English learners, facilitate English fluency and improve listening comprehension.

  20. The role of race and respectability in attributions of responsibility for acquaintance rape.

    Science.gov (United States)

    Dupuis, Erin C; Clay, Jason A

    2013-01-01

    Previous researchers have explored the role of race and respectability, independently, on attributions of responsibility; however, the interaction between race and respectability has not been analyzed in situations of acquaintance rape. Participants (N = 241) read a vignette detailing a case of acquaintance rape that manipulated the race of both the victim and the perpetrator and the respectability of the victim. Regression and ANOVA analyses indicated that victim race and respectability interacted in such a way that when Black victims were respectable, they were held less responsible than respectable White victims; however, less respected Black victims were held more responsible than less respected White victims. Manipulating perpetrator race revealed surprising results; the White perpetrator was found guilty more often than the Black perpetrator (although this appeared to be related to victim race). PMID:24547682

  1. Judge me, judge me not: The role of eye size and observer gender on acquaintance rape

    OpenAIRE

    María Clara Ferrão; Gabriela Gonçalves; Jean Christophe Giger; Tiago Parreira

    2016-01-01

    The purpose of this study was to examine the effect of eye size and observer gender on perceived initial attraction, honesty, and attributions of responsibility for rape. A 3 (eye size: small vs. normal vs. large) x 2 (observer gender: female vs. male) experimental design was tested. Ninety participants (45 women and 45 men) observed one of three randomly assigned female faces (with eye size manipulation), and rated initial attraction and honesty. They were then asked to read an acquaintance ...

  2. Romantic Partners, Friends, Friends with Benefits, and Casual Acquaintances As Sexual Partners

    OpenAIRE

    Furman, Wyndol; Shaffer, Laura

    2011-01-01

    The purpose of the present study was to provide a detailed examination of sexual behavior with different types of partners. A sample of 163 young adults reported on their light nongenital, heavy nongenital, and genital sexual activity with romantic partners, friends, and casual acquaintances. They described their sexual activity with “friends with benefits” as well as with friends in general. Young adults were most likely to engage in sexual behavior with romantic partners, but sexual behavio...

  3. 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.  

  4. THE IMPROVING OF ASSORTMENT BY «BUMFA GROUP» IN CHERKESSK

    Directory of Open Access Journals (Sweden)

    Gayduk V. I.

    2015-09-01

    Full Text Available The article presents and analyzes the assortment of "Bumfa Group" with the methods of ABC analysis, XYZ-analysis. It gives the description of the goods offered by the organization, its customers and its main competitors. The profile of competitive advantages and disadvantages is compiled. It presents the results of marketing research of consumers acquiring products offered by LLC "Bumfa Group" - the goods in terms of popularity, the factors influencing the decision to purchase, customers’ satisfaction in price, packaging and product quality, the results of customers’choice of new products to update the assortment, customers’ satisfaction in volume of incoming advertising information about the products of "Bumfa Group." The necessity to optimize the assortment of the organization is founded. To achieve this aim we developed a project to introduce new products in the range of goods - wet wipes for office equipment. The characteristics of the new product, the production plan and performance indicators of the project are supplied

  5. 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;

    food retailers focus on whether they offer the "right" assort-ment to consumers. Under headings such as efficient consumer response (ECR) and cate-gory management (CM), retailers have been readjusting their assortments, delisting many brands that were deemed to be under-performing and including...... 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 in the....... In doing so we adapt the concept of brand architecture to a retail context. The concept of 'brand architecture', as originally developed by (Aaker & Joachimsthaler 2002), describes how the different brands used to market a range of products from the same manufacturer are related. The concept of brand...

  6. Robustness and assortativity for diffusion-like processes in scale-free networks

    Science.gov (United States)

    D'Agostino, G.; Scala, A.; Zlatić, V.; Caldarelli, G.

    2012-03-01

    By analysing the diffusive dynamics of epidemics and of distress in complex networks, we study the effect of the assortativity on the robustness of the networks. We first determine by spectral analysis the thresholds above which epidemics/failures can spread; we then calculate the slowest diffusional times. Our results shows that disassortative networks exhibit a higher epidemiological threshold and are therefore easier to immunize, while in assortative networks there is a longer time for intervention before epidemic/failure spreads. Moreover, we study by computer simulations the sandpile cascade model, a diffusive model of distress propagation (financial contagion). We show that, while assortative networks are more prone to the propagation of epidemic/failures, degree-targeted immunization policies increases their resilience to systemic risk.

  7. 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.

  8. 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.

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

    CERN Document Server

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

    2013-01-01

    In this paper, inspired by the analysis on 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 intension. It is shown that the model can reproduce the remarkable properties observed in empirical online social networks, particularly, that the assortative coefficients are neural or negative and the power law exponents are smaller than 2. Moreover, we demonstrate that, under feasible conditions, the modeling networks naturally convert from assortative to disassortative, and from sparse to dense. Our model is helpful for understanding the formation and evolution of online social networks.

  10. Effect of assortative mixing in the second-order Kuramoto model

    CERN Document Server

    Peron, Thomas K DM; Rodrigues, Francisco A; Kurths, Jürgen

    2015-01-01

    In this paper we analyze the second-order Kuramoto model presenting a positive correlation between the heterogeneity of the connections and the natural frequencies in scale-free networks. We numerically show that discontinuous transitions emerge not just in disassortative but also in assortative networks, in contrast with the first-order model. We also find that the effect of assortativity on network synchronization can be compensated by adjusting the phase damping. Our results show that it is possible to control collective behavior of damped Kuramoto oscillators by tuning the network structure or by adjusting the dissipation related to the phases movement.

  11. Assimilation in multilingual cities

    OpenAIRE

    Ortega, Javier; Verdugo, Gregory

    2015-01-01

    International audience We characterise how the assimilation patterns of minorities into the strong and the weak language differ in a situation of asymmetric bilingualism. Using large variations in language composition in Canadian cities from the 2001 and 2006 Censuses, we show that the differences in the knowledge of English by immigrant allophones (i.e. the immigrants with a mother tongue other than English and French) in English-majority cities are mainly due to sorting across cities. In...

  12. ASESMENT POST TRAUMATIC STRESS DISORDER (PTSD PADA PEREMPUAN KORBAN PERKOSAAN (ACQUAINTANCE RAPE

    Directory of Open Access Journals (Sweden)

    Mutingatu Solichah

    2013-08-01

    Full Text Available AbstractThis research was intended to find out whether Post Traumatic Stress Disorder (PTSD symptom manifested in 5 women acquaintance rape survivors.PTSD Symptom was measured by the Clinician-Administered PTSD Scale (CAPS, a semi structured interview guide that assesses 17 clinical symptoms of PTSD outlines in DSM IV criterion along with 3 associated features of PTSD symptoms. Quantitative data is used todetermine the categorical rating of the PTSD diagnostic status of the participants (PTSD present or absent, symptom severity, and changes gradations of symptom severity over time. Participants were 5 women survivors of acquaintance rape, aged 17 – 35 years old. The results show 4 from 5 participants was diagnosed having PTSD which symptom severity varied. The CAPS’ PTSD diagnostic procedure is combined between the DSM IV defined 20 symptom criteria and its symptom’s frequency and intensity, so the score should range from 20 the lowest up to 160. The participants score range from 35– 125, but one participant was not eligiblefor PTSD diagnostic status due to failure to meet DSM IV criterion for PTSD. The interval time between the traumatic event (rape and research was ranging from 4 to 31 years, however PTSD symptom’s severity in participants remain high.Keywords: acquaintance rape, Clinician-Administered PTSD Scale (CAPS, DSM IV.

  13. VA-Index: Quantifying Assortativity Patterns in Networks with Multidimensional Nodal Attributes.

    Directory of Open Access Journals (Sweden)

    Konstantinos Pelechrinis

    Full Text Available Network connections have been shown to be correlated with structural or external attributes of the network vertices in a variety of cases. Given the prevalence of this phenomenon network scientists have developed metrics to quantify its extent. In particular, the assortativity coefficient is used to capture the level of correlation between a single-dimensional attribute (categorical or scalar of the network nodes and the observed connections, i.e., the edges. Nevertheless, in many cases a multi-dimensional, i.e., vector feature of the nodes is of interest. Similar attributes can describe complex behavioral patterns (e.g., mobility of the network entities. To date little attention has been given to this setting and there has not been a general and formal treatment of this problem. In this study we develop a metric, the vector assortativity index (VA-index for short, based on network randomization and (empirical statistical hypothesis testing that is able to quantify the assortativity patterns of a network with respect to a vector attribute. Our extensive experimental results on synthetic network data show that the VA-index outperforms a baseline extension of the assortativity coefficient, which has been used in the literature to cope with similar cases. Furthermore, the VA-index can be calibrated (in terms of parameters fairly easy, while its benefits increase with the (co-variance of the vector elements, where the baseline systematically over(underestimate the true mixing patterns of the network.

  14. VA-Index: Quantifying Assortativity Patterns in Networks with Multidimensional Nodal Attributes.

    Science.gov (United States)

    Pelechrinis, Konstantinos; Wei, Dong

    2016-01-01

    Network connections have been shown to be correlated with structural or external attributes of the network vertices in a variety of cases. Given the prevalence of this phenomenon network scientists have developed metrics to quantify its extent. In particular, the assortativity coefficient is used to capture the level of correlation between a single-dimensional attribute (categorical or scalar) of the network nodes and the observed connections, i.e., the edges. Nevertheless, in many cases a multi-dimensional, i.e., vector feature of the nodes is of interest. Similar attributes can describe complex behavioral patterns (e.g., mobility) of the network entities. To date little attention has been given to this setting and there has not been a general and formal treatment of this problem. In this study we develop a metric, the vector assortativity index (VA-index for short), based on network randomization and (empirical) statistical hypothesis testing that is able to quantify the assortativity patterns of a network with respect to a vector attribute. Our extensive experimental results on synthetic network data show that the VA-index outperforms a baseline extension of the assortativity coefficient, which has been used in the literature to cope with similar cases. Furthermore, the VA-index can be calibrated (in terms of parameters) fairly easy, while its benefits increase with the (co-)variance of the vector elements, where the baseline systematically over(under)estimate the true mixing patterns of the network. PMID:26816262

  15. 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.

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

    NARCIS (Netherlands)

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

    2009-01-01

    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 ot

  17. The small world phenomenon and assortative mixing in Polish corporate board and director networks

    Science.gov (United States)

    Sankowska, Anna; Siudak, Dariusz

    2016-02-01

    This paper investigates the corporate board and director networks in the Polish capital market in 2014. We examined real board and director networks in comparison with networks that were randomly constructed. Through empirical analyses, we demonstrated that the real networks have the characteristics of small-world networks. In addition, the networks are assortative and highly clustered, which imposes certain behaviors on them.

  18. 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

    2016-01-01

    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 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. PMID:26887684

  19. The genetic correlation between height and IQ: shared genes or assortative mating?

    Directory of Open Access Journals (Sweden)

    Matthew C Keller

    2013-04-01

    Full Text Available Traits that are attractive to the opposite sex are often positively correlated when scaled such that scores increase with attractiveness, and this correlation typically has a genetic component. Such traits can be genetically correlated due to genes that affect both traits ("pleiotropy" and/or because assortative mating causes statistical correlations to develop between selected alleles across the traits ("gametic phase disequilibrium". In this study, we modeled the covariation between monozygotic and dizygotic twins, their siblings, and their parents (total N = 7,905 to elucidate the nature of the correlation between two potentially sexually selected traits in humans: height and IQ. Unlike previous designs used to investigate the nature of the height-IQ correlation, the present design accounts for the effects of assortative mating and provides much less biased estimates of additive genetic, non-additive genetic, and shared environmental influences. Both traits were highly heritable, although there was greater evidence for non-additive genetic effects in males. After accounting for assortative mating, the correlation between height and IQ was found to be almost entirely genetic in nature. Model fits indicate that both pleiotropy and assortative mating contribute significantly and about equally to this genetic correlation.

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

    DEFF Research Database (Denmark)

    Farley, Adam

    2015-01-01

    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...... 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...

  1. ASESMENT POST TRAUMATIC STRESS DISORDER (PTSD) PADA PEREMPUAN KORBAN PERKOSAAN (ACQUAINTANCE RAPE)

    OpenAIRE

    Mutingatu Solichah

    2013-01-01

    AbstractThis research was intended to find out whether Post Traumatic Stress Disorder (PTSD) symptom manifested in 5 women acquaintance rape survivors.PTSD Symptom was measured by the Clinician-Administered PTSD Scale (CAPS), a semi structured interview guide that assesses 17 clinical symptoms of PTSD outlines in DSM IV criterion along with 3 associated features of PTSD symptoms. Quantitative data is used todetermine the categorical rating of the PTSD diagnostic status of the participan...

  2. Young heterosexual men’s use of the miscommunication model in explaining acquaintance rape

    OpenAIRE

    Hansen, Susan; O'Byrne, Racheal; Rapley, Mark

    2010-01-01

    This article describes a program of research that systematically examined the ways in which young heterosexual men draw on widely culturally shared accounts of rape to account for sexual coercion and sexual assault. In particular, the authors discuss the reliance placed on a lay version of Tannen’s (1992) miscommunication model of (acquaintance) rape—the claim that rape is a consequence of men’s not knowing—and young men’s use of this account as a device to accomplish exculpation. The authors...

  3. Data assimilation in hydrological modelling

    OpenAIRE

    Drecourt, Jean-Philippe; Rosbjerg, Dan

    2004-01-01

    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. In this thesis, the Kalman filter is used for data assimilation with a focus on groundwater modelling. However the developed techniques are general and can be applied also in other modelling domains. Mo...

  4. Assimilation: central and peripheral effects

    OpenAIRE

    Weert, C.M.M. de; Kruysbergen, N.A.W.H. van

    1997-01-01

    Assimilation and contrast have opposite effects: Contrast leads to an increase of perceived differences between neighbouring fields, whereas assimilation leads to a reduction. It is relatively easy to demonstrate these effects, but the precise localisation of these effects in the perceptual system is not yet possible. In an experiment the strength of assimilation effects was modified by adding spatial noise. By varying the localisation in perceived space of the added noise (by presentation of...

  5. Assortative mating and gene flow generate clinal phenological variation in trees

    Directory of Open Access Journals (Sweden)

    Soularue Jean-Paul

    2012-06-01

    Full Text Available Abstract Background On-going climate change is shifting the timing of bud burst (TBB of broad leaf and conifer trees in temperate areas, raising concerns about the abilities of natural populations to respond to these shifts. The level of expected evolutionary change depends on the level and distribution of genetic variation of TBB. While numerous experimental studies have highlighted the role of divergent selection in promoting clinal TBB differentiation, we explored whether the observed patterns of variation could be generated by the joint effects of assortative mating for TBB and gene flow among natural populations. We tested this hypothesis using an in silico approach based on quantitative genetic models. Results Our simulations showed that genetic clines can develop even without divergent selection. Assortative mating in association with environmental gradients substantially shifted the mean genetic values of populations. Owing to assortative mating, immigrant alleles were screened for proximal or distant populations depending on the strength of the environmental cline. Furthermore, we confirmed that assortative mating increases the additive genetic variance within populations. However, we observed also a rapid decline of the additive genetic variance caused by restricted gene flow between neighboring populations resulting from preferential matings between phenologically-matching phenotypes. Conclusions We provided evidence that the patterns of genetic variation of phenological traits observed in forest trees can be generated solely by the effects of assortative mating and gene flow. We anticipate that predicted temperature increases due to climate change will further enhance genetic differentiation across the landscape. These trends are likely to be reinforced or counteracted by natural selection if phenological traits are correlated to fitness.

  6. 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....

  7. 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...

  8. 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,...

  9. Regional Ocean Data Assimilation

    Science.gov (United States)

    Edwards, Christopher A.; Moore, Andrew M.; Hoteit, Ibrahim; Cornuelle, Bruce D.

    2015-01-01

    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.

  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. Assimilating seizure dynamics.

    Science.gov (United States)

    Ullah, Ghanim; Schiff, Steven J

    2010-05-01

    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. PMID:20463875

  12. 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.

  13. Assimilate Partitioning and Plant Development

    Institute of Scientific and Technical Information of China (English)

    Yong-Ling Ruan; John W.Patrick; Hans Weber

    2010-01-01

    @@ It has been a pleasure to organize this special issue of Molecular Plant on 'Assimilate Partitioning and Plant Development'. Assimilate, a collective term describing organic carbon (C) and nitrogen (N), is of paramount importance for plant development and realization of crop productivity.

  14. 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. In...

  15. Coevolutionary, coexisting learning and teaching agents model for prisoner’s dilemma games enhancing cooperation with assortative heterogeneous networks

    Science.gov (United States)

    Tanimoto, Jun

    2013-07-01

    Unlike other natural network systems, assortativity can be observed in most human social networks, although it has been reported that a social dilemma situation represented by the prisoner’s dilemma favors dissortativity to enhance cooperation. We established a new coevolutionary model for both agents’ strategy and network topology, where teaching and learning agents coexist. Remarkably, this model enables agents’ enhancing cooperation more than a learners-only model on a time-frozen scale-free network and produces an underlying assortative network with a fair degree of power-law distribution. The model may imply how and why assortative networks are adaptive in human society.

  16. Spatial Assimilation in Denmark?

    DEFF Research Database (Denmark)

    Andersen, Hans Skifter

    2010-01-01

    In most European countries ethnic minorities have had a tendency to settle in certain parts of cities, and often in social housing, together with other immigrants in so-called multiethnic neighbourhoods. An explanation for this could be low income combined with lack of knowledge of the housing...... market and discrimination, which limits the housing possibilities for ethnic minorities. Another explanation could be that immigrants for different reasons choose to settle in so-called ethnic enclaves where they can find an ethnic social network, which can support them in their new country. 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 of the...

  17. 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.

  18. Relative importance of social synergy, assortation and networks in the evolution of social cooperation

    CERN Document Server

    Montoreano, Claudia

    2013-01-01

    We compare the likelihood of different socially relevant features to allow the evolutionary emergence and maintenance of cooperation in a generalized variant of the iterated Prisoners Dilemma game. Results show that the average costs/benefit balance of cooperation is the primary constraint for its establishment and maintenance. Behavior increasing inclusive fitness such as assortation, homophily, kin-selection and tagging of individuals, is second in importance. Networks characteristics were the least important in favoring the establishment and maintenance of cooperation, despite being the most popular in recent research on the subject. Results suggest that inclusive fitness theory with its expansions to include assortative and economic considerations is more general, powerful and relevant in analyzing social phenomena than kin selection theory with its emphasis on genetic relatedness. Merging economics with evolutionary theory will be necessary to reveal more about the nature of social dynamics.

  19. Effect of genetic heterogeneity and assortative mating on linkage analysis: a simulation study.

    OpenAIRE

    Falk, C T

    1997-01-01

    Linkage studies of complex genetic traits raise questions about the effects of genetic heterogeneity and assortative mating on linkage analysis. To further understand these problems, I have simulated and analyzed family data for a complex genetic disease in which disease phenotype is determined by two unlinked disease loci. Two models were studied, a two-locus threshold model and a two-locus heterogeneity model. Information was generated for a marker locus linked to one of the disease-definin...

  20. Why Does Spousal Education Matter for Earnings? Assortative Mating or Cross-productivity

    OpenAIRE

    Chong Huang; Hongbin Li; Pak Wai Liu; Junsen Zhang

    2006-01-01

    In interpreting the positive relationship between spousal education and one's earnings, economists have two major hypotheses: cross-productivity between couples and assortative mating. However, no prior empirical study has been able to separate the two effects. This paper empirically disentangles the two effects by using twins data that we collected from urban China. We have two major innovations: we use twins data to control for the unobserved mating effect in our estimations, and we estimat...

  1. VA-Index: Quantifying Assortativity Patterns in Networks with Multidimensional Nodal Attributes

    OpenAIRE

    Konstantinos Pelechrinis; Dong Wei

    2016-01-01

    Network connections have been shown to be correlated with structural or external attributes of the network vertices in a variety of cases. Given the prevalence of this phenomenon network scientists have developed metrics to quantify its extent. In particular, the assortativity coefficient is used to capture the level of correlation between a single-dimensional attribute (categorical or scalar) of the network nodes and the observed connections, i.e., the edges. Nevertheless, in many cases a mu...

  2. The gender divide in urban China: Singlehood and assortative mating by age and education

    OpenAIRE

    Yue Qian; Zhenchao Qian

    2014-01-01

    Objective: Chinese media labels highly educated, urban women who are still single in their late 20s as "leftover ladies". We investigate whether indeed highly educated women are less likely to marry than their less-educated counterparts, and how assortative mating patterns by age and education play a role in singleness. Methods: We use data from the urban samples of the Chinese General Social Surveys in the 2000s. In the analysis we calculate marriage rates to examine the likelihood of ent...

  3. 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.

  4. Fund Assortments and 401(k) Plan Participation: The Moderating Effect of Gender

    OpenAIRE

    Maureen Morrin; Susan Broniarczyk; J. Jeffrey Inman

    2009-01-01

    We report the results of a decision simulation conducted among 349 adults whose task was to invest in a hypothetical 401(k) retirement plan. We varied the number of mutual funds offered for investment and observed the effects on the incidence and extent of participation. The results indicate that larger fund assortments tend to reduce participation among women, but increase it among men. Implications and suggestions for future research are discussed.

  5. Modeling and forecasting different stumpage price assortments in Finnish roundwood market

    OpenAIRE

    Zhang, Qiongchao

    2013-01-01

    With the global changes in supply and demand for forest products and their international trade, analyzing the long-term development of the Finnish stumpage market and forecasting different assortments of Finnish stumpage prices is more and more important. There are limited number of studies on forecasting Finnish stumpage prices and even less up to date information about forecasting the markets. According to the previous studies, it is difficult to get precise forecasting results in real-life...

  6. Marketing Strategy Development Directions of Web Assortment in the Republic of Serbia

    OpenAIRE

    Jelena Končar; Zita Petrović-Katai; Goran Vukmirović

    2010-01-01

    Electronic commerce is a contemporary way of doing trade activities based on the use of information and communication technologies. In contemporary business conditions, trade faces numerous changes, which are mostly, before all, the result of market globalization, as well as information technology development. The Web assortment in electronic commerce is the key marketing instrument in a trade organization. The basic task of Serbian companies understands the need of tracking all the changes i...

  7. Prices and the assortment offer of the mineral fertilizers in the farmers’ opinion

    OpenAIRE

    Arkadiusz Piwowar

    2011-01-01

    The mineral fertilizers are the basic means of production used by agriculturalists in order to improve the size and quality of the cultivated plants. The retail prices of the most popular mineral fertilizers have risen in the last years. The paper discusses the research results concerning the agriculturalists' opinion about the mineral fertilizers’ prices and assortment in the market. The research revealed that the high prices and their disadvantageous relation to the fruits' of the earth pri...

  8. CO-AUTHORSHIP AND INDIVIDUAL RESEARCH PRODUCTIVITY IN ECONOMICS: ASSESSING THE ASSORTATIVE MATCHING HYPOTHESIS

    OpenAIRE

    Besancenot, Damien; Huynh, Kim; Serranito, Francisco

    2015-01-01

    This paper aims at estimating the determinants of co-authorship in economics. More specifically, we test the existence of a potential relationship between the research efficiency of an individual and that of his co-authors (the so called assortative matching hypothesis) using a novel database of French academic scholars. However, individual research productivity should be an endogenous regressor as the quality of an academic's publication will depend somehow on the quality of his co-authors. ...

  9. 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...

  10. Judge me, judge me not: The role of eye size and observer gender on acquaintance rape

    Directory of Open Access Journals (Sweden)

    María Clara Ferrão

    2016-01-01

    Full Text Available The purpose of this study was to examine the effect of eye size and observer gender on perceived initial attraction, honesty, and attributions of responsibility for rape. A 3 (eye size: small vs. normal vs. large x 2 (observer gender: female vs. male experimental design was tested. Ninety participants (45 women and 45 men observed one of three randomly assigned female faces (with eye size manipulation, and rated initial attraction and honesty. They were then asked to read an acquaintance rape scenario with a traditional woman, rating the victim and perpetrator responsibility. Eye size was shown to affect all the study variables: the female face with large eyes was seen as more attractive and honest, was held less responsible for her own victimization, and the offender was held more responsible. Gender was proven to affect perceived initial attraction and victim responsibility. Theoretical and práctical implications were discussed.

  11. 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. 

  12. THEORY OF JOINT LIABILITIES, ADVERSE SELECTION, ASSORTATIVE MATCHING AND SELF-FINANCING

    Directory of Open Access Journals (Sweden)

    Ramu Maurya

    2011-10-01

    Full Text Available Microfinance is seen to be a remedy of poverty eradication and globally it is perceived that microfinance can remove the problem of poverty. Basically microfinance works on joint liability model. Traditional theories of credit lending say that rural credit markets are imperfectly competitive and acquiring information about borrowers type that is who is risky and who is safe is not costless. This market imperfection leads to high interest rate and drives out safe borrower from the credit market. In economic literature this problem is considered as adverse selection problem. Joint liability model try to solve the problem of adverse selection through group lending.This paper explores the idea of joint liability model and tries to solve the problem of adverse selection through the positive assortative matching. Paper concludes that in positive assortative matching, the payoffs of borrowers would be more than the payoffs of negative assortative matching. Paper, also try to show that self financing can bring down the interest rate and size of penalty and improve the borrower’s expected payoffs

  13. Assessment of the effect of quality factors on the assortment structure in poplar plantations

    Directory of Open Access Journals (Sweden)

    Danilović Milorad

    2008-01-01

    Full Text Available Quality factors affecting the assortment quality structure in poplar plantations were researched on nine temporary sample plots in the period 1997-2004, from the aspect of the implementation of roundwood standards. Sample plots were selected depending on the factors, the effect of which was studied. The following factors were researched: clonal species, planting pattern, flood risk, pruning of branches, plantation position and age. The study was performed by the original methodology. Based on the study results, it is concluded that knots have the highest effect on the assortment quality structure in poplar plantations, regardless of the site and stand conditions. Their effect rises significantly with the increase of tree diameter. Also, the analyses show that the number of large and rotten knots on the tree trunk increases considerably with the older age. In the flooded area, the sweep of the lower part of the stem is more intensive and multiple curvatures are frequent on the trees growing immediately along the river, whereas curvature decreases with the distance from the river bank. Based on the study results, it is concluded that the percentage of best quality assortments is considerably reduced by the above wood defects.

  14. Povezave med kakovostjo bukovih dreves in iz njih izdelanih sortimentov: Links between beech tree quality and assortments made of them:

    OpenAIRE

    Marenče, Jurij; Šega, Bogdan

    2015-01-01

    In our research we dealt with the standing tree, estimation of the standing tree, evaluation of its quality and evaluation of quality of assortments made of it. Thereby we critically discussed diverse criteria, currently used in the practice - the five-grade scale for standing tree evaluation, used on permanent sampling plots, and current standards for evaluating the quality of the produced assortments. On the basis of a small analyzed sample of the evaluated and afterwards felled trees we we...

  15. Retail Choice Architecture: The Effects of Benefit- and Attribute-Based Assortment Organization on Consumer Perceptions and Choice

    OpenAIRE

    Cait Poynor Lamberton; Kristin Diehl

    2013-01-01

    This article explores the effects of two distinct retail choice architectures--those that organize assortments by attributes and those that organize items by benefits. Relative to attribute-based organizations, benefit-based organizations lead to more abstract construal and heighten similarity perceptions among items in an assortment. Such changes in similarity perceptions alter consumers' strength of preference among items: when choosing from benefit- as opposed to attribute-based organizati...

  16. No evidence for size-assortative mating in the wild despite mutual mate choice in sex-role-reversed pipefishes

    OpenAIRE

    Mobley, K.; Abou Chakra, M.; Jones, A.

    2014-01-01

    Size-assortative mating is a nonrandom association of body size between members of mating pairs and is expected to be common in species with mutual preferences for body size. In this study, we investigated whether there is direct evidence for size-assortative mating in two species of pipefishes, Syngnathus floridae and S. typhle, that share the characteristics of male pregnancy, sex-role reversal, and a polygynandrous mating system. We take advantage of microsatellite- based “genetic-capture”...

  17. Multiple mating reveals complex patterns of assortative mating by personality and body size.

    Science.gov (United States)

    Montiglio, Pierre-Olivier; Wey, Tina W; Chang, Ann T; Fogarty, Sean; Sih, Andrew

    2016-01-01

    Understanding patterns of non-random mating is central to predicting the consequences of sexual selection. Most studies quantifying assortative mating focus on testing for correlations among partners' phenotypes in mated pairs. Few studies have distinguished between assortative mating arising from preferences for similar partners (expressed by all or a subset of the population) vs. from phenotypic segregation in the environment. Also, few studies have assessed the robustness of assortative mating against temporal changes in social conditions. We tracked multiple matings by stream water striders (Aquarius remigis) across variable social conditions to investigate mating patterns by both body size and behavioural type (personality). We documented temporal changes in partner availability and used a mixed model approach to analyse individual behaviours and changes in mating status recorded on an hourly basis. We assessed whether all or only a subset of individuals in the population expressed a tendency to mate with similar phenotypes. Our analyses took into account variation in the level of competition and in the phenotypes of available partners. Males and females exhibited significant assortative mating by body size: the largest males and females, and the smallest males and females mated together more often than random. However, individuals of intermediate size were equally likely to mate with small, intermediate or large partners. Individuals also displayed two contrasting patterns of assortative mating by personality (activity level). Individuals generally mated preferentially with partners of similar activity level. However, beyond that general trend, individuals with more extreme personalities tended to exhibit disassortative mating: the most active males mated disproportionately with less active females and the least active males tended to mate with more active females. Our analyses thus revealed multiple, distinct patterns of nonrandom mating. These mating

  18. Assessing the Impact of Acquaintance Rape: Interviews with Women Who Are Victims/Survivors of Sexual Assault while in College

    Science.gov (United States)

    Guerette, Sarah M.; Caron, Sandra L.

    2007-01-01

    This is a study consisting of in-depth interviews with 12 women who were victims/survivors of acquaintance rape while attending a university in the Northeast. The interviews focused on research questions concerning actions taken by the victim/survivor after the assault, reactions to her disclosure of the assault, and the impact of assault. It was…

  19. Gender, Gender Identity, Rape Myth Acceptance, and Time of Initial Resistance on the Perception of Acquaintance Rape Blame and Avoidability.

    Science.gov (United States)

    Kopper, Beverly A.

    1996-01-01

    Investigated the role of gender, gender role identity, rape myth acceptance, and initial resistance in assigning blame in the case of acquaintance rape, and studied the perceived avoidability of the assault for 355 female and 179 male college students. The gender differences in responses are discussed. (SLD)

  20. Beyond "No Means No." Outcomes of an Intensive Program to Train Peer Facilitators for Campus Acquaintance Rape Education.

    Science.gov (United States)

    Lonsway, Kimberly A.; Klaw, Elena L.; Berg, Dianne R.; Waldo, Craig R.; Kothari, Chevon; Mazurek, Christopher J.; Hegeman, Kurt E.

    1998-01-01

    Examines the effects of a university course designed to train peer facilitators to conduct rape education workshops, Campus Acquaintance Rape Education (CARE). Participants (N=74) experienced comprehensive attitude change; both men and women participants became more willing and able to directly express themselves and assert their needs in ways…

  1. Date and Acquaintance Rape: The Legal Point of View. Part 2. Reform of Rape Laws and Alternatives to Criminal Prosecution.

    Science.gov (United States)

    Julian, Frank H.

    1993-01-01

    Second article in two-part series on date and acquaintance rape examines modern reforms in rape laws and alternatives to criminal prosecution. Explains the Rape Shield Law, designed to prevent victim's sexual history from being used against her to prove promiscuity, tendency to lie, or low moral character. Other common statutory revisions are…

  2. Beyond No Means No: Outcomes of an Intensive Program To Train Peer Facilitators for Campus Acquaintance Rape Education.

    Science.gov (United States)

    Lonsway, Kimberly A.; Klaw, Elena L.; Berg, Dianne R.; Waldo, Craig R.; Kothari, Chevon; Mazurek, Christopher J.; Hegeman, Kurt E.

    As part of a larger multimethod evaluation, the present study examined the effects of a uniquely intensive rape education program. Participants included 74 undergraduates (53 women and 21 men) enrolled in Campus Acquaintance Rape Education (CARE), a semester-long university course designed to train peer facilitators to conduct rape education…

  3. WAVE ASSIMILATION AND NUMERICAL PREDICTION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An adjoint variational method for wave data assimilation in the LAGFD-WAM wave model is proposed. The adjoint equation of the wavenumber energy spectrum balance equation is derived. And fortunately, its characteristic equations are the same as those in the LAGFD-WAM wave model. Simple experiments on the functional optimization and assimilation effectiveness during the prediction period indicated that the adjoint variational method is effective for wave assimilation and that the initial optimization of the wave model is important for the short-range wave prediction. All of this is under the assumption that the wind field is accurate, the method is the important first step for combined wind and wave data assimilation systems.

  4. 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...

  5. 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...

  6. 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.

  7. Data Assimilation Applications in Hydrology

    OpenAIRE

    Deliu, Ciprian; Giurma, Ion

    2014-01-01

    In this paper we review some data assimilation applications in hydrology and we investigate the benefits of applying the ensemble Kalman filter methods on a specific hydrodynamic model of a river network using the MIKE 11 software. We explore the efects of assimilating measurements from different locations (generated by a reference model) into a model forced with erroneous boundary conditions and also examine the effect of using coloured noise for describing uncertainty in the upstream bounda...

  8. Ethnic goods and immigrant assimilation

    OpenAIRE

    Abdulloev, Ilhom; Epstein, Gil S.; 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.

  9. Recent social environment affects colour-assortative shoaling in juvenile angelfish (Pterophyllum scalare).

    Science.gov (United States)

    Gómez-Laplaza, Luis M

    2009-09-01

    Theory predicts that fish should show colour-assortative shoaling in order to avoid the oddity effect whereby individuals that differ in some feature from the group majority appear to incur increased risk of predation. It has also been shown that early experience plays an important role in affecting social preferences in some fish species. In this study, the importance of colour phenotype in promoting assortative shoaling and the role played by the recent social environment on its expression were investigated in juvenile angelfish, Pterophyllum scalare. Individuals of the uniformly black and golden colour morphs were housed in a group with conspecifics of like and unlike body colour to themselves, as well as in mixed-colour groups for 4 weeks. Subsequently, they were subjected to a binary choice to shoal with a group of conspecifics composed of unfamiliar fish of either a like or unlike colour phenotype to themselves. The response of the individuals to the colour attributes of the shoals was related to their recent social environment. Fish in like- and mixed-colour previous treatments showed a preferential association with like colour conspecifics. In contrast, the shoaling behaviour exhibited by fish previously maintained with a group of unlike-coloured conspecifics (cross-housed treatment) indicated no significant preference for any of the shoals. The results suggest that angelfish use body colouration as an intraspecific shoaling cue and that learning, in the form of recent familiarization with a specific colour phenotype of conspecifics, can affect colour-assortative shoaling preferences in this species. This learning component of the choice need not be restricted to early developmental stages. PMID:19376208

  10. Comparison of different assimilation schemes in a sequential Kalman filter assimilation system

    OpenAIRE

    Yan, Yajing; Barth, Alexander; Beckers, Jean-Marie

    2014-01-01

    In this paper, four assimilation schemes, including an intermittent assimilation scheme (INT) and three incremental assimilation schemes (IAU 0, IAU 50 and IAU 100), are compared in the same assimilation experiments with a nonlinear ocean circulation model using the Ensemble Kalman Filter as assimilation method. The three IAU schemes differ from each other in the position of the increment update window that has the same size as the assimilation window. 0, 50 and 100 correspond to the degree o...

  11. Effect of quality factors especially of sweep of poplar trees on assortment structure

    Directory of Open Access Journals (Sweden)

    Danilović Milorad

    2006-01-01

    Full Text Available The factors of quality which affect the sawing yield were researched for poplar plantations, from the aspect of the application of national standards for roundwood. The research was performed in the period 2002-2003 on two temporary sample plots, in poplar plantations Populus×euramericana I-214 aged 25 years. The sample plots were selected depending on the clone species, planting pattern, and plantation flood risk, and branch pruning. The analyzed quality factors are: knots, minimal dimensions, sweep, false heart, ovality and tapering. The measured data were processed according to the original methodology. Based on the study results, the significance of quality factors was ranked in two different stand situations. Of all the study factors, knots have the highest effect on log yield, which is especially significant in marking for cross cutting of the larger trees. The sweep of trees in poplar plantations with higher flood risk is greater compared to the sweep of trees in plantations which are in the zone protected from floods. In poplar plantation Populus×euramericana I-214 which is exposed to frequents flooding (OP-2, sweep is the third significant factor, compared to the plantation protected from floods (OP‑3, where sweep is the fifth factor according to significance. The effect of sweep in the plantation exposed to flooding is 2.4 times higher than the effect of sweep in the plantation protected from floods. Total value of the assortments made of tree trunk grows with the increase of tree diameter on both sample plots. This correlation is represented by the function Y=a·Xb, and the correlation between the variables is complete. The value of assortments of a certain quality for the study stand conditions can be calculated by the selected model functions, i.e. represented by assortment tables. This study shows inter alia, that there is not a unique model for all poplar plantations when the value percentage of assortments is determined

  12. PHYLLOXERA-RESISTANT HYBRID FORM OF GRAPES OF TECHNICAL SORTS FOR IMPROVING THE ASSORTMENT

    OpenAIRE

    Larkina M. D.; Nikulushkina G. E.

    2015-01-01

    Many old varieties of grapes do not meet modern requirements, so there is a need for improved assortment of new high-quality varieties. The translation of the vineyards of the black sea coast of the Krasnodar region on inoculated culture is not fully decided the fate of the viticulture of the area. Weak resistance of American rootstocks to increased content of calcium and salts in the soil, caused the weakening of the bushes, reducing the vigor of the shoots, their maturation and yield of gra...

  13. Physically-based data assimilation

    Directory of Open Access Journals (Sweden)

    G. Levy

    2010-05-01

    Full Text Available Ideally, a validation and assimilation scheme should maintain the physical principles embodied in the model and be able to evaluate and assimilate lower dimensional features (e.g., discontinuities contained within a bulk simulation, even when these features are not directly observed or represented by model variables. We present such a scheme and suggest its potential to resolve or alleviate some outstanding problems that stem from making and applying required, yet often non-physical, assumptions and procedures in common operational data assimilation. As proof of concept, we use a sea-ice model with remotely sensed observations of leads in a one-step assimilation cycle. Using the new scheme in a sixteen day simulation experiment introduces model skill (against persistence several days earlier than in the control run, improves the overall model skill and delays its drop off at later stages of the simulation. The potential and requirements to extend this scheme to different applications, and to both empirical and statistical multivariate and full cycle data assimilation schemes, are discussed.

  14. Physically-based data assimilation

    Directory of Open Access Journals (Sweden)

    G. Levy

    2010-11-01

    Full Text Available Ideally, a validation and assimilation scheme should maintain the physical principles embodied in the model and be able to evaluate and assimilate lower dimensional features (e.g., discontinuities contained within a bulk simulation, even when these features are not directly observed or represented by model variables. We present such a scheme and suggest its potential to resolve or alleviate some outstanding problems that stem from making and applying required, yet often non-physical, assumptions and procedures in common operational data assimilation. As proof of concept, we use a sea-ice model with remotely sensed observations of leads in a one-step assimilation cycle. Using the new scheme in a sixteen day simulation experiment introduces model skill (against persistence several days earlier than in the control run, improves the overall model skill and delays its drop off at later stages of the simulation. The potential and requirements to extend this scheme to different applications, and to both empirical and statistical multivariate and full cycle data assimilation schemes, are discussed.

  15. Physically-based data assimilation

    Science.gov (United States)

    Levy, G.; Coon, M.; Nguyen, G.; Sulsky, D.

    2010-11-01

    Ideally, a validation and assimilation scheme should maintain the physical principles embodied in the model and be able to evaluate and assimilate lower dimensional features (e.g., discontinuities) contained within a bulk simulation, even when these features are not directly observed or represented by model variables. We present such a scheme and suggest its potential to resolve or alleviate some outstanding problems that stem from making and applying required, yet often non-physical, assumptions and procedures in common operational data assimilation. As proof of concept, we use a sea-ice model with remotely sensed observations of leads in a one-step assimilation cycle. Using the new scheme in a sixteen day simulation experiment introduces model skill (against persistence) several days earlier than in the control run, improves the overall model skill and delays its drop off at later stages of the simulation. The potential and requirements to extend this scheme to different applications, and to both empirical and statistical multivariate and full cycle data assimilation schemes, are discussed.

  16. Fear of acquaintance versus stranger rape as a "master status": towards refinement of the "shadow of sexual assault".

    Science.gov (United States)

    Wilcox, Pamela; Jordan, Carol E; Pritchard, Adam J

    2006-06-01

    Using a sample of 1010 women from a southeastern state university, we explore whether associations between fear of sexual assault and other crime-specific fears vary based on presumed victim-offender relationship. More specifically, we assess the extent to which fear of stranger- and acquaintance-perpetrated sexual assaults differ in the extent to which they are correlated with fear of other crime victimizations. Multivariate logistic regression analysis revealed that both fear of stranger-perpetrated sexual assault and fear of acquaintance-perpetrated sexual assault were positively associated with nearly all other crime-specific fears under examination. However, associations were particularly strong between fear of sexual assault by a stranger and fear of other stranger-perpetrated crimes. Findings have significant implications for how academic institutions should comprehensively address direct and indirect negative influences of violence against college women. PMID:16761859

  17. Assortative mating and the maintenance of population structure in a natural hybrid zone.

    Science.gov (United States)

    Culumber, Zachary W; Ochoa, Olivia M; Rosenthal, Gil G

    2014-08-01

    Understanding the factors that give rise to natural hybrid zones and govern their dynamics and structure is important to predicting the evolutionary consequences of hybridization. Here we use a combination of multigenerational population genetic data, mating patterns from a natural population, behavioral assays, and mark-recapture data within clinal hybrid zones of the genus Xiphophorus to test the role of assortative mating in maintaining population structure and the potential for ongoing genetic exchange between heterospecifics. Our data demonstrate that population structure is temporally robust and driven largely by assortative mating stemming from precopulatory isolation between pure species. Furthermore, mark-recapture data revealed that rates of migration within the same stream reach are far below the level needed to support population structure. In contrast to many empirical studies of natural hybrid zones, there appeared to be no hybrid male dysfunction or discrimination against hybrid males by pure parental females, and hybrid females mated and associated with pure species and hybrid males at random. Despite strong isolation between pure parentals, hybrids therefore can act as a conduit for genetic exchange between heterospecifics, which has been shown to increase the tempo of evolutionary change. Additionally, our findings highlight the complexity of natural hybrid zone dynamics, demonstrating that sexual and ecological selection together can give rise to patterns that do not fit classical models of hybrid zone evolution. PMID:25058282

  18. 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. PMID:27468393

  19. 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.

  20. The gendered embodiment of shame: Intersections of acquaintance rape, trauma and self-blame in Pompidou posse by Sarah Lotz

    OpenAIRE

    Jessica Murray

    2014-01-01

    This article offers a feminist literary analysis of the gendered embodiment of shame in Pompidou posse by Sarah Lotz. In this novel, Lotz depicts female characters who are sexually assaulted by acquaintances and the resultant shame and trauma reside in their bodies. I will demonstrate that the embodied shame of these characters is distinctly gendered and that this shapes their attempts to cope with the aftermath of the sexual assaults. A close reading of the text reveals that the characters a...

  1. 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.

  2. 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. PMID:24215167

  3. No evidence for size-assortative mating in the wild despite mutual mate choice in sex-role-reversed pipefishes.

    Science.gov (United States)

    Mobley, Kenyon B; Abou Chakra, Maria; Jones, Adam G

    2014-01-01

    Size-assortative mating is a nonrandom association of body size between members of mating pairs and is expected to be common in species with mutual preferences for body size. In this study, we investigated whether there is direct evidence for size-assortative mating in two species of pipefishes, Syngnathus floridae and S. typhle, that share the characteristics of male pregnancy, sex-role reversal, and a polygynandrous mating system. We take advantage of microsatellite-based "genetic-capture" techniques to match wild-caught females with female genotypes reconstructed from broods of pregnant males and use these data to explore patterns of size-assortative mating in these species. We also develop a simulation model to explore how positive, negative, and antagonistic preferences of each sex for body size affect size-assortative mating. Contrary to expectations, we were unable to find any evidence of size-assortative mating in either species at different geographic locations or at different sampling times. Furthermore, two traits that potentially confer a fitness advantage in terms of reproductive success, female mating order and number of eggs transferred per female, do not affect pairing patterns in the wild. Results from model simulations demonstrate that strong mating preferences are unlikely to explain the observed patterns of mating in the studied populations. Our study shows that individual mating preferences, as ascertained by laboratory-based mating trials, can be decoupled from realized patterns of mating in the wild, and therefore, field studies are also necessary to determine actual patterns of mate choice in nature. We conclude that this disconnect between preferences and assortative mating is likely due to ecological constraints and multiple mating that may limit mate choice in natural populations. PMID:24455162

  4. Data assimilation the ensemble Kalman filter

    CERN Document Server

    Evensen, Geir

    2006-01-01

    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.

  5. The Analysis Of The Correlations And Regressions Between Some Characters On A Wheat Isogenic Varities Assortment

    Science.gov (United States)

    Păniţă, Ovidiu

    2015-09-01

    In the years 2012-2014 on Banu-Maracine DRS there were tested an assortment of 25 isogenic lines of wheat (Triticum aestivum ssp.vulgare), the analyzed characters being the number of seeds/spike, seeds weight/spike (g), no. of spikes/m2, weight of a thousand seeds (WTS) (g) and no. of emerged plants/m2. Based on recorded data and statistical processing of those, they were identified a numbers of links between these characters. Also available regression models were identified between some of the studied characters. Based on component analysis, no. of seeds/spike and seeds weight/spike are components that influence in excess of 88% variance analysis, a total of seven genotypes with positive scores for both factors.

  6. Uranium recovery from assorted laboratory organic waste solutions using centrifugal contractors

    International Nuclear Information System (INIS)

    Countercurrent extraction runs, carried out in our laboratory for the evaluation studies of N,N-dihexyloctanamide (DHOA) as an alternative of tributyl phosphate (TBP) for spent fuel reprocessing, have led to generation of large volumes of organic wastes containing varying amounts of uranium. It was desirable to recover uranium from such waste solutions prior to the disposal of organic waste solutions. Even though, batch stripping can be used for this purpose, it may take several days to achieve the desired goal. In this context, the centrifugal contactors appear attractive due to high liquid through-put, which may simplify the uranium recovery process. Uranium recovery studies from assorted organic waste solutions were therefore carried out using centrifugal contactors

  7. 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; Gamborg, Michael; Allison, David B; Baker, Jennifer L; Sørensen, Thorkild I A

    2012-01-01

    -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...... 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 small and stable during the past 65 years. Yet, there were assorted marriages between spouses with high BMI at age 13 years and the tendency increased...

  8. Intergenerational income mobility – top incomes and assortative mating in Denmark

    DEFF Research Database (Denmark)

    Hussain, M. Azhar; Bonke, Jens; Munk, Martin D.

    2011-01-01

    This article investigates intergenerational income mobility among top-income people in Denmark focusing on the impact of assortative mating. Earnings and capital income are the variables of interest included in the analyzes testing the hypothesis that both wealth and social heritage are transferred...... from rich parents to their children. Using administrative registers allow us to look at small fractions of the populations, i.e. dynasties, and to distinguish between sons and daughters and to observe their eventual spouses’ incomes. We find that intergenerational mobility is lower in the top, in...... particular, when including capital income in the total income. Also we find the marriage match has a stronger impact on the family-to-family income transfer in the top of the income distribution where the daughter marries a man more like her father than herself. The highest persistence, however, is between...

  9. 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. PMID:26606886

  10. Variation in sexual dimorphism and assortative mating do not predict genetic divergence in the sexually dimorphic Goodeid fish Girardinichthys multiradiatus

    Institute of Scientific and Technical Information of China (English)

    C.MAC(I)AS GARCIA; G SMITH; C.GONZ(A)LEZ ZUARTH; J.A.GRAVES; M.G.RITCHIE

    2012-01-01

    Sexual dimorphism is often used as a proxy for the intensity of sexual selection in comparative studies of sexual selection and diversification.The Mexican Goodeinae are a group of livebearing freshwater fishes with large variation between species in sexual dimorphism in body shape.Previously we found an association between variation in morphological sexual dimorphism between species and the amount of gene flow within populations in the Goodeinae.Here we have examined if morphological differentiation within a single dimorphic species is related to assortative mating or gene flow between populations.In the Amarillo fish Girardinichthys multiradiatus studies have shown that exaggerated male fins are targets of female preferences.We find that populations of the species differ in the level of sexual dimorphism displayed due to faster evolution of differences in male than female morphology.However,this does not predict variation in assortative mating tests in the laboratory; in fact differences in male morphology are negatively correlated with assortative mating.Microsatellite markers reveal significant genetic differences between populations.However,gene flow is not predicted by either morphological differences or assortative mating.Rather,it demonstrates a pattern of isolation by distance with greater differentiation between watersheds.We discuss the caveats of predicting behavioural and genetic divergence from so-called proxies of sexual selection.

  11. Variation in sexual dimorphism and assortative mating do not predict genetic divergence in the sexually dimorphic Goodeid fish Girardinichthys multiradiatus

    Directory of Open Access Journals (Sweden)

    C.MACÍAS GARCIA, G.SMITH, C.GONZÁLEZ ZUARTH, J.A. GRAVES,M.G.RITCHIE

    2012-06-01

    Full Text Available Sexual dimorphism is often used as a proxy for the intensity of sexual selection in comparative studies of sexual selection and diversification. The Mexican Goodeinae are a group of livebearing freshwater fishes with large variation between species in sexual dimorphism in body shape. Previously we found an association between variation in morphological sexual dimorphism between species and the amount of gene flow within populations in the Goodeinae. Here we have examined if morphological differentiation within a single dimorphic species is related to assortative mating or gene flow between populations. In the Amarillo fish Girardinichthys multiradiatus studies have shown that exaggerated male fins are targets of female preferences. We find that populations of the species differ in the level of sexual dimorphism displayed due to faster evolution of differences in male than female morphology. However, this does not predict variation in assortative mating tests in the laboratory; in fact differences in male morphology are negatively correlated with assortative mating. Microsatellite markers reveal significant genetic differences between populations. However, gene flow is not predicted by either morphological differences or assortative mating. Rather, it demonstrates a pattern of isolation by distance with greater differentiation between watersheds. We discuss the caveats of predicting behavioural and genetic divergence from so-called proxies of sexual selection [Current Zoology 58 (3: 437-449, 2012].

  12. Imposing Nonlinear Constraints When Estimating Genetic and Cultural Transmission Under Assortative Mating: A Simulation Study Using Mx and BUGS

    NARCIS (Netherlands)

    Berg, van den Stephanie M.

    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 Bayesian-o

  13. Accuracy in estimation of timber assortments and stem distribution - A comparison of airborne and terrestrial laser scanning techniques

    Science.gov (United States)

    Kankare, Ville; Vauhkonen, Jari; Tanhuanpää, Topi; Holopainen, Markus; Vastaranta, Mikko; Joensuu, Marianna; Krooks, Anssi; Hyyppä, Juha; Hyyppä, Hannu; Alho, Petteri; Viitala, Risto

    2014-11-01

    Detailed information about timber assortments and diameter distributions is required in forest management. Forest owners can make better decisions concerning the timing of timber sales and forest companies can utilize more detailed information to optimize their wood supply chain from forest to factory. The objective here was to compare the accuracies of high-density laser scanning techniques for the estimation of tree-level diameter distribution and timber assortments. We also introduce a method that utilizes a combination of airborne and terrestrial laser scanning in timber assortment estimation. The study was conducted in Evo, Finland. Harvester measurements were used as a reference for 144 trees within a single clear-cut stand. The results showed that accurate tree-level timber assortments and diameter distributions can be obtained, using terrestrial laser scanning (TLS) or a combination of TLS and airborne laser scanning (ALS). Saw log volumes were estimated with higher accuracy than pulpwood volumes. The saw log volumes were estimated with relative root-mean-squared errors of 17.5% and 16.8% with TLS and a combination of TLS and ALS, respectively. The respective accuracies for pulpwood were 60.1% and 59.3%. The differences in the bucking method used also caused some large errors. In addition, tree quality factors highly affected the bucking accuracy, especially with pulpwood volume.

  14. Assimilate partitioning during reproductive growth

    International Nuclear Information System (INIS)

    Leaves having various phyllotactic relationships to fruitlets were labeled for 1 hour with 10/sub r/Ci of 14CO2. Fruitlets were also labeled. Fruitlets did fix 14CO2. Translocation of radioactivity from the peel into the fruit occurred slowly and to a limited extent. No evidence of translocation out of the fruitlets was observed. Assimilate partitioning in avocado was strongly influenced by phyllotaxy. If a fruit and the labeled leaf had the same phyllotaxy then greater than 95% of the radiolabel was present in this fruit. When the fruit did not have the same phyllotaxy as the labeled leaf, the radiolabel distribution was skewed with 70% of the label going to a single adjacent position. Avocado fruitlets exhibit uniform labeling throughout a particular tissue. In avocado, assimilates preferentially move from leaves to fruits with the same phyllotaxy

  15. Assimilation, Criminality and Ethnic Conflict

    OpenAIRE

    Dasgupta, Indraneel; Mukherjee, Diganta

    2014-01-01

    We examine the consequences, of integrating large minorities into productivity-relevant majority ethno-linguistic norms, for distribution, ethnic conflict and crime. We develop a two-community model where such assimilation generates social gains by: (a) facilitating economic interaction, and (b) dampening religious or racial conflict over symbolic and normative contents of the public sphere. However, integration shifts the distribution of both material and symbolic goods against the minority....

  16. Financial assimilation of immigrants conference

    OpenAIRE

    anonymous

    2003-01-01

    On June 24, the Consumer and Community Affairs division of the Federal Reserve Bank of Chicago convened, “An Informed Discussion of the Financial Assimilation of Immigrants” in Des Moines, Iowa. The conference was part of the larger, long-term program by the Chicago Reserve Bank to study the ways and means by which immigrants to the United States access mainstream financial services. This Special Edition of PNV comprises summaries of each of the conference presentations.

  17. Wavelet Approximation in Data Assimilation

    Science.gov (United States)

    Tangborn, Andrew; Atlas, Robert (Technical Monitor)

    2002-01-01

    Estimation of the state of the atmosphere with the Kalman filter remains a distant goal because of high computational cost of evolving the error covariance for both linear and nonlinear systems. Wavelet approximation is presented here as a possible solution that efficiently compresses both global and local covariance information. We demonstrate the compression characteristics on the the error correlation field from a global two-dimensional chemical constituent assimilation, and implement an adaptive wavelet approximation scheme on the assimilation of the one-dimensional Burger's equation. In the former problem, we show that 99%, of the error correlation can be represented by just 3% of the wavelet coefficients, with good representation of localized features. In the Burger's equation assimilation, the discrete linearized equations (tangent linear model) and analysis covariance are projected onto a wavelet basis and truncated to just 6%, of the coefficients. A nearly optimal forecast is achieved and we show that errors due to truncation of the dynamics are no greater than the errors due to covariance truncation.

  18. An open framework for hydrological data assimilation

    Science.gov (United States)

    Madsen, H.; Ridler, M. E.; Velzen, N. V.; Hummel, S.; Sandholt, I.; Falk, A. K.; Heemink, A.

    2013-12-01

    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. Thus far, many of the efforts on implementation of data assimilation in hydrological modeling have been model specific. This requires access to as well as an in-depth knowledge of the numerical core of the models. A means to deal with the interaction between model and data assimilation algorithm in a more generic way is the use of the Open Model Interface (OpenMI). This open source standard interface allows models to exchange data during runtime, thus transforming a complex numerical model to a plug and play like component. For data assimilation, the OpenDA data assimilation toolbox is an open interface standard that includes a set of tools, assimilation algorithms, and numerical techniques to quickly implement data assimilation in numerical models. This paper presents a new generic data assimilation framework that uses OpenMI to interface models within OpenDA. This enables the many OpenMI hydrological models already available access to a robust and flexible data assimilation library. A synthetic test case is presented that highlights the potential of this new framework. An ensemble based Kalman filter is demonstrated for assimilation of groundwater levels in the MIKE SHE distributed and integrated hydrological

  19. On the mathematics of data assimilation

    OpenAIRE

    Talagrand, Olivier

    2011-01-01

    The problem of convergence of a “forward-backward” assimilation is considered for the most general dynamical system. Using elementary techniques of stability theory, it is shown that the variation, over one assimilation cycle, of the difference between the assimilating model and the state to be reconstructed is, to the first order, determined by a perfectly defined amplification matrix. This leads to a straightforward criterion for convergence, depending on the eigenvalues of that matrix. Th...

  20. Ensemble Data Assimilation: Algorithms and Software

    OpenAIRE

    Nerger, Lars

    2014-01-01

    Ensemble data assimilation is nowadays applied to various problems to estimate a model state and model parameters by combining the model predictions with observational data. At the Alfred Wegener Institute, the assimilation focuses on ocean-sea ice models and coupled ocean-biogeochemical models. The high dimension of realistic models requires particularly efficient algorithms that are also usable on supercomputers. For the application of such filters, the Parallel Data Assimilation Framework ...

  1. Assimilation and integration of immigrants in Europe

    OpenAIRE

    Aleksynska, Mariya; ALGAN, Yann

    2010-01-01

    This paper documents assimilation of immigrants in European destinations along cultural, civic, and economic dimensions, distinguishing by immigrants' generation, duration of stay, and origin. Based on the European Social Survey, 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 and cultural outcomes may be correlated, such correlations are not systematic, and imply that progre...

  2. Outline of an Economic Theory of Assimilation

    OpenAIRE

    Schaeffer, Peter V.

    2006-01-01

    In an age of mass immigration, assimilation is critical not only to the success of the immigrants but also to the success of their descendants and of the host society. This paper presents an outline for an economic theory of assimilation based on the assumption that both immigrants and natives invest in assimilation, that both may in fact move in the direction of the "other," and that the notion of "distance" is subjective and reversible.

  3. Immigrant Job Search Assimilation in Canada

    OpenAIRE

    Bowlus, Audra J.; Miyairi, Masashi; Robinson, Chris

    2013-01-01

    Immigrant assimilation is a major issue in many countries. While most of the literature studies assimilation through a human capital framework, we examine the role of job search assimilation. To do so, we estimate an equilibrium search model of immigrants operating in the same labor market as natives, where newly arrived immigrants have lower job offer arrival rates than natives but can acquire the same arrival rates according to a stochastic process. Using Canadian panel data, we find substa...

  4. Towards Operational Data Assimilation in the North and Baltic Seas with the Parallel Data Assimilation Framework

    OpenAIRE

    Nerger, Lars; Loza, Svetlana; Schröter, Jens; Hiller, Wolfgang; F. Janssen

    2010-01-01

    Within the GMES-related project DeMarine Environment, the operational circulation model of the German Maritime and Hydrographic Agency (BSH) is extended into a data assimilation system. The aim of the data assimilation is to improve the forecast of sea surface height, temperatura, currents and salinity in the North and Baltic Seas. For the data assimilation component, the Parallel Data Assimilation Framework (PDAF, http://pdaf.awi.de) is coupled to the operational circulation model. PDAF prov...

  5. 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 te...... for the Fokker-Planck equation on a 2 dimensional flexible mesh system. The report details the construction of the finite element solver and investigates the potential benefits of a parallel FORTRAN implementation through a series of experiments....

  6. 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…

  7. Assortative mating and differential fertility by phenotype and genotype across the 20th century.

    Science.gov (United States)

    Conley, Dalton; Laidley, Thomas; Belsky, Daniel W; Fletcher, Jason M; Boardman, Jason D; Domingue, Benjamin W

    2016-06-14

    This study asks two related questions about the shifting landscape of marriage and reproduction in US society over the course of the last century with respect to a range of health and behavioral phenotypes and their associated genetic architecture: (i) Has assortment on measured genetic factors influencing reproductive and social fitness traits changed over the course of the 20th century? (ii) Has the genetic covariance between fitness (as measured by total fertility) and other traits changed over time? The answers to these questions inform our understanding of how the genetic landscape of American society has changed over the past century and have implications for population trends. We show that husbands and wives carry similar loadings for genetic factors related to education and height. However, the magnitude of this similarity is modest and has been fairly consistent over the course of the 20th century. This consistency is particularly notable in the case of education, for which phenotypic similarity among spouses has increased in recent years. Likewise, changing patterns of the number of children ever born by phenotype are not matched by shifts in genotype-fertility relationships over time. Taken together, these trends provide no evidence that social sorting is becoming increasingly genetic in nature or that dysgenic dynamics have accelerated. PMID:27247411

  8. ABC & XYZ – ANALYSIS OF ASSORTMENT OF ENTERPRISES OF BAKERY INDUSTRIES OF CONSUMER COOPERATIVES

    Directory of Open Access Journals (Sweden)

    Baranovskaya T. P.

    2015-12-01

    Full Text Available To develop detailed and effective business model of bakery enterprises of consumer cooperation it is necessary to have knowledge on strategic goods displayed on a busy segment of the market, not only in volumetric terms, but in the parameters that characterize the stability of sales or consumption. The particular relevance of this study reveals in modern conditions of functioning. The outcome of the baking enterprises of consumer cooperatives is more than 760 tons per day, distributed between 41 baking enterprise producing more than 300 kinds of products. Of course, the information on quantitative and qualitative characteristics of the strategic positions of the range will be a key in making managerial decisions about the production of the program, resourcing, turnover, etc. To solve the problem we have chosen the method of ABC - and XYZ-analysis of assortment of production, based on the criteria of ease of use and breadth of the resulting information. As a result of the application of the methods of ABC and XYZ-analysis and combining the obtained results, we present a classification of the range of the baking enterprises of consumer cooperation product based on the criteria of the contribution of commodity positions in revenue and stability of sales

  9. Male mate preference and size-assortative mating in convict cichlids: A role for female aggression?

    Science.gov (United States)

    Bloch, A N; Estela, V J; Leese, J M; Itzkowitz, M

    2016-09-01

    Many monogamous species demonstrate size-assortative mating patterns within natural populations. To better understand the role of intersexual selection in this process, we examined the effect of male preference for female body size in the convict cichlid (Amatitlania siquia). We provided males with a choice between females that differed in size, relative to each other and in relation to the focal male. Based on previous work, we expected males to prefer the largest available female mates across all treatments. Surprisingly, males spent more time near the smaller of two available females, but only when the other female was larger than the male. Additionally, males spent little time with either of two potential female mates when both females were larger than the male. We hypothesized that while males might prefer the largest of available females, female behavior might limit males from acting on this preference. To test this, males were force paired with a smaller or larger female. Pair formation only occurred when the female was smaller than the male, and females that were larger than their male counterparts showed significantly more aggression when compared to smaller females. Together, these data suggest that in the absence of intrasexual competition, male mate preference for large females in convict cichlids might be limited by female aggression. PMID:27444247

  10. Collaboration in sensor network research: an in-depth longitudinal analysis of assortative mixing patterns.

    Science.gov (United States)

    Pepe, Alberto; Rodriguez, Marko A

    2010-09-01

    Many investigations of scientific collaboration are based on statistical analyses of large networks constructed from bibliographic repositories. These investigations often rely on a wealth of bibliographic data, but very little or no other information about the individuals in the network, and thus, fail to illustrate the broader social and academic landscape in which collaboration takes place. In this article, we perform an in-depth longitudinal analysis of a relatively small network of scientific collaboration (N = 291) constructed from the bibliographic record of a research centerin the development and application of wireless and sensor network technologies. We perform a preliminary analysis of selected structural properties of the network, computing its range, configuration and topology. We then support our preliminary statistical analysis with an in-depth temporal investigation of the assortative mixing of selected node characteristics, unveiling the researchers' propensity to collaborate preferentially with others with a similar academic profile. Our qualitative analysis of mixing patterns offers clues as to the nature of the scientific community being modeled in relation to its organizational, disciplinary, institutional, and international arrangements of collaboration. PMID:20700373

  11. 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.

  12. Incipient speciation despite little assortative mating: the yellow-rumped warbler hybrid zone.

    Science.gov (United States)

    Brelsford, Alan; Irwin, Darren E

    2009-12-01

    Hybrid zones between recently diverged taxa are natural laboratories for speciation research, allowing us to determine whether there is reproductive isolation between divergent forms and the causes of that isolation. We present a study of a classic avian hybrid zone in North America between two subspecies of the yellow-rumped warbler (Dendroica coronata). Although previous work has shown very little differentiation in mitochondrial DNA across this hybrid zone, we identified two nuclear loci (one sex-linked and one autosomal) that show fixed differences across the hybrid zone, in a close concordance with patterns of plumage variation. Temporal stability and limited width of the hybrid zone, along with substantial linkage disequilibrium between these two diagnostic markers in the center of the zone, indicate that there is moderate reproductive isolation between these populations, with an estimated strength of selection maintaining the zone of 18%. Pairing data indicate that assortative mating is either very weak or absent, suggesting that this reproductive isolation is largely due to postmating barriers. Thus, despite extensive hybridization the two forms are distinct evolutionary groups carrying genes for divergent adaptive peaks, and this situation appears relatively stable. PMID:19624726

  13. PHYLLOXERA-RESISTANT HYBRID FORM OF GRAPES OF TECHNICAL SORTS FOR IMPROVING THE ASSORTMENT

    Directory of Open Access Journals (Sweden)

    Larkina M. D.

    2015-10-01

    Full Text Available Many old varieties of grapes do not meet modern requirements, so there is a need for improved assortment of new high-quality varieties. The translation of the vineyards of the black sea coast of the Krasnodar region on inoculated culture is not fully decided the fate of the viticulture of the area. Weak resistance of American rootstocks to increased content of calcium and salts in the soil, caused the weakening of the bushes, reducing the vigor of the shoots, their maturation and yield of grape plantations in some areas of the district while reducing their quality indicators. In this regard, the development of new high-yielding varieties suitable for own-rooted viticulture remains the most urgent task for breeders. The article shows the potential of many years of breeding work and study of grapes of technical varieties in Anapa Zone Station, tolerant to phylloxera and resistant to fungal diseases and frost, with high quality products and gives a brief description of some prominent grape varieties

  14. 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. PMID:22419447

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

    International Nuclear Information System (INIS)

    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. (paper)

  16. Data assimilation with inequality constraints

    Science.gov (United States)

    Thacker, W. C.

    If values of variables in a numerical model are limited to specified ranges, these restrictions should be enforced when data are assimilated. The simplest option is to assimilate without regard for constraints and then to correct any violations without worrying about additional corrections implied by correlated errors. This paper addresses the incorporation of inequality constraints into the standard variational framework of optimal interpolation with emphasis on our limited knowledge of the underlying probability distributions. Simple examples involving only two or three variables are used to illustrate graphically how active constraints can be treated as error-free data when background errors obey a truncated multi-normal distribution. Using Lagrange multipliers, the formalism is expanded to encompass the active constraints. Two algorithms are presented, both relying on a solution ignoring the inequality constraints to discover violations to be enforced. While explicitly enforcing a subset can, via correlations, correct the others, pragmatism based on our poor knowledge of the underlying probability distributions suggests the expedient of enforcing them all explicitly to avoid the computationally expensive task of determining the minimum active set. If additional violations are encountered with these solutions, the process can be repeated. Simple examples are used to illustrate the algorithms and to examine the nature of the corrections implied by correlated errors.

  17. 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.

  18. Male size does not correlate with fertilization success in two bufonid toads that show size-assortative mating

    Directory of Open Access Journals (Sweden)

    Xiao-Li FAN, Zhi-Hua LIN, Xiang JI

    2013-12-01

    Full Text Available We examined sexual size dimorphism (SSD, mating pattern, fertilization efficiency and female reproductive traits in two bufonid toads (Bufo gargarizans and Duttaphrynus melanostictus to test the idea that importance of male body size for egg fertilization success depends on the mating pattern. Female-biased SSD was evident only in D. melanostictus. Female B. gargarizans laid fewer larger eggs nearly three months earlier than did female D. melanostictus. Fertilization efficiencies on average were higher in B. gargarizans (95% than in D. melanostictus (91%. Though differing in the degree of SSD, body size, breeding season, clutch size, egg size and fertilization efficiency, the two toads were similar in four aspects: (1 both showed size-assortative mating; (2 females did not tradeoff egg size against egg number; (3 male size, clutch size and clutch dry mass were greater in male-larger than in female-larger pairs after accounting for female snout-vent length (SVL; and (4 the ratio of male to female SVL did not affect fertilization efficiency. Our data show that: (1 a female preference for large males is likely not important in terms of egg fertilization success; (2 a male preference for large females is likely important because larger females are more fecund; and (3 size-assortative mating arises from a male preference for large females. Our study demonstrates that male size is not always important for egg fertilization success in anurans that show size-assortative mating [Current Zoology 59 (6: 740–746, 2013].

  19. The effect of assortativity by degree on emerging cooperation in a 2×2 dilemma game played on an evolutionary network

    Science.gov (United States)

    Tanimoto, Jun

    2010-08-01

    A series of numerical experiments on 2×2 games using a co-evolutionary model, including both networks and strategies, was performed. A relationship between assortativity by degree of the evolved network and emerging cooperation was investigated. In the Prisoner’s Dilemma (PD) game class, the evolutionary trajectory for a weak dilemma game favors a network with positive assortative coefficient and easily attains a cooperative situation. A game implemented with a stronger dilemma, however, makes the network very heterogeneous, with a negative assortative coefficient required to solve the dilemma situation. This implies that the dilemma strength in the PD significantly affects the direction adopted by the assortative coefficient during evolutionary processes in the co-evolutionary model.

  20. 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…

  1. Strong assortative mating by diet, color, size, and morphology but limited progress toward sympatric speciation in a classic example: Cameroon crater lake cichlids.

    Science.gov (United States)

    Martin, Christopher H

    2013-07-01

    Models predict that sympatric speciation depends on restrictive parameter ranges, such as sufficiently strong disruptive selection and assortative mating, but compelling examples in nature have rarely been used to test these predictions. I measured the strength of assortative mating within a species complex of Tilapia in Lake Ejagham, Cameroon, a celebrated example of incipient sympatric adaptive radiation. This species complex is in the earliest stages of speciation: morphological and ecological divergence are incomplete, species differ primarily in breeding coloration, and introgression is common. I captured 27 mated pairs in situ and measured the diet, color, size, and morphology of each individual. I found strong assortative mating by color, size, head depth, and dietary source of benthic or pelagic prey along two independent dimensions of assortment. Thus, Ejagham Tilapia showed strong assortative mating most conducive to sympatric speciation. Nonetheless, in contrast to a morphologically bimodal Sarotherodon cichlid species pair in the lake, Ejagham Tilapia show more limited progress toward speciation, likely due to insufficient strength of disruptive selection on morphology estimated in a previous study (γ = 0.16). This supports the predicted dependence of sympatric speciation on strong assortment and strong disruptive selection by examining a potentially stalled example in nature. PMID:23815664

  2. 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. PMID:26808306

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

    Directory of Open Access Journals (Sweden)

    Dharmendra Singh

    Full Text Available 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. 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...

  5. Justifying Educational Acquaintance with the Moral Horrors of History on Psycho-Social Grounds: "Facing History and Ourselves" in Critical Perspective

    Science.gov (United States)

    Maxwell, Bruce

    2008-01-01

    This paper challenges a pervasive curricular justification for educationally acquainting young people with stories of genocide and other moral horrors from history. According to this justification, doing so favours the development of psycho-social soft skills connected with interpersonal awareness and the establishment and maintenance of positive…

  6. A New Approach to Data Assimilation

    Institute of Scientific and Technical Information of China (English)

    Wang Bin; ZHAO Ying

    2006-01-01

    A significant attempt to design a timesaving and efficient four-dimensional variational data assimilation dimensional variational data assimilation of mapped observation (3DVM)' is proposed, based on the new concept of mapped observation and the new idea of backward 4DVar. Like the available 4DVar, 3DVM produces an optimal initial condition (IC) that is consistent with the prediction model due to the inclusion of model constraints and best fits the observations in the assimilation window through the model solution trajectory. Different from the 4DVar, the IC derived from 3DVM is located at the end of the assimilation window rather than at the beginning conventionally. This change greatly reduces the computing cost for the new approach, which is almost the same as that of the three-dimensional variational data assimilation (3DVar). Especially, such a change is able to improve assimilation accuracy because it does not need the tangential linear and adjoint approximations to calculate the gradient of cost function. Therefore,in numerical test, the new approach produces better IC than 4DVar does for 72-h simulation of TY9914(Dan), by assimilating the three-dimensional fields of temperature and wind retrieved from the Advanced Microwave Sounding Unit-A (AMSU-A) observations. Meanwhile, it takes only 1/7 of the computing cost that the 4DVar requires for the same initialization with the same retrieved data.

  7. Skill Assessment in Ocean Biological Data Assimilation

    Science.gov (United States)

    Gregg, Watson W.; Friedrichs, Marjorie A. M.; Robinson, Allan R.; Rose, Kenneth A.; Schlitzer, Reiner; Thompson, Keith R.; Doney, Scott C.

    2008-01-01

    There is growing recognition that rigorous skill assessment is required to understand the ability of ocean biological models to represent ocean processes and distributions. Statistical analysis of model results with observations represents the most quantitative form of skill assessment, and this principle serves as well for data assimilation models. However, skill assessment for data assimilation requires special consideration. This is because there are three sets of information in the free-run model, data, and the assimilation model, which uses Data assimilation information from both the flee-run model and the data. Intercom parison of results among the three sets of information is important and useful for assessment, but is not conclusive since the three information sets are intertwined. An independent data set is necessary for an objective determination. Other useful measures of ocean biological data assimilation assessment include responses of unassimilated variables to the data assimilation, performance outside the prescribed region/time of interest, forecasting, and trend analysis. Examples of each approach from the literature are provided. A comprehensive list of ocean biological data assimilation and their applications of skill assessment, in both ecosystem/biogeochemical and fisheries efforts, is summarized.

  8. Surface Temperature Assimilation in the Global Land Data Assimilation System (GLDAS)

    Science.gov (United States)

    Bosilovich, Michael G.; Radakovich, Jon D.; daSilva, Arlindo; Houser, Paul R.; Atlas, Robert M. (Technical Monitor)

    2002-01-01

    The Global Land Data Assimilation System (GLDAS) is a global land parameterization that uses prescribed meteorology as forcing in order to determine regular gridded land surface states (temperature and moisture) and other properties (e.g. water and heat fluxes). In the present experiment, the assimilation of surface skin temperature is incorporated into the land parameterizations. The meteorological forcing was derived from the Goddard Earth Observing System (GEOS-3) Data Assimilation System (DAS) for the full year of 1998 GLDAS can use several land parameterizations, but here we use the Mosaic land surface model and the Common Land Model (CLM). TOVS surface temperature observations are assimilated into GLDAS. The TOVS observations are less frequent that observations used in previous experiments (ISCCP). The purpose of this presentation is to evaluate the impact of the TOVS assimilation on both Mosaic and CLM. We will especially consider the impact of coarse temporal observations on the assimilation and bias correction.

  9. Compensation for complete assimilation in speech perception: The case of Korean labial-to-velar assimilation

    OpenAIRE

    Mitterer, H.; Kim, S.; Cho, T.

    2013-01-01

    In connected speech, phonological assimilation to neighboring words can lead to pronunciation variants (e.g., 'garden bench'→ "gardem 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 pronunciation of "garden" that carries cues for both a labial [m] and an alveolar [n]). In the current paper, we show that a similar context effect is observed for an as...

  10. Scalable sequential data assimilation with the Parallel Data Assimilation Framework PDAF

    OpenAIRE

    Nerger, Lars; Hiller, Wolfgang; Schröter, Jens

    2011-01-01

    Data assimilation applications with high-dimensional numerical models exhibit extreme requirements on computational resources. Good scalability of the assimilation system is necessary to make these applications feasible. Sequential data assimilation methods based on ensemble forecasts, like ensemble-based Kalman filters, provide such good scalability, because the forecast of each ensemble member can be performed independently. However, this parallelism has to be combined with the paralleli...

  11. 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...

  12. Extending NEMO for ensemble data assimilation on supercomputers with the parallel data assimilation framework PDAF

    OpenAIRE

    Nerger, Lars; Kirchgessner, Paul

    2014-01-01

    The NEMO model is a state-of-the-art ocean circulation model. For data assimilation applications with ensemble Kalman filters like the SEEK filter, e.g. for operational ocean forecasting, NEMO is typically run separately from the assimilation algorithm. Thus, NEMO is used to generate a set of restart files on disks that hold the ensemble of model forecasts providing the error covariance matrix information for the ensemble Kalman filter. These files need to be read by a separate assimilation p...

  13. 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...

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

    Science.gov (United States)

    Kimura, Eiji; Kuroki, Mikako

    2014-01-01

    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 the OC luminance (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 luminance (IC contrast) was smaller in size 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, i.e., 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 the 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 and Mingolla, 1985) and extended for the watercolor effect (Pinna and Grossberg, 2005). However, the present results suggest that additional mechanisms are needed to account for the non-assimilative color spreading. PMID:25285074

  15. 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.

  16. 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.

    Three main classes of procedures in data analysis and assimilation viz. Objective Analysis, Optimal Interpolation and variational method, used to process the observed data on atmospheric and ocean parameters are briefly reviewed. The variational...

  17. 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.

  18. Assimilation of ammonia in Paracoccus denitrificans.

    Science.gov (United States)

    Mikes, V; Chválová, H; Mátlová, L

    1991-01-01

    Two pathways serve for assimilation of ammonia in Paracoccus denitrificans. Glutamate dehydrogenase (NADP+) catalyzes the assimilation at a high NH4+ concentration. If nitrate serves as the nitrogen source, glutamate is synthesized by glutamate-ammonia ligase and glutamate synthase (NADPH). At a very low NH4+ concentration, all three enzymes are synthesized simultaneously. No direct relationship exists between glutamate dehydrogenase (NADP+) and glutamate-ammonia ligase in P. denitrificans, while the glutamate synthase (NADPH) activity changes in parallel with that of the latter enzyme. Ammonia does not influence the induction or repression of glutamate dehydrogenase (NADP+). The inner concentration of metabolites indicates a possible repression of glutamate dehydrogenase (NADP+) by the high concentration of glutamine or its metabolic products as in the case when NH4+ is formed by assimilative nitrate reduction. No direct effect of the intermediates of nitrate assimilation on the synthesis of glutamate dehydrogenase (NADP+) was observed. PMID:1688163

  19. Management of potential transuranium assimilation cases

    International Nuclear Information System (INIS)

    This review deals primarily with the duties of Health Protection personnel assigned to Savannah River's operatig facilities - as opposed to the role of bioassay and dosimetry specialists - in handling potential transuranium assimilation cases

  20. Data assimilation for air quality models

    DEFF Research Database (Denmark)

    Silver, Jeremy David

    2014-01-01

    higher uncertainties. It is possible, however, to combine information from measurements and models to more accurately estimate the state of the atmosphere using a statistically consistent framework known as “data assimilation”. In this study, three data assimilation schemes are implemented and evaluated....... The data assimilation schemes are coupled to the Danish Eulerian Hemispheric Model (DEHM), a large-scale three-dimensional off-line CTM, and the data ingested were retrievals of atmospheric composition from polar-orbiting satellites. The three assimilation techniques applied were: a three......-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...

  1. ITERATIVE ALGORITHMS FOR DATA ASSIMILATION PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Iterative algorithms for solving the data assimilation problems are considered, based on the main and adjoint equations. Spectral properties of the control operators of the problem are studied, the iterative algorithms are justified.

  2. 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 and......It is important to incorporate all available observations when large-scale mathematical models arising in different fields of science and engineering are used to study various physical and chemical processes. Variational data assimilation techniques can be used in the attempts to utilize...... assimilation technique is applied. Therefore, it is important to study the interplay between the three components of the variational data assimilation techniques as well as to apply powerful parallel computers in the computations. Some results obtained in the search for a good combination of numerical methods...

  3. A wildland fire model with data assimilation

    OpenAIRE

    Mandel, Jan; Bennethum, Lynn S.; Beezley, Jonathan D.; Coen, Janice L.; Douglas, Craig C.; Kim, Minjeong; Vodacek, Anthony

    2007-01-01

    A wildfire model is formulated based on balance equations for energy and fuel, where the fuel loss due to combustion corresponds to the fuel reaction rate. The resulting coupled partial differential equations have coefficients that can be approximated from prior measurements of wildfires. An ensemble Kalman filter technique with regularization is then used to assimilate temperatures measured at selected points into running wildfire simulations. The assimilation technique is able to modify the...

  4. CHOLESTEROL ASSIMILATION BY COMMERCIAL YOGHURT STARTER CULTURES

    OpenAIRE

    Małgorzata Ziarno; Ewa Sękul; Alvaro Aguado Lafraya

    2007-01-01

    The ability to in vitro cholesterol level reduction in laboratory media has been shown for numerous strains of lactic acid bacteria, but not for all strains of lactic bacteria used in the dairy industry. The aim of this work was the determination of the ability of selected thermophilic lactic acid bacteria to cholesterol assimilation during 24 h culture in MRS broth. Commercial starter cultures showed various ability to cholesterol assimilation from laboratory medium. In case of starter cultu...

  5. Migration, Friendship Ties, and Cultural Assimilation

    OpenAIRE

    Facchini, Giovanni; Patacchini, Eleonora; Steinhardt, Max

    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...

  6. Effective assimilation of global precipitation: simulation experiments

    OpenAIRE

    Lien, Guo-Yuan; Kalnay, Eugenia; Miyoshi, Takemasa

    2013-01-01

    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 i...

  7. On errors in meteorological data assimilation

    OpenAIRE

    Lindskog, Magnus

    2007-01-01

    Data assimilation in Numerical Weather Prediction (NWP) optimally blends observations with atmospheric model data in order to obtain the best possible initial state for an atmospheric model prediction. Specification of error characteristics is an important part of data assimilation. This thesis is concerned with representation of background error standard deviations, with handling of observations, and with observation error characteristics. The research includes both the study of basic assimi...

  8. 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 ...

  9. 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

  10. Evidence of New Immigrant Assimilation in Canada

    OpenAIRE

    Mary L. Grant

    1999-01-01

    Previous studies of the labour market experience of male immigrants to Canada have uncovered two disturbing trends: declining entry earnings for successive new immigrant cohorts and low assimilation rates. These findings suggest that many of these cohorts may never assimilate. The 1991 Census provides a first look at the immigrant cohorts arriving in the 1980s. These immigrants appear to avoid the plight of their predecessors; entry earnings have stopped falling, and those immigrants arriving...

  11. 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...

  12. Immigrants on Welfare: Assimilation and Benefit Substitution

    OpenAIRE

    Ekhaugen, Tyra

    2005-01-01

    Non-western immigrants in Norway are shown to rely heavily on welfare transfers for several years after immigration. While refugee immigrants assimilate slightly out of welfare, other non-western immigrants assimilate rapidly into welfare. Re-migration is selective for both non-western and western immigrants, insofar as the probability of re-migration correlates negatively with the probability of receiving welfare. We argue that previous studies may have reached biased estimates of welfare as...

  13. The heterogeneity in immigrants unhealthy assimilation

    OpenAIRE

    Barbieri, Paolo Nicola

    2016-01-01

    Immigrants upon their arrival in the United States are in better health condition with respect to their American counterpart however such advantage erodes over time. In this paper, we study the heterogeneity of such unhealthy behaviours assimilation among different arrival cohorts. We focus our analysis on binge drinking and cigarette consumption as a proxy for unhealthy behaviour assimilation by immigrants. Regarding binge drinking we show that more recent immigrant cohorts arriv...

  14. Interethnic Marriages and Economic Assimilation of Immigrants

    OpenAIRE

    Kantarevic, Jasmin

    2004-01-01

    This paper examines the relationship between interethnic marriages and economic assimilation among immigrants in the United States. Two competing hypotheses are evaluated: the productivity hypothesis, according to which immigrants married to native-born spouses assimilate faster than comparable immigrants married to foreign-born spouses because spouses play an integral role in the human capital accumulation of their partners; and the selection hypothesis, according to which the relationship b...

  15. The Acceleration of Immigrant Unhealthy Assimilation

    OpenAIRE

    Giuntella, Osea; Stella, Luca

    2016-01-01

    It is well-known that immigrants tend to be healthier than US natives and that this advantage erodes with time spent in the US. 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 US. Focusing on obes...

  16. Data Assimilation: Making Sense of Earth Observation

    Directory of Open Access Journals (Sweden)

    WilliamAlbertLahoz

    2014-05-01

    Full Text Available Climate change, air quality and environmental degradation are important societal challenges for the 21st Century. These challenges require an intelligent response from society, which in turn requires access to information about the Earth System. This information comes from observations and prior knowledge, the latter typically embodied in a model describing relationships between variables of the Earth System. Data assimilation provides an objective methodology to combine observational and model information to provide an estimate of the most likely state and its uncertainty for the whole Earth System. This approach adds value to the observations – by filling in the spatio-temporal gaps in observations; and to the model – by constraining it with the observations. In this review paper we motivate data assimilation as a methodology to fill in the gaps in observational information; illustrate the data assimilation approach with examples that span a broad range of features of the Earth System (atmosphere, including chemistry; ocean; land surface; and discuss the outlook for data assimilation, including the novel application of data assimilation ideas to observational information obtained using Citizen Science. Ultimately, a strong motivation of data assimilation is the many benefits it provides to users. These include: providing the initial state for weather and air quality forecasts; providing analyses and reanalyses for studying the Earth System; evaluating observations, instruments and models; assessing the relative value of elements of the Global Observing System (GOS; and assessing the added value of future additions to the GOS.

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

    Directory of Open Access Journals (Sweden)

    van Kleef Ellen

    2012-12-01

    Full Text Available Abstract Background 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. Methods 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. Results 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

  18. Assessing Immigrant Assimilation: New Empirical and Theoretical Challenges

    OpenAIRE

    Waters, Mary; Jimenez, Tomas R.

    2005-01-01

    This review examines research on the assimilation of immigrant groups. We review research on four primary benchmarks of assimilation: socioeconomic status, spatial concentration, language assimilation, and intermarriage. The existing literature shows that today's immigrants are largely assimilating into American society along each of these dimensions. This review also considers directions for future research on the assimilation of immigrant groups in new southern and midwestern gateways and h...

  19. The gendered embodiment of shame: Intersections of acquaintance rape, trauma and self-blame in Pompidou posse by Sarah Lotz

    Directory of Open Access Journals (Sweden)

    Jessica Murray

    2014-08-01

    Full Text Available This article offers a feminist literary analysis of the gendered embodiment of shame in Pompidou posse by Sarah Lotz. In this novel, Lotz depicts female characters who are sexually assaulted by acquaintances and the resultant shame and trauma reside in their bodies. I will demonstrate that the embodied shame of these characters is distinctly gendered and that this shapes their attempts to cope with the aftermath of the sexual assaults. A close reading of the text reveals that the characters are exposed to overwhelming social messages of female culpability in a larger context that is rife with misogyny. As a result, they anticipate blame to such an extent that they blame themselves and internalise this blame as shame. By focusing on the bodies of the survivors, Lotz demonstrates the embodiment of shame, but she also suggests a corporeal challenge to silencing. The bodies of these characters speak loudly, albeit sometimes in the halting language of trauma, and they function to alert them to danger, to help them excavate memories that are made inaccessible and to testify to traumatic sexual assault.

  20. 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. PMID:21572546

  1. Assimilation of the Microwave Limb Sounder Radiances

    Science.gov (United States)

    Wargan, K.; Read, W.; Livesey, N.; Wagner, P.; Nguyen. H.; Pawson, S.

    2012-01-01

    It has been shown that the assimilation of limb-sounder data can significantly improve the representation of ozone in NASA's GEOS Data Assimilation Systems (GEOS-DAS), particularly in the stratosphere. The studies conducted so far utilized retrieved data from the MIPAS, POAM, ILAS and EOS Microwave Limb Sounder (EOS MLS) instruments. Direct assimilation of the radiance data can be seen as the natural next step to those studies. The motivation behind working with radiances is twofold. First, retrieval algorithms use a priori data which are either climatological or are obtained from previous analyses. This introduces additional uncertainty and, in some cases, may lead to "self-contamination"- when the a priori is taken from the same assimilation system in which subsequently ingests the retrieved observations. Second, radiances can be available in near real time thus providing an opportunity for operational assimilation, which could help improve the use of infrared radiance instruments from operational satellite instruments. In this presentation we summarize our ongoing work on an implementation of the assimilation of EOS MLS radiances into the GEOS-5 DAS. This work focuses on assimilation of band 7 brightness temperatures which are sensitive to ozone. Our implementation uses the MLS Callable Forward Model developed by the MLS team at NASA JPL as the observation operator. We will describe our approach and recent results which are not yet final. In particular, we will demonstrate that this approach has a potential to improve the vertical structure of ozone in the lower tropical stratosphere as compared with the retrieved MLS product. We will discuss the computational efficiency of this implementation.

  2. [Critical perspective of the family and acquaintances on family and community risk factors in illicit drug use in São Jose, Costa Rica].

    Science.gov (United States)

    Granados Hernández, Mabell; Brands, Bruna; Adlaf, Edward; Giesbrecht, Norman; Simich, Laura; Wright, Maria da Gloria Miotto

    2009-01-01

    This article presents the results of a quantitative study. The purpose was to describe the perspective of family members and acquaintances of illicit drug users about family and community risk factors that can contribute to addiction to illicit drugs. A questionnaire was used for data collection. The population consisted of 100 individuals, 18 years of age or older, who reported being affected by their relationship with an illicit drug user (relative or acquaintance). Most users (82%) were men, with an average age of 27.3 years. Family risk factors included: family rejection (99%), not feeling loved (98%), lack of communication (95%), family conflicts and violence (95%). Social or community factors included: 99% having friends who use drugs, 99% peer pressure, 93% living in an unsafe area, and 99% experienced a stressful event. The critical perspective proposes to use more prevention strategies to avoid risk factors in the family and community. PMID:20011900

  3. CHOLESTEROL ASSIMILATION BY COMMERCIAL YOGHURT STARTER CULTURES

    Directory of Open Access Journals (Sweden)

    Małgorzata Ziarno

    2007-03-01

    Full Text Available The ability to in vitro cholesterol level reduction in laboratory media has been shown for numerous strains of lactic acid bacteria, but not for all strains of lactic bacteria used in the dairy industry. The aim of this work was the determination of the ability of selected thermophilic lactic acid bacteria to cholesterol assimilation during 24 h culture in MRS broth. Commercial starter cultures showed various ability to cholesterol assimilation from laboratory medium. In case of starter cultures used for production of traditional yoghurt, consisting of Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, the quantity of assimilated cholesterol did not exceed 27% of its initial contents (0.7 g in 1 dm3. Starter cultures used for bioyoghurt production, containing also probiotic strains (came from Lactobacillus acidophilus species or Bifidobacterium genus assimilated from almost 18% to over 38% of cholesterol. For one monoculture of Lb. acidophilus, cholesterol assimilation ability of 49-55% was observed, despite that the number of bacterial cells in this culture was not different from number of bacteria in other cultures.

  4. Estimating Evapotranspiration with Land Data Assimilation Systems

    Science.gov (United States)

    Peters-Lidard, C. D.; Kumar, S. V.; Mocko, D. M.; Tian, Y.

    2011-01-01

    Advancements in both land surface models (LSM) and land surface data assimilation, especially over the last decade, have substantially advanced the ability of land data assimilation systems (LDAS) to estimate evapotranspiration (ET). This article provides a historical perspective on international LSM intercomparison efforts and the development of LDAS systems, both of which have improved LSM ET skill. In addition, an assessment of ET estimates for current LDAS systems is provided along with current research that demonstrates improvement in LSM ET estimates due to assimilating satellite-based soil moisture products. Using the Ensemble Kalman Filter in the Land Information System, we assimilate both NASA and Land Parameter Retrieval Model (LPRM) soil moisture products into the Noah LSM Version 3.2 with the North American LDAS phase 2 (NLDAS-2) forcing to mimic the NLDAS-2 configuration. Through comparisons with two global reference ET products, one based on interpolated flux tower data and one from a new satellite ET algorithm, over the NLDAS2 domain, we demonstrate improvement in ET estimates only when assimilating the LPRM soil moisture product.

  5. On Variational Data Assimilation in Continuous Time

    CERN Document Server

    Bröcker, Jochen

    2010-01-01

    Variational data assimilation in continuous time is revisited. The central techniques applied in this paper are in part adopted from the theory of optimal nonlinear control. Alternatively, the investigated approach can be considered as a continuous time generalisation of what is known as weakly constrained four dimensional variational assimilation (WC--4DVAR) in the geosciences. The technique allows to assimilate trajectories in the case of partial observations and in the presence of model error. Several mathematical aspects of the approach are studied. Computationally, it amounts to solving a two point boundary value problem. For imperfect models, the trade off between small dynamical error (i.e. the trajectory obeys the model dynamics) and small observational error (i.e. the trajectory closely follows the observations) is investigated. For (nearly) perfect models, this trade off turns out to be (nearly) trivial in some sense, yet allowing for some dynamical error is shown to have positive effects even in th...

  6. Dark Matter Assimilation into the Baryon Asymmetry

    CERN Document Server

    D'Eramo, Francesco; Thaler, Jesse

    2011-01-01

    Pure singlets are typically disfavored as dark matter candidates, since they generically have a thermal relic abundance larger than the observed value. In this paper, we propose a new dark matter mechanism called "assimilation", which takes advantage of the baryon asymmetry of the universe to generate the correct relic abundance of singlet dark matter. Through assimilation, dark matter itself is efficiently destroyed, but dark matter number is stored in new quasi-stable heavy states which carry the baryon asymmetry. The subsequent annihilation and late-time decay of these heavy states yields (symmetric) dark matter as well as (asymmetric) standard model baryons. We study in detail the case of pure bino dark matter by augmenting the minimal supersymmetric standard model with vector-like chiral multiplets. In the parameter range where this mechanism is effective, the LHC can discover long-lived charged particles which were responsible for assimilating dark matter.

  7. Correction of deposition predictions with data assimilation

    International Nuclear Information System (INIS)

    Model predictions for rapid assessment and prognosis of possible radiological consequences after an accidental release of radionuclides play an important role in nuclear emergency management. Radiological measurements (e. g., dose rate measurements) can be used to improve such model predictions. This paper describes a method for combining model predictions and measurements (data assimilation) in the deposition model of the European radiological decision support system RODOS. The data assimilation approach is based on the Ensemble Kalman Filter, a Monte Carlo variant of the Kalman filter. (orig.)

  8. Processing technology of assorted spiced rabbit meat%卤味兔肉加工工艺

    Institute of Scientific and Technical Information of China (English)

    陈兴; 盛本国; 王军锋; 李海龙; 严文慧

    2012-01-01

    阐述了卤味兔肉的加工工艺、操作关键点及质量要求,此加工工艺简化了传统的酱卤工艺,且卤香味与兔肉的结合,既去除了兔肉的腥膻味,也赋予了兔肉特色的卤香味。%The assorted spiced rabbit meat processing technology, operating key points and quality requirements were elaborated; using this processing technology could simplify the traditional sauce halogen and halogen technology, and combine the fragrance with rabbit meat, which not only removed fishy and sheepy smell of rabbit meat, but also gave the meat characteristic bittern flavor.

  9. 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...

  10. 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.

  11. 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 ...

  12. Assimilation violation and spoken-language processing: A supplementary report

    OpenAIRE

    Weber, A

    2002-01-01

    Previous studies have shown that spoken-language processing is inhibited by violation of obligatory regressive assimilation. Weber (2001) replicated this inhibitory effect in a phoneme-monitoring study examining regressive place assimilation of nasals, but found facilitation for violation of progressive assimilation. German listeners detected the velar fricative [x] more quickly when fricative assimilation was violated (e.g., *[bIxt] or *[blInx@n]) than when no violation occurred (e.g., [baxt...

  13. ASSIMILATION SYSTEM AT DHMZ: DEVELOPMENT AND FIRST VERIFICATION RESULTS

    OpenAIRE

    Stanešić, Antonio

    2011-01-01

    Abstract: In this paper, a description of the setup for a local assimilation system for a limited area model, ALADIN (Aire Limiteé Adaptation Dynamique dévelopement InterNational), is given with a comprehensive description of the assimilation techniques used. The assimilation system at DHMZ (Meteorological and Hydrological Service of Croatia) consisted of two parts: the surface assimilation, which was used to change the state of a model land surface variables, and the upper air assimilatio...

  14. Data ingestion and assimilation in ionospheric models

    Czech Academy of Sciences Publication Activity Database

    Burešová, Dalia; Nava, B.; Galkin, I.; Angling, M.; Stankov, S. M.; Coisson, P.

    2009-01-01

    Roč. 52, 3/4 (2009), s. 235-253. ISSN 1593-5213 R&D Projects: GA ČR GA205/08/1356; GA MŠk OC 091 Institutional research plan: CEZ:AV0Z30420517 Keywords : ionosphere * models * data assimilation * data ingestion Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 0.548, year: 2009

  15. The Silent Minority: Assimilated or Marginal?

    Science.gov (United States)

    Howell, Gladys David

    In this paper, the concept of "invisible ethnic" is used to refer to an individual who is identified as different by dominant members of society and who is caught between an ancestral identity and culture on the one hand, and a wish to be assimilated, on the other. This concept is discussed in relation to Stonequist's "marginal man" and the social…

  16. A new sequential data assimilation method

    Institute of Scientific and Technical Information of China (English)

    HAN YueQi; ZHANG YaoCun; WANG YunFeng; YE Song; FANG HanXian

    2009-01-01

    A new sequential data assimilation method named "Monte Carlo H∞ filter" is Introduced based on H∞ filter technique and Monte Carlo method in this paper. This method applies to nonlinear systems in condition of lacking the statistical properties of observational errors. In order to compare the assimilation capability of Monte Carlo H= filter with that of the ensemble Kalman filter (EnKF) in solving practical problems caused by temporal correlation or spatial correlation of observational errors, two numerical experiments are performed by using Lorenz (1963) system and shallow-water equations respectively. The result is that the assimilation capability of the new method is better than that of EnKF method. It is also shown that Monte Carlo H∞ filter assimilation method is effective and suitable to nonlinear systems in that it does not depend on the statistical properties of observational errors and has better robustnesa than EnKF method when the statistical properties of observational errors are varying. In addition, for the new method, the smallest level factor founded by search method is flow-dependent.

  17. Strengths and Limitations of Data Assimilation Models

    Science.gov (United States)

    Schunk, R. W.; Scherliess, L.; Sojka, J. J.; Thompson, D. C.; Zhu, L.

    2006-12-01

    As part of the Global Assimilation of Ionospheric Measurements (USU-GAIM) program, we developed two Kalman filter data assimilation models of the global ionosphere, including Gauss-Markov (GM) and Full Physics (FP) models. Our Gauss-Markov model uses a physics-based ionospheric model and a Kalman filter as a basis for assimilating the measurements. The physics-based model is the Ionosphere Forecast Model (IFM), which is a multi-ion global model that covers the E-region, F-region, and topside from 90 to 1400 km. The GM model has both regional and global capabilities and the output of the model is a 3-dimensional Ne distribution at specified times. With the GM model the ionospheric densities obtained from the IFM constitute a background ionospheric density field on which perturbations are superimposed based on the available data sources and their errors. The density perturbations and the associated errors evolve over time via a statistical Gauss-Markov process. Our full physics data assimilation model is more sophisticated than the Gauss-Markov model. This model is based on a physics-based ionosphere-plasmasphere-polar wind model, which includes six ion species (NO+, O2+, N2+, O+, H+, and He+) and covers the low-mid latitudes from 90 to 20,000 km. In addition to the global Ne distribution, the full physics model also provides global distributions of the self-consistent drivers (neutral winds and composition, electric fields, and particle precipitation). Both models can assimilate in situ electron densities from 4 DMSP satellites, bottomside Ne profiles from 30 ionosondes, slant TECs from up to 1000 ground GPS/TEC receivers, occultation data and line-of-sight UV emissions. The USU-GAIM models are now being widely used, but as with all physics-based data assimilation models, care must be exercised because these models have both strengths and limitations. Some of the important issues relate to the quality, amount and distribution of the data, the ability to obtain

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

    OpenAIRE

    Eiji eKimura; Mikako eKuroki

    2014-01-01

    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 effe...

  19. The Parallel Data Assimilation Framework PDAF - a flexible software framework for ensemble data assimilation

    OpenAIRE

    Nerger, Lars; Hiller, Wolfgang; Schröter, Jens

    2012-01-01

    Ensemble filter algorithms can be implemented in a generic way such that they can be applied with various models with only a minimum amount of recoding. This is possible due to the fact that ensemble filters can operate on abstract state vectors and require only limited information about the numerical model and the observational data used for a data assimilation application. To build an assimilation system, the analysis step of a filter algorithm needs to be connected to t...

  20. Effect of S-07 on 14CO2 assimilation and distribution of assimilates during ripening stage of wheat

    International Nuclear Information System (INIS)

    The effect of S-07 (S-3307, uniconazole) on 14CO2 assimilation and distribution of assimilates during ripening stage of wheat was studied. The experimental results showed that the amount of 14Co2 assimilates in leaves of the wheat plant sprayed with 10∼40 ppm S-07 at heading stage was higher than that of the control. The distribution of 14CO2 assimilates in ear and root of wheat plant increased. It is also found that S-07 treatment made more assimilates transferring from primary stem to tillers

  1. 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. PMID:25664882

  2. Complexity Computational Environment: Data Assimilation SERVOGrid

    Science.gov (United States)

    Donnellan, Andrea; Parker, Jay; Fox, Geoffrey; Pierce, Marlon; Rundle, John; McLeod, Dennis

    2004-01-01

    We are using Web (Grid) service technology to demonstrate the assimilation of multiple distributed data sources (a typical data grid problem) into a major parallel high-performance computing earthquake forecasting code. Such a linkage of Geoinformatics with Geocomplexity demonstrates the value of the Solid Earth Research Virtual Observatory (SERVO) Grid concept, and advance Grid technology by building the first real-time large-scale data assimilation grid Here we develop the next steps for both the SERVO concept and the identified need for a Solid Earth problem-solving environment. We use a challenging motivating problem of importance to NASA namely integrating NASA space geodetic observations with numerical simulations of a changing earth.

  3. 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...

  4. Ethnic Persistence, Assimilation and Risk Proclivity

    OpenAIRE

    Bonin, Holger; Constant, Amelie; Tatsiramons, Konstantinos; Zimmermann, Klaus F.

    2007-01-01

    The paper investigates the role of social norms as a determinant of individual attitudes by analyzing risk proclivity reported by immigrants and natives in a unique representative German survey. We employ factor analysis to construct measures of immigrants' ethnic persistence and assimilation. The estimated effect of these measures on risk proclivity suggests that adaptation to the attitudes of the majority population closes the immigrant-native gap in risk proclivity, while stronger commitme...

  5. 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...

  6. Downscaling in the Context of Data Assimilation

    Czech Academy of Sciences Publication Activity Database

    Juruš, Pavel

    Praha : Ústav informatiky AV ČR & MATFYZPRESS, 2006 - (Hakl, F.), s. 35-43 ISBN 80-86732-87-8. [Doktorandský den '06. Monínec (CZ), 20.09.2006-22.10.2006] R&D Projects: GA AV ČR 1ET400300414 Institutional research plan: CEZ:AV0Z10300504 Keywords : data assimilation * model output statistics * probabilistic forecast

  7. National Identity and Immigrants’ Assimilation in France

    OpenAIRE

    Gabin Langevin; Pascaline Vincent

    2013-01-01

    Determination and changes of immigrants' identity resulting from intercultural contacts impact their socio-economic integration. To precisely assess individuals’ identity, we propose a continuous index which aims to overcome interpretation troubles faced by usual measures of ethnic identity. Then, we investigate the determinants of immigrants' ethnic identity in France. We compare our composite and continuous index exhibiting individuals' assimilation with a usual measure of ethnic identity –...

  8. Immigrant Assimilation, Trust and Social Capital

    OpenAIRE

    Cox, James C.; Orman, Wafa Hakim

    2010-01-01

    Trust is a crucial component of social capital. We use an experimental moonlighting game with a representative sample of the U.S. population, oversampling immigrants, to study trust, positive, and negative reciprocity between first-generation immigrants and native-born Americans as a measure of immigrant assimilation. We also survey subjects in order to relate trusting and trustworthy behavior with demographic characteristics and traditional, survey-based measures of social capital. We find t...

  9. 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 ...

  10. Wage Assimilation of Immigrants in Spain

    OpenAIRE

    Zenón Jiménez-Ridruejo; Carlos Borondo Arribas

    2011-01-01

    In this study we quantify the effect of the years of residence in Spain on the earnings of immigrants. We take sex, origin, education and age into account. The results are clearly positive, the longer the length of residence the more earnings, confirming the hypothesis of wage assimilation of immigrants as their human capital is adapted to the Spanish labor market. The information used comes from the Social Security’s Continuous Sample of Working Lives 2007. Additionally, we merge the earning...

  11. Intermarriage and the Economic Assimilation of Immigrants

    OpenAIRE

    Xin Meng; Robert G Gregory

    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 ...

  12. IMMIGRANT ASSIMILATION:DO NEIGHBORHOODS MATTER?

    OpenAIRE

    Natasha T. Duncan; Waldorf, Brigitte S.

    2008-01-01

    The United States provides a path to citizenship for its newcomers. Unlike other immigration countries, however, the United States does not have policies that ease assimilation or directly promote naturalization such as easily accessible and widely advertised language and civic instruction courses. Immigrants are by and large left on their own when facing legal and financial barriers or seeking instruction to pass the citizenship test. Not surprisingly, thus, we find that immigrants’ attribut...

  13. Services innovation: assimilation, differentiation, inversion and integration

    OpenAIRE

    Gallouj, FaÏz

    2002-01-01

    This chapter aims to provide a review of the literature on innovation in services and to focus on the analytical strategies carried out in order to fill in the innovation gap in the service economy (i.e. the difference between what the traditional innovation indicators are capable of capturing, and the reality of innovation activities undertaken in a given economy). Four analytical perspectives are distinguished in this chapter, which are labeled: assimilation, differentiation, inversion and ...

  14. Precision variational approximations in statistical data assimilation

    Directory of Open Access Journals (Sweden)

    J. Ye

    2014-10-01

    Full Text Available Data assimilation transfers information from observations of a complex system to physically-based system models with state variables x(t. Typically, the observations are noisy, the model has errors, and the initial state of the model is uncertain, so the data assimilation is statistical. One can thus ask questions about expected values of functions ⟨G(X⟩ on the path X = {x(t0, ..., x(tm} of the model as it moves through an observation window where measurements are made at times {t0, ..., tm}. The probability distribution on the path P(X = exp[−A0(X] determines these expected values. Variational methods seeking extrema of the "action" A0(X, widely known as 4DVar (Talagrand and Courtier, 1987; Evensen, 2009,, are widespread for estimating ⟨G(X ⟩ in many fields of science. In a path integral formulation of statistical data assimilation, we consider variational approximations in a standard realization of the action where measurement and model errors are Gaussian. We (a discuss an annealing method for locating the path X0 giving a consistent global minimum of the action A0(X0, (b consider the explicit role of the number of measurements at each measurement time in determining A0(X0, and (c identify a parameter regime for the scale of model errors which allows X0 to give a precise estimate of ⟨G(X0⟩ with computable, small higher order corrections.

  15. 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.

  16. Middle Atmosphere Transport Properties of Assimilated Datasets

    Science.gov (United States)

    Pawson, Steven; Rood, Richard

    1999-01-01

    One of the most compelling reasons for performing data assimilation in the middle atmosphere is to obtain global, balanced datasets for studies of trace gas transport and chemistry. This is a major motivation behind the Goddard Earth observation System-Data Assimilation System (GEOS-DAS). Previous studies have shown that while this and other data assimilation systems can generally obtain good estimates of the extratropical rotational velocity field, the divergent part of the dynamical field is deficient; this impacts the "residual circulation" and leads to spurious trace gas transport on seasonal and interannual timescales. These problems are impacted by the quality and the method of use of the observational data and by deficiencies in the atmospheric general circulation model. Whichever the cause at any place and time, the "solution" is to introduce non-physical forcing terms into the system (the so-called incremental analysis updates); these can directly (thermal) or indirectly (mechanical) affect the residual circulation. This paper will illustrate how the divergent circulation is affected by deficiencies in both observations and models. Theoretical considerations will be illustrated with examples from the GEOS-DAS and from simplified numerical experiments. These are designed to isolate known problems, such as the inability of models to sustain a quasi-biennial oscillation and sparse observational constraints on tropical dynamics, or radiative inconsistencies in the presence of volcanic aerosols.

  17. Middle Atmospheric Transport Properties of Assimilated Datasets

    Science.gov (United States)

    Pawson, Steven; Rood, Richard

    1999-01-01

    One of the most compelling reasons for performing data assimilation in the middle atmosphere is to obtain global, balanced datasets for studies of trace gas transport and chemistry. This is a major motivation behind the Goddard Earth observation System-Data Assimilation System (GEOS-DAS). Previous studies have shown that while this and other data assimilation systems can generally obtain good estimates of the extratropical rotational velocity field, the divergent part of the dynamical field is deficient; this impacts the "residual circulation" and leads to spurious trace gas transport on seasonal and interannual timescales. These problems are impacted by the quality and the method of use of the observational data and by deficiencies in the atmospheric general circulation model. Whichever the cause at any place and time, the "solution" is to introduce non-physical forcing terms into the system (the so-called incremental analysis updates); these can directly (thermal) or indirectly (mechanical) affect the residual circulation. This paper will illustrate how the divergent circulation is affected by deficiencies in both observations and models. Theoretical considerations will be illustrated with examples from the GEOS-DAS and from simplified numerical experiments. These are designed to isolate known problems, such as the inability of models to sustain a quasi-biennial oscillation and sparse observational constraints on tropical dynamics, or radiative inconsistencies in the presence of volcanic aerosols.

  18. Data assimilation and model evaluation experiment datasets

    Science.gov (United States)

    Lai, Chung-Cheng A.; Qian, Wen; Glenn, Scott M.

    1994-01-01

    The Institute for Naval Oceanography, in cooperation with Naval Research Laboratories and universities, executed the Data Assimilation and Model Evaluation Experiment (DAMEE) for the Gulf Stream region during fiscal years 1991-1993. Enormous effort has gone into the preparation of several high-quality and consistent datasets for model initialization and verification. This paper describes the preparation process, the temporal and spatial scopes, the contents, the structure, etc., of these datasets. The goal of DAMEE and the need of data for the four phases of experiment are briefly stated. The preparation of DAMEE datasets consisted of a series of processes: (1) collection of observational data; (2) analysis and interpretation; (3) interpolation using the Optimum Thermal Interpolation System package; (4) quality control and re-analysis; and (5) data archiving and software documentation. The data products from these processes included a time series of 3D fields of temperature and salinity, 2D fields of surface dynamic height and mixed-layer depth, analysis of the Gulf Stream and rings system, and bathythermograph profiles. To date, these are the most detailed and high-quality data for mesoscale ocean modeling, data assimilation, and forecasting research. Feedback from ocean modeling groups who tested this data was incorporated into its refinement. Suggestions for DAMEE data usages include (1) ocean modeling and data assimilation studies, (2) diagnosis and theoretical studies, and (3) comparisons with locally detailed observations.

  19. A new sequential data assimilation method

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A new sequential data assimilation method named "Monte Carlo H ∞ filter" is introduced based on H ∞ filter technique and Monte Carlo method in this paper. This method applies to nonlinear systems in condition of lacking the statistical properties of observational errors. In order to compare the as- similation capability of Monte Carlo H ∞ filter with that of the ensemble Kalman filter (EnKF) in solving practical problems caused by temporal correlation or spatial correlation of observational errors, two numerical experiments are performed by using Lorenz (1963) system and shallow-water equations re- spectively. The result is that the assimilation capability of the new method is better than that of EnKF method. It is also shown that Monte Carlo H ∞ filter assimilation method is effective and suitable to nonlinear systems in that it does not depend on the statistical properties of observational errors and has better robustness than EnKF method when the statistical properties of observational errors are varying. In addition, for the new method, the smallest level factor founded by search method is flow-dependent.

  20. 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...

  1. The Analysis Of The Strain Influence On Some Yield Elemnts On An Assortment Of Isogenic Wheat Varieties

    Science.gov (United States)

    Păniţă, Ovidiu

    2015-09-01

    In the years 2012-2014 on Banu-Maracine DRS were tested an assortment consists of 25 isogenic lines of common wheat (Triticum aestivum ssp.vulgare), with the combination of Rht1&rht8 genes, the analyzed characters being the hight of the strain (cm), the number of seeds/spike, seeds weight/spike (g), no. of spikes/m2, weight of a thousand seeds (WTS) (g) and no. of emerged plants/m2. Based on recorded data and statistical processing of those, they were identified a numbers of links between these characters, links quantified by using the correlation. Regarding the classification based on the average high of the strain, it was found that that there is a strong link between some characters too. Based on component analysis, the no. of seeds/spike and the seeds weight/spikes are components that influence in excess of 83% variance analysis, a total of five genotypes having positive scores for both factors.

  2. 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”.

  3. 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...

  4. Application of statistical emulation to an agent-based model: assortative mating and the reversal of gender inequality in education in Belgium.

    OpenAIRE

    De Mulder, Wim; Grow, André; Molenberghs, Geert; Verbeke, Geert

    2015-01-01

    We describe the application of statistical emulation to the outcomes of an agent-based model. The agent-based model simulates the mechanisms that might have linked the reversal of gender inequality in higher education with observed changes in educational assortative mating in Belgium. Using the statistical emulator as a computationally fast approximation to the expensive agent-based model, it is feasible to use a genetic algorithm in nding the parameter values for which the correspondin...

  5. 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.

  6. Construction and Experiment of Hierarchical Bayesian Network in Data Assimilation

    International Nuclear Information System (INIS)

    A Hierarchical Bayesian Network Algorithm (HBN) is developed for data assimilation and tested with an instance of soil moisture assimilation from hydrological model and ground observations. In this work, data assimilation separates into data level, process level and parameter level, and conditional probability models are defined for each level. The data model mainly deals with the scale differences between multiple data, while the process model is designed to take account of non-stationary process. Soil moisture from Soil Moisture Experiment in 2003 and Variable Infiltration Capacity Model is sequentially assimilated with HBN. The result shows that the assimilation with HBN provides spatial and temporal distribution information of soil moisture and the assimilation result agrees well with the ground observations

  7. 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. PMID:26708247

  8. Data Assimilation in Forest Inventory: First Empirical Results

    OpenAIRE

    Mattias Nyström; Nils Lindgren; Jörgen Wallerman; Anton Grafström; Anders Muszta; Kenneth Nyström; Jonas Bohlin; Erik Willén; Johan E.S. Fransson; Sarah Ehlers; Håkan Olsson; Göran Ståhl

    2015-01-01

    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-bor...

  9. Data assimilation in forest inventory: first empirical results

    OpenAIRE

    Nyström, Mattias; Lindgren, Nils; Wallerman, Jörgen; Grafström, Anton; Muszta, Anders; Nyström, Kenneth; Bohlin, Jonas; Fransson, Johan E. S.; Ehlers, Sarah; Olsson, Håkan; Ståhl, Göran

    2015-01-01

    Data assimilation techniques were used to estimate forest stand data in 2011 bysequentially combining remote sensing based estimates of forest variables with predictions fromgrowth models. Estimates of stand data, based on canopy height models obtained from imagematching of digital aerial images at six different time-points between 2003 and 2011, served asinput to the data assimilation. The assimilation routines were built on the extended Kalman filter.The study was conducted in hemi-boreal f...

  10. Evaluation of an ensemble-based incremental variational data assimilation

    OpenAIRE

    Yang, Yin; Robinson, Cordelia; Heitz, Dominique; Mémin, Etienne

    2014-01-01

    In this work, we aim at studying ensemble based optimal control strategies for data assimilation. Such formulation nicely combines the ingredients of ensemble Kalman filters and variational data assimilation (4DVar). In the same way as variational assimilation schemes, it is formulated as the minimization of an objective function, but similarly to ensemble filter, it introduces in its objective function an empirical ensemble-based background-error covariance and works in an off-line smoothing...

  11. The effect of model errors in variational assimilation

    OpenAIRE

    Wergen, Werner

    2011-01-01

    A linearized, one-dimensional shallow water model is used to investigate the effect of model errors in four-dimensional variational assimilation. A suitable initialization scheme for variational assimilation is proposed. Introducing deliberate phase speed errors in the model, the results from variational assimilation are compared to standard analysis/forecast cycle experiments. While the latter draws to the data and reflects the model errors only in the datavoid areas, variational assimilatio...

  12. Assimilation of GNSS radio occultation observations in GRAPES

    OpenAIRE

    Liu, Y; Xue, J.

    2014-01-01

    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 ...

  13. Using ensemble data assimilation to forecast hydrological flumes

    OpenAIRE

    Amour, I.; Mussa, Z.; Bibov, A.; Kauranne, T.

    2013-01-01

    Data assimilation, commonly used in weather forecasting, means combining a mathematical forecast of a target dynamical system with simultaneous measurements from that system in an optimal fashion. We demonstrate the benefits obtainable from data assimilation with a dam break flume simulation in which a shallow-water equation model is complemented with wave meter measurements. Data assimilation is conducted with a Variational Ensemble Kalman Filter (VEnKF) algorithm. The resu...

  14. Organizational assimilation of collaborative information technologies: Global comparisons

    OpenAIRE

    Bawja, Deepinder S.; Lewis, L. Floyd; Pervan, Graham; Lai, Vincent; Munkvold, Bjørn E.; Schwabe, Gerhard

    2007-01-01

    This paper reports on a global initiative to investigate the assimilation of collaborative information technologies (CITs) in task-oriented collaboration. The two classes of CITs explored include conferencing and groupware technologies. Based upon the level of technology access/availability and utilization, four assimilation states are identified. Data collected from 538 organizations in the US, Australia, Hong Kong, Norway, and Switzerland is mapped in the four CIT assimilation states. The r...

  15. Robust data assimilation using $L_1$ and Huber norms

    OpenAIRE

    Rao, Vishwas; Sandu, Adrian; Ng, Michael; Nino-Ruiz, Elias

    2015-01-01

    Data assimilation is the process to fuse information from priors, observations of nature, and numerical models, in order to obtain best estimates of the parameters or state of a physical system of interest. Presence of large errors in some observational data, e.g., data collected from a faulty instrument, negatively affect the quality of the overall assimilation results. This work develops a systematic framework for robust data assimilation. The new algorithms continue to produce good analyse...

  16. An Ensemble Algorithm Based Component for Geomagnetic Data Assimilation

    OpenAIRE

    Zhibin Sun and Weijia Kuang

    2015-01-01

    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 mat...

  17. Negative and Positive Assimilation, Skill Transferability, and Linguistic Distance

    OpenAIRE

    Chiswick, Barry R; Paul W. Miller

    2012-01-01

    There are two complementary models of immigrants' economic and social adjustment - the positive assimilation model of Chiswick (1978, 1979), and the negative assimilation model of Chiswick and Miller (2011). The negative assimilation model is applicable for immigrants from countries that are very similar in terms of the transferability of skills, culture, and labor market institutions to the host country, and has been tested previously primarily using migration among the English-speaking deve...

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

    OpenAIRE

    Greenman, Emily

    2011-01-01

    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. R...

  19. The negative assimilation of immigrants: a special case

    OpenAIRE

    Chiswick, Barry R; Paul W. Miller

    2008-01-01

    Research on the economic or labor market assimilation of immigrants has to date focused on the degree of improvement in their economic status with duration in the destination. The theoretical underpinning for this finding is the international transferability of skills. This paper addresses whether positive assimilation will be found if skills are very highly transferable internationally. It outlines the conditions for “negative” assimilation in the context of the traditional immigration assim...

  20. Assimilation Effects on Poverty Among Immigrants in Norway.

    OpenAIRE

    Galloway, Taryn Ann; Aaberge, Rolf

    2003-01-01

    This paper discusses the question of whether or not the high incidence of poverty among immigrants in Norway persists even after immigrants have been in the country for a long period, i.e. after they have had the opportunity to integrate and adapt their skills to the expectations in their new home. While similar to traditional studies of wage assimilation, a study of assimilation in relation to poverty propensity nevertheless measures something different than labor market assimilation, and th...

  1. Satellite data assimilation to improve forecasts of volcanic ash concentrations

    OpenAIRE

    Fu, Guangliang; Lin, Hai-Xiang; Heemink, Arnold; SEGERS Arjo; Prata, Fred; Lu, Sha

    2016-01-01

    Data assimilation is a powerful tool that requires available observations to improve model forecast accuracy. Infrared satellite measurements of volcanic ash mass loadings are often used as input observations into the assimilation scheme. However, these satellite-retrieved data are often two-dimensional (2D), and cannot be easily combined with a three-dimensional (3D) volcanic ash model to continuously improve the volcanic ash state in a data assimilation system. By integrating available data...

  2. Negative and Positive Assimilation By Prices and By Quantities

    OpenAIRE

    Barry R. Chiswick; Paul W. Miller

    2013-01-01

    This paper considers the labor market assimilation of immigrants in terms of earnings and employment (employment probability, unemployment probability, and hours worked per week). Using the 2006 Australian Census of Population and Housing the analyses are performed separately by gender, and separately by whether or not the origin is an English-speaking developed country (ESDC). Among men in general, 'negative assimilation' is found for immigrants from the ESDC, and positive assimilation for o...

  3. Application of altimetry data assimilation on mesoscale eddies simulation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Mesoscale eddy plays an important role in the ocean circulation. In order to improve the simulation accuracy of the mesoscale eddies, a three-dimensional variation (3DVAR) data assimilation system called Ocean Variational Analysis System (OVALS) is coupled with a POM model to simulate the mesoscale eddies in the Northwest Pacific Ocean. In this system, the sea surface height anomaly (SSHA) data by satellite altimeters are assimilated and translated into pseudo temperature and salinity (T-S) profile data. Then, these profile data are taken as observation data to be assimilated again and produce the three-dimensional analysis T-S field. According to the characteristics of mesoscale eddy, the most appropriate assimilation parameters are set up and testified in this system. A ten years mesoscale eddies simulation and comparison experiment is made, which includes two schemes: assimilation and non-assimilation. The results of comparison between two schemes and the observation show that the simulation accuracy of the assimilation scheme is much better than that of non-assimilation, which verified that the altimetry data assimilation method can improve the simulation accuracy of the mesoscale dramatically and indicates that it is possible to use this system on the forecast of mesoscale eddies in the future.

  4. On optimization of data assimilation in the HBM -circulation model

    OpenAIRE

    VÀhÀ-Piikkiö, Olga

    2015-01-01

    The purpose of this study is to develop a method for optimizing the data assimilation system of the HIROMB-BOOS -model at the Finnish Meteorological Institute by finding an optimal time interval and an optimal grid for the data assimilation. This is needed to balance the extra time the data assimilation adds to the runtime of the model and the improved accuracy it provides. Data assimilation is the process of combining observations with a numerical model to improve the accuracy of the mod...

  5. Development of airborne remote sensing data assimilation system

    International Nuclear Information System (INIS)

    In this paper, an airborne remote sensing data assimilation system for China Airborne Remote Sensing System is introduced. This data assimilation system is composed of a land surface model, data assimilation algorithms, observation data and fundamental parameters forcing the land surface model. In this data assimilation system, Variable Infiltration Capacity hydrologic model is selected as the land surface model, which also serves as the main framework of the system. Three-dimensional variation algorithm, four-dimensional variation algorithms, ensemble Kalman filter and Particle filter algorithms are integrated in this system. Observation data includes ground observations and remotely sensed data. The fundamental forcing parameters include soil parameters, vegetation parameters and the meteorological data

  6. Spatial dependence of color assimilation by the watercolor effect

    OpenAIRE

    Devinck, Frédéric; Delahunt, Peter B.; Hardy, Joseph L.; Spillmann, Lothar; Werner, John S.

    2006-01-01

    Color assimilation with bichromatic contours was quantified for spatial extents ranging from von Bezold-type color assimilation to the watercolor effect. The magnitude and direction of assimilative hue change was measured as a function of the width of a rectangular stimulus. Assimilation was quantified by hue cancellation. Large hue shifts were required to null the color of stimuli ≤ 9.3 min of arc in width, with an exponential decrease for stimuli increasing up to 7.4 deg. When stimuli were ...

  7. 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...

  8. Testbed model and data assimilation for ARM

    International Nuclear Information System (INIS)

    The objectives of this contract are to further develop and test the ALFA (AER Local Forecast and Assimilation) model originally designed at AER for local weather prediction and apply it to three distinct but related purposes in connection with the Atmospheric Radiation Measurement (ARM) program: (a) to provide a testbed that simulates a global climate model in order to facilitate the development and testing of new cloud parametrizations and radiation models; (b) to assimilate the ARM data continuously at the scale of a climate model, using the adjoint method, thus providing the initial conditions and verification data for testing parameumtions; (c) to study the sensitivity of a radiation scheme to cloud parameters, again using the adjoint method, thus demonstrating the usefulness of the testbed model. The data assimilation will use a variational technique that minimizes the difference between the model results and the observation during the analysis period. The adjoint model is used to compute the gradient of a measure of the model errors with respect to nudging terms that are added to the equations to force the model output closer to the data. The radiation scheme that will be included in the basic ALFA model makes use of a gen two-stream approximation, and is designed for vertically inhonogeneous, multiple-scattering atmospheres. The sensitivity of this model to the definition of cloud parameters will be studied. The adjoint technique will also be used to compute the sensitivities. This project is designed to provide the Science Team members with the appropriate tools and modeling environment for proper testing and tuning of new radiation models and cloud parametrization schemes

  9. 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.

  10. Nitrogen uptake and assimilation by corn roots

    International Nuclear Information System (INIS)

    The site of nitrogen uptake in the apical root zone of corn was experimentally investigated. Two experiments were performed. The one is to see the assimilation of nitrate and ammonium and the effects of low temperature on it. The 4-day-old roots were treated with 15N-labelled inorganic nitrogen of 20 ppm N in 5 x 10-4M CaSO4 solution at 30 deg. C and 0 deg. C. The other is to see the nitrogen uptake at apical root zone and the utilization of newly absorbed nitrogen at the root top. The 4-day-old roots were transferred into 5 x 10-4M CaSO4 solution containing 15N-labelled ammonium nitrate of 40 ppm N. As a result, the effect of low temperature on the nitrogen uptake appeared to be more drastic in the case of nitrate than ammonium. The 15N content of amino acids indicates that ammonium is assimilated into amino acids even at 0 deg. C, but nitrate is not. The ammonium nitrogen seemed to be absorbed at both cell dividing and elongating zones. On the other hand, nitrate nitrogen seemed to be strongly absorbed at cell elongating zone. The nitrogen in the apical part may be supplied not only by direct absorption but also by translocation from the basal part. The clear difference was found in the utilization of nitrate and ammonium nitrogen at the root top when the root was elongating. This may be due to the difference of assimilation products of inorganic nitrogen. Newly absorbed ammonium nitrogen is more utilizable for the growth of root top than nitrate nitrogen. (Iwakiri, K.)

  11. 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.

  12. Ionospheric data assimilation and forecasting during storms

    Science.gov (United States)

    Chartier, Alex T.; Matsuo, Tomoko; Anderson, Jeffrey L.; Collins, Nancy; Hoar, Timothy J.; Lu, Gang; Mitchell, Cathryn N.; Coster, Anthea J.; Paxton, Larry J.; Bust, Gary S.

    2016-01-01

    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 but does not capture all the behavior of the storms. In particular, a ridge-like enhancement over the continental USA is not predicted, indicating the importance of predicting storm time electric field behavior to the problem of ionospheric forecasting.

  13. Improving carbon model phenology using data assimilation

    Science.gov (United States)

    Exrayat, Jean-François; Smallman, T. Luke; Bloom, A. Anthony; Williams, Mathew

    2015-04-01

    Carbon cycle dynamics is significantly impacted by ecosystem phenology, leading to substantial seasonal and inter-annual variation in the global carbon balance. Representing inter-annual variability is key for predicting the response of the terrestrial ecosystem to climate change and disturbance. Existing terrestrial ecosystem models (TEMs) often struggle to accurately simulate observed inter-annual variability. TEMs often use different phenological models based on plant functional type (PFT) assumptions. Moreover, due to a high level of computational overhead in TEMs they are unable to take advantage of globally available datasets to calibrate their models. Here we describe the novel CARbon DAta MOdel fraMework (CARDAMOM) for data assimilation. CARDAMOM is used to calibrate the Data Assimilation Linked Ecosystem Carbon version 2 (DALEC2) model using Bayes' Theorem within a Metropolis Hastings - Markov Chain Monte Carlo (MH-MCMC). CARDAMOM provides a framework which combines knowledge from observations, such as remotely sensed LAI, and heuristic information in the form of Ecological and Dynamical Constraints (EDCs). The EDCs are representative of real world processes and constrain parameter interdependencies and constrain carbon dynamics. We used CARDAMOM to bring together globally spanning datasets of LAI and the DALEC2 and DALEC2-GSI models. These analyses allow us to investigate the sensitivity ecosystem processes to the representation of phenology. DALEC2 uses an analytically solved model of phenology which is invariant between years. In contrast DALEC2-GSI uses a growing season index (GSI) calculated as a function of temperature, vapour pressure deficit (VPD) and photoperiod to calculate bud-burst and leaf senescence, allowing the model to simulate inter-annual variability in response to climate. Neither model makes any PFT assumptions about the phenological controls of a given ecosystem, allowing the data alone to determine the impact of the meteorological

  14. Effective actions for statistical data assimilation

    International Nuclear Information System (INIS)

    Data assimilation is a problem in estimating the fixed parameters and state of a model of an observed dynamical system as it receives inputs from measurements passing information to the model. Using methods developed in statistical physics, we present effective actions and equations of motion for the mean orbits associated with the temporal development of a dynamical model when it has errors, there is uncertainty in its initial state, and it receives information from noisy measurements. If there are statistical dependences among errors in the measurements they can be included in this approach.

  15. 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...... degree of parameterization which results in significant model uncertainty which cannot be reduced much due to observations often being scarce and often taking the form of point measurements. Data assimilation shows great promise for use in integrated hydrological models , as it allows for observations to...

  16. 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...... the radioactive contamination in inhabited areas, predictions of a large scale deposition model have been combined with hypothetical measurements on a local scale. In both examples the accuracy of the model predictions has been improved and the uncertainties have been reduced. © EDP Sciences, 2010...

  17. 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.

  18. 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.

  19. 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.

  20. An ionospheric assimilation model along a meridian plane

    Science.gov (United States)

    Le, Huijun; Liu, Libo; Ren, Zhipeng; Hu, Lianhuan; Chen, Yiding; Wan, Weixing

    2016-07-01

    In this paper, we developed a two-dimensional ionospheric assimilation model that assimilates the observations of peak electron density of F2-layer (NmF2) and the peak height of F2-layer (hmF2) derived from five ionosonde stations along the 120°E meridian, using three-dimensional variation techniques (3DVAR) based on a physics-based ionosphere theoretical model. The assimilation system can well produce the assimilated results along the 120°E meridian plane by using the data of NmF2 and hmF2 at five ionosonde stations from Mohe (52.0°N) to Sanya (18.3°N). The root mean square error (RMSE) between the analysis results of the assimilation model and the ionosonde observations is much lower than that between the results from international reference ionosphere (IRI) and the ionosonde observations. In addition, we carried out the assimilation test by taking the IRI results as the observations to check the assimilated results in the regions without observations. The assimilated result in the southern hemisphere (RMSE=0.29) is much worse than that in the northern hemisphere (RMSE=0.10) because no observations in the southern hemisphere were used. If the data derived from the four ionosonde stations in Australia are used, the assimilated result in the southern hemisphere would be much more accurate. In addition to NmF2 and hmF2, the assimilation model can also adjust the total electron content (TEC). The RMSE between the TEC after assimilation and the observed GPS TEC is much lower than that between the TEC from the IRI model and the observed GPS TEC.

  1. Data Assimilation by delay-coordinate nudging

    Science.gov (United States)

    Pazo, Diego; Lopez, Juan Manuel; Carrassi, Alberto

    2016-04-01

    A new nudging method for data assimilation, delay-coordinate nudging, is presented. Delay-coordinate nudging makes explicit use of present and past observations in the formulation of the forcing driving the model evolution at each time-step. Numerical experiments with a low order chaotic system show that the new method systematically outperforms standard nudging in different model and observational scenarios, also when using an un-optimized formulation of the delay-nudging coefficients. A connection between the optimal delay and the dominant Lyapunov exponent of the dynamics is found based on heuristic arguments and is confirmed by the numerical results, providing a guideline for the practical implementation of the algorithm. Delay-coordinate nudging preserves the easiness of implementation, the intuitive functioning and the reduced computational cost of the standard nudging, making it a potential alternative especially in the field of seasonal-to-decadal predictions with large Earth system models that limit the use of more sophisticated data assimilation procedures.

  2. Hormonal control of sulfate uptake and assimilation.

    Science.gov (United States)

    Koprivova, Anna; Kopriva, Stanislav

    2016-08-01

    Plant hormones have a plethora of functions in control of plant development, stress response, and primary metabolism, including nutrient homeostasis. In the plant nutrition, the interplay of hormones with responses to nitrate and phosphate deficiency is well described, but relatively little is known about the interaction between phytohormones and regulation of sulfur metabolism. As for other nutrients, sulfate deficiency results in modulation of root architecture, where hormones are expected to play an important role. Accordingly, sulfate deficiency induces genes involved in metabolism of tryptophane and auxin. Also jasmonate biosynthesis is induced, pointing to the need of increase the defense capabilities of the plants when sulfur is limiting. However, hormones affect also sulfate uptake and assimilation. The pathway is coordinately induced by jasmonate and the key enzyme, adenosine 5'-phosphosulfate reductase, is additionally regulated by ethylene, abscisic acid, nitric oxid, and other phytohormones. Perhaps the most intriguing link between hormones and sulfate assimilation is the fact that the main regulator of the response to sulfate starvation, SULFATE LIMITATION1 (SLIM1) belongs to the family of ethylene related transcription factors. We will review the current knowledge of interplay between phytohormones and control of sulfur metabolism and discuss the main open questions. PMID:26810064

  3. Climate Field Reconstruction via Data Assimilation

    Science.gov (United States)

    Steiger, N. J.; Hakim, G. J.; Steig, E. J.; Battisti, D. S.; Roe, G.

    2012-12-01

    We illustrate the utility of a data assimilation (DA) technique in producing climate field reconstructions (CFR) of surface temperature. Our "off-line" DA technique assimilates time-averaged observations with a novel Ensemble Square-root Filter. We perform several pseudoproxy experiments with both general circulation model (GCM) and 20th Century Reanalysis data (20CR). These experiments highlight some advantages of our DA approach with reference to a conventional CFR approach based on Principal Component Analysis. We find important agreements as well as disparities: both approaches reproduce GCM global mean temperature with similar magnitudes and correlation coefficients; DA improves GCM temperature reconstructions around isolated pseudoproxies; DA has much higher correlations in the global mean and in most geographical regions when reconstructing 20CR temperatures. Our results suggest that pseudoproxy experiments which rely solely on GCM data may give a false impression of reconstruction skill. Additionally, we present CFRs with our DA approach based on actual proxy data and discuss the results. While we employ "off-line" DA via the "state-update" step, our DA technique can be extended to "live" climate models.

  4. Continuous data assimilation with stochastically noisy data

    International Nuclear Information System (INIS)

    We analyse the performance of a data-assimilation algorithm based on a linear feedback control when used with observational data that contains measurement errors. Our model problem consists of dynamics governed by the two-dimensional incompressible Navier–Stokes equations, observational measurements given by finite volume elements or nodal points of the velocity field and measurement errors which are represented by stochastic noise. Under these assumptions, the data-assimilation algorithm consists of a system of stochastically forced Navier–Stokes equations. The main result of this paper provides explicit conditions on the observation density (resolution) which guarantee explicit asymptotic bounds, as the time tends to infinity, on the error between the approximate solution and the actual solutions which is corresponding to these measurements, in terms of the variance of the noise in the measurements. Specifically, such bounds are given for the limit supremum, as the time tends to infinity, of the expected value of the L2-norm and of the H1 Sobolev norm of the difference between the approximating solution and the actual solution. Moreover, results on the average time error in mean are stated. (paper)

  5. Phosphorus stress effects on assimilation of nitrate

    International Nuclear Information System (INIS)

    An experiment was conducted to investigate alterations in uptake and assimilation of NO3- by phosphorus-stressed plants. Young tobacco plants (Nicotiana tabacum [L.], cv NC 2326) growing in solution culture were derived of an external phosphorus (P) supply for 12 days. On selected days, plants were exposed to 15NO3- during the 12 hour light period to determine changes in NO3- assimilation as the P deficiency progressed. Decreased whole-plant growth was evident after 3 days of P deprivation and became more pronounced with time, but root growth was unaffected until after day 6. Uptake of 15NO3- per gram root dry weight and translocation of absorbed 15NO3- out of the root were noticeably restricted in -P plants by day 3, and effects on both increased in severity with time. Whole-plant reduction of 15NO3- and 15N incorporation into insoluble reduced-N in the shoot decreased after day 3. Although the P limitation was associated with a substantial accumulation of amino acids in the shoot, there was no indication of excessive accumulation of soluble reduced-15N in the shoot during the 12 hour 15NO3- exposure periods. The results indicate that alterations in NO3- transport processes in the root system are the primary initial responses limiting synthesis of shoot protein in P-stressed plants. Elevated amino acid levels evidently are associated with enhanced degradation of protein rather than inhibition of concurrent protein synthesis

  6. Using data assimilation for systematic model improvement

    Science.gov (United States)

    Lang, Matthew S.; van Leeuwen, Peter Jan; Browne, Phil

    2016-04-01

    In Numerical Weather Prediction parameterisations are used to simulate missing physics in the model. These can be due to a lack of scientific understanding or a lack of computing power available to address all the known physical processes. Parameterisations are sources of large uncertainty in a model as parameter values used in these parameterisations cannot be measured directly and hence are often not well known, and the parameterisations themselves are approximations of the processes present in the true atmosphere. Whilst there are many efficient and effective methods for combined state/parameter estimation in data assimilation, such as state augmentation, these are not effective at estimating the structure of parameterisations. A new method of parameterisation estimation is proposed that uses sequential data assimilation methods to estimate errors in the numerical models at each space-time point for each model equation. These errors are then fitted to predetermined functional forms of missing physics or parameterisations, that are based upon prior information. The method picks out the functional form, or that combination of functional forms, that bests fits the error structure. The prior information typically takes the form of expert knowledge. We applied the method to a one-dimensional advection model with additive model error, and it is shown that the method can accurately estimate parameterisations, with consistent error estimates. It is also demonstrated that state augmentation is not successful. The results indicate that this new method is a powerful tool in systematic model improvement.

  7. Assimilation of GRACE Hydrology Data: Recent Progress

    Science.gov (United States)

    Rodell, Matthew; Li, Bailing; Zaitchik, Benjamin; Reichle, Rolf; van Dam, Tonie

    2010-05-01

    GRACE is unique among remote sensing systems in its ability to detect changes in total terrestrial water storage (TWS; the sum of groundwater, soil moisture, surface water, and snow). However, three factors have limited the value of GRACE data for hydrological research and applications: (1) low spatial and temporal resolutions relative to other observations; (2) product latency; (3) TWS is an unfamiliar quantity. Land surface models (LSMs) simulate the redistribution of water and energy incident on the land surface, but their accuracy is a function of the quality of the input data used to parameterize and force the models, the model developers' understanding of the physics involved, and the simplifications necessary to depict the Earth system economically. The advantages of GRACE and other observations and LSMs can be harnessed via data assimilation, which synthesizes discontinuous and imperfect observations with our knowledge of physical processes, as represented in a LSM. The model fills observational gaps, provides quality control, and enables data from disparate measurement systems to be merged, while the observations anchor the results in reality. Previously we have demonstrated assimilation of GRACE derived TWS anomalies into the Catchment LSM over the Mississippi River basin, using an Ensemble Smoother approach. We are now improving that capability, extending it to other parts of the world, evaluating the results, and applying the technique for scientific research and socially relevant applications. Here we describe recent progress in these areas.

  8. Assimilative Mapping of Interhemispheric Polar Ionospheric Electrodynamics

    Science.gov (United States)

    Matsuo, T.; Richmond, A. D.; Knipp, D. J.; McGranaghan, R. M.

    2015-12-01

    The Earth's main magnetic field is asymmetric between hemispheres due to its non-dipolar component, leading to various hemispherical differences in the coupling among the solar wind, magnetosphere and ionosphere. Manifestation of the asymmetric coupling through different electrodynamic parameters reported in past studies is considerably diverse. To fill the gap in our current understanding, obtained so far by analyzing individual parameters separately and comparing statistical behaviors of the parameters, we quantify the degree of instantaneous inter-hemispheric imbalance of electromagnetic energy deposition (Poynting flux), field-aligned currents, and convection electric fields though global and self-consistent analysis of electrodynamic variables at both polar regions, by means of data assimilation. Inter-hemispheric assimilative maps of different high-latitude electrodynamical parameters are obtained from simultaneous analysis of multiple types of space-based and ground-based observations made available though the AMPERE, SuperDARN, SuperMAG and DMSP programs with rigorous consideration of the uncertainty associated with each observation.

  9. Data assimilation in the decision support system RODOS

    DEFF Research Database (Denmark)

    Rojas-Palma, C.; Madsen, H.; Gering, F.; Puch, R.; Turcanu, C.; Astrup, P.; Müller, H.; Richter, K.; Zheleznyak, M.; Treebushny, D.; Kolomeev, M.; Kamaev, D.; Wynn, H.

    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...

  10. A Cross-Linguistic Examination of Assimilation Context Effects

    Science.gov (United States)

    Gow, David W. Jr.; Im, Aaron M.

    2004-01-01

    Language-specific phonological processes routinely affect the pronunciation of words spoken in context, but do not appear to interfere with spoken word recognition. Five experiments are presented in which native and non-speakers of Hungarian and Korean monitored for segments in assimilated and non-assimilated control contexts related to…

  11. An adaptive ensemble Kalman filter for soil moisture data assimilation

    Science.gov (United States)

    In a 19-year twin experiment for the Red-Arkansas river basin we assimilate synthetic surface soil moisture retrievals into the NASA Catchment land surface model. We demonstrate how poorly specified model and observation error parameters affect the quality of the assimilation products. In particul...

  12. SST data assimilation experiments using an adaptive variational method

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An adaptive variational data assimilation method is proposed by Zhu and Kamachi[1]. This method can adaptively adjust the model state without knowing explicitly the model error covariance matrix. The method enables very flexible ways to form some reduced order problems. A proper reduced order problem not only reduces computational burden but also leads to corrections that are more consistent with the model dynamics that trends to produce better forecast. These features make the adaptive variational method a good candidate for SST data assimilation because the model error of an ocean model is usually difficult to estimate. We applied this method to an SST data assimilation problem using the LOTUS data sets and an ocean mixed layer model (Mellor-Yamada level 2.5). Results of assimilation experiments showed good skill of improvement subsurface temperatures by assimilating surface observation alone.

  13. Are modeling uncertainties properly considered in neutronics data assimilation analysis?

    International Nuclear Information System (INIS)

    Data assimilation employs the body of available experimental data to reduce nuclear data uncertainties. The assimilation algorithm is based on the assumption that nuclear data constitute the major source of simulation uncertainty, implying that modeling uncertainties are negligible. This manuscript questions this basic assumption and proposes a further extension of the assimilation algorithm to allow one to differentiate between modeling and nuclear data-introduced uncertainties. This is particularly important when the objective of the analysis is to improve predictions at reactor conditions that are not covered by the available body of experimental data, e.g., prediction of hot reactor conditions based on the assimilation of cold benchmark experiments. We employ representative BWR pin cell models to demonstrate the challenges of the current assimilation algorithm, and compare its performance to the proposed algorithm. (author)

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

    Science.gov (United States)

    Anderson, Jeffrey; Raeder, Kevin; Hoar, Tim; Collins, Nancy; Romine, Glen; Barre, Jerome; Gaubert, Benjamin; Arellano, Ave; Wuerth, Stephanie

    2016-04-01

    The Data Assimilation Research Testbed (DART) is a community facility for ensemble data assimilation developed and supported by the National Center for Atmospheric Research. DART provides a comprehensive suite of software, documentation, examples and tutorials that can be used for ensemble data assimilation research, operations, and education. Scientists and software engineers from the Data Assimilation Research Section at NCAR are available to actively support DART users who want to use existing DART products or develop their own new 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: 1). Using CAM/DART to understand whether OCO-2 Total Precipitable Water observations can be useful in numerical weather prediction. 2). Impacts of the synergistic use of Infra-red CO retrievals (MOPITT, IASI) in CAMCHEM/DART assimilations. 3). Assimilation and Analysis of Observations of Amazonian Biomass Burning Emissions by MOPITT (aerosol optical depth), MODIS (carbon monoxide) and MISR (plume height). 4). Long term evaluation of the chemical response of MOPITT-CO assimilation in CAM-CHEM/DART OSSEs for satellite planning and emission inversion capabilities. 5). Improved forward observation operators for land models that have multiple land use/land cover segments in a single grid cell, enabling studies of the inherent variability in a single gridcell. Future enhancements are also discussed: 1). The CICE component of the Community Earth System Model will be added to the existing suite of components, which can be used for data assimilation. 2). Fully coupled

  15. Diverse Applications of Occultation Data in Ozone Assimilation

    Science.gov (United States)

    Markowitz, A.; Uttley, P.

    2005-01-01

    Ozone profiles from solar occultation instruments provide invaluable information that can be used to evaluate the quality of assimilated ozone fields, from case studies to long-term phenomena. Occultation data can also be applied to include physical constraints while developing components of an assimilation system. Conversely, assimilation of occultation data can help in their validation, and it provides a framework for evaluation of the impact of occultation data on constraining global ozone fields within models. We illustrate these diverse applications by a series of examples using the ozone assimilation system at NASA/Goddard. In a case study, low ozone in the lower stratosphere due to transport of air from the Tropics to northern high latitudes that was captured by assimilation of Aura Microwave Limb Sounder (MLS) and Solar Backscatter Ultraviolet (SBUV) data, was found to agree with SAGE III data. For long-term monitoring, the quality of a multi-year SBUV-only assimilation was evaluated using monthly-mean time series of POAM, HALOE, and SAGE I1 data. We found realism in the representation of the annual cycle in ozone and in some aspects of interannual variability. Assimilation of POAM data was shown to improve the representation of lower stratospheric ozone, especially over Antarctica. More recently, we assimilated ILAS II ozone data in order to help in their validation. Solar occultation data are used to estimate parameters in a new model for forecast error variances that is being developed. These examples demonstrate the importance of occultation data for ozone assimilation, and potential of assimilation to increase the impact and the value of occultation data.

  16. Incremental 4D-VAR assimilation scheme based on Lorenz model

    Institute of Scientific and Technical Information of China (English)

    WANG Xidong; XU Dongfeng; XU Xiaohua

    2008-01-01

    Four-dimensional variational(4D-VAR) data assimilation method is a perfect data assimilation solution in theory, but the compu- tational issue is quite difficult in operational implementation. The incremental 4D-VAR assimilation scheme is set up in order to re- duce the computational cost. It is shown that the accuracy of the observations, the length of the assimilation window and the choice of the first guess have an important influence on the assimilation outcome through the contrast experiment. Compared with the standard 4D-VAR assimilation scheme, the incremental 4D-VAR assimilation scheme shows its advantage in the computation speed through an assimilation experiment.

  17. Effects of sample density on the assimilation performance of an explicit four-dimensional variational data assimilation method

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The concepts of sample sphere radius and sample density are proposed in this paper to help illustrate that different vector transformations result in diverse sample density with the same sample ensemble, which finally affects their assimilation performance. Several numerical experiments using a onedimensional (1-D) soil water equation and synthetic observations are conducted to evaluate this new theory in land data assimilation.

  18. Ensemble Data Assimilation Without Ensembles: Methodology and Application to Ocean Data Assimilation

    Science.gov (United States)

    Keppenne, Christian L.; Rienecker, Michele M.; Kovach, Robin M.; Vernieres, Guillaume

    2013-01-01

    Two methods to estimate background error covariances for data assimilation are introduced. While both share properties with the ensemble Kalman filter (EnKF), they differ from it in that they do not require the integration of multiple model trajectories. Instead, all the necessary covariance information is obtained from a single model integration. The first method is referred-to as SAFE (Space Adaptive Forecast error Estimation) because it estimates error covariances from the spatial distribution of model variables within a single state vector. It can thus be thought of as sampling an ensemble in space. The second method, named FAST (Flow Adaptive error Statistics from a Time series), constructs an ensemble sampled from a moving window along a model trajectory. The underlying assumption in these methods is that forecast errors in data assimilation are primarily phase errors in space and/or time.

  19. The dynamic radiation environment assimilation model (DREAM)

    International Nuclear Information System (INIS)

    The Dynamic Radiation Environment Assimilation Model (DREAM) is a 3-year effort sponsored by the US Department of Energy to provide global, retrospective, or real-time specification of the natural and potential nuclear radiation environments. The DREAM model uses Kalman filtering techniques that combine the strengths of new physical models of the radiation belts with electron observations from long-term satellite systems such as GPS and geosynchronous systems. DREAM includes a physics model for the production and long-term evolution of artificial radiation belts from high altitude nuclear explosions. DREAM has been validated against satellites in arbitrary orbits and consistently produces more accurate results than existing models. Tools for user-specific applications and graphical displays are in beta testing and a real-time version of DREAM has been in continuous operation since November 2009.

  20. The dynamic radiation environment assimilation model (DREAM)

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, Geoffrey D [Los Alamos National Laboratory; Koller, Josef [Los Alamos National Laboratory; Tokar, Robert L [Los Alamos National Laboratory; Chen, Yue [Los Alamos National Laboratory; Henderson, Michael G [Los Alamos National Laboratory; Friedel, Reiner H [Los Alamos National Laboratory

    2010-01-01

    The Dynamic Radiation Environment Assimilation Model (DREAM) is a 3-year effort sponsored by the US Department of Energy to provide global, retrospective, or real-time specification of the natural and potential nuclear radiation environments. The DREAM model uses Kalman filtering techniques that combine the strengths of new physical models of the radiation belts with electron observations from long-term satellite systems such as GPS and geosynchronous systems. DREAM includes a physics model for the production and long-term evolution of artificial radiation belts from high altitude nuclear explosions. DREAM has been validated against satellites in arbitrary orbits and consistently produces more accurate results than existing models. Tools for user-specific applications and graphical displays are in beta testing and a real-time version of DREAM has been in continuous operation since November 2009.

  1. Transgenic plants that exhibit enhanced nitrogen assimilation

    Science.gov (United States)

    Coruzzi, Gloria M.; Brears, Timothy

    1999-01-01

    The present invention relates to a method for producing plants with improved agronomic and nutritional traits. Such traits include enhanced nitrogen assimilatory and utilization capacities, faster and more vigorous growth, greater vegetative and reproductive yields, and enriched or altered nitrogen content in vegetative and reproductive parts. More particularly, the invention relates to the engineering of plants modified to have altered expression of key enzymes in the nitrogen assimilation and utilization pathways. In one embodiment of the present invention, the desired altered expression is accomplished by engineering the plant for ectopic overexpression of one of more the native or modified nitrogen assimilatory enzymes. The invention also has a number of other embodiments, all of which are disclosed herein.

  2. The Assimilation Process of Mexican Immigrants in New York City: From Assimilation to Integration

    OpenAIRE

    González Salazar, Ada Elvira

    2003-01-01

    This thesis is a study of the assimilation process of Mexican immigrants in New York City, taking as a case study the work of Tepeyac Association of New York. This case was chosen because Tepeyac Association has been able to mobilize the largest number of Mexican immigrants in that city, serving as a liaison between them and the City's social, economic and political life. The hypothesis is that Mexican immigrants' ideal relation to American life, as compared to that of earli...

  3. Improving information assimilation by modeling warfighter context

    Science.gov (United States)

    Zaientz, Jack D.; Wood, Scott D.; Hawkins, Robert L.

    2005-05-01

    In order to wage successful campaigns, the next generation of intelligence analysts and battle commanders will need to assimilate an enormous amount of information that will come from a wide range of heterogeneous data sources. Complicating this problem further is the fact that warfighters need to be able to manage information in an environment of rapidly changing events and priorities. The consequence of not addressing this problem, or not addressing it as effectively as hostile forces do, is a potential loss of assets, personnel, or tactical advantage. To design effective information displays there needs to be an extensible framework that models the warfighters context including characteristics of the information sources being displayed, the current Intelligence Surveillance Reconnaissance (ISR) picture or Common Operating Picture (COP), the warfighters current state and task, and the state of the information display. BINAH (Battlespace Information and Notification through Adaptive Heuristics) uses an agent-based modeling approach coupled with research into temporal and spatial reasoning, novel display management techniques, and development of a formal high-level language for describing model-based information configuration. The result is an information configuration pipeline designed to provide perceptual and cognitive analysis support to Air Force analysts engaged in Time-Critical Targeting target nomination. It has been integrated with the Air Force Research Laboratory's (AFRL) XML-based Joint Battlespace Infosphere (JBI) combat information management system and combines JBI delivered sensor data with a local user model and display strategies to configure a geospatial information display. The BINAH framework will provide a firm grounding for developing new C4ISR displays that maximize the ability of warfighters to assimilate the information presented.

  4. Assorted morphosynthesis: access to multi-faceted nano-architectures from a super-responsive dual π-functional amphiphilic construct.

    Science.gov (United States)

    Asthana, Deepak; Shukla, Jyoti; Dana, Srikanta; Rani, Varsha; Ajayakumar, M R; Rawat, Kamla; Mandal, Kalyanashis; Yadav, Premlata; Ghosh, Subhasis; Mukhopadhyay, Pritam

    2015-10-25

    An electronically segmented amphiphile was created by conjugating two π-functional units hydroxyquinoline and naphthalenediimide (HQ/NDI) for the first time. The differential electrostatic potential of the π-surfaces, H-bonding units, etc. trigger a manifold response and direct the assembly of a unique collection of seven diverse nano-architectures. Chiral assembly, distinct classes of fibers, 3-D sheets, and metallo-spheres/fibrils with μM levels of Co/Cu/Zn(ii) ions emerged from this new approach of assorted morphosynthesis under ambient conditions. PMID:26194349

  5. Assimilation of stratospheric ozone in the chemical transport model STRATAQ

    Directory of Open Access Journals (Sweden)

    B. Grassi

    2004-09-01

    Full Text Available We describe a sequential assimilation approach useful for assimilating tracer measurements into a three-dimensional chemical transport model (CTM of the stratosphere. The numerical code, developed largely according to Kha00, uses parameterizations and simplifications allowing assimilation of sparse observations and the simultaneous evaluation of analysis errors, with reasonable computational requirements. Assimilation parameters are set by using χ2 and OmF (Observation minus Forecast statistics. The CTM used here is a high resolution three-dimensional model. It includes a detailed chemical package and is driven by UKMO (United Kingdom Meteorological Office analyses. We illustrate the method using assimilation of Upper Atmosphere Research Satellite/Microwave Limb Sounder (UARS/MLS ozone observations for three weeks during the 1996 antarctic spring. The comparison of results from the simulations with TOMS (Total Ozone Mapping Spectrometer measurements shows improved total ozone fields due to assimilation of MLS observations. Moreover, the assimilation gives indications on a possible model weakness in reproducing polar ozone values during springtime.

  6. Recent Developments in Helioseismic Analysis Methods and Solar Data Assimilation

    CERN Document Server

    Schad, Ariane; Duvall, Tom L; Roth, Markus; Vorontsov, Sergei V

    2016-01-01

    We review recent advances and results in enhancing and developing helioseismic analysis methods and in solar data assimilation. In the first part of this paper we will focus on selected developments in time-distance and global helioseismology. In the second part, we review the application of data assimilation methods on solar data. Relating solar surface observations as well as helioseismic proxies with solar dynamo models by means of the techniques from data assimilation is a promising new approach to explore and to predict the magnetic activity cycle of the Sun.

  7. Assimilation characteristics of vanadium ferroalloys in liquid steel

    International Nuclear Information System (INIS)

    The assimilation characteristics of various vanadium ferroalloys were identified in a ''dynamic way'' using the load cell technique. The ferrovanadium alloys which have a vanadium content less than 68 wt % belong to class 1 ferroalloys. They utilize a melting mechanism during their assimilation in liquid steel. The ferrovanadium alloys which have a vanadium content greater than 68 wt % belong to class 2 ferroalloys. These follow a dissolution mechanism during their assimilation in liquid steel. Their mass transfer kinetics is at least seven times slower than the previously mentioned ferrovanadium alloys

  8. Assimilative Learning with the Aid of Cognitive Maps

    Directory of Open Access Journals (Sweden)

    D. Läge

    2008-06-01

    Full Text Available Assimilative learning is understood asintegrating new information into existing knowledge orcognitive structures without restructuring the currentschema. If new information causes inconsistencies, cognitiveefforts are necessary to reorganize or to accommodate theold knowledge. Thus, assimilative learning is more efficientand economic. Nonetheless a stable and most notably acorrect memory representation which “spans” theknowledge space is essential. The current article highlightsthe logic of assimilative learning and shows how buildingelaborately a basic structure as well as the assimilativeintegration of new information can be eased with the aid ofcognitive maps. Such a didactical scenario can be easilyimplemented in the field of eLearning and thus, isadaptively and automatically supporting the learningprocess.

  9. 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

  10. 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.

  11. The assimilation of elements ingested by marine copepods

    International Nuclear Information System (INIS)

    The efficiency with which a variety of ingested elements (Ag, Am, C, Cd, P, S, Se, and Zn) were assimilated in marine calanoid copepods fed uniformly radiolabeled diatoms ranged from 0.9% for Am to 97.1% for Se. Assimilation efficiencies were directly related to the cytoplasmic content of the diatoms. This relation indicates that the animals obtained nearly all their nutrition from this source. The results suggest that these zooplankton, which have short gut residence times, have developed a gut lining and digestive strategy that provides for assimilation of only soluble material. Because the fraction of total cellular protein in the cytoplasm of the diatoms increased markedly with culture age, copepods feeding on senescent cells should obtain more protein than those feeding on rapidly dividing cells. Elements that are appreciably incorporated into algal cytoplasm and assimilated in zooplankton should be recycled in surface waters and have longer oceanic residence times than elements bound to cell surfaces

  12. 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...

  13. 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....

  14. 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)...

  15. 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...

  16. 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....

  17. Assimilating compact phase space retrievals of atmospheric composition with WRF-Chem/DART: a regional chemical transport/ensemble Kalman filter data assimilation system

    Science.gov (United States)

    Mizzi, Arthur P.; Arellano, Avelino F., Jr.; Edwards, David P.; Anderson, Jeffrey L.; Pfister, Gabriele G.

    2016-03-01

    This paper introduces the Weather Research and Forecasting Model with chemistry/Data Assimilation Research Testbed (WRF-Chem/DART) chemical transport forecasting/data assimilation system together with the assimilation of compact phase space retrievals of satellite-derived atmospheric composition products. WRF-Chem is a state-of-the-art chemical transport model. DART is a flexible software environment for researching ensemble data assimilation with different assimilation and forecast model options. DART's primary assimilation tool is the ensemble adjustment Kalman filter. WRF-Chem/DART is applied to the assimilation of Terra/Measurement of Pollution in the Troposphere (MOPITT) carbon monoxide (CO) trace gas retrieval profiles. Those CO observations are first assimilated as quasi-optimal retrievals (QORs). Our results show that assimilation of the CO retrievals (i) reduced WRF-Chem's CO bias in retrieval and state space, and (ii) improved the CO forecast skill by reducing the Root Mean Square Error (RMSE) and increasing the Coefficient of Determination (R2). Those CO forecast improvements were significant at the 95 % level. Trace gas retrieval data sets contain (i) large amounts of data with limited information content per observation, (ii) error covariance cross-correlations, and (iii) contributions from the retrieval prior profile that should be removed before assimilation. Those characteristics present challenges to the assimilation of retrievals. This paper addresses those challenges by introducing the assimilation of compact phase space retrievals (CPSRs). CPSRs are obtained by preprocessing retrieval data sets with an algorithm that (i) compresses the retrieval data, (ii) diagonalizes the error covariance, and (iii) removes the retrieval prior profile contribution. Most modern ensemble assimilation algorithms can efficiently assimilate CPSRs. Our results show that assimilation of MOPITT CO CPSRs reduced the number of observations (and assimilation computation

  18. Hybrid Data Assimilation without Ensemble Filtering

    Science.gov (United States)

    Todling, Ricardo; Akkraoui, Amal El

    2014-01-01

    The Global Modeling and Assimilation Office is preparing to upgrade its three-dimensional variational system to a hybrid approach in which the ensemble is generated using a square-root ensemble Kalman filter (EnKF) and the variational problem is solved using the Grid-point Statistical Interpolation system. As in most EnKF applications, we found it necessary to employ a combination of multiplicative and additive inflations, to compensate for sampling and modeling errors, respectively and, to maintain the small-member ensemble solution close to the variational solution; we also found it necessary to re-center the members of the ensemble about the variational analysis. During tuning of the filter we have found re-centering and additive inflation to play a considerably larger role than expected, particularly in a dual-resolution context when the variational analysis is ran at larger resolution than the ensemble. This led us to consider a hybrid strategy in which the members of the ensemble are generated by simply converting the variational analysis to the resolution of the ensemble and applying additive inflation, thus bypassing the EnKF. Comparisons of this, so-called, filter-free hybrid procedure with an EnKF-based hybrid procedure and a control non-hybrid, traditional, scheme show both hybrid strategies to provide equally significant improvement over the control; more interestingly, the filter-free procedure was found to give qualitatively similar results to the EnKF-based procedure.

  19. Kimberlite ascent by assimilation-fuelled buoyancy.

    Science.gov (United States)

    Russell, James K; Porritt, Lucy A; Lavallée, Yan; Dingwell, Donald B

    2012-01-19

    Kimberlite magmas have the deepest origin of all terrestrial magmas and are exclusively associated with cratons. During ascent, they travel through about 150 kilometres of cratonic mantle lithosphere and entrain seemingly prohibitive loads (more than 25 per cent by volume) of mantle-derived xenoliths and xenocrysts (including diamond). Kimberlite magmas also reputedly have higher ascent rates than other xenolith-bearing magmas. Exsolution of dissolved volatiles (carbon dioxide and water) is thought to be essential to provide sufficient buoyancy for the rapid ascent of these dense, crystal-rich magmas. The cause and nature of such exsolution, however, remains elusive and is rarely specified. Here we use a series of high-temperature experiments to demonstrate a mechanism for the spontaneous, efficient and continuous production of this volatile phase. This mechanism requires parental melts of kimberlite to originate as carbonatite-like melts. In transit through the mantle lithosphere, these silica-undersaturated melts assimilate mantle minerals, especially orthopyroxene, driving the melt to more silicic compositions, and causing a marked drop in carbon dioxide solubility. The solubility drop manifests itself immediately in a continuous and vigorous exsolution of a fluid phase, thereby reducing magma density, increasing buoyancy, and driving the rapid and accelerating ascent of the increasingly kimberlitic magma. Our model provides an explanation for continuous ascent of magmas laden with high volumes of dense mantle cargo, an explanation for the chemical diversity of kimberlite, and a connection between kimberlites and cratons. PMID:22258614

  20. Variational assimilation of Lagrangian data in oceanography

    CERN Document Server

    Nodet, Maëlle

    2008-01-01

    We consider the assimilation of Lagrangian data into a primitive equations circulation model of the ocean at basin scale. The Lagrangian data are positions of floats drifting at fixed depth. We aim at reconstructing the four-dimensional space-time circulation of the ocean. This problem is solved using the four-dimensional variational technique and the adjoint method. In this problem the control vector is chosen as being the initial state of the dynamical system. The observed variables, namely the positions of the floats, are expressed as a function of the control vector via a nonlinear observation operator. This method has been implemented and has the ability to reconstruct the main patterns of the oceanic circulation. Moreover it is very robust with respect to increase of time-sampling period of observations. We have run many twin experiments in order to analyze the sensitivity of our method to the number of floats, the time-sampling period and the vertical drift level. We compare also the performances of th...

  1. 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.

  2. Simplified aerosol modeling for variational data assimilation

    Directory of Open Access Journals (Sweden)

    F. Chevallier

    2009-06-01

    Full Text Available We have developed a simplified aerosol model together with its tangent linear and adjoint versions for variational assimilation of aerosol optical depth with the aim to optimize aerosol emissions over the globe. The model was derived from the general circulation model LMDz; it groups together the 24 aerosol species simulated in LMDz into 4 species, namely gaseous precursors, fine mode aerosols, coarse mode desert dust and coarse mode sea salt. The emissions have been kept as in the original model. Modifications, however, were introduced in the computation of aerosol optical depth and in the processes of sedimentation, dry and wet deposition and sulfur chemistry to ensure consistency with the new set of species and their composition.

    The simplified model successfully manages to reproduce the main features of the aerosol distribution in LMDz. Differences between the original and simplified models are mainly associated to the new deposition and sedimentation velocities consistent with the definition of species in the simplified model and the simplification of the sulfur chemistry. Furthermore, simulated aerosol optical depth remains within the variability of AERONET observations for all aerosol types and all sites throughout most of the year.

    Sensitivity analyses with the tangent linear version show that the simplified sulfur chemistry is the dominant process responsible for the strong non-linearity of the model.

  3. Assimilate partitioning in avocado, Persea americana

    International Nuclear Information System (INIS)

    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 13μCi of 14CO2. 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 14C-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 14C. Source leaves for single non-abscising fruitlets retained 3X more 14C-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

  4. Discharge assimilation in a distributed flood forecasting model

    OpenAIRE

    RABUFFETTI, D

    2006-01-01

    In the field of operational flood forecasting, uncertainties linked to hydrological forecast are often crucial. In this work, data assimilation techniques are employed to improve hydrological variable estimates coming from numerical simulations using all the available real-time water level measurements. The proposed assimilation scheme, a classical Kalman filter extension to non-linear systems, is applied in a rainfall-runoff distributed model based on the SCS-CN approach. The complex hydrolo...

  5. Assimilation of Remote Sensed Data for River Hydraulic Simulations

    OpenAIRE

    Monnier, Jerome; Honnorat, Marc; Lai, Xijun; Le Dimet, François-Xavier

    2007-01-01

    In river hydraulics, observations are available only in very small quantities. Consequently, in order to take full advantages of data assimilation for river and flooding models, we think to use remote sensing data which can bring extra information on the flow. Here, we present two studies related to variationnal data assimilation methods for river flows when remote sensed data are available: 1) a real flood event (Moselle river) where we identify inflow discharge when one satellite image and ...

  6. Enhanced ensemble-based 4DVar scheme for data assimilation

    OpenAIRE

    Yang, Yin; Robinson, Cordelia; Heitz, Dominique; Mémin, Etienne

    2015-01-01

    International audience Ensemble based optimal control schemes combine the components of ensemble Kalman filters and variational data assimilation (4DVar). They are trendy because they are easier to implement than 4DVar. In this paper, we evaluate a modified version of an ensemble based optimal control strategy for image data assimilation. This modified method is assessed with a Shallow Water model combined with synthetic data and original incomplete experimental depth sensor observations. ...

  7. Von Bezold assimilation effect reverses in stereoscopic conditions

    OpenAIRE

    Soranzo, Alessandro; Galmonte, Alessandro; Agostini, Tiziano

    2010-01-01

    Lightness contrast and lightness assimilation are opposite phenomena: in contrast, grey targets appear darker when bordering bright surfaces (inducers) rather than dark ones; in assimilation, the opposite occurs. The question is: which visual process favours the occurrence of one phenomenon over the other? Researchers provided three answers to this question. The first asserts that both phenomena are caused by peripheral processes; the second attributes their occurrence to centr...

  8. Sensitivity tests for an ensemble Kalman filter for aerosol assimilation

    OpenAIRE

    N. A. J. Schutgens; T. Miyoshi; Takemura, T.; Nakajima, T

    2010-01-01

    We present sensitivity tests for a global aerosol assimilation system utilizing AERONET observations of AOT (aerosol optical thickness) and AAE (aerosol Ångström exponent). The assimilation system employs an ensemble Kalman filter which requires optimization of three numerical parameters: ensemble size nens, local patch size npatch and inflation factor ρ. In addition, experiments are performed to test ...

  9. Economic assimilation of immigrants : a comparison between Norway and Canada

    OpenAIRE

    2007-01-01

    The economic assimilation of immigrants in Norway is analyzed in this thesis. Since Norway and Canada have different immigration policies, the economic assimilations of immigrants in these two countries are compared. Unlike Norway, Canada uses a “point system” to target economic and demographic growth which results in a large class of economic immigrants. The entry effect, the years effect, the cohort effect and the period effect, as defined in previous academic literature, are considered....

  10. Absorptive Capacity and Contextual Factors that Influence Green IT Assimilation

    OpenAIRE

    Vanessa A Cooper; Alemayehu Molla

    2014-01-01

    The first wave of research in Green IT has often focused on organisational adoption. As Green IT matures in organisations it is important to look beyond adoption and to investigate the assimilation of Green IT. To this end we draw from and compare two theories – contextual theory and absorptive capacity – and investigate which of the two theories better explains the level of Green IT assimilation in organisations. Results from an international survey of 148 large organisations show that both ...

  11. Socioeconomic assimilation and wealth accumulation of migrants in Australia

    OpenAIRE

    Vaira-Lucero, Matias; Nahm, Daehoon; Tani, Massimiliano

    2012-01-01

    This paper investigates to what extent the wealth accumulation of immigrants is explained by their degree of assimilation, defined as the immigrants' capacity to become more similar over time to the local people in terms of their norms, values, behaviours, and socioeconomic characteristics. The existing practice to measure assimilation is the use of a time-dimensioned variable like years since migration, which reflects the individual's adaptation to the host country through the implied acquis...

  12. Variational Data Assimilation for Optimizing Boundary Conditions in Ocean Models

    CERN Document Server

    Kazantsev, Christine; Tolstykh, Mikhail

    2016-01-01

    The review describes the development of ideas Gury Ivanovich Marchuk in the field of variational data assimilation for ocean models applied in particular in coupled models for long-range weather forecasts. Particular attention is paid to the optimization of boundary conditions on rigid boundaries. As idealized and realistic model configurations are considered. It is shown that the optimization allows us to determine the most sensitive model operators and bring the model solution closer to the assimilated data.

  13. Data assimilation: Particle filter and artificial neural networks

    International Nuclear Information System (INIS)

    The goal of this work is to present the performance of the Neural Network Multilayer Perceptrons trained to emulate a Particle Filter in the context of data assimilation. Techniques for data assimilation are applied for the Lorenz system, which presents a strong nonlinearity and chaotic nature. The cross validation method was used for training the network. Good results were obtained applying the multilayer perceptrons neural network.

  14. ALTERED STATES OF LITERATURE: SHAMANIC ASSIMILATION AND ROMANTIC INSPIRATION

    OpenAIRE

    Marcel de Lima Santos

    2012-01-01

    This article deals with the connections between the assimilation of certain shamanic practices related to Romantic inspiration in English literature. The interest in the world of altered states of consciousness as a manifestation of the sacred is typical among Romantic writers in nineteenth-century England. These writers in fact sought the manifestation of the world of dreams by means of ingesting substances that alter consciousness, thus assimilating a practice that is likewise and primarily...

  15. Autoregressive Models of Background Errors for Chemical Data Assimilation

    OpenAIRE

    Constantinescu, Emil M.; Chai, Tianfeng; Sandu, Adrian; Gregory R. Carmichael

    2006-01-01

    The task of providing an optimal analysis of the state of the atmosphere requires the development of dynamic data-driven systems that efficiently integrate the observational data and the models. Data assimilation (DA) is the process of adjusting the states or parameters of a model in such a way that its outcome (prediction) is close, in some distance metric, to observed (real) states. It is widely accepted that a key ingredient of successful data assimilation is a realistic estimation of th...

  16. Endogenous assimilation and immigrant adjustment in longitudinal data

    OpenAIRE

    Beenstock, Michael; Chiswick, Barry R; Paltiel, Ari

    2005-01-01

    We create a longitudinal data set by matching immigrants in Israel's censuses for 1983 and 1995. These panel data reject the Immigrant Assimilation Hypothesis (IAH), which predicts that immigrants with shorter durations in 1983 should have experienced faster earnings growth between 1983 and 1995. By contrast, IAH is corroborated by the synthetic cohort methodology (SCM) over the same period. We suggest that SCM is subject to survivor bias, which increases the apparent degree of assimilation. ...

  17. Labor Market Assimilation of Recent Immigrants in Spain

    OpenAIRE

    Amuedo-Dorantes, Catalina; de la Rica, Sara

    2006-01-01

    This paper provides a preliminary analysis of the employment and occupational assimilation of recent immigrant waves to the Spanish labor market as their residencies lengthen. Using Spanish data from the 2001 Population Census and the 2002 Earnings Structure Survey, we find evidence of immigrant employment and occupational assimilation significantly varying by gender, origin and educational attainment. For instance, EU15 immigrants do not display an employment or occupational gap with respect...

  18. Immigrant quality and assimilation: A review of the US literature

    OpenAIRE

    T. Paul Schultz

    1998-01-01

    Empirical research on US immigrants is reviewed: their productivity and assimilation; their contribution and use of public services; and their impact on native Americans. I discuss the characteristics of cohorts of immigrants that enter the United States at different times, and then quantify the assimilation of immigrants, typically in terms of economic productivity of immigrants compared with natives. Few have found quantifiable negative effects of immigrants on native wages or unemployment ...

  19. Does better pre-migration performance accelerate immigrants' wage assimilation?

    OpenAIRE

    Hirsch, Boris; Jahn, Elke J.; Toomet, Ott; Hochfellner, Daniela

    2013-01-01

    This paper analyzes wage assimilation of ethnic German immigrants to Germany. We use unique administrative data that include a standardized measure of immigrants' pre-migration wage based on occupation, industry, tenure, qualification, and the German wage structure. We find that immigrants experience a substantial initial wage disadvantage compared to natives. During their first 15 years in the host country they manage to close a considerable part of this gap, though assimilation is only part...

  20. 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...

  1. How do immigrants spend their time? The process of assimilation

    OpenAIRE

    Hamermesh, Daniel S; Trejo, Stephen J.

    2010-01-01

    Using 2004-2008 data from the American Time Use Survey, we show that sharp differences between the time use of immigrants and natives become noticeable when activities are distinguished by incidence and intensity. We develop a theory of the process of assimilation – what immigrants do with their time – based on the notion that assimilating activities entail fixed costs. The theory predicts that immigrants will be less likely than natives to undertake such activities, but conditional on undert...

  2. Immigrants' Assimilation Process In A Segmented Labor Market

    OpenAIRE

    Miguel Ángel Alcobendas; Núria Rodríquez-Planas

    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...

  3. Ionian Sea circulation as clarified by assimilation of glider observations

    OpenAIRE

    Dobricic, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Pinardi, N.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Testor, P.; Send, U.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia

    2008-01-01

    Glider observations of temperature and salinity in the Ionian Sea (Eastern Mediterranean Sea), made in the period October 2004-December 2004, were assimilated into an operational forecasting model together with other in-situ and satellite observations. The impact of glider data on the estimation of the circulation is studied and it is found that the assimilation of glider data significantly improve the vertical structure of temperature and salinity fields and remove biases. The...

  4. Nitrate assimilation in plant shoots depends on photorespiration

    OpenAIRE

    Rachmilevitch, Shimon; Cousins, Asaph B.; Bloom, Arnold J.

    2004-01-01

    Photorespiration, a process that diminishes net photosynthesis by ≈25% in most plants, has been viewed as the unfavorable consequence of plants having evolved when the atmosphere contained much higher levels of carbon dioxide than it does today. Here we used two independent methods to show that exposure of Arabidopsis and wheat shoots to conditions that inhibited photorespiration also strongly inhibited nitrate assimilation. Thus, nitrate assimilation in both dicotyledonous and monocotyledono...

  5. How Do Immigrants Spend Time?: The Process of Assimilation

    OpenAIRE

    Hamermesh, Daniel S.; Stephen J. Trejo

    2010-01-01

    Using 2004-2008 data from the American Time Use Survey, we show that sharp differences between the time use of immigrants and natives become noticeable when activities are distinguished by incidence and intensity. We develop a theory of the process of assimilation--what immigrants do with their time--based on the notion that assimilating activities entail fixed costs. The theory predicts that immigrants will be less likely than natives to undertake such activities, but conditional on undertak...

  6. 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...

  7. 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. PMID:25295259

  8. Cholesterol Assimilation by Lactobacillus Probiotic Bacteria: An In Vitro Investigation

    Directory of Open Access Journals (Sweden)

    Catherine Tomaro-Duchesneau

    2014-01-01

    Full Text Available 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/1010 cfu in MRS broth. L. reuteri NCIMB 701089 assimilated over 67% (2254.70 ± 63.33 mg/1010 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.

  9. Balanced Data Assimilation For Improving Zonal Equatorial Currents

    Science.gov (United States)

    Burgers, G.; Balmaseda, M. A.; Vossepoel, F. C.; van Oldenborgh, G. J.; van Leeuwen, P. J.

    Assimilation schemes that are used for seasonal prediction can have a problem in estimating zonal velocities near the equator. This is the case for OI schemes that use density information for updating only the model density field. In some situations, this leads to a detoriation of the zonal velocity field around the equator. The problem is studied first for the assimilation of height observations in a simple linear 1.5 layer shallow-water model of the equatorial Pacific. It is found that equa- torial zonal velocities can be degraded if velocity is not updated in the assimilation procedure, even if the assimilation increments for height are spread over time. Adding updates to the zonal velocity which are related by geostrophic balance to the height updates is shown to be a simple remedy for the shallow-water model. A straightforward generalisation of the balanced data assimilation method has been implemented in the ocean circulation model of the ECMWF seasonal forecasting sys- tem. First tests are encouraging: upper-ocean surface currents are improved, and cou- pled hindcasts are improved if balanced assimilation is used for the ocean analyses.

  10. A diagnostic statistical cloud scheme for data assimilation purposes

    Science.gov (United States)

    Tompkins, A. M.; Janiskova, M.

    2003-04-01

    The task of assimilating cloud and rainfall information is steadily increasing in importance with a new generation of observing platforms. The inherent non-linearity of many cloud related processes exacerbates the archetypical assimilation dilemma. Overly simplistic schemes may not represent the physical cloud processes adequately for assimilation purposes. At the other extreme, many current cloud schemes used in forecast or climate models are simply too complex for the tangent linear and adjoint codes to be constructed. Even if the latter is achievable, the full schemes in forecast models often contain discrete switches and non linear processes to maximize forecast performance, but render the linear approximation invalid for perturbations of the magnitude of typical analysis increments. This may cause convergence problems over typical assimilation windows (currently 12 hours) in 4D variational assimilation (4DVAR). The existing ECMWF cloud scheme used in the assimilating model is deficient since there is no connection between diagnosed cloud cover, water/ice and precipitation generation. We thus present a new non-linear diagnostic cloud scheme for which the tangent linear and adjoint codes have been constructed. The scheme is based on prognostic humidity and temperature variables and a diagnostic assumption concerning subgrid variability is used to derive cloud water, ice and cover characteristics. Results using the new scheme are shown.

  11. Forecasting the Solar Photosphere's Magnetic Flux with Local Data Assimilation

    Science.gov (United States)

    Hickmann, K. S.; Godinez, H. C.; Henney, C. J.; Arge, C. N.

    2014-12-01

    Accurate forecasts of the photospheric magnetic flux are important since the photosphere provides the driving bound-ary conditions for the Corona and Solar wind which impact near Earth space weather. These space weather phenomenaeffect satellite trajectories and communication systems as well as safety on manned space missions. In this presen-tation we detail our recent improvements to the data assimilation mechanisms in the Air Force Data AssimilativePhotospheric flux Transport (ADAPT) model. These include implementation of the local ensemble transform Kalmanfilter (LETKF) for the assimilation of satellite observations. In the past non-local ensemble methods have been usedto assimilate data into photosphere models. Due to the small ensemble sizes allowed for Solar forecasts spuriouscorrelations were introduced in the sample covariance, causing model divergence from observations. With our imple-mentation of the LETKF in ADAPT this ensemble divergence has been reduced. In addition multi-scale techniqueshave been implemented in ADAPT to deal with the lack of active region creation in the photosphere model. Lackof large scale active region creation in the ADAPT model caused ensemble bias when assimilating observations ofnewly created regions using ensemble Kalman methods. Separating the scales at which active regions occur allowsobservational noise for such regions to be controlled independently. We show that our consideration of the multi-scalenature of photosphere flux transport has allowed more accurate assimilation of large active regions.

  12. A multimodel data assimilation framework via the ensemble Kalman filter

    Science.gov (United States)

    Xue, Liang; Zhang, Dongxiao

    2014-05-01

    The ensemble Kalman filter (EnKF) is a widely used data assimilation method that has the capacity to sequentially update system parameters and states as new observations become available. One noticeable feature of the EnKF is that it not only can provide real-time updates of model parameters and state variables, but also can give the uncertainty associated with them in each assimilation step. The natural system is open and complex, rendering it prone to multiple interpretations and mathematical descriptions. In this paper, a multimodel data assimilation method is proposed by embedding the EnKF into the Bayesian model averaging framework to account for the uncertainty stemming from the model itself. An illustrative example, considering both hydrogeological and groundwater flow uncertainties, is employed to demonstrate the proposed multimodel data assimilation approach via the EnKF. Results show that statistical bias and uncertainty underestimation can occur when the data assimilation process relies on a single postulated model. The posterior model weight can adjust itself dynamically in time according to its consistency with observations. The performances of log conductivity estimation and head prediction are compared to the standard EnKF method based on the postulated single model and the proposed multimodel EnKF method. Comparisons show that the multimodel EnKF performs better in terms of statistical measures, such as log score and coverage, when sufficient observations have been assimilated in this case.

  13. A comparison of two operational wave assimilation methods

    CERN Document Server

    Voorrips, A C

    1997-01-01

    A comparison is carried out between two operational wave forecasting/assimilation models for the North Sea, with the emphasis on the assimilation schemes. One model is the WAM model, in combination with an optimal interpolation method (OIP). The other model, DASWAM, consists of the third generation wave model PHIDIAS in combination with an approximate implementation of the adjoint method. In an experiment over the period February 19 - March 30, 1993, the models are driven by the same wind field (HIRLAM analysis winds), and the same observation data set is assimilated. This set consists of a) spectra from three pitch-and-roll buoys and b) Synthetic Aperture Radar (SAR) spectra from the ERS-1 satellite. Three analysis/forecast runs are performed: one without assimilation, one with assimilation of buoy measurements only, and one with all data assimilated. For validation, observations from four buoys, altimeter data from ERS-1 and Topex-Poseidon, and scatterometer data from ERS-1 are used. A detailed analysis of ...

  14. Assortment Structure, Prior Knowledge and Brand Choice%商品陈列方式、先验品牌知识与品牌选择决策--弱势品牌的视角

    Institute of Scientific and Technical Information of China (English)

    黄赞; 王新新

    2015-01-01

    Consumers tend to have a higher evaluation and purchase intention toward the products with stronger brands. Compared to foreign products, Chinese alternatives usually occupy a weaker brand position. Hence, Chinese manufacturers who want to increase market share commonly adopt a low-price strategy. However, such strategy may greatly weaken the organization’s ability to gain profits and undermine its long-term development. Moreover, low price is likely to be used by consumers as a signal of poor quality of the products. Therefore, it is important for Chinese manufacturers with weak brands to adopt new competitive strategies. The purpose of this study was to examine how assortment structure affects consumer’s brand choice. The key hypothesis was that the manufacturers with weaker brands, rather than stronger ones, could optimize the assortment structure to affect consumers’ brand choice in a retail environment. We conducted three empirical studies to test our hypotheses. In Study 1, we conducted three separated experiments to examine the impact of the assortment structure on consumers’ perceived variety of products. In particular, Study 1a explored the main effect of the assortment structure (attribute-based vs. benefit-based) on consumers’ perceived variety. Then, studies 1b and 1c composed a Chain-of-Experiments and tested the intermediate mechanism of the construal level in the causal relationship between the assortment structure and consumers’ perceived variety: Study 1b examined the impact of assortment structure on consumers’ construal level, and Study 1c tested the impact of the construal level on consumers’ perceived variety. Study 2 investigated the causal relationship between the assortment structure and consumers’ brand choice. Studies 1 and 2 adopted a one-way between-subject design. Study 3 explored the moderating effect of consumers’ prior knowledge of brand strength in the causal relationship and used a 2 (attribute-based vs. benefit

  15. A hybrid variational ensemble data assimilation for the HIgh Resolution Limited Area Model (HIRLAM)

    OpenAIRE

    N. Gustafsson; J. Bojarova; O. Vignes

    2014-01-01

    A hybrid variational ensemble data assimilation has been developed on top of the HIRLAM variational data assimilation. It provides the possibility of applying a flow-dependent background error covariance model during the data assimilation at the same time as full rank characteristics of the variational data assimilation are preserved. The hybrid formulation is based on an augmentation of the assimilation control variable with localised weights to be assigned to a set of ense...

  16. Assimilation of IRS-P4 (MSMR) meteorological data in the NCMRWF global data assimilation system

    Indian Academy of Sciences (India)

    Rupa Kamineni; S R H Rizvi; S C Kar; U C Mohanty; R K Paliwal

    2002-09-01

    Oceansat-1 was successfully launched by India in 1999, with two payloads, namely Multi-frequency Scanning Microwave Radiometer (MSMR) and Ocean Color Monitor (OCM) to study the biological and physical parameters of the ocean. The MSMR sensor is configured as an eight-channel radiometer using four frequencies with dual polarization. The MSMR data at 75km resolution from the Oceansat-I have been assimilated in the National Centre for Medium Range Weather Forecasting (NCMRWF) data assimilation forecast system. The operational analysis and forecast system at NCMRWF is based on a T80L18 global spectral model and Spectral Statistical Inter-polation (SSI) scheme for data analysis. The impact of the MSMR data is seen globally, however it is significant over the oceanic region where conventional data are rare. The dry-nature of the control analyses have been removed by utilizing the MSMR data. Therefore, the total precipitable water data from MSMR has been identified as a very crucial parameter in this study. The impact of surface wind speed from MSMR is to increase easterlies over the tropical Indian Ocean. Shifting of the positions of westerly troughs and ridges in the south Indian Ocean has contributed to reduction of temperature to around 30°S.

  17. 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.

  18. 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.

  19. 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

  20. Development of an EUV data assimilation technique for plasmasphere modeling

    International Nuclear Information System (INIS)

    Complete text of publication follows. The structure of the plasmasphere is strongly controlled by the electric field imposed on the magnetosphere. In order to model the dynamics of the plasmasphere, it is important to know the spatial structure of the electric potential in the inner magnetosphere. However, since it is difficult to know the global electric potential distribution in the magnetosphere due to the lack of observation, it is difficult to grasp the dynamics of the plasmasphere using in-situ measurements. Recently we have developed a data assimilation technique which incorporates a remote observation of energetic neutral atoms (ENAs) from the IMAGE satellite into a ring current model. This ENA data assimilation technique provides estimates of the distributions of the ring current ions and electric potential in the inner magnetosphere. The present study is conducted aiming at applying a similar approach for modeling the plasmasphere. We are now engaged in the development of a data assimilation technique for providing estimates of the spatial structures of the plasmasphere and electric potential. The estimation is performed by incorporating remote imaging data of extreme ultra-violet (EUV) from the IMAGE satellite into a simulation model of the plasmasphere. We assume the magnetospheric electric potential distribution to be unknown, and estimate it in the course of the assimilation process. The plasmaspheric ion distribution is estimated according to the estimated electric potential and the plasmasphere simulation model. At present, we are conducting data assimilation experiments using artificial EUV data sets to evaluate the EUV data assimilation approach. The experimental result suggests that the data assimilation of the EUV imaging data provides useful information for understanding the temporal and spatial variations of the plasmasphere.

  1. Impacts of data assimilation on the global ocean carbonate system

    Science.gov (United States)

    Visinelli, L.; Masina, S.; Vichi, M.; Storto, A.; Lovato, T.

    2016-06-01

    In an ocean reanalysis, historical observations are combined with ocean and biogeochemical general circulation models to produce a reconstruction of the oceanic properties in past decades. This is one possible method to better constrain the role of the ocean carbon cycle in the determination of the air-sea CO2 flux. In this work, we investigate how the assimilation of physical variables and subsequently the combined assimilation of physical data and inorganic carbon variables - namely dissolved inorganic carbon (DIC) and alkalinity - affect the modelling of the marine carbonate system and the related air-sea CO2 fluxes. The performance of the two assimilation exercises are quantitatively assessed against the assimilated DIC and alkalinity data and the independent ocean surface pCO2 observations from global datasets. We obtain that the assimilation of physical observations has contrasting effects in different ocean basins when compared with the DIC and alkalinity data: it reduces the root-mean square error against the observed pCO2 in the Atlantic and Southern oceans, while increases the model error in the North Pacific and Indian Oceans. In both cases the corrected evaporation rates are the major factor determining the changes in concentrations. The assimilation of inorganic carbon variables on top of the physical data gives a generalized improvement in the model error of inorganic carbon variables, also improving the annual mean and spatial distribution of air-sea fluxes in agreement with other published estimates. These results indicate that data assimilation of physical and inorganic carbon data does not guarantee the improvement of the simulated pCO2 in all the oceanic regions; nevertheless, errors in pCO2 are reduced by a factor corresponding to those associated with the air-sea flux formulations.

  2. The Changing Role of Education in the Marriage Market: Assortative Marriage in Canada and the United States since the 1970s

    Directory of Open Access Journals (Sweden)

    Feng Hou

    2008-07-01

    Full Text Available Whether or not relative rates of assortative marriage have been rising in the affluent democracies has been subject to considerable dispute. First, we show how the conflicting empirical findings that have fueled the debate are frequently an artifact of alternative methodological strategies for answering the question. Then, drawing on comparable census data for Canada and the United States, we examine trends in educational homogamy and intermarriage with log-linear models for all marriages among young adults under 35 over three decades. Our results show that educational homogamy, the tendency of like to marry like, has unambiguously risen in both countries since the 1970s. Rising levels of marital homogamy were the result of declining intermarriage at both ends of the educational distribution.

  3. Architecting Service Based Sensor Networks for the Intelligent Assimilation

    Directory of Open Access Journals (Sweden)

    R. S. Ponmagal

    2014-01-01

    Full Text Available The aim of this paper is to propose an architectural model for assimilating distributed sensor networks through cloud paradigm. This strategy can be applied to monitor and control the physical parameters such as temperature, pressure, and level. It is proposed to consider the use of service oriented architecture to program and deploy the sensed parameters. The service oriented architecture for sensor network has been implemented in such a way that, for every specific requirement of the monitor center, the assimilation agent invokes the services of the sensors through a registry and the specific changes in the sensed parameters are also notified as auditable event using push interaction pattern of SOA. The assimilation agent serves as an intelligent component by providing authentication services. This SOA is extended to integrate different types of sensor networks through cloud environment. Hence several sensors can be networked together to monitor different process parameters and they have been assimilated with Internet by registering them as services, hence a complete distributed assimilation environment is exploited.

  4. Data Assimilation in Hydrodynamic Models of Continental Shelf Seas

    DEFF Research Database (Denmark)

    Sørensen, Jacob Viborg Tornfeldt

    2004-01-01

    This thesis consists of seven research papers published or submitted for publication in the period 2002-2004 together with a summary report. The thesis mainly deals with data assimilation of tide gauge data in two- and three-dimensional hydrodynamic models of the continental shelf seas. Assimilat......This thesis consists of seven research papers published or submitted for publication in the period 2002-2004 together with a summary report. The thesis mainly deals with data assimilation of tide gauge data in two- and three-dimensional hydrodynamic models of the continental shelf seas....... 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...... robust state estimate. The assimilation schemes used in this work are primarily based on two ensemble based schemes, the Ensemble Kalman Filter and the Reduced Rank Square Root Kalman Filter. In order to investigate the applicability of these and derived schemes, the sensitivity to filter parameters...

  5. Kinetics of 15NH4+ assimilation in Zea mays

    International Nuclear Information System (INIS)

    Comparative studies of 15NH4+ assimilation were undertaken with a GDH1-null mutant of Zea mays and a related (but not strictly isogenic) GDH1-positive wild type from which this mutant was derived. The kinetics of 15NH4+ assimilation into free amino acids and total reduced nitrogen were monitored in both roots and shoots of 2-week-old seedlings supplied with 5 millimolar 99% (15NH4)2SO4 via the aerated root medium in hydroponic culture over a 24-h period. The GDH1-null mutant, with a 10- to 15-fold lower total root GDH activity in comparison to the wild type, was found to exhibit a 40 to 50% lower rate of 15NH4+ assimilation into total reduced nitrogen. The lower rates of 15NH4+ assimilation in the mutant was associated with lower rates of labeling of several free amino acids (including glutamate, glutamine-amino N, aspartate, asparagine-amino N, and alanine) in both roots and shoots of the mutant in comparison to the wild type. Qualitatively, these labeling kinetics appear consistent with a reduced flux of 15N via glutamate in the GDH1-null mutant. However, the responses of the two genotypes to the potent inhibitor of glutamine synthetase, methionine sulfoximine, and differences in morphology of the two genotypes (particularly a lower shoot:root ratio in the GDH1-null mutant) urge caution in concluding that GDH1 is solely responsible for these differences in ammonia assimilation rate

  6. Assimilate transfer and accumulation with in the maize pedicel

    International Nuclear Information System (INIS)

    This study was conducted to characterize assimilate transfer through the pedicel of the maize (Zea mays L.) kernel and assess this transfer process as a possible limitation to kernel dry matter accumulation. Sugar, amino acid, and 14C-assimilate unloading from the pedicel were studied following removal of the endosperm and embryo. Unloading was not affected by potassium or a 10-min treatment with p-chloromercuribenzene sulfonic acid (PCMBS), a slowly penetrating sulfhydryl group inhibitor. These observations are consistent with the recent hypothesis of passive assimilate unloading from the pedicel cells, followed by uptake into the endosperm. Sugar content of the pedicel parenchyma-placento-chalazal tissue (PPPC) of the maize kernel was measured following light periods of varying duration and following source-sink manipulation. Source-sink ratio manipulation, imposed by partial defoliation and ear removal at 12 d postpollination, did not influence PPPC sugar content 10 d after treatment. PPPC sugar content was 16-21% higher in the afternoon than in the morning. Using compartmental analysis techniques, it was determined that fluctuations in PPPC sugar content occurred primarily within the free space. These observations support the hypothesis that assimilate uptake into the endosperm, rather unloading from the pedicel, is a rate-limiting transfer process. Source-sink manipulation affected kernel number per ear, kernel weight, kernel growth rate, and stalk dry weight. On a long-term basis, PPPC sugar content was maintained at relatively constant levels by changes in kernel growth patterns, assimilate partitioning, and remobilization

  7. Assimilation of Passive and Active Microwave Soil Moisture Retrievals

    Science.gov (United States)

    Draper, C. S.; Reichle, R. H.; DeLannoy, G. J. M.; Liu, Q.

    2012-01-01

    Root-zone soil moisture is an important control over the partition of land surface energy and moisture, and the assimilation of remotely sensed near-surface soil moisture has been shown to improve model profile soil moisture [1]. To date, efforts to assimilate remotely sensed near-surface soil moisture at large scales have focused on soil moisture derived from the passive microwave Advanced Microwave Scanning Radiometer (AMSR-E) and the active Advanced Scatterometer (ASCAT; together with its predecessor on the European Remote Sensing satellites (ERS. The assimilation of passive and active microwave soil moisture observations has not yet been directly compared, and so this study compares the impact of assimilating ASCAT and AMSR-E soil moisture data, both separately and together. Since the soil moisture retrieval skill from active and passive microwave data is thought to differ according to surface characteristics [2], the impact of each assimilation on the model soil moisture skill is assessed according to land cover type, by comparison to in situ soil moisture observations.

  8. Assimilation of GNSS radio occultation observations in GRAPES

    Science.gov (United States)

    Liu, Y.; Xue, J.

    2014-07-01

    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 Enviromental Prediction) analysis. Finally, as a result of the new onboard payload of the Chinese FengYun-3 (FY-3) satellites, the research status of the RO of FY-3 satellites is also presented.

  9. Assimilation of GNSS radio occultation observations in GRAPES

    Directory of Open Access Journals (Sweden)

    Y. Liu

    2014-07-01

    Full Text Available 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 Enviromental Prediction analysis. Finally, as a result of the new onboard payload of the Chinese FengYun-3 (FY-3 satellites, the research status of the RO of FY-3 satellites is also presented.

  10. OpenDA-NEMO framework for ocean data assimilation

    Science.gov (United States)

    van Velzen, Nils; Altaf, Muhammad Umer; Verlaan, Martin

    2016-05-01

    Data assimilation methods provide a means to handle the modeling errors and uncertainties in sophisticated ocean models. In this study, we have created an OpenDA-NEMO framework unlocking the data assimilation tools available in OpenDA for use with NEMO models. This includes data assimilation methods, automatic parallelization, and a recently implemented automatic localization algorithm that removes spurious correlations in the model based on uncertainties in the computed Kalman gain matrix. We have set up a twin experiment where we assimilate sea surface height (SSH) satellite measurements. From the experiments, we can conclude that the OpenDA-NEMO framework performs as expected and that the automatic localization significantly improves the performance of the data assimilation algorithm by successfully removing spurious correlations. Based on these results, it looks promising to extend the framework with new kinds of observations and work on improving the computational speed of the automatic localization technique such that it becomes feasible to include large number of observations.

  11. Assimilating uncertain, dynamic and intermittent streamflow observations in hydrological models

    Science.gov (United States)

    Mazzoleni, Maurizio; Alfonso, Leonardo; Chacon-Hurtado, Juan; Solomatine, Dimitri

    2015-09-01

    Catastrophic floods cause significant socio-economical losses. Non-structural measures, such as real-time flood forecasting, can potentially reduce flood risk. To this end, data assimilation methods have been used to improve flood forecasts by integrating static ground observations, and in some cases also remote sensing observations, within water models. Current hydrologic and hydraulic research works consider assimilation of observations coming from traditional, static sensors. At the same time, low-cost, mobile sensors and mobile communication devices are becoming also increasingly available. The main goal and innovation of this study is to demonstrate the usefulness of assimilating uncertain streamflow observations that are dynamic in space and intermittent in time in the context of two different semi-distributed hydrological model structures. The developed method is applied to the Brue basin, where the dynamic observations are imitated by the synthetic observations of discharge. The results of this study show how model structures and sensors locations affect in different ways the assimilation of streamflow observations. In addition, it proves how assimilation of such uncertain observations from dynamic sensors can provide model improvements similar to those of streamflow observations coming from a non-optimal network of static physical sensors. This can be a potential application of recent efforts to build citizen observatories of water, which can make the citizens an active part in information capturing, evaluation and communication, helping simultaneously to improvement of model-based flood forecasting.

  12. Regulating effect of density and top-dressing time of nitrogen fertilizer on 14C-assimilation and distribution of assimilate of large-spike cultivar of wheat

    International Nuclear Information System (INIS)

    The results of present study indicated that laminas, especially first and second lamina from top, were the most important assimilating organs of large-spike cultivar of wheat at flag leaf stage. More than ninety percent of assimilate of a single stem was made by laminas, while the assimilate amount of sheathes only accounted for less than 10%. Not only assimilating rate but also transport and distribution efficiency was declined when the density was too high. Deferring top-dressing time of nitrogen fertilizer could increase both assimilate amount and transport and distribution efficiency

  13. 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)

  14. 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...... 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....... 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...

  15. Assimilation of HF radar data into the SWAN wave model

    Science.gov (United States)

    Siddons, L. A.; Wyatt, L. R.; Wolf, J.

    2009-05-01

    Data assimilation is a method used for optimally combining information to improve forecasting and model parameters. Three data assimilation algorithms are investigated and used for assimilating HF radar data into the SWAN wave model. The schemes under consideration are the Ensemble Kalman Filter, Ensemble Optimal Interpolation and a Three-Dimensional Variational scheme. Two approaches for updating the ocean wave spectrum are considered which consist of describing the spectrum using integral wave parameters of the whole spectrum and wave parameters within various frequency bands. The results show improvement in the wave parameters at the buoy location for the 3DVAR and ENS-OI scheme. The EnKF only shows good performance in one of the considered runs which leads to a conclusion that the methods used for calculating the errors for the EnKF scheme need further analysis.

  16. Data assimilation on atmospheric dispersion of radioactive materials

    DEFF Research Database (Denmark)

    Drews, Martin

    2006-01-01

    During a nuclear accident in which radionuclides are released to the atmosphere, off-site dose assessment using atmospheric dispersion models play an important role in facilitating optimized interventions, i.e. for mitigating the radiological consequences. By using data assimilation methods......, 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...... greatly improved dose rate assessment. The Kalman filter method is found to be computationally efficient and therefore has the potential of becoming an efficient operational assimilation tool for nuclear emergency management. Empirical dispersion data are crucial in order to evaluate dose rate models and...

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

    Science.gov (United States)

    Long, Joseph W.; Plant, Nathaniel G.

    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.

  18. Impact of Assimilated and Interactive Aerosol on Tropical Cyclogenesis

    Science.gov (United States)

    Reale, O.; Lau, K. M.; daSilva, A.; Matsui, T.

    2014-01-01

    This article investigates the impact 3 of Saharan dust on the development of tropical cyclones in the Atlantic. A global data assimilation and forecast system, the NASA GEOS-5, is used to assimilate all satellite and conventional data sets used operationally for numerical weather prediction. In addition, this new GEOS-5 version includes assimilation of aerosol optical depth from the Moderate Resolution Imaging Spectroradiometer (MODIS). The analysis so obtained comprises atmospheric quantities and a realistic 3-d aerosol and cloud distribution, consistent with the meteorology and validated against Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and CloudSat data. These improved analyses are used to initialize GEOS-5 forecasts, explicitly accounting for aerosol direct radiative effects and their impact on the atmospheric dynamics. Parallel simulations with/without aerosol radiative effects show that effects of dust on static stability increase with time, becoming highly significant after day 5 and producing an environment less favorable to tropical cyclogenesis.

  19. Data Assimilation in Integrated and Distributed Hydrological Models

    DEFF Research Database (Denmark)

    Zhang, Donghua

    point of view, different assimilation methodologies and techniques have been developed or customized to better serve hydrological assimilation. From the application point of view, real data and real-world complex catchments are used with the focus of investigating the models’ improvements with data......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 to...

  20. Deterministic treatment of model error in geophysical data assimilation

    CERN Document Server

    Carrassi, Alberto

    2015-01-01

    This chapter describes a novel approach for the treatment of model error in geophysical data assimilation. In this method, model error is treated as a deterministic process fully correlated in time. This allows for the derivation of the evolution equations for the relevant moments of the model error statistics required in data assimilation procedures, along with an approximation suitable for application to large numerical models typical of environmental science. In this contribution we first derive the equations for the model error dynamics in the general case, and then for the particular situation of parametric error. We show how this deterministic description of the model error can be incorporated in sequential and variational data assimilation procedures. A numerical comparison with standard methods is given using low-order dynamical systems, prototypes of atmospheric circulation, and a realistic soil model. The deterministic approach proves to be very competitive with only minor additional computational c...

  1. [Post-photosynthetic use of labeled assimilates in fiber flax].

    Science.gov (United States)

    Chikov, V I; Avvakumova, N Iu; Bakirova, G G

    2003-01-01

    The distribution of 14C in various tissues of fiber flax was assayed 1, 17, and 21 days after 30-min assimilation of 14CO@2 by the whole rapidly growing plant. Polymeric photosynthetic products were largely hydrolyzed in the 14C-donor part of the shoot and the hydrolysates were transported upward. The content of 14C in pigments and lipids of the donor leaves (that absorbed 14CO2) was significantly higher than that in the 14C-acceptor ones. An additional nitrogen feeding decreased the labeled sucrose: hexose ratio and inhibited transport of the assimilates from both 14C-donor and acceptor leaves. 14C transported to the shoot tip was largely used for synthesis of poorly soluble proteins (extractable with alkali and Triton X-100) in the acceptor tissues. In the donor part of the shoot, particularly in the bast, cellulose was mainly synthesized from the "new" assimilates. PMID:12942752

  2. Assimilation of stream discharge for flood forecasting: Updating a semidistributed model with an integrated data assimilation scheme

    Science.gov (United States)

    Li, Yuan; Ryu, Dongryeol; Western, Andrew W.; Wang, Q. J.

    2015-05-01

    Real-time discharge observations can be assimilated into flood models to improve forecast accuracy; however, the presence of time lags in the routing process and a lack of methods to quantitatively represent different sources of uncertainties challenge the implementation of data assimilation techniques for operational flood forecasting. To address these issues, an integrated error parameter estimation and lag-aware data assimilation (IEELA) scheme was recently developed for a lumped model. The scheme combines an ensemble-based maximum a posteriori (MAP) error estimation approach with a lag-aware ensemble Kalman smoother (EnKS). In this study, the IEELA scheme is extended to a semidistributed model to provide for more general application in flood forecasting by including spatial and temporal correlations in model uncertainties between subcatchments. The result reveals that using a semidistributed model leads to more accurate forecasts than a lumped model in an open-loop scenario. The IEELA scheme improves the forecast accuracy significantly in both lumped and semidistributed models, and the superiority of the semidistributed model remains in the data assimilation scenario. However, the improvements resulting from IEELA are confined to the outlet of the catchment where the discharge observations are assimilated. Forecasts at "ungauged" internal locations are not improved, and in some instances, even become less accurate.

  3. 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

  4. 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

  5. Photosynthetic carbon assimilation in C3- and C4-plants

    International Nuclear Information System (INIS)

    The photosynthetic mechanisms of plants have become to be well understood by the use of radioactive and stable isotopes. This review included the distribution of 14C in photosynthetic intermediates by assimilation with 14CO2, resultant CO2 receptors, Calvin cycle, C4 photosynthetic pathway, differences between the photosynthetic pathway for C3-plants and that for C4-plants, photorespiration, glycolate pathway, the yield of photosynthetic quanta and the relationship between assimilation with 14CO2 and 13C values. Reference was made to the photosynthetic mechanism in 13C-NMR follow-up with 13CO2. (Chiba, N.)

  6. Oxidation and Assimilation of Atmospheric Methane by Soil Methane Oxidizers

    OpenAIRE

    Roslev, P.; Iversen, N.; Henriksen, K.

    1997-01-01

    The metabolism of atmospheric methane in a forest soil was studied by radiotracer techniques. Maximum (sup14)CH(inf4) oxidation (163.5 pmol of C cm(sup-3) h(sup-1)) and (sup14)C assimilation (50.3 pmol of C cm(sup-3) h(sup-1)) occurred at the A(inf2) horizon located 15 to 18 cm below the soil surface. At this depth, 31 to 43% of the atmospheric methane oxidized was assimilated into microbial biomass; the remaining methane was recovered as (sup14)CO(inf2). Methane-derived carbon was incorporat...

  7. What Can Data Assimilation Tell Us about Our Models?

    Science.gov (United States)

    Nearing, G. S.

    2015-12-01

    Data assimilation is a process of combining information from imperfect models and imperfect observations. To the extent that models used for data assimilation are probabilistic to account for epistemic uncertainty, we expect data assimilation to attenuate the effect of model errors on estimates of hydrologic states and fluxes. Intuitively, if data assimilation can mitigate model deficiencies, we would expect it to be informative of the nature of these deficiencies. We address two related questions. The first is about how to store information gained via data assimilation into the structure of the model so that this information is not lost outside the period of observation. We show the general (theoretical) strategy for storing this information, and propose a practical algorithm based on the EnFK. Doing this results in improved forecasts of energy and carbon fluxes from land surface models, as well as improved estimates of streamflow in a rainfall-runoff model. Storing information in a model structure is done purely by statistical analysis of DA innovations, and so provides no insight about the adequacy of model hypotheses. We show that this type of insight can be gained by measuring how data assimilation changes the way information moves within the model. By treating the model as an information processing system, we can visualize explicitly how assimilating observations changes strengths and time-scales of couplings between modeled variables. The insight is that measuring Shannon-type information fluxes instead of mass and energy fluxes allows us to relate any variable with any other at any time-scale. We produce a concise set of statistics that are easily interpreted and directly highlight how DA effectively changes the way that the model behaves. We applied these techniques to the Noah LSM after assimilating both in situ (FluxNet, SCAN) and remote sensing (AMSR-E, MODIS) observations. Results indicate that major deficiencies in the way that Noah translates

  8. 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

  9. Satra, Sanskritisation and Assamese Society: Understanding Social Assimilation

    Directory of Open Access Journals (Sweden)

    Anupal Saikia

    2013-07-01

    Full Text Available In Assam, vaishnavism has been constantly playing a significant role in the process of assimilating diverse elements-indigenous and non-indigenous into Assamese culture. With the initiatives of Satra Institution, which is the greatest contribution of Neo-Vaishnavism of Assam the process of assimilating the non-Hindus to the Hindu fold started with new spirit. Satras play a vital role in the life as well as in the formation of Assamese society. In this paper an attempt is made to understand the role of Satra in legitimizing and popularizing the process of Sanskritisation in Assam, which was started long years back in the Brahmaputra Valley.

  10. Assimilation of LAI time-series in crop production models

    Science.gov (United States)

    Kooistra, Lammert; Rijk, Bert; Nannes, Louis

    2014-05-01

    Agriculture is worldwide a large consumer of freshwater, nutrients and land. Spatial explicit agricultural management activities (e.g., fertilization, irrigation) could significantly improve efficiency in resource use. In previous studies and operational applications, remote sensing has shown to be a powerful method for spatio-temporal monitoring of actual crop status. As a next step, yield forecasting by assimilating remote sensing based plant variables in crop production models would improve agricultural decision support both at the farm and field level. In this study we investigated the potential of remote sensing based Leaf Area Index (LAI) time-series assimilated in the crop production model LINTUL to improve yield forecasting at field level. The effect of assimilation method and amount of assimilated observations was evaluated. The LINTUL-3 crop production model was calibrated and validated for a potato crop on two experimental fields in the south of the Netherlands. A range of data sources (e.g., in-situ soil moisture and weather sensors, destructive crop measurements) was used for calibration of the model for the experimental field in 2010. LAI from cropscan field radiometer measurements and actual LAI measured with the LAI-2000 instrument were used as input for the LAI time-series. The LAI time-series were assimilated in the LINTUL model and validated for a second experimental field on which potatoes were grown in 2011. Yield in 2011 was simulated with an R2 of 0.82 when compared with field measured yield. Furthermore, we analysed the potential of assimilation of LAI into the LINTUL-3 model through the 'updating' assimilation technique. The deviation between measured and simulated yield decreased from 9371 kg/ha to 8729 kg/ha when assimilating weekly LAI measurements in the LINTUL model over the season of 2011. LINTUL-3 furthermore shows the main growth reducing factors, which are useful for farm decision support. The combination of crop models and sensor

  11. 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. PMID:24443631

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    The present study introduces a nowcast scheme that assimilates radar extrapolation data (RED) into a nowcasting version of the high resolution limited area model (HIRLAM) numerical weather prediction (NWP) model covering the area of Denmark. The RED are based on the Co-TREC (tracking radar echoes...... 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...

  13. Comparative analysis of various real-time data assimilation approaches for assimilating streamflow into a hydrologic routing model

    Science.gov (United States)

    Noh, Seong Jin; Mazzoleni, Maurizio; Lee, Haksu; Liu, Yuqiong; Seo, Dong Jun; Solomatine, Dimitri

    2016-04-01

    Reliable water depth estimation is an extremely important issue in operational early flood warning systems. Different water system models have been implemented in the last decades, and, in parallel, data assimilation approaches have been introduced in order to reduce the uncertainty of such models. The goal of this study is to compare the performances of a distributed hydrologic routing model with streamflow assimilation using six different data assimilation methods, including direct insertion, nudging, Kalman filter, Ensemble Kalman filter, Asynchronous Ensemble Kalman filter and variational method. The model used in this study is a 3-parameter Muskingum (O'Donnell 1985) which was implemented in the Trinity River, within the Dallas-Fort-Worth Metroplex area in Texas, USA. The first methodological step is to discretize the river reach into multiple 1-km sub-reaches in order to estimate water depth in a distributed fashion. Then, different data assimilation approaches were implemented using the state-space approach formulation of the Muskingum model proposed by Georgakakos (1990). Finally, streamflow observations were assimilated at two points where flow sensors are located. The results of this work pointed out that assimilation of streamflow observations can noticeably improve the hydrologic routing model prediction and that ensemble definition is particularly important for both Ensemble Kalman filter and Asynchronous Ensemble Kalman filter. This study is part of the FP7 European Project WeSenseIt Citizen Water Observatory (www.http://wesenseit.eu/) and NSF Project Integrated Sensing and Prediction of urban Water for Sustainable Cities (http://ispuw.uta.edu/nsf)

  14. Operational Assimilation of glider temperature and salinity in a mesoscale flow field: Eastern Mediterranean test case

    OpenAIRE

    Hayes, Daniel R.; Dobricic, Srdjan; Gildor, Hezi

    2016-01-01

    An operational data assimilation system for the Eastern Mediterranean is described and evaluated for a 6-month twin experiment. In the assimilative run, glider profiles of temperature and salinity are assimilated daily into a high resolution ocean forecast, after an initial spin up of one week. In the control run, the same initial and boundary conditions are used to produce an operational forecast, but without assimilation of in situ data. While both runs were similar for most of the time and...

  15. Assimilation of Immigrants: Implications for Human Capital Accumulation of the Second Generation

    OpenAIRE

    Slobodan Djajic

    2004-01-01

    Immigrants assimilate in various dimensions at different rates. Moreover, in each of these dimensions they assimilate at rates that may differ from those of their children. The purpose of this paper is to examine how the pace of assimilation of immigrants in various dimensions affects the rate of human capital accumulation of immigrant children. It is argued that rapid assimilation in certain dimensions serves to increase the rate of human capital accumulation of the second generation, while ...

  16. Cervical Myelopathy Secondary to Atlanto-occipital Assimilation: The Usefulness of the Simple Decompressive Surgery

    OpenAIRE

    Kim, Kang Rae; Lee, Young Min; Kim, Young Zoon; Cho, Yong Woon; Kim, Joon Soo; Kim, Kyu Hong; Lee, In Chang

    2013-01-01

    Atlanto-occipital assimilation is one of the most common osseous anomalies observed at the craniocervical junction. Most patients with atlas assimilation show no symptom, but some have neurological problems such as myelopathy that may require surgical treatment. Occipitocervical fusion may be required if atlato-occipital assimilation is accompanied by occipito-axial instability. However, in cases of symptomatic atlas assimilation with minor cord compression without instability, simple decompr...

  17. Employment assimilation of immigrants in the Netherlands: dip and catchup by source country

    OpenAIRE

    Aslan Zorlu; Joop Hartog

    2012-01-01

    Using two Dutch labour force surveys, we compare employment assimilation of immigrants by source country, after ranking countries by presumed social-cultural distance to The Netherlands. We test this ranking of human capital transferability on the ranking by initial performance dip at entry as an immigrant and speed of assimilation as measured by the slope on years-since-migration. We also test the predicted association between entry gap and speed of assimilation (faster assimilation if the i...

  18. Effect of high temperature on transportation of assimilate from wheat flag leaf during grain filling stage

    International Nuclear Information System (INIS)

    The effect of high temperature (30 degree C and 40 degree C) on the transportation of 14C-assimilate from wheat flag leaf during grain filling stage were studied by using a living crop multiple-probe measurer. The results are as follows: at high temperature, the assimilating efficiency of flag leaf was reduced and the transportation of 14C-assimilate was in disorder. The accumulation of assimilate in grain was inhibited, which resulted in the significant decrease of grain weight

  19. Music playlist generation by assimilating GMMs into SOMs

    NARCIS (Netherlands)

    Balkema, Wietse; Heijden, van der Ferdi

    2010-01-01

    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 su

  20. 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, an...

  1. 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.

  2. A framework for variational data assimilation with superparameterization

    Science.gov (United States)

    Grooms, I.; Lee, Y.

    2015-10-01

    Superparameterization (SP) is a multiscale computational approach wherein a large scale atmosphere or ocean model is coupled to an array of simulations of small scale dynamics on periodic domains embedded into the computational grid of the large scale model. SP has been successfully developed in global atmosphere and climate models, and is a promising approach for new applications, but there is currently no practical data assimilation framework that can be used with these models. The authors develop a 3D-Var variational data assimilation framework for use with SP; the relatively low cost and simplicity of 3D-Var in comparison with ensemble approaches makes it a natural fit for relatively expensive multiscale SP models. To demonstrate the assimilation framework in a simple model, the authors develop a new system of ordinary differential equations similar to the two-scale Lorenz-'96 model. The system has one set of variables denoted {Yi}, with large and small scale parts, and the SP approximation to the system is straightforward. With the new assimilation framework the SP model approximates the large scale dynamics of the true system accurately.

  3. The Perception of Assimilation in Newly Learned Novel Words

    Science.gov (United States)

    Snoeren, Natalie D.; Gaskell, M. Gareth; Di Betta, Anna Maria

    2009-01-01

    The present study investigated the mechanisms underlying perceptual compensation for assimilation in novel words. During training, participants learned canonical versions of novel spoken words (e.g., "decibot") presented in isolation. Following exposure to a second set of novel words the next day, participants carried out a phoneme monitoring…

  4. 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…

  5. Coarse-grained sensitivity for multiscale data assimilation

    CERN Document Server

    Sugiura, Nozomi

    2015-01-01

    We show that the effective average action and its gradient are useful for solving multiscale data assimilation problems. We also present a procedure for numerically evaluating the gradient of the effective average action, and demonstrate that the variational problem for slow degrees of freedom can be solved properly using the "effective gradient."

  6. 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…

  7. 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,…

  8. Formate Assimilation: The Metabolic Architecture of Natural and Synthetic Pathways.

    Science.gov (United States)

    Bar-Even, Arren

    2016-07-19

    Formate may become an ideal mediator between the physicochemical and biological realms, as it can be produced efficiently from multiple available sources, such as electricity and biomass, and serve as one of the simplest organic compounds for providing both carbon and energy to living cells. However, limiting the realization of formate as a microbial feedstock is the low diversity of formate-fixing enzymes and thereby the small number of naturally occurring formate-assimilation pathways. Here, the natural enzymes and pathways supporting formate assimilation are presented and discussed together with proposed synthetic routes that could permit growth on formate via existing as well as novel formate-fixing reactions. By considering such synthetic routes, the diversity of metabolic solutions for formate assimilation can be expanded dramatically, such that different host organisms, cultivation conditions, and desired products could be matched with the most suitable pathway. Astute application of old and new formate-assimilation pathways may thus become a cornerstone in the development of sustainable strategies for microbial production of value-added chemicals. PMID:27348189

  9. 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…

  10. 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.

  11. Assimilation versus Multiculturalism: Bilingual Education and the Latino Challenge

    Science.gov (United States)

    Burdick-Will, Julia; Gomez, Christina

    2006-01-01

    This article analyzes the public rhetoric during the November 2002 vote over bilingual education in Colorado and Massachusetts. We argue that the neoassimilationist views displayed in both states represent a new step in the evolution of assimilation theory and ideology--one that has adapted to both the current immigrant environment and to…

  12. The optimality of potential rescaling approaches in land data assimilation

    Science.gov (United States)

    It is well-known that systematic differences exist between modeled and observed realizations of hydrological variables like soil moisture. Prior to data assimilation, these differences must be removed in order to obtain an optimal analysis. A number of rescaling approaches have been proposed for rem...

  13. New data assimilation system DNDAS for high-dimensional models

    Science.gov (United States)

    Qun-bo, Huang; Xiao-qun, Cao; Meng-bin, Zhu; Wei-min, Zhang; Bai-nian, Liu

    2016-05-01

    The tangent linear (TL) models and adjoint (AD) models have brought great difficulties for the development of variational data assimilation system. It might be impossible to develop them perfectly without great efforts, either by hand, or by automatic differentiation tools. In order to break these limitations, a new data assimilation system, dual-number data assimilation system (DNDAS), is designed based on the dual-number automatic differentiation principles. We investigate the performance of DNDAS with two different optimization schemes and subsequently give a discussion on whether DNDAS is appropriate for high-dimensional forecast models. The new data assimilation system can avoid the complicated reverse integration of the adjoint model, and it only needs the forward integration in the dual-number space to obtain the cost function and its gradient vector concurrently. To verify the correctness and effectiveness of DNDAS, we implemented DNDAS on a simple ordinary differential model and the Lorenz-63 model with different optimization methods. We then concentrate on the adaptability of DNDAS to the Lorenz-96 model with high-dimensional state variables. The results indicate that whether the system is simple or nonlinear, DNDAS can accurately reconstruct the initial condition for the forecast model and has a strong anti-noise characteristic. Given adequate computing resource, the quasi-Newton optimization method performs better than the conjugate gradient method in DNDAS. Project supported by the National Natural Science Foundation of China (Grant Nos. 41475094 and 41375113).

  14. 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

  15. 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

  16. Better constraints on the sea-ice state using global sea-ice data assimilation

    Directory of Open Access Journals (Sweden)

    P. Mathiot

    2012-06-01

    Full Text Available Short-term and decadal sea-ice prediction systems need a realistic initial state, generally obtained using ice-ocean model simulations with data assimilation. However, only sea-ice concentration and velocity data are currently assimilated. In this work, an Ensemble Kalman Filter system is used to assimilate observed ice concentration and freeboard (i.e. thickness of emerged sea ice data into a global coupled ocean–sea-ice model. The impact and effectiveness of our data assimilation system is assessed in two steps: firstly, through the assimilation of synthetic data (i.e., model-generated data and, secondly, through the assimilation of satellite data. While ice concentrations are available daily, freeboard data used in this study are only available during six one-month periods spread over 2005–2007. Our results show that the simulated Arctic and Antarctic sea-ice extents are improved by the assimilation of synthetic ice concentration data. Assimilation of synthetic ice freeboard data improves the simulated sea-ice thickness field. Using real ice concentration data enhances the model realism in both hemispheres. Assimilation of ice concentration data significantly improves the total hemispheric sea-ice extent all year long, especially in summer. Combining the assimilation of ice freeboard and concentration data leads to better ice thickness, but does not further improve the ice extent. Moreover, the improvements in sea-ice thickness due to the assimilation of ice freeboard remain visible well beyond the assimilation periods.

  17. The primal application research of figure assimilation theory in the nuclear accident consequence forecast

    International Nuclear Information System (INIS)

    The deepgoing research of figure assimilation theory promotes many subjects' rapid development. This article outlooks the application of figure assimilation technique in the nuclear accident consequence forecast. The nuclear accident consequence forecast is a complicated system which needs rapidity and precision, so it is quiet difficult. but after the insertion of figure assimilation, it pushes on one step about the question. (authors)

  18. Comparison between AATSR and MODIS AOD and assimilation in a regional chemistry transport model

    NARCIS (Netherlands)

    Schoemaker, R.M.; Leeuw, G. de; Builtjes, P.; Schaap, M.; Timmermans, R.; Koelemeijer, R.

    2007-01-01

    An intercomparison study shows a large bias in MODIS total AOD in summer as compared to the AERONET data. Inclusion of MODIS AOD_fine appears to largely solve this bias problem for the assimilation study. Assimilation studies show that the system is able to assimilate AOD. Innovations are significan

  19. The changes of assimilate exportation from wheat flag leaf after anthesis

    International Nuclear Information System (INIS)

    The changes of assimilate transportation from wheat flag leaf after anthesis were analysed by living crops multiple-probe measurer. The exponential equations were established to fit the changes of assimilate transport to ear and the vegetative organs below flag leaf. IAA positively but ABA negatively affected the exporting ratio, transporting rate and effective transporting time of photosynthetic assimilate

  20. Snow multivariable data assimilation for hydrological predictions in mountain areas

    Science.gov (United States)

    Piazzi, Gaia; Campo, Lorenzo; Gabellani, Simone; Rudari, Roberto; Castelli, Fabio; Cremonese, Edoardo; Morra di Cella, Umberto; Stevenin, Hervé; Ratto, Sara Maria

    2016-04-01

    The seasonal presence of snow on alpine catchments strongly impacts both surface energy balance and water resource. Thus, the knowledge of the snowpack dynamics is of critical importance for several applications, such as water resource management, floods prediction and hydroelectric power production. Several independent data sources provide information about snowpack state: ground-based measurements, satellite data and physical models. Although all these data types are reliable, each of them is affected by specific flaws and errors (respectively dependency on local conditions, sensor biases and limitations, initialization and poor quality forcing data). Moreover, there are physical factors that make an exhaustive reconstruction of snow dynamics complicated: snow intermittence in space and time, stratification and slow phenomena like metamorphism processes, uncertainty in snowfall evaluation, wind transportation, etc. Data Assimilation (DA) techniques provide an objective methodology to combine observational and modeled information to obtain the most likely estimate of snowpack state. Indeed, by combining all the available sources of information, the implementation of DA schemes can quantify and reduce the uncertainties of the estimations. This study presents SMASH (Snow Multidata Assimilation System for Hydrology), a multi-layer snow dynamic model, strengthened by a robust multivariable data assimilation algorithm. The model is physically based on mass and energy balances and can be used to reproduce the main physical processes occurring within the snowpack: accumulation, density dynamics, melting, sublimation, radiative balance, heat and mass exchanges. The model is driven by observed forcing meteorological data (air temperature, wind velocity, relative air humidity, precipitation and incident solar radiation) to provide a complete estimate of snowpack state. The implementation of an Ensemble Kalman Filter (EnKF) scheme enables to assimilate simultaneously ground

  1. The Impact of "Bad" Argo Profiles on Ocean Data Assimilation

    Institute of Scientific and Technical Information of China (English)

    YAN Chang-Xiang; ZHU Jiang

    2010-01-01

    Recent studies have found cold biases in a fraction of Argo profiles (hereinafter referred to as bad Array for Real-time Geostrophic Oceanography (Argo) profiles) due to the pressure drifts during 2003 and 2006. These bad Argo profiles have had an important impact on in situ observation-based global ocean heat content estimates. This study investigated the impact of bad Argo profiles on ocean data assimilation results that were based on observations from diverse ocean observation systems, such as in situ profiles (e.g., Argo, expendable bathythermograph (XBT), and Tropical Atmosphere Ocean (TAO), remote-sensing sea surface temperature products and satellite altimetry between 2004 and 2006. Results from this work show that the upper ocean heat content analysis is vulnerable to bad Argo profiles and demonstrate a cooling trend in the studied period despite the multiple independent data types that were assimilated. When the bad Argo profiles were excluded from the assimilation, the decreased heat content disappeared and a warming occurred. Combination of satellite altimetry and mass variation data from gravity satellite demonstrated an increase, which agrees well with the increased heat content. Additionally, when an additional Argo profile quality control procedure was utilized that simply removed the profiles that presented static unstable water columns, the results were very similar to those obtained when the bad Argo profiles were excluded from the assimilation. This indicates that an ocean data assimilation that uses multiple data sources with improved quality control could be less vulnerable to a major observation system failure, such as a bad Argo event.

  2. A virtual reality catchment for data assimilation experiments

    Science.gov (United States)

    Schalge, Bernd; Rihani, Jehan; Haese, Barbara; Baroni, Gabriele; Erdal, Daniel; Neuweiler, Insa; Hendricks-Franssen, Harrie-Jan; Geppert, Gernot; Ament, Felix; Kollet, Stefan; Cirpka, Olaf; Saavedra, Pablo; Han, Xujun; Attinger, Sabine; Kunstmann, Harald; Vereecken, Harry; Simmer, Clemens

    2016-04-01

    Current data assimilation (DA) systems often lack the possibility to assimilate measurements across compartments to accurately estimate states and fluxes in subsurface-land surface-atmosphere systems (SLAS). In order to develop a new DA framework that is able to realize this cross-compartmental assimilation a comprehensive testing environment is needed. Therefore a virtual reality (VR) catchment is constructed with the Terrestrial System Modeling Platform (TerrSysMP). This catchment mimics the Neckar catchment in Germany. TerrSysMP employs the atmospheric model COSMO, the land surface model CLM and the hydrological model ParFlow coupled with the external coupler OASIS. We will show statistical tests to prove the plausibility of the VR. The VR is running in a fully-coupled mode (subsurface - land surface - atmosphere) which includes the interactions of subsurface dynamics with the atmosphere, such as the effects of soil moisture, which can influence near-surface temperatures, convection patterns or the surface heat fluxes. A reference high resolution run serves as the "truth" from which virtual observations are extracted with observation operators like virtual rain gauges, synoptic stations and satellite observations (amongst others). This effectively solves the otherwise often encountered data scarcity issues with respect to DA. Furthermore an ensemble of model runs at a reduced resolution is performed. This ensemble serves also for open loop runs to be compared with data assimilation experiments. The model runs with this ensemble served to identify sets of parameters that are especially sensitive to changes and have the largest impact on the system. These parameters were the focus of subsequent ensemble simulations and DA experiments. We will show to what extend the VR states can be re-constructed using data assimilation methods with only a limited number of virtual observations available.

  3. 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.

  4. 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.

  5. Estimation of model error variances during data assimilation

    Science.gov (United States)

    Dee, D.

    2003-04-01

    Data assimilation is all about understanding the error characteristics of the data and models that are used in the assimilation process. Reliable error estimates are needed to implement observational quality control, bias correction of observations and model fields, and intelligent data selection. Meaningful covariance specifications are obviously required for the analysis as well, since the impact of any single observation strongly depends on the assumed structure of the background errors. Operational atmospheric data assimilation systems still rely primarily on climatological background error covariances. To obtain error estimates that reflect both the character of the flow and the current state of the observing system, it is necessary to solve three problems: (1) how to account for the short-term evolution of errors in the initial conditions; (2) how to estimate the additional component of error caused by model defects; and (3) how to compute the error reduction in the analysis due to observational information. Various approaches are now available that provide approximate solutions to the first and third of these problems. However, the useful accuracy of these solutions very much depends on the size and character of the model errors and the ability to account for them. Model errors represent the real-world forcing of the error evolution in a data assimilation system. Clearly, meaningful model error estimates and/or statistics must be based on information external to the model itself. The most obvious information source is observational, and since the volume of available geophysical data is growing rapidly, there is some hope that a purely statistical approach to model error estimation can be viable. This requires that the observation errors themselves are well understood and quantifiable. We will discuss some of these challenges and present a new sequential scheme for estimating model error variances from observations in the context of an atmospheric data

  6. Application of Observed Precipitation in NCEP Global and Regional Data Assimilation Systems, Including Reanalysis and Land Data Assimilation

    Science.gov (United States)

    Mitchell, K. E.

    2006-12-01

    The Environmental Modeling Center (EMC) of the National Centers for Environmental Prediction (NCEP) applies several different analyses of observed precipitation in both the data assimilation and validation components of NCEP's global and regional numerical weather and climate prediction/analysis systems (including in NCEP global and regional reanalysis). This invited talk will survey these data assimilation and validation applications and methodologies, as well as the temporal frequency, spatial domains, spatial resolution, data sources, data density and data quality control in the precipitation analyses that are applied. Some of the precipitation analyses applied by EMC are produced by NCEP's Climate Prediction Center (CPC), while others are produced by the River Forecast Centers (RFCs) of the National Weather Service (NWS), or by automated algorithms of the NWS WSR-88D Radar Product Generator (RPG). Depending on the specific type of application in data assimilation or model forecast validation, the temporal resolution of the precipitation analyses may be hourly, daily, or pentad (5-day) and the domain may be global, continental U.S. (CONUS), or Mexico. The data sources for precipitation include ground-based gauge observations, radar-based estimates, and satellite-based estimates. The precipitation analyses over the CONUS are analyses of either hourly, daily or monthly totals of precipitation, and they are of two distinct types: gauge-only or primarily radar-estimated. The gauge-only CONUS analysis of daily precipitation utilizes an orographic-adjustment technique (based on the well-known PRISM precipitation climatology of Oregon State University) developed by the NWS Office of Hydrologic Development (OHD). The primary NCEP global precipitation analysis is the pentad CPC Merged Analysis of Precipitation (CMAP), which blends both gauge observations and satellite estimates. The presentation will include a brief comparison between the CMAP analysis and other global

  7. Assimilation of Dual-Polarimetric Radar Observations with WRF GSI

    Science.gov (United States)

    Li, Xuanli; Mecikalski, John; Fehnel, Traci; Zavodsky, Bradley; Srikishen, Jayanthi

    2014-01-01

    Dual-polarimetric (dual-pol) radar typically transmits both horizontally and vertically polarized radio wave pulses. From the two different reflected power returns, more accurate estimate of liquid and solid cloud and precipitation can be provided. The upgrade of the traditional NWS WSR-88D radar to include dual-pol capabilities will soon be completed for the entire NEXRAD network. Therefore, the use of dual-pol radar network will have a broad impact in both research and operational communities. The assimilation of dual-pol radar data is especially challenging as few guidelines have been provided by previous research. It is our goal to examine how to best use dual-pol radar data to improve forecast of severe storm and forecast initialization. In recent years, the Development Testbed Center (DTC) has released the community Gridpoint Statistical Interpolation (GSI) DA system for the Weather Research and Forecasting (WRF) model. 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 study explores regional assimilation of the dual-pol radar variables from the WSR-88D radars for real case storms. Our presentation will highlight our recent effort on incorporating the horizontal reflectivity (ZH), differential reflectivity (ZDR), specific differential phase (KDP), and radial velocity (VR) data for initializing convective storms, with a significant focus being on an improved representation of hydrometeor fields. In addition, discussion will be provided on the development of enhanced assimilation procedures in the GSI system with respect to dual-pol variables. Beyond the dual-pol variable assimilation procedure developing within a GSI framework, highresolution (=1 km) WRF model simulations and storm scale data assimilation experiments will be examined, emphasizing both model initialization and short-term forecast

  8. Prices and the assortment offer of the mineral fertilizers in the farmers’ opinion Ceny i oferta asortymentowa nawozów mineralnych w opinii producentów rolnych

    OpenAIRE

    Arkadiusz Piwowar

    2011-01-01

    The mineral fertilizers are the basic means of production used by agriculturalists in order to improve the size and quality of the cultivated plants. The retail prices of the most popular mineral fertilizers have risen in the last years. The paper discusses the research results concerning the agriculturalists' opinion about the mineral fertilizers’ prices and assortment in the market. The research revealed that the high prices and their disadvantageous relation to the fruits' of the ear...

  9. 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.

  10. Assimilation and its discontents: between rhetoric and reality.

    Science.gov (United States)

    Rumbaut, R G

    1997-01-01

    "It is in [the] conceptual interstices between theory, rhetoric, and reality that paradoxes (or at least what may appear as paradoxes) emerge. By focusing on paradoxes--on evidence that contradicts orthodox expectations and points instead to assimilation's discontents--the aim of this article is to test empirically the conception of assimilation as a linear process leading to improvements in immigrant outcomes over time and generation in the United States, to unmask underlying pre-theoretical ethnocentric pretensions, and to identify areas in need of conceptual, analytical and theoretical refinement. It is precisely through the examination of paradoxical cases--in effect, deviant case analyses--that fruitful reformulations can be stimulated, considered, and advanced." PMID:12293210

  11. Operational hydrological data assimilation with the recursive ensemble Kalman filter

    Directory of Open Access Journals (Sweden)

    H. K. McMillan

    2013-01-01

    Full Text Available This paper describes the design and use of a recursive ensemble Kalman filter (REnKF to assimilate streamflow data in an operational flow forecasting system of seven catchments in New Zealand. The REnKF iteratively updates past and present model states (soil water, aquifer and surface storages, with lags up to the concentration time of the catchment, to improve model initial conditions and hence flow forecasts. We found the REnKF overcame instabilities in the standard EnKF, which were associated with the natural lag time between upstream catchment wetness and flow at the gauging locations. The forecast system performance was correspondingly improved in terms of Nash–Sutcliffe score, persistence index and bounding of the measured flow by the model ensemble. We present descriptions of filter design parameters and explanations and examples of filter behaviour, as an information source for other groups wishing to assimilate discharge observations for operational forecasting.

  12. 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.

  13. Integrating biogeochemistry and ecology into ocean data assimilation systems

    DEFF Research Database (Denmark)

    Brasseur, Pierre; Gruber, Nicolas; Barciela, Rosa;

    2009-01-01

    Monitoring and predicting the biogeochemical state of the ocean and marine ecosystems is an important application of operational oceanography that needs to be expanded. The accurate depiction of the ocean's physical environment enabled by Global Ocean Data Assimilation Experiment (GODAE) systems...... temporal scales. In this paper, we discuss recent developments that enable coupling new biogeochemical models and assimilation components with the existing GODAE systems, and we examine the potential of such systems in several areas of interest: phytoplankton biomass monitoring in the open ocean, ocean...... that are not yet considered essential, such as upper-ocean vertical fluxes that are critically important to biological activity. Further, the observing systems will need to be expanded in terms of in situ platforms (with intensified deployments of sensors for O-2 and chlorophyll, and inclusion of new...

  14. Robustness of Nuclear Core Activity Reconstruction by Data Assimilation

    Science.gov (United States)

    Bouriquet, Bertrand; Argaud, Jean-Philippe; Erhard, Patrick; Massart, Sébastien; Ponçot, Angélique; Ricci, Sophie; Thual, Olivier

    Inspired from meteorological applications, data assimilation techniques can be used to perform an optimal reconstruction of the neutronic field in a nuclear reactor core. Measurements and simulation information, coming from a numerical model, are merged together to build a better estimation of the whole field. In this paper, we first study the robustness of the method when the amount of measured information varies. We then study the influence of the nature of the instruments and their spatial repartition on the efficiency of the field reconstruction. This study also highlights the instruments providing most information within a data assimilation procedure. The study of various network configurations of instruments in the nuclear core establishes that the influence of each instrument depends both on the individual instrumentation location as well as on the chosen network.

  15. Herbicides effect on the nitrogen fertilizer assimilation by sensitive plants

    International Nuclear Information System (INIS)

    It has been established in studying the effect of herbicides on pea plants that the penetration of the preparations into the tissues of leaves and stems results in a slight increase of the rate of formation of dry substance in the leaves of the treated plants within 24 hours after treatment as compared with control, whereas in the last period of the analysis the herbicides strongly inhibit the formation of dry substance in leaves. The applied herbicide doses have resulted in drastic changes of the distribution of the plant-assimilated nitrogen between the protein and non-protein fractions in the leaves and stems of pea. When affected by the studied herbicides, the fertilizer nitrogen supply to the pea plants changes and the rate of the fertilizer nitrogen assimilation by the plants varies noticeably. The regularities of the fertilizer nitrogen inclusion in the protein and non-protein nitrogen compounds of the above-ground pea organs have been studied

  16. Robustness of nuclear core activity reconstruction by data assimilation

    International Nuclear Information System (INIS)

    Inspired from meteorological applications, data assimilation techniques can be used to perform an optimal reconstruction of the neutronic field in a nuclear reactor core. Measurements and simulation information, coming from a numerical model, are merged together to build a better estimation of the whole field. In this paper, we first study the robustness of the method when the amount of measured information varies. We then study the influence of the nature of the instruments and their spatial repartition on the efficiency of the field reconstruction. This study also highlights the instruments providing most information within a data assimilation procedure. The study of various network configurations of instruments in the nuclear core establishes that the influence of each instrument depends both on the individual instrumentation location as well as on the chosen network. (author)

  17. Robustness of nuclear core activity reconstruction by data assimilation

    International Nuclear Information System (INIS)

    The purpose of this paper is the use data assimilation techniques, inspired from meteorological applications, to perform an optimal reconstruction of the neutronic field in a nuclear core. Both measurements, and information coming from a numerical model, are used in this purpose. We first study the robustness of the method when the amount of measured information varies. We then study the influence of the nature of the instruments and their spatial repartition on the efficiency of the field reconstruction. Such study allows, also enlightening the instruments providing the most information within a data assimilation procedure. The study of various network configurations of instruments in the nuclear core establishes that influence of the instruments depends both on the individual instrumentation location as well as on the chosen network. (author)

  18. Altered NO3- assimilation in P-stressed plants

    International Nuclear Information System (INIS)

    To examine P stress effects on NO3- uptake and assimilation, young tobacco plants were deprived of external P for 12 days and at selected times exposed to 15NO3- for 12h uptake periods. In -P plants, tissue P concentrations and growth decreased progressively with time relative to controls. Uptake of 15NO3- per g root DW was restricted markedly, being 70% of the control rate on the day 3 and only 17% on day 9. Additional disruptions in the NO3- assimilation pathway were evident, as larger proportions of absorbed 15NO3- were retained in the root and soluble reduced-15N accumulated in leaves with increasing P stress. The results indicate that transport processes controlling NO3- uptake into the root symplasm and its release into the xylem are major points of regulations in plants responding to P deficiency

  19. ALTERED STATES OF LITERATURE: SHAMANIC ASSIMILATION AND ROMANTIC INSPIRATION

    Directory of Open Access Journals (Sweden)

    Marcel de Lima Santos

    2012-12-01

    Full Text Available This article deals with the connections between the assimilation of certain shamanic practices related to Romantic inspiration in English literature. The interest in the world of altered states of consciousness as a manifestation of the sacred is typical among Romantic writers in nineteenth-century England. These writers in fact sought the manifestation of the world of dreams by means of ingesting substances that alter consciousness, thus assimilating a practice that is likewise and primarily shamanic. This search is the object under investigation in this article, which aims at showing that, despite conspicuous cultural differences, there are indeed similarities that pervade shamanic practices and the Romantic ideal in their quests toward the sacred.

  20. Adaptive Covariance Inflation in a Multi-Resolution Assimilation Scheme

    Science.gov (United States)

    Hickmann, K. S.; Godinez, H. C.

    2015-12-01

    When forecasts are performed using modern data assimilation methods observation and model error can be scaledependent. During data assimilation the blending of error across scales can result in model divergence since largeerrors at one scale can be propagated across scales during the analysis step. Wavelet based multi-resolution analysiscan be used to separate scales in model and observations during the application of an ensemble Kalman filter. However,this separation is done at the cost of implementing an ensemble Kalman filter at each scale. This presents problemswhen tuning the covariance inflation parameter at each scale. We present a method to adaptively tune a scale dependentcovariance inflation vector based on balancing the covariance of the innovation and the covariance of observations ofthe ensemble. Our methods are demonstrated on a one dimensional Kuramoto-Sivashinsky (K-S) model known todemonstrate non-linear interactions between scales.