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Sample records for homologs tie social

  1. PDK1 and HR46 gene homologs tie social behavior to ovary signals.

    Directory of Open Access Journals (Sweden)

    Ying Wang

    Full Text Available The genetic basis of division of labor in social insects is a central question in evolutionary and behavioral biology. The honey bee is a model for studying evolutionary behavioral genetics because of its well characterized age-correlated division of labor. After an initial period of within-nest tasks, 2-3 week-old worker bees begin foraging outside the nest. Individuals often specialize by biasing their foraging efforts toward collecting pollen or nectar. Efforts to explain the origins of foraging specialization suggest that division of labor between nectar and pollen foraging specialists is influenced by genes with effects on reproductive physiology. Quantitative trait loci (QTL mapping of foraging behavior also reveals candidate genes for reproductive traits. Here, we address the linkage of reproductive anatomy to behavior, using backcross QTL analysis, behavioral and anatomical phenotyping, candidate gene expression studies, and backcross confirmation of gene-to-anatomical trait associations. Our data show for the first time that the activity of two positional candidate genes for behavior, PDK1 and HR46, have direct genetic relationships to ovary size, a central reproductive trait that correlates with the nectar and pollen foraging bias of workers. These findings implicate two genes that were not known previously to influence complex social behavior. Also, they outline how selection may have acted on gene networks that affect reproductive resource allocation and behavior to facilitate the evolution of social foraging in honey bees.

  2. Social Ties for Labor Market Access

    DEFF Research Database (Denmark)

    Dorner, Matthias; Harhoff, Dietmar; Hinz, Tina

    such ties. However, mobility decisions made by inventors with outstanding patenting track records (star inventors) were not impacted by social ties. We conclude that social ties support labor market access for migrant inventors and determine regional choices while dependence on these ties is substantially......We study the impact of social ties on the migration of inventors from East to West Germany, using the fall of the Iron Curtain and German reunification as a natural experiment. We identify East German inventors via their patenting track records prior to 1990 and their social security records...... in the German labor market after reunification. Modeling inventor migration to West German regions after 1990, we find that Western regions with stronger historically determined social ties across the former East-West border attracted more inventors after the fall of the Iron Curtain than regions without...

  3. Analyzing negative ties in social networks

    Directory of Open Access Journals (Sweden)

    Mankirat Kaur

    2016-03-01

    Full Text Available Online social networks are a source of sharing information and maintaining personal contacts with other people through social interactions and thus forming virtual communities online. Social networks are crowded with positive and negative relations. Positive relations are formed by support, endorsement and friendship and thus, create a network of well-connected users whereas negative relations are a result of opposition, distrust and avoidance creating disconnected networks. Due to increase in illegal activities such as masquerading, conspiring and creating fake profiles on online social networks, exploring and analyzing these negative activities becomes the need of hour. Usually negative ties are treated in same way as positive ties in many theories such as balance theory and blockmodeling analysis. But the standard concepts of social network analysis do not yield same results in respect of each tie. This paper presents a survey on analyzing negative ties in social networks through various types of network analysis techniques that are used for examining ties such as status, centrality and power measures. Due to the difference in characteristics of flow in positive and negative tie networks some of these measures are not applicable on negative ties. This paper also discusses new methods that have been developed specifically for analyzing negative ties such as negative degree, and h∗ measure along with the measures based on mixture of positive and negative ties. The different types of social network analysis approaches have been reviewed and compared to determine the best approach that can appropriately identify the negative ties in online networks. It has been analyzed that only few measures such as Degree and PN centrality are applicable for identifying outsiders in network. For applicability in online networks, the performance of PN measure needs to be verified and further, new measures should be developed based upon negative clique concept.

  4. The power of indirect social ties

    OpenAIRE

    Zuo, Xiang; Blackburn, Jeremy; Kourtellis, Nicolas; Skvoretz, John; Iamnitchi, Adriana

    2014-01-01

    While direct social ties have been intensely studied in the context of computer-mediated social networks, indirect ties (e.g., friends of friends) have seen little attention. Yet in real life, we often rely on friends of our friends for recommendations (of good doctors, good schools, or good babysitters), for introduction to a new job opportunity, and for many other occasional needs. In this work we attempt to 1) quantify the strength of indirect social ties, 2) validate it, and 3) empiricall...

  5. Reciprocity, social ties, and competition in markets for experience goods

    DEFF Research Database (Denmark)

    Huck, Steffen; Tyran, Jean-Robert

    2007-01-01

    a positive externality for non-reciprocal customers who would, in the absence of reciprocal types, face market breakdown. This efficiency-enhancing effect of reciprocity is boosted when there are social ties between consumers and competition between firms. The existence of social ties or competition alone...

  6. Employees and Creativity: Social Ties and Access to Heterogeneous Knowledge

    Science.gov (United States)

    Huang, Chiung-En; Liu, Chih-Hsing Sam

    2015-01-01

    This study dealt with employee social ties, knowledge heterogeneity contacts, and the generation of creativity. Although prior studies demonstrated a relationship between network position and creativity, inadequate attention has been paid to network ties and heterogeneity knowledge contacts. This study considered the social interaction processes…

  7. Older women play predominant role in building social ties and ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2016-08-03

    Aug 3, 2016 ... Older women play predominant role in building social ties and preventing ... brief demonstrates their contribution to building social cohesion and driving ... From learning to policy-oriented research: Lessons from South Africa's ...

  8. The social tie and the malaise facing the helplessness

    Directory of Open Access Journals (Sweden)

    Cristina Aparecida Tannure Cavalcanti

    2015-12-01

    Full Text Available In this article we intend to approach the discourses as social ties, indicated by Lacan, relating them to the freudian concepts of helplessness (Hilflosigkeit and the malaise of civilization. The theory of discourses opens up a new way of thinking about clinical structures and social ties, by articulating language and enjoyment camps, the subject and the unconscious knowledge. This theory, while it takes over Freudian principles, it advances in impasses left by the Viennese master, in particular on the relationship between the metapsychological foundations of the subjective constitution and the conceptual bases concerning culture and actual social ties.

  9. Social Identity, Social Ties and Social Capital: A Study in Gaming Context

    Science.gov (United States)

    Jiang, Hao

    2012-01-01

    This work will focus on how different social relationships, namely shared identity and personal tie, will impact cooperative behavior, a form of social capital. I designed and conducted an economic game study to show that shared identity and personal ties work differently on cooperation among people and resource flow in social groups. Many factors…

  10. Leaving Libertarianism: : Social Ties in Robert Nozick's New Philosophy

    OpenAIRE

    Herbjørnsrud, Dag

    2002-01-01

    SUMMARY This thesis Leaving Libertarianism: Social Ties in Robert Nozick s New Philosophy challenges the general and most widespread portrayals of the American philosopher Robert Nozick (1938-2002) by studying the notion of social ties in his later philosophy. The point of departure is the present descriptions of Nozick s philosophy. Mostly these depictions are based upon three postulates: That Nozick is an extreme individualist, that the libertarian Anarchy, State, and Utopia (1...

  11. Social ties and risk for cancer - a prospective cohort study

    DEFF Research Database (Denmark)

    Bergelt, Corinna; Prescott, Eva; Grønbaek, Morten

    2009-01-01

    consisted of 8 548 Danes who had been examined in 1991-1994 within the Copenhagen City Heart Study. The median length of follow-up was 9.3 years (range, 0-11.2 years). Social ties were measured from answers to a questionnaire on social networks. Regression analyses for cancers at the most frequent sites......BACKGROUND: Poor social support and small social networks have been associated with increased risks for conditions such as coronary heart disease as well as with overall mortality. We investigated the association between social ties and risk for cancer. MATERIAL AND METHODS: The study sample...... (breast, lung, prostate and colon and rectum) were conducted with the Cox proportional hazards model, with adjustment for a number of well-known risk factors for cancer. RESULTS: While we found no significant association between social ties and risk for cancer in men, women with high social network scores...

  12. Social ties and risk for cancer - a prospective cohort study

    DEFF Research Database (Denmark)

    Bergelt, C.; Prescott, E.; Gronbaek, M.

    2009-01-01

    consisted of 8 548 Danes who had been examined in 1991-1994 within the Copenhagen City Heart Study. The median length of follow-up was 9.3 years (range, 0-11.2 years). Social ties were measured from answers to a questionnaire on social networks. Regression analyses for cancers at the most frequent sites......Background. Poor social support and small social networks have been associated with increased risks for conditions such as coronary heart disease as well as with overall mortality. We investigated the association between social ties and risk for cancer. Material and methods. The study sample...... (breast, lung, prostate and colon and rectum) were conducted with the Cox proportional hazards model, with adjustment for a number of well-known risk factors for cancer. Results. While we found no significant association between social ties and risk for cancer in men, women with high social network scores...

  13. Affective social ties - missing link in governance theory

    NARCIS (Netherlands)

    van Winden, F.A.A.M.

    2012-01-01

    Although governance is about interpersonal relationships, it appears that the antecedents and consequences of affective bonds (social ties) in social groups dealing with common-pool resources and public goods have been neglected. The welfare costs of the neglect of such bonds and their dynamic

  14. Social support and social interaction ties on internet addiction: integrating online and offline contexts.

    Science.gov (United States)

    Wang, Edward Shih-Tse; Wang, Michael Chih-Hung

    2013-11-01

    This study explores the relationship between social support and social interaction ties on Internet addiction by integrating both online and offline social encounters. A total of 1,642 members of online social communities participated in this research, for which structural equation modeling was used for analysis. The findings show that social support is positively associated with social interaction ties in both online and offline contexts. In addition, online social support and online social interaction ties are positively associated with Internet addiction, whereas offline social support and social interaction ties on Internet addiction are negatively associated. This finding has important implications not only for understanding the cause of Internet addiction but also for understanding the diminishing Internet addiction due to social support and social interaction ties.

  15. The Social Ties That Bind. Online Treasures

    Science.gov (United States)

    Balas, Janet L.

    2006-01-01

    This article discusses how, in the new world of the information age, libraries must seek to bring relevant services to their technically savvy patrons. This includes designing a library that can serve not only the geographic community, but also the virtual online community. Software used to create online communities is known as social software and…

  16. Student Mobility and Transnational Social Ties as Factors of Reflexivity

    Directory of Open Access Journals (Sweden)

    Tea Golob

    2018-03-01

    Full Text Available The article seeks to develop and apply new quantitative measurement instruments capable of significantly improving understanding of the relationship between the transnational mobility and transnational social ties of students, along with their reflexive capacities. With a focus on students building their personal networks, educational and professional activities that extend beyond the nation’s borders and organising their day-to-day routines in transnational social spaces, we analyse the role of mobility in their reflexive capacities. Applying a tool that is line with Archer’s theory and indicators to measure reflexivity, and transnational social ties as proposed by Molina et al., we analyse data collected via an on-line survey questionnaire administered to Slovenian students. In addition, students from the Middle East (Lebanon and the USA (Hawai’i are added for comparative purposes. The results of path analysis show the Slovenian students’ mobility as such implies higher scores for meta reflexivity, combined with lower scores for communicative and fractured reflexivity. Further, social transactions reaching beyond one’s physical localities in terms of transnational social ties implies they have higher levels of reflexivity in general.

  17. Mobile phones, social ties, and collective action mobilization in China

    DEFF Research Database (Denmark)

    Liu, Jun

    2017-01-01

    To provide a better understanding of mobile phones as a recruitment tool in collective actions, this study explores the use of mobile phones for mobilizing protest in China. Using in-depth interviews and investigating four cases in which Chinese people employed mobile devices to recruit...... participants for protests, this study observes that mobile communication in China embodies guanxi, the indigenous social tie in Chinese society that introduces reciprocity as an influential facilitator of collective actions. The embedment of reciprocity facilitates the proliferation of mobilizing calls......, legitimizes mobilizing appeals, generates obligations and consolidates solidarity for collective actions. The study concludes with a consideration of the relevance of mobile phones for the embedment of reciprocity in social ties in the mobilization of collective action in authoritarian regimes such as China....

  18. The social ties that bind: social anxiety and academic achievement across the university years.

    Science.gov (United States)

    Brook, Christina A; Willoughby, Teena

    2015-05-01

    Given that engagement and integration in university/college are considered key to successful academic achievement, the identifying features of social anxiety, including fear of negative evaluation and distress and avoidance of new or all social situations, may be particularly disadvantageous in the social and evaluative contexts that are integral to university/college life. Thus, the purpose of this study was to examine the direct effects of social anxiety on academic achievement, as well as investigate an indirect mechanism through which social anxiety might impact on academic achievement, namely, the formation of new social ties in university. The participants were 942 (71.7 % female; M = 19 years at Time 1) students enrolled in a mid-sized university in Southern Ontario, Canada. Students completed annual assessments of social anxiety, social ties, and academic achievement for three consecutive years. The results from an autoregressive cross-lag path analysis indicated that social anxiety had a significant and negative direct relationship with academic achievement. Moreover, the negative indirect effect of social anxiety on academic achievement through social ties was significant, as was the opposing direction of effects (i.e., the indirect effect of academic achievement on social anxiety through social ties). These findings highlight the critical role that social ties appear to play in successful academic outcomes and in alleviating the effects of social anxiety during university/college.

  19. Social network ties beyond nonredundancy: an experimental investigation of the effect of knowledge content and tie strength on creativity.

    Science.gov (United States)

    Perry-Smith, Jill E

    2014-09-01

    Social network research emphasizes the access to nonredundant knowledge content that network ties provide. I suggest that some content is more beneficial than others and that tie strength may affect creativity for reasons other than the associated structure. That is, tie strength may affect how individuals process nonredundant knowledge. I investigate 2 types of knowledge content--information (i.e., facts or data) and frames (i.e., interpretations or impressions)--and explore whether tie strength influences their effect on creativity. Drawing on creativity theory, I employ an experimental design to provide greater theoretical clarity and to isolate causality. According to the results from 2 studies, distinct frames received from contacts facilitate creativity, but the effect of distinct information is more complex. When individuals receive distinct information from strong ties, it constrains creativity compared to distinct frames. Content from weak ties appears to facilitate creativity across all scenarios. The results of mediated moderation analysis indicate the effect of framing versus information for strong ties is driven by decision-making time, as an indicator of cognitive expansion. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  20. Cooperation prevails when individuals adjust their social ties.

    Directory of Open Access Journals (Sweden)

    Francisco C Santos

    2006-10-01

    Full Text Available Conventional evolutionary game theory predicts that natural selection favours the selfish and strong even though cooperative interactions thrive at all levels of organization in living systems. Recent investigations demonstrated that a limiting factor for the evolution of cooperative interactions is the way in which they are organized, cooperators becoming evolutionarily competitive whenever individuals are constrained to interact with few others along the edges of networks with low average connectivity. Despite this insight, the conundrum of cooperation remains since recent empirical data shows that real networks exhibit typically high average connectivity and associated single-to-broad-scale heterogeneity. Here, a computational model is constructed in which individuals are able to self-organize both their strategy and their social ties throughout evolution, based exclusively on their self-interest. We show that the entangled evolution of individual strategy and network structure constitutes a key mechanism for the sustainability of cooperation in social networks. For a given average connectivity of the population, there is a critical value for the ratio W between the time scales associated with the evolution of strategy and of structure above which cooperators wipe out defectors. Moreover, the emerging social networks exhibit an overall heterogeneity that accounts very well for the diversity of patterns recently found in acquired data on social networks. Finally, heterogeneity is found to become maximal when W reaches its critical value. These results show that simple topological dynamics reflecting the individual capacity for self-organization of social ties can produce realistic networks of high average connectivity with associated single-to-broad-scale heterogeneity. On the other hand, they show that cooperation cannot evolve as a result of "social viscosity" alone in heterogeneous networks with high average connectivity, requiring the

  1. Integrating Micro-level Interactions with Social Network Analysis in Tie Strength Research

    DEFF Research Database (Denmark)

    Torre, Osku; Gupta, Jayesh Prakash; Kärkkäinen, Hannu

    2017-01-01

    of tie strength based on reciprocal interaction from publicly available Facebook data, and suggest that this approach could work as a basis for further tie strength studies. Our approach makes use of weak tie theory, and enables researchers to study micro-level interactions (i.e. discussions, messages......A social tie is a target for ongoing, high-level scientific debate. Measuring the tie strength in social networks has been an important topic for academic studies since Mark Granovetter's seminal papers in 1970's. However, it is still a problematic issue mainly for two reasons: 1) existing tie...... strengthening process in online social networks. Therefore, we suggest a new approach to tie strength research, which focuses on studying communication patterns (edges) more rather than actors (nodes) in a social network. In this paper we build a social network analysis-based approach to enable the evaluation...

  2. It's the recipient that counts: spending money on strong social ties leads to greater happiness than spending on weak social ties.

    Directory of Open Access Journals (Sweden)

    Lara B Aknin

    Full Text Available Previous research has shown that spending money on others (prosocial spending increases happiness. But, do the happiness gains depend on who the money is spent on? Sociologists have distinguished between strong ties with close friends and family and weak ties--relationships characterized by less frequent contact, lower emotional intensity, and limited intimacy. We randomly assigned participants to reflect on a time when they spent money on either a strong social tie or a weak social tie. Participants reported higher levels of positive affect after recalling a time they spent on a strong tie versus a weak tie. The level of intimacy in the relationship was more important than the type of relationship; there was no significant difference in positive affect after recalling spending money on a family member instead of a friend. These results add to the growing literature examining the factors that moderate the link between prosocial behaviour and happiness.

  3. It's the recipient that counts: spending money on strong social ties leads to greater happiness than spending on weak social ties.

    Science.gov (United States)

    Aknin, Lara B; Sandstrom, Gillian M; Dunn, Elizabeth W; Norton, Michael I

    2011-02-10

    Previous research has shown that spending money on others (prosocial spending) increases happiness. But, do the happiness gains depend on who the money is spent on? Sociologists have distinguished between strong ties with close friends and family and weak ties--relationships characterized by less frequent contact, lower emotional intensity, and limited intimacy. We randomly assigned participants to reflect on a time when they spent money on either a strong social tie or a weak social tie. Participants reported higher levels of positive affect after recalling a time they spent on a strong tie versus a weak tie. The level of intimacy in the relationship was more important than the type of relationship; there was no significant difference in positive affect after recalling spending money on a family member instead of a friend. These results add to the growing literature examining the factors that moderate the link between prosocial behaviour and happiness.

  4. Social position, social ties and adult's oral health: 13 year cohort study.

    Science.gov (United States)

    Vettore, Mario Vianna; Faerstein, Eduardo; Baker, Sarah Ruth

    2016-01-01

    This study explored different pathways by which social position and social ties influence adult's oral health over a 13-year period. A cohort investigation (Pro-Saúde Study) was conducted of non-faculty civil servants at a university in Rio de Janeiro, Brazil (N=1613). Baseline data collected in 1999 included age, social position, social ties, and access to dental care. Psychological factors and smoking were assessed in 2001, whereas tooth loss and self-rated oral health (SROH) were collected in 2012. A hypothesised model exploring different direct and indirect pathways was developed and tested using structural equation modelling. The model was a good fit to the data and accounted for 40% and 27% of the variance in tooth loss and SROH, respectively. A greater social position was linked to more social ties (β=0.31), health insurance (β=0.48), low psychological distress (β=0.07), less smoking (β=-0.21), more regular dental visiting (β=0.30), less tooth loss (β=-0.44) and better SROH (β=-0.25) over time. Social position (β=0.0005) and social ties (β=-0.0015) were linked indirectly with psychological distress, smoking and tooth loss. Social position was linked indirectly with social ties, psychological distress and SROH (β=-0.0071). Poor social position and weak social ties were important predictors for tooth loss and poor SROH in adults over the 13-year period. Direct and indirect pathways via psychological factors and smoking on the aforementioned relationships were identified, suggesting different areas of intervention to promote adults' oral health. Adult's oral health is influenced by social conditions through direct and indirect pathways, including via psychological factors and smoking. Copyright © 2015. Published by Elsevier Ltd.

  5. Experimental Effects of Program Management Approach on Teachers' Professional Ties and Social Capital

    Science.gov (United States)

    Quinn, David M.; Kim, James S.

    2018-01-01

    Theory and empirical work suggest that teachers' social capital influences school improvement efforts. Social ties are prerequisite for social capital, yet little causal evidence exists on how malleable factors, such as instructional management approaches, affect teachers' ties. In this cluster-randomized trial, we apply a decision-making…

  6. Understanding the process of social network evolution: Online-offline integrated analysis of social tie formation.

    Science.gov (United States)

    Kwak, Doyeon; Kim, Wonjoon

    2017-01-01

    It is important to consider the interweaving nature of online and offline social networks when we examine social network evolution. However, it is difficult to find any research that examines the process of social tie formation from an integrated perspective. In our study, we quantitatively measure offline interactions and examine the corresponding evolution of online social network in order to understand the significance of interrelationship between online and offline social factors in generating social ties. We analyze the radio signal strength indicator sensor data from a series of social events to understand offline interactions among the participants and measure the structural attributes of their existing online Facebook social networks. By monitoring the changes in their online social networks before and after offline interactions in a series of social events, we verify that the ability to develop an offline interaction into an online friendship is tied to the number of social connections that participants previously had, while the presence of shared mutual friends between a pair of participants disrupts potential new connections within the pre-designed offline social events. Thus, while our integrative approach enables us to confirm the theory of preferential attachment in the process of network formation, the common neighbor theory is not supported. Our dual-dimensional network analysis allows us to observe the actual process of social network evolution rather than to make predictions based on the assumption of self-organizing networks.

  7. Understanding the process of social network evolution: Online-offline integrated analysis of social tie formation.

    Directory of Open Access Journals (Sweden)

    Doyeon Kwak

    Full Text Available It is important to consider the interweaving nature of online and offline social networks when we examine social network evolution. However, it is difficult to find any research that examines the process of social tie formation from an integrated perspective. In our study, we quantitatively measure offline interactions and examine the corresponding evolution of online social network in order to understand the significance of interrelationship between online and offline social factors in generating social ties. We analyze the radio signal strength indicator sensor data from a series of social events to understand offline interactions among the participants and measure the structural attributes of their existing online Facebook social networks. By monitoring the changes in their online social networks before and after offline interactions in a series of social events, we verify that the ability to develop an offline interaction into an online friendship is tied to the number of social connections that participants previously had, while the presence of shared mutual friends between a pair of participants disrupts potential new connections within the pre-designed offline social events. Thus, while our integrative approach enables us to confirm the theory of preferential attachment in the process of network formation, the common neighbor theory is not supported. Our dual-dimensional network analysis allows us to observe the actual process of social network evolution rather than to make predictions based on the assumption of self-organizing networks.

  8. Neural dynamics of social tie formation in economic decision-making.

    Science.gov (United States)

    Bault, Nadège; Pelloux, Benjamin; Fahrenfort, Johannes J; Ridderinkhof, K Richard; van Winden, Frans

    2015-06-01

    The disposition for prosocial conduct, which contributes to cooperation as arising during social interaction, requires cortical network dynamics responsive to the development of social ties, or care about the interests of specific interaction partners. Here, we formulate a dynamic computational model that accurately predicted how tie formation, driven by the interaction history, influences decisions to contribute in a public good game. We used model-driven functional MRI to test the hypothesis that brain regions key to social interactions keep track of dynamics in tie strength. Activation in the medial prefrontal cortex (mPFC) and posterior cingulate cortex tracked the individual's public good contributions. Activation in the bilateral posterior superior temporal sulcus (pSTS), and temporo-parietal junction was modulated parametrically by the dynamically developing social tie-as estimated by our model-supporting a role of these regions in social tie formation. Activity in these two regions further reflected inter-individual differences in tie persistence and sensitivity to behavior of the interaction partner. Functional connectivity between pSTS and mPFC activations indicated that the representation of social ties is integrated in the decision process. These data reveal the brain mechanisms underlying the integration of interaction dynamics into a social tie representation which in turn influenced the individual's prosocial decisions. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  9. Importance of tie strengths in the prisoner's dilemma game on social networks

    Science.gov (United States)

    Xu, Bo; Liu, Lu; You, Weijia

    2011-06-01

    Though numerous researches have shown that tie strengths play a key role in the formation of collective behavior in social networks, little work has been done to explore their impact on the outcome of evolutionary games. In this Letter, we studied the effect of tie strength in the dynamics of evolutionary prisoner's dilemma games by using online social network datasets. The results show that the fraction of cooperators has a non-trivial dependence on tie strength. Weak ties, just like previous researches on epidemics and information diffusion have shown, play a key role by the maintenance of cooperators in evolutionary prisoner's dilemma games.

  10. Neural dynamics of social tie formation in economic decision-making

    NARCIS (Netherlands)

    Bault, N.; Pelloux, B.; Fahrenfort, J.J.; Ridderinkhof, K.R.; van Winden, F.

    2015-01-01

    The disposition for prosocial conduct, which contributes to cooperation as arising during social interaction, requires cortical network dynamics responsive to the development of social ties, or care about the interests of specific interaction partners. Here, we formulate a dynamic computational

  11. Do Social Ties Affect Our Health? Exploring the Biology of Relationships

    Science.gov (United States)

    ... Do Social Ties Affect Our Health? Exploring the Biology of Relationships En español Send us your comments ... neighbors, or others, social connections can influence our biology and well-being. Wide-ranging research suggests that ...

  12. Importance of tie strengths in the prisoner's dilemma game on social networks

    International Nuclear Information System (INIS)

    Xu, Bo; Liu, Lu; You, Weijia

    2011-01-01

    Though numerous researches have shown that tie strengths play a key role in the formation of collective behavior in social networks, little work has been done to explore their impact on the outcome of evolutionary games. In this Letter, we studied the effect of tie strength in the dynamics of evolutionary prisoner's dilemma games by using online social network datasets. The results show that the fraction of cooperators has a non-trivial dependence on tie strength. Weak ties, just like previous researches on epidemics and information diffusion have shown, play a key role by the maintenance of cooperators in evolutionary prisoner's dilemma games. -- Highlights: → Tie strength is used to measure heterogeneous influences of different pairs of nodes. → Weak ties play a role in maintaining cooperation in prisoner's dilemma games. → Micro-dynamics of nodes are illustrated to explain the conclusion.

  13. Importance of tie strengths in the prisoner's dilemma game on social networks

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Bo, E-mail: xubosuper@163.com [Department of Information Systems, School of Economics and Management, Beihang University (China); Liu, Lu; You, Weijia [Department of Information Systems, School of Economics and Management, Beihang University (China)

    2011-06-13

    Though numerous researches have shown that tie strengths play a key role in the formation of collective behavior in social networks, little work has been done to explore their impact on the outcome of evolutionary games. In this Letter, we studied the effect of tie strength in the dynamics of evolutionary prisoner's dilemma games by using online social network datasets. The results show that the fraction of cooperators has a non-trivial dependence on tie strength. Weak ties, just like previous researches on epidemics and information diffusion have shown, play a key role by the maintenance of cooperators in evolutionary prisoner's dilemma games. -- Highlights: → Tie strength is used to measure heterogeneous influences of different pairs of nodes. → Weak ties play a role in maintaining cooperation in prisoner's dilemma games. → Micro-dynamics of nodes are illustrated to explain the conclusion.

  14. Let the Weakest Link Go! Empirical Explorations on the Relative Importance of Weak and Strong Ties on Social Networking Sites

    OpenAIRE

    Nicole C. Krämer; Leonie Rösner; Sabrina C. Eimler; Stephan Winter; German Neubaum

    2014-01-01

    Theoretical approaches as well as empirical results in the area of social capital accumulation on social networking sites suggest that weak ties/bridging versus strong ties/bonding social capital should be distinguished and that while bonding social capital is connected to emotional support, bridging social capital entails the provision of information. Additionally, recent studies imply the notion that weak ties/bridging social capital are gaining increasing importance in today’s social media...

  15. Group formation in a public good experiment: on the dynamics of social ties structures

    NARCIS (Netherlands)

    Sonnemans, J.H.; van Dijk, F.; van Winden, F.A.A.M.

    1999-01-01

    Economic behavior often takes place in groups of small numbers of peopleinteracting with each other (like work teams, neighborhoods, socialnetworks, etc.). Characteristic of such interaction is the development of(affective) interpersonal relationships, or social ties. According tosociologists, the

  16. Social organization and social ties: their effects on sexual harassment victimization in the workplace.

    Science.gov (United States)

    Snyder, Jamie A; Scherer, Heidi L; Fisher, Bonnie S

    2012-01-01

    Despite work organizations' attempts to reduce sexual harassment, it continues to be a salient issue for employers across all occupations. Extending social disorganization theory to the work environment, this study examines the relationship between workplace organization, social ties, and sexual harassment victimization. Survey responses to the 2002 and 2006 Quality of Working Life module from the General Social Survey by a sample of 3,530 adult men and women employees in the United States were used. Logistic regression models were estimated for men and women separately to estimate the effect of workplace characteristics on the risk of sexual harassment victimization. Employees who reported poor workplace relations between management and employees and lower coworker social ties were more likely to experience sexual harassment in their work environments. Specific workplace characteristics such as low productivity, poor time management, and inadequate administrative support were significantly related to increased sexual harassment risk. No significant gender differences were found across models suggesting that the predictors of sexual harassment are similar for men and women. This study demonstrates that workplace characteristics are related to sexual harassment risk in the workplace. Suggestions for sexual harassment prevention, including management and organizational strategies, are discussed.

  17. The centrality of social ties to climate migration and mental health.

    Science.gov (United States)

    Torres, Jacqueline M; Casey, Joan A

    2017-07-06

    Climate change-related hazards and disasters, known to adversely impact physical and mental health outcomes, are also expected to result in human migration above current levels. Environmentally-motivated migration and displacement may lead to the disruption of existing social ties, with potentially adverse consequences for mobile populations as well as their family members who remain in places of origin. We propose that the disruption of social ties is a key mechanism by which climate-related migration may negatively impact mental health, in particular. Existing social ties may provide social and material resources that buffer mental health stressors related to both prolonged and acute climate events. Preparation for such events may also strengthen these same ties and protect mental health. Communities may leverage social ties, first to mitigate climate change, and second, to adapt and rebuild post-disaster in communities of origin. Additionally, social ties can inform migration decisions and destinations. For example, scholars have found that the drought-motivated adaptive migration of West African Fulbe herders only occurred because of the long-term development of social networks between migrants and non-migrants through trade and seasonal grazing. On the other hand, social ties do not always benefit mental health. Some migrants, including those from poor regions or communities with no formal safety net, may face considerable burden to provide financial and emotional resources to family members who remain in countries of origin. In destination communities, migrants often face significant social marginalization. Therefore, policies and programs that aim to maintain ongoing social ties among migrants and their family and community members may be critically important in efforts to enhance population resilience and adaptation to climate change and to improve mental health outcomes. Several online platforms, like Refugee Start Force, serve to integrate refugees by

  18. The centrality of social ties to climate migration and mental health

    Directory of Open Access Journals (Sweden)

    Jacqueline M. Torres

    2017-07-01

    Full Text Available Abstract Climate change-related hazards and disasters, known to adversely impact physical and mental health outcomes, are also expected to result in human migration above current levels. Environmentally-motivated migration and displacement may lead to the disruption of existing social ties, with potentially adverse consequences for mobile populations as well as their family members who remain in places of origin. We propose that the disruption of social ties is a key mechanism by which climate-related migration may negatively impact mental health, in particular. Existing social ties may provide social and material resources that buffer mental health stressors related to both prolonged and acute climate events. Preparation for such events may also strengthen these same ties and protect mental health. Communities may leverage social ties, first to mitigate climate change, and second, to adapt and rebuild post-disaster in communities of origin. Additionally, social ties can inform migration decisions and destinations. For example, scholars have found that the drought-motivated adaptive migration of West African Fulbe herders only occurred because of the long-term development of social networks between migrants and non-migrants through trade and seasonal grazing. On the other hand, social ties do not always benefit mental health. Some migrants, including those from poor regions or communities with no formal safety net, may face considerable burden to provide financial and emotional resources to family members who remain in countries of origin. In destination communities, migrants often face significant social marginalization. Therefore, policies and programs that aim to maintain ongoing social ties among migrants and their family and community members may be critically important in efforts to enhance population resilience and adaptation to climate change and to improve mental health outcomes. Several online platforms, like Refugee Start Force

  19. An Exploratory Examination of Social Ties and Crime in Mobile Home Communities

    Directory of Open Access Journals (Sweden)

    William P. McCarty

    2013-11-01

    Full Text Available Guided by the systemic model of social disorganization, the purpose of this study was to explore the nature of social ties in mobile home communities and examine how that relates to rates of violent and property crime. Interviews with a small sample of mobile home residents, owners, and managers in Omaha, Nebraska, indicate a wide spectrum of communities, from those characterized by an atomized population to those with strong social ties. Fear of crime, ethnically heterogeneous populations, and lax management were cited by respondents as factors that undermined relationships. Proactive management and a desire to help neighbors were cited by respondents as factors that helped strengthen relationships. Violent and property crime rates for the mobile home communities were largely consistent with the interview data, providing support for the importance of social networks and a systemic model of social disorganization. The implications of these findings for research and policy are also explored.

  20. The Role of Social Ties in Word-of-Mouth Effectiveness

    DEFF Research Database (Denmark)

    Martensen, Anne Duhr; Grønholdt, Lars

    2015-01-01

    This article develops consumer segmentation based on the strength of social ties in word-of-mouth (WOM) communication and examines the influence of WOM on behavioral attitude and intention in these segments. Data were collected through a survey among receivers of retail banking WOM. A cluster...

  1. Social ties within school classes : The roles of gender, ethnicity, and having older siblings

    NARCIS (Netherlands)

    Soetevent, AR; Kooreman, P

    2005-01-01

    In this paper we identify the lines along which social ties between high-school teenagers are primarily formed. To this end, we introduce interaction weights between pupils in the same school class that are a function of exogenous individual background characteristics, such as gender, ethnicity, and

  2. Which Peers Matter: How Social Ties Affect Peer-Group Effects

    Science.gov (United States)

    Poldin, Oleg; Valeeva, Diliara; Yudkevich, Maria

    2016-01-01

    We study how the achievements of university students are influenced by the characteristics and achievements of peers in individuals' social networks. Defining peer group in terms of friendship and study partner ties enables us to apply a network regression model and thereby disentangle the influence of peers' performance from that of peers'…

  3. Peer monitoring, social ties and moral hazard in group lending programmes : evidence from Eritrea

    NARCIS (Netherlands)

    Hermes, C.L.M.; Lensink, B.W.; Mehrteab, H.T.

    2003-01-01

    In this paper, we provide an empirical analysis of the impact of monitoring and social ties within group lending programs on moral hazard behavior of its participants, based on data from an extensive questionnaire held in Eritrea among participants of 102 groups. We find support for the fact that

  4. Peer monitoring, social ties and moral hazard in group lending programs : Evidence from Eritrea

    NARCIS (Netherlands)

    Hermes, N; Lensink, R; Mehrteab, HT

    In this paper, we investigate the impact of monitoring and social ties on moral hazard behavior within group lending programs. Our study is based on data from an extensive questionnaire held in Eritrea among participants of 102 groups. We separately analyze the impact of group leaders and other

  5. An Agent Model for a Human’s Social Support Network Tie Preference During Depression

    NARCIS (Netherlands)

    Aziz, A.A.; Klein, M.C.A.; Treur, J.; Baeza-Yates, R.; Lang, J.; Mitra, S.; Parsons, S.; Pasi, G.

    2009-01-01

    Seeking support from their environment is important for people suffering from a depression. People usually have different social networks to which they are attached with different ties. In this paper, a computational model is presented that describes the selection of network members for seeking

  6. Which Peers Matter : How Social Ties Affect Peer-group Effects

    NARCIS (Netherlands)

    Poldin, O.; Valeeva, D.; Yudkevich, M.

    We study how the achievements of university students are influenced by the characteristics and achievements of peers in individuals’ social networks. Defining peer group in terms of friendship and study partner ties enables us to apply a network regression model and thereby disentangle the influence

  7. Let the Weakest Link Go! Empirical Explorations on the Relative Importance of Weak and Strong Ties on Social Networking Sites

    Directory of Open Access Journals (Sweden)

    Nicole C. Krämer

    2014-12-01

    Full Text Available Theoretical approaches as well as empirical results in the area of social capital accumulation on social networking sites suggest that weak ties/bridging versus strong ties/bonding social capital should be distinguished and that while bonding social capital is connected to emotional support, bridging social capital entails the provision of information. Additionally, recent studies imply the notion that weak ties/bridging social capital are gaining increasing importance in today’s social media environments. By means of a survey (N = 317 we challenged these presuppositions by assessing the social support functions that are ascribed to three different types of contacts from participants’ network (weak, medium, or strong tie. In contrast to theoretical assumptions, we do not find that weak ties are experienced to supply informational support whereas strong ties first and foremost provide emotional support. Instead we find that within social networking sites, strong ties are perceived to provide both emotional and informational support and weak ties are perceived as less important than recent literature assumes.

  8. A 10-Year Follow-Up Study of Social Ties and Functional Health among the Old: The AGES Project.

    Science.gov (United States)

    Murata, Chiyoe; Saito, Tami; Tsuji, Taishi; Saito, Masashige; Kondo, Katsunori

    2017-07-03

    In Asian nations, family ties are considered important. However, it is not clear what happens among older people with no such ties. To investigate the association, we used longitudinal data from the Aichi Gerontological Evaluation Study (AGES) project. Functionally independent older people at baseline ( N = 14,088) in 10 municipalities were followed from 2003 to 2013. Social ties were assessed by asking about their social support exchange with family, relatives, friends, or neighbors. Cox proportional hazard models were employed to investigate the association between social ties and the onset of functional disability adjusting for age, health status, and living arrangement. We found that social ties with co-residing family members, and those with friends or neighbors, independently protected functional health with hazard ratios of 0.81 and 0.85 among men. Among women, ties with friend or neighbors had a stronger effect on health compared to their male counterparts with a hazard ratio of 0.89. The fact that social ties with friends or neighbors are associated with a lower risk of functional decline, independent of family support, serves to underscore the importance of promoting social ties, especially among those lacking family ties.

  9. Strengthening Social Ties to Increase Confidence and Self-Esteem Among Sexual and Gender Minority Youth.

    Science.gov (United States)

    Romijnders, Kim A; Wilkerson, J Michael; Crutzen, Rik; Kok, Gerjo; Bauldry, Jessica; Lawler, Sylvia M

    2017-05-01

    Sexual and gender minority (SGM) youth too often live in nonsupportive environments. This study reports the influence of social support from primary and secondary social ties on confidence and self-esteem among participants in Hatch Youth, a drop-in group-level intervention for SGM youth. Each 3-hour Hatch Youth meeting consists of a social, educational, and youth-led support hour. Over 14 weeks, these meetings were randomly observed and individual interviews with participating youth ( n = 12) and staff and volunteers ( n = 12) were conducted; data underwent a content analysis. Participants perceived an increase in confidence and self-esteem through enhanced bonding with family and friends, a sense of belonging, and community empowerment because of their involvement with Hatch Youth, suggesting drop-in centers can strengthen secondary social ties and improve confidence and self-esteem.

  10. Problematic Alcohol Use and Problem Gambling: Associations to Structural and Functional aspects of Social Ties in a Finnish Population Sample

    Directory of Open Access Journals (Sweden)

    Nordmyr Johanna

    2016-09-01

    Full Text Available AIMS – This study aims to explore associations between structural and functional aspects of social networks and relationships (here labelled social ties among individuals exhibiting problematic alcohol use and problem gambling, respectively.

  11. Can Social Ties be Harmful? Examining the Spread of Suicide in Early Adulthood.

    Science.gov (United States)

    Mueller, Anna S; Abrutyn, Seth; Stockton, Cynthia

    2015-06-01

    Durkheim posited that social relationships protect individuals against suicide; however, substantial research demonstrates that suicide can spread through the very ties Durkheim theorized as protective. With this study, we use Waves I, III, and IV of the National Longitudinal Study of Adolescent Health, to investigate whether young adults' suicide attempts and thoughts are in part products of exposure to suicidal behaviors via their social relationships. We find that young adults who have had family members or friends attempt suicide are more likely to report suicide ideation or even suicide attempts, over both the short and long run. This finding is robust to many important controls for risk and protective factors for suicide. Our findings have implications for the sociology of suicide, not the least of which, is that social ties have the power to harm in addition to the power to protect.

  12. Religious and Non-religious Activity Engagement as Assets in Promoting Social Ties Throughout University: The Role of Emotion Regulation.

    Science.gov (United States)

    Semplonius, Thalia; Good, Marie; Willoughby, Teena

    2015-08-01

    Emerging adulthood is a time of many changes. For example, one change that occurs for a subset of emerging adults is leaving home and starting university. Importantly, the creation of social ties can aid in promoting positive adjustment during university. This study investigated whether involvement in religious activities promotes social ties among university students directly and/or indirectly through emotion regulation. Importantly, involvement in religious activities may promote self-regulatory skills, and the ability to effectively regulate emotions can aid in navigating social interactions. To rule out potentially important confounding variables, spirituality and involvement in non-religious clubs were statistically controlled in all analyses. The participants included 1,132 university students (70.5 % female) from a university in Ontario, Canada who were surveyed each year over a period of 3 years. The results indicated that involvement in religious activities indirectly predicted more social ties over time through emotion regulation. Spirituality did not predict social ties or emotion regulation. Furthermore, non-religious clubs directly predicted more social ties over time. Thus, although involvement in religious and non-religious activities both predicted more social ties in a university setting over time, the mechanism by which these activities promote social ties differed.

  13. Differential Disclosure Across Social Network Ties Among Women Living with HIV

    OpenAIRE

    Rice, Eric; Comulada, Scott; Green, Sara; Arnold, Elizabeth Mayfield; Rotheram-Borus, Mary Jane

    2009-01-01

    Women?s disclosure of their HIV serostatus across social network ties was examined in a sample of women living in Los Angeles (n?=?234), using multivariate random intercept logistic regressions. Women with disclosure-averse attitudes were less likely to disclose, while women with higher CD4+ counts were significantly more likely to disclose, regardless of relationship type. Relative to all other types of relationships, spouses/romantic partners were greater than four times more likely to be t...

  14. Social Relationships and Health: Is Feeling Positive, Negative, or Both (Ambivalent) about your Social Ties Related to Telomeres?

    Science.gov (United States)

    Uchino, Bert N.; Cawthon, Richard M.; Smith, Timothy W.; Light, Kathleen C.; McKenzie, Justin; Carlisle, McKenzie; Gunn, Heather; Birmingham, Wendy; Bowen, Kimberly

    2012-01-01

    Objective The quality of one’s personal relationships has been linked to morbidity and mortality across different diseases. As a result, it is important to examine more integrative mechanisms that might link relationships across diverse physical health outcomes. In this study, we examine associations between relationships and telomeres which predict general disease risk. These questions are pursued in the context of a more comprehensive model of relationships that highlights the importance of jointly considering positive and negative aspects of social ties. Method 136 individuals from a community sample (ages 48 to 77) completed the social relationships index which allows a determination of relationships that differ in their positive and negative substrates (i.e., ambivalent, supportive, aversive, indifferent). Telomere length was determined from peripheral blood mononuclear cells via quantitative PCR. Results Participants who had a higher number of ambivalent ties in their social networks evidenced shorter telomeres. These results were independent of other relationships types (e.g., supportive), as well as standard control variables (e.g., age, health behaviors, medication use). Gender moderated the links between ambivalent ties and telomere length with these associations seen primarily in women. Follow-up analyses revealed that the links between ambivalent ties and telomeres were primarily due to friendships, parents, and social acquaintances. Conclusions Consistent with epidemiological findings, these data highlight a novel and integrative biological mechanism by which social ties may impact health across diseases, and further suggests the importance of incorporating both positivity and negativity in the study of specific relationships and physical health. PMID:22229928

  15. Close social ties and health in later life: Strengths and vulnerabilities.

    Science.gov (United States)

    Rook, Karen S; Charles, Susan T

    2017-09-01

    The world is aging at an unprecedented rate, with older adults representing the fastest-growing segment of the population in most economically developed and developing countries. This demographic shift leaves much uncharted territory for researchers who study social relationships and health. Social relationships exert powerful influences on physical health in later adulthood, a critical consideration given age-related increases in the prevalence of chronic health conditions and physical disability. A large body of research indicates that older adults report greater satisfaction with their social networks than do younger adults, and that they often take measures to minimize their exposure to negative social encounters. These emotionally satisfying and generally positive social ties afford some health protection against a backdrop of mounting physical limitations and play an important role when juxtaposed with the potentially health-damaging frictions that sometimes emerge in older adults' social relationships. Although most older adults report that they are satisfied with their social ties, some older adults experience frequent conflicts or ambivalent exchanges with members of their social networks, and these experiences detract from their health. In addition, many older adults will experience the loss of one or more close relationships during the course of their lives, with ramifications for their health and, often, for the reorganization of their social lives over time. Understanding how both the strengths and vulnerabilities of close social relationships affect health and well-being in later life is an important goal, particularly in view of the accelerating rate of population aging worldwide. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  16. [From one generation to another, the threats of the disintegration of social ties].

    Science.gov (United States)

    Blondel, Frédéric; Delzescaux, Sabine

    2010-01-01

    In our modern societies, social ties are reflected in three forms of social relationships which merge with each other: social norms, local social networks and relationships within families. In times of abundance these three forms tend to lead to the same ethical attitude towards elderly and dependent people. Each agrees on the importance of providing a level of care which guarantees elderly people a state of well-being which we would all like to enjoy ourselves. In times of crisis however these three forms tend to fall out of synch with each other as the expectations of one can contradict those of another. What are the risks of such a de-synchronisation in the support given to elderly people?

  17. How Social Ties Influence Consumer: Evidence from Event-Related Potentials.

    Directory of Open Access Journals (Sweden)

    Jing Luan

    Full Text Available A considerable amount of marketing research has reported that consumers are more saliently influenced by friends (strong social ties than by acquaintances and strangers (weak social ties. To shed light on the neural and psychological processes underlying such phenomenon, in this study we designed an amended S1-S2 paradigm (product-[reviewer-review] that is based on realistic consumer purchase experiences. After incoming all given information (product, reviewer, review, participants were required to state their purchase intentions. The neurocognitive and emotional processes related to friend and stranger stimuli were delineated to suggest how social ties influence consumers during their shopping processes. Larger P2 (fronto-central scalp areas and P3 (central and posterior-parietal scalp areas components under stranger condition were elicited successfully. These findings demonstrate that the cognitive and emotional processing of friend and stranger stimuli occurs at stages of neural activity, and can be indicated by the P2 and P3 components. Electrophysiological data also support the hypothesis that different neural and emotional processing magnitude and strength underlie friend and stranger effect in the context of consumer purchase. During this process, the perception of stimuli evoked P2, subsequently emotional processing and attention modulation were activated and indicated by P2 and P3. The friend dominated phenomenon can be interpreted as the result of distinctive neurocognitive and emotional processing magnitude, which suggests that psychological and emotional factors can guide consumer decision making. This study consolidates that event related potential (ERP methodology is likely to be a more sensitive method for investigating consumer behaviors. From the perspectives of management and marketing, our findings show that the P2 and P3 components can be employed as an indicator to probe the influential factors of consumer purchase

  18. How Social Ties Influence Consumer: Evidence from Event-Related Potentials.

    Science.gov (United States)

    Luan, Jing; Yao, Zhong; Bai, Yan

    2017-01-01

    A considerable amount of marketing research has reported that consumers are more saliently influenced by friends (strong social ties) than by acquaintances and strangers (weak social ties). To shed light on the neural and psychological processes underlying such phenomenon, in this study we designed an amended S1-S2 paradigm (product-[reviewer-review]) that is based on realistic consumer purchase experiences. After incoming all given information (product, reviewer, review), participants were required to state their purchase intentions. The neurocognitive and emotional processes related to friend and stranger stimuli were delineated to suggest how social ties influence consumers during their shopping processes. Larger P2 (fronto-central scalp areas) and P3 (central and posterior-parietal scalp areas) components under stranger condition were elicited successfully. These findings demonstrate that the cognitive and emotional processing of friend and stranger stimuli occurs at stages of neural activity, and can be indicated by the P2 and P3 components. Electrophysiological data also support the hypothesis that different neural and emotional processing magnitude and strength underlie friend and stranger effect in the context of consumer purchase. During this process, the perception of stimuli evoked P2, subsequently emotional processing and attention modulation were activated and indicated by P2 and P3. The friend dominated phenomenon can be interpreted as the result of distinctive neurocognitive and emotional processing magnitude, which suggests that psychological and emotional factors can guide consumer decision making. This study consolidates that event related potential (ERP) methodology is likely to be a more sensitive method for investigating consumer behaviors. From the perspectives of management and marketing, our findings show that the P2 and P3 components can be employed as an indicator to probe the influential factors of consumer purchase intentions.

  19. Building Social Capital: How the news and the strength of the ties in the political discussion foster reciprocity

    Directory of Open Access Journals (Sweden)

    Alberto Ardèvol-Abreu

    2018-03-01

    Full Text Available Reciprocity, a social principle that emerges in non-negotiated, inter-personal exchange, is arguably a key construct in generating social capital. However, little research has made this empirical connection. Building on an Orientation-Stimulus-Reasoning-Orientation-Response model, this study advances a theoretical and empirical model in which news use and political discussion tie strength contributes to the development of reciprocity and social capital. Drawing on two-wave panel data, results suggest that reciprocity is a strong predictor of social capital. News media use also directly predicts reciprocity, as well as political discussion with both strong and weak ties, and social capital. Additionally, discussion with weak ties and reciprocity mediate the relationship between news use and social capital.

  20. Does Visual Impairment Affect Social Ties in Late Life? Findings of a Multicenter Prospective Cohort Study in Germany.

    Science.gov (United States)

    Hajek, A; Brettschneider, C; Lühmann, D; Eisele, M; Mamone, S; Wiese, B; Weyerer, S; Werle, J; Pentzek, M; Fuchs, A; Stein, J; Luck, T; Bickel, H; Weeg, D; Heser, K; Jessen, F; Maier, W; Scherer, M; Riedel-Heller, S G; König, H-H

    2017-01-01

    To investigate how visual impairment affects social ties in late life longitudinally. Population-based prospective cohort study. Individuals in old age were recruited via general practitioners' offices (at six study centers) in Germany. They were interviewed every 18 months. Individuals aged 75 years and above at baseline. Follow-up wave 2 (36 months after baseline, n=2,443) and wave 4 (72 months after baseline, n=1,618) were used for the analyses presented here. Social ties were assessed using the 14-item form of the questionnaire for social support (F-SozU K-14). Visual impairment was self-rated on a three level Likert scale (no impairment, mild visual impairment, or severe/profound visual impairment). Adjusting for sociodemographic factors, hearing impairment and comorbidity, fixed effects regressions revealed that the onset of mild visual impairment decreased the social support score, in particular the emotional support score. Additionally, the onset of mild hearing impairment decreased the social support score in men. Moreover, increasing age decreased the social support score in the total sample and in both sexes. Loss of spouse and increasing comorbidity did not affect the social support score. Our results highlight the importance of visual impairment for social ties in late life. Consequently, appropriate strategies in order to delay visual impairment might help to maintain social ties in old age.

  1. Ties That Bond: Youth Sport as a Vehicle for Social Identity and Positive Youth Development.

    Science.gov (United States)

    Bruner, Mark W; Balish, Shea M; Forrest, Christopher; Brown, Sarah; Webber, Kristine; Gray, Emily; McGuckin, Matthew; Keats, Melanie R; Rehman, Laurene; Shields, Christopher A

    2017-06-01

    An emerging area of research has focused on understanding how the group dynamics of a sport team influence positive youth development (PYD). The identities that youth form through their membership in sport teams (i.e., social identities) have been found to influence teammate behavior and team performance. Yet, minimal work exists on social identity and PYD in youth sport. The purpose of this study was to investigate the relationship between social identity and PYD in sport. Youth engaged in recreational sport (N = 219; M age  = 11.61 years, SD = 1.39 years) completed measures of social identity and PYD in sport. The social identity measure assessed 3 dimensions including ingroup ties (IGT; perceptions of similarity, bonding, belongingness), cognitive centrality (importance of being a team member), and ingroup affect (IGA; feelings associated with group membership). A regression analysis was performed separately for 4 PYD outcomes (personal and social skills, goal setting, initiative, negative experiences) with the 3 dimensions of social identity entered as predictors. Regression analyses revealed that IGT and IGA were positively associated with personal and social skills (R 2 Adj. = .29). Further, IGT predicted initiative (R 2 Adj. = .16), whereas IGA was positively associated with goal setting (R 2 Adj. = .17) and negatively associated with negative experiences (R 2 Adj. = .08). The findings extend previous research highlighting the benefits of social identity on teammate behavior and team performance and demonstrate how social identity may contribute to PYD through sport.

  2. Creative benefits from well-connected leaders: leader social network ties as facilitators of employee radical creativity.

    Science.gov (United States)

    Venkataramani, Vijaya; Richter, Andreas W; Clarke, Ronald

    2014-09-01

    Employee radical creativity critically depends on substantive informational resources from others across the wider organization. We propose that the social network ties of employees' immediate leaders assume a central role in garnering these resources, thereby fostering their employees' radical creativity both independent of and interactively with employees' own network ties. Drawing on data from 214 employees working in 30 teams of a public technology and environmental services organization, we find that team leaders' betweenness centrality in the idea network within their teams as well as among their peer leaders provides creative benefits beyond employees' own internal and external ties. Further, employees' and leaders' ties within and external to the team interactively predict employee radical creativity. Implications for theory and practice are discussed. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  3. Identifying Weak Ties from Publicly Available Social Media Data in an Event

    DEFF Research Database (Denmark)

    Prakash Gupta, Jayesh; Menon, Karan; Kärkkäinen, Hannu

    2016-01-01

    The concept of weak ties was introduced by Granovetter through the seminal paper titled "Strength of weak ties". Since then the role of weak ties in general and their specific role as occupying the structural hole has been explored in many different fields. In this study, we identify actual or po...

  4. Impact of weak social ties and networks on poor sleep quality: A case study of Iranian employees.

    Science.gov (United States)

    Masoudnia, Ebrahim

    2015-12-01

    The poor sleep quality is one of the major risk factors of somatic, psychiatric and social disorders and conditions as well as the major predictors of quality of employees' performance. The previous studies in Iran had neglected the impacts of social factors including social networks and ties on adults sleep quality. Thus, the aim of the current research was to determine the relationship between social networks and adult employees' sleep quality. This study was conducted with a correlational and descriptive design. Data were collected from 360 participants (183 males and 177 females) who were employed in Yazd public organizations in June and July of 2014. These samples were selected based on random sampling method. In addition, the measuring tools were the Pittsburgh Sleep Quality Index (PSQI) and Social Relations Inventory (SRI). Based on the results, the prevalence rate of sleep disorder among Iranian adult employees was 63.1% (total PSQI>5). And, after controlling for socio-demographic variables, there was significant difference between individuals with strong and poor social network and ties in terms of overall sleep quality (p<.01), subjective sleep quality (p<.01), habitual sleep efficiency (p<.05), and daytime dysfunction (p<.01). The results also revealed that the employees with strong social network and ties had better overall sleep quality, had the most habitual sleep efficiency, and less daytime dysfunction than employees with poor social network and ties. It can be implied that the weak social network and ties serve as a risk factor for sleep disorders or poor sleep quality for adult employees. Therefore, the social and behavioral interventions seem essential to improve the adult's quality sleep. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. The dynamic evolution of social ties and user-generated content: a case study on a Douban group

    Science.gov (United States)

    Shan, Siqing; Ren, Jie; Li, Cangyan

    2017-11-01

    As platforms based on user-generated content (UGC), social media platforms emphasise the social ties between users and user participation, which promote the communication and propagation of ideas and help to build and maintain relationships. However, many researchers have studied only predefined social networks, such as academic social networks. We believe that there are certain characteristics associated with the network's UGC worth evaluating. We conducted research in communities in which content attracts discussion and new members and examined the evolution patterns of social and content networks in a topic-oriented Douban group. Datasets of user and content information in communities of interest were collected through web crawler software. Networks based on social and content ties were constructed and analysed. We chose scale, density, centrality, average path length and cluster coefficient as measures for exploring the evolution and correlation of both types of networks. These findings are valuable for social media marketing and helpful in directing and controlling public opinion.

  6. Does the rise of the Internet bring erosion of strong ties? Analyses of social media use and changes in core discussion networks

    NARCIS (Netherlands)

    Vriens, Eva; van Ingen, Erik

    2017-01-01

    We derive hypotheses from popular accounts of how use of social media affects our strong ties. Several authors have suggested that social media use erodes our strong ties by increasing the volume of social interactions and decreasing their depth. Using two-wave panel data representative of the Dutch

  7. The effect of interaction topic and social ties on media choice and the role of four underlying mechanisms

    NARCIS (Netherlands)

    Croes, Emmelyn; Antheunis, Marjolijn; Schouten, Alexander; Krahmer, Emiel

    2018-01-01

    This study employed a scenario-based approach whereby participants were asked to choose which communication channel they prefer in certain situations. The first aim was to determine the effect of the topic of interactions and social ties on channel choice. The second aim was to examine the

  8. With Some Help From My Network: Supplementing eHealth Literacy With Social Ties.

    Science.gov (United States)

    Hayat, Tsahi Zack; Brainin, Esther; Neter, Efrat

    2017-03-30

    others compared to Israeli Jews. Although the availability of help and the notion of ethnicity have been discussed extensively within the context of social capital and health, our findings offer initial evidence for the relevancy of these concepts when studying individuals' eHealth literacy. Specifically, our findings enable a better understanding of the role of social ties and ethnicity in moderating the interplay between eHealth literacy and perceived health outcomes. Given the increased importance of eHealth information, our findings enhance understanding of how social ties can potentially compensate for low eHealth literacy. ©Tsahi (Zack) Hayat, Esther Brainin, Efrat Neter. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 30.03.2017.

  9. The Best of Both Worlds? Online Ties and the Alternating Use of Social Network Sites in the Context of Migration

    Directory of Open Access Journals (Sweden)

    Jens F. Binder

    2014-12-01

    Full Text Available While an ever-growing body of research is concerned with user behavior on individual social network sites (SNSs—mostly Facebook—studies addressing an alternating use of two or more SNS are rare. Here, we investigate the relationship between alternating SNS use and social capital in the context of migration. Alternating SNS use avoids some of the problems associated with large networks located on one site; in particular the management of different social or cultural spheres. Not only does this strategy hold potential for increased social capital, it also provides a particular incentive for migrants faced with the challenge of staying in touch with back home and managing a new social environment. Two survey studies are presented that focus on the relationship between alternating SNS use and online ties in a migrant context involving Indian nationals. Study 1 looked at migration within India, whereas Study 2 compared international with domestic SNS users. In both studies, alternating SNS use added to the prediction of online network size and accounted for differences in network size found for migrant and non-migrant users. Differences were due to the number of peripheral ties, rather than core ties. Findings suggest that alternating SNS use may constitute a compensatory strategy that helps to overcome lower levels of socializing represented through a single SNS.

  10. O discurso e o laço social dos meninos de rua Street boys discourse and social ties

    Directory of Open Access Journals (Sweden)

    Miriam Debieux Rosa

    1999-01-01

    Full Text Available O artigo relata pesquisa que quer compreender como a constituição subjetiva de crianças e adolescentes que vivem na rua, os chamados meninos de rua, articula-se ao laço social, a partir da especificidade da escuta psicanalítica de crianças e adolescentes. Um processo de desqualificação e desvalorização social da família destes jovens, propicia a ruptura destes com a família e escola, levando-os para a rua. Tal ruptura faz surgir o discurso social, que substitui o discurso dos pais, de onde poderiam extrair os significantes de sua filiação e sexuação, e destitui estes meninos do lugar de crianças e adolescentes, justifica o abandono, o descaso e o medo, e oferece-lhes como única possibilidade de nomeação a identidade de delinqüente.The article reports a research on how the subjective constitution of children and adolescents who live on the streets, known as street kids, relate to the social ties, based on the specific psychoanalical hearing of children and adolescents. A process of social disqualification and depreciation of these children’s families, conducts them to break up with their families and schools, leading them to the streets. This rupture brings the social address about, which substitutes the parents address, from which they could take the meaning of their filiation and sexuality. This rupture also deprives them of the condition of being children and adolescents, justifying the abandonment, the neglect and the fear and offering them the only possibility of an identity as a delinquent.

  11. Homeless but Connected: The Role of Heterogeneous Social Network Ties and Social Networking Technology in the Mental Health Outcomes of Street-Living Youth

    OpenAIRE

    Rice, Eric; Ray, Diana; Kurzban, Seth

    2011-01-01

    Although social integration tends to have positive effects on the mental health of housed adolescents, the role of homeless adolescents’ social networks is more ambiguous. Social network data were collected from 136 homeless adolescents in Hollywood, California to examine how network ties are associated with symptoms of anxiety and depression. Face-to-face relationships with street-based peers were a risk factor for both anxiety and depression, while contacting home-based friends through soci...

  12. Social Tie Strength and Online Victimization: An Analysis of Young People Aged 15–30 Years in Four Nations

    Directory of Open Access Journals (Sweden)

    Teo Keipi

    2017-01-01

    Full Text Available Online interaction through the use of social networking sites (SNS continues to be a significant component of the socialization of young people today, yet little research exists toward linking various relational forms to prevalent and much-studied online risks cross-nationally. This article provides a link between relational dynamics and online risks identified in previous research toward a new perspective on how social tie strength is related to experiences of hate victimization and harassment online. The analysis is based on survey data of Finnish ( n  = 555, American ( n  = 1033, German ( n  = 978, and British ( n  = 999 young people aged 15–30 years. Variables, including age, gender, main activity, SNS use, quantity, and extent of online and offline social networks including social tie strength and online community identification, were analyzed toward finding their associations with online hate victimization and harassment. Results showed that experiences of hate victimization and harassment were similar cross-nationally and that those who were personally harassed online also reported high SNS activity. Furthermore, no association was found between social network size and negative experiences. Notable cross-national differences were also detected in the results. Findings emphasize the importance of understanding variables fostering online risks for young people while providing a new perspective on what aspects of social life may help negate negative effects online.

  13. A community of strangers: the dis-embedding of social ties.

    Science.gov (United States)

    Parigi, Paolo; State, Bogdan; Dakhlallah, Diana; Corten, Rense; Cook, Karen

    2013-01-01

    In this paper we explore two contrasting perspectives on individuals' participation in associations. On the one hand, some have considered participation the byproduct of pre-existing friendship ties--the more friends one already has in the association, the more likely he or she is to participate. On the other hand, some have considered participation to be driven by the association's capacity to form new identities--the more new friends one meets in the association, the more likely he or she is to participate. We use detailed temporal data from an online association to adjudicate between these two mechanisms and explore their interplay. Our results show a significant impact of new friendship ties on participation, compared to a negligible impact of pre-existing friends, defined here as ties to other members formed outside of the organization's context. We relate this finding to the sociological literature on participation and we explore its implications in the discussion.

  14. A community of strangers: the dis-embedding of social ties.

    Directory of Open Access Journals (Sweden)

    Paolo Parigi

    Full Text Available In this paper we explore two contrasting perspectives on individuals' participation in associations. On the one hand, some have considered participation the byproduct of pre-existing friendship ties--the more friends one already has in the association, the more likely he or she is to participate. On the other hand, some have considered participation to be driven by the association's capacity to form new identities--the more new friends one meets in the association, the more likely he or she is to participate. We use detailed temporal data from an online association to adjudicate between these two mechanisms and explore their interplay. Our results show a significant impact of new friendship ties on participation, compared to a negligible impact of pre-existing friends, defined here as ties to other members formed outside of the organization's context. We relate this finding to the sociological literature on participation and we explore its implications in the discussion.

  15. No creative person is an island : Organisational culture, academic project-based creativity, and the mediating role of intra-organisational social ties

    NARCIS (Netherlands)

    van Kessel, F.G.A.; Oerlemans, L.A.G.; van Stroe-Biezen, S.A.M.

    2014-01-01

    This paper examines the relationship between perceptions of organizational culture, academics’ social embeddedness, and their creative paper project output. It argues that the extent to which researchers working on paper projects are socially embedded by having social ties with colleagues inside and

  16. The intersection of class origin and immigration background in structuring social capital: the role of transnational ties.

    Science.gov (United States)

    Andersson, Anton; Edling, Christofer; Rydgren, Jens

    2018-03-01

    The study investigates inequalities in access to social capital based on social class origin and immigration background and examines the role of transnational ties in explaining these differences. Social capital is measured with a position generator methodology that separates between national and transnational contacts in a sample of young adults in Sweden with three parental backgrounds: at least one parent born in Iran or Yugoslavia, or two Sweden-born parents. The results show that having socioeconomically advantaged parents is associated with higher levels of social capital. Children of immigrants are found to have a greater access to social capital compared to individuals with native background, and the study shows that this is related to transnational contacts, parents' education and social class in their country of origin. Children of immigrants tend to have more contacts abroad, while there is little difference in the amount of contacts living in Sweden across the three groups. It is concluded that knowledge about immigration group resources help us predict its member's social capital, but that the analysis also needs to consider how social class trajectories and migration jointly structure national and transnational contacts. © London School of Economics and Political Science 2017.

  17. Assessing the Impact of De Novo Social Ties within Health Intervention Settings: New Questions for Health Behavior Intervention Research.

    Science.gov (United States)

    Tesdahl, Eric; Gesell, Sabina B

    2015-12-01

    Recent developments in the study of health and social networks have focused on linkages between health outcomes and naturally occurring social relations, such as friendship or kinship. Based on findings in this area, a new generation of health behavior intervention programs have been implemented that rely on the formation of new social relations among program participants. However, little is known about the qualities of these de novo social relations. We examined the social networks of 59 participants within a randomized controlled trial of an intervention designed to prevent excessive gestational weight gain. We employed exponential random graph modeling techniques to analyze supportive relationships formed between participants in the intervention arm, to detect unique effects of program participation on the likelihood of forming ties. Program participation had a positive effect on the likelihood of forming supportive social relations, however, in this particular timeframe we did not detect any additional effect of such relations on the health behaviors or outcomes of interest. Our findings raise two critical questions: do short-term group-level programs reliably lead to the formation of new social relations among participants; and do these relations have a unique effect on health outcomes relative to standard methods of health behavior intervention? © 2015 Wiley Periodicals, Inc.

  18. Perceived support from a caregiver's social ties predicts subsequent care-recipient health

    Directory of Open Access Journals (Sweden)

    Dannielle E. Kelley

    2017-12-01

    Full Text Available Most social support research has examined support from an individual patient perspective and does not model the broader social context of support felt by caregivers. Understanding how social support networks may complement healthcare services is critical, considering the aging population, as social support networks may be a valuable resource to offset some of the demands placed on the healthcare system. We sought to identify how caregivers' perceived organizational and interpersonal support from their social support network influences care-recipient health.We created a dyadic dataset of care-recipient and caregivers from the first two rounds of the National Health and Aging Trends survey (2011, 2012 and the first round of the associated National Study of Caregivers survey (2011. Using structural equation modeling, we explored how caregivers' perceived social support is associated with caregiver confidence to provide care, and is associated with care-recipient health outcomes at two time points. All data were analyzed in 2016.Social engagement with members from caregivers' social support networks was positively associated with caregiver confidence, and social engagement and confidence were positively associated with care-recipient health at time 1. Social engagement positively predicted patient health at time 2 controlling for time 1. Conversely, use of organizational support negatively predicted care-recipient health at time 2.Care-recipients experience better health outcomes when caregivers are able to be more engaged with members of their social support network. Keywords: Informal caregiving, Social support, Social support network, Patient-caregiver dyads

  19. Relevant ties matter

    DEFF Research Database (Denmark)

    Larsen, Christian Albrekt; Pedersen, Jacob; Mouw, Ted

    What is the effect of social networks on labor market outcomes? The tradition following Grannovetter claims that social ties have a positive effect on wages, job prestige and job satisfaction. Although a number of studies have found positive correlations between friendship characteristics and lab...

  20. Perceived support from a caregiver's social ties predicts subsequent care-recipient health.

    Science.gov (United States)

    Kelley, Dannielle E; Lewis, Megan A; Southwell, Brian G

    2017-12-01

    Most social support research has examined support from an individual patient perspective and does not model the broader social context of support felt by caregivers. Understanding how social support networks may complement healthcare services is critical, considering the aging population, as social support networks may be a valuable resource to offset some of the demands placed on the healthcare system. We sought to identify how caregivers' perceived organizational and interpersonal support from their social support network influences care-recipient health. We created a dyadic dataset of care-recipient and caregivers from the first two rounds of the National Health and Aging Trends survey (2011, 2012) and the first round of the associated National Study of Caregivers survey (2011). Using structural equation modeling, we explored how caregivers' perceived social support is associated with caregiver confidence to provide care, and is associated with care-recipient health outcomes at two time points. All data were analyzed in 2016. Social engagement with members from caregivers' social support networks was positively associated with caregiver confidence, and social engagement and confidence were positively associated with care-recipient health at time 1. Social engagement positively predicted patient health at time 2 controlling for time 1. Conversely, use of organizational support negatively predicted care-recipient health at time 2. Care-recipients experience better health outcomes when caregivers are able to be more engaged with members of their social support network.

  1. The ties that bind: perceived social support, stress, and IBS in severely affected patients.

    Science.gov (United States)

    Lackner, J M; Brasel, A M; Quigley, B M; Keefer, L; Krasner, S S; Powell, C; Katz, L A; Sitrin, M D

    2010-08-01

    This study assessed the association between social support and the severity of irritable bowel syndrome (IBS) symptoms in a sample of severely affected IBS patients recruited to an NIH-funded clinical trial. In addition, we examined if the effects of social support on IBS pain are mediated through the effects on stress. Subjects were 105 Rome II diagnosed IBS patients (F = 85%) who completed seven questionnaires which were collected as part of a pretreatment baseline assessment. Partial correlations were conducted to clarify the relationships between social support and clinically relevant variables with baseline levels of psychopathology, holding constant number of comorbid medical diseases, age, gender, marital status, ethnicity, and education. Analyses indicated that social support was inversely related to IBS symptom severity. Social support was positively related with less severe pain. A similar pattern of data was found for perceived stress but not quality of life impairment. Regression analyses examined if the effects of social support on pain are mediated by stress. The effects of social support on bodily pain were mediated by stress such that the greater the social support the less stress and the less pain. This effect did not hold for symptom severity, quality of life, or psychological distress. This study links the perceived adequacy of social support to the global severity of symptoms of IBS and its cardinal symptom (pain). It also suggests that the mechanism by which social support alleviates pain is through a reduction in stress levels.

  2. Ties that Bind: A Social Network Approach To Understanding Student Integration and Persistence.

    Science.gov (United States)

    Thomas, Scott L.

    2000-01-01

    This study used a social network paradigm to examine college student integration of 329 college freshmen at a private liberal arts college. Analysis of the structural aspects of students' on-campus associations found differential effects of various social network characteristics on student commitment and persistence. (DB)

  3. The Ties That Bind: How Social Capital Is Forged and Forfeited in Teacher Communities

    Science.gov (United States)

    Bridwell-Mitchell, E. N.; Cooc, North

    2016-01-01

    The effects of social capital on school improvement make it important to understand how teachers forge, maintain, or forfeit collegial relationships. Two common explanations focused on formal organizational features and individual characteristics do not address how social capital accrues from informal dynamics of teachers' interactions in…

  4. Happy but unhealthy: The relationship between social ties and health in an emerging network.

    NARCIS (Netherlands)

    Howell, Jennifer L.; Koudenburg, Namkje; Loschelder, David D.; Weston, Dale; Fransen, Katrien; De Dominices, Stefano; Gallagher, Stephen; Haslam, S. Alexander

    2014-01-01

    Social connections are essential to health and well-being. However, when pursing social acceptance, people may sometimes engage in behavior that is detrimental to their health. Using a multi-time-point design, we examined whether the structure of an emerging network of students in an academic summer

  5. No creative person is an island: Organisational culture, academic project-based creativity, and the mediating role of intra-organisational social ties

    OpenAIRE

    van Kessel, F.G.A.; Oerlemans, L.A.G.; van Stroe-Biezen, S.A.M.

    2014-01-01

    This paper examines the relationship between perceptions of organizational culture, academics’ social embeddedness, and their creative paper project output. It argues that the extent to which researchers working on paper projects are socially embedded by having social ties with colleagues inside and outside their academic department (but within the same university) is a causal step linking organizational values and norms to creative outputs. This study, however, does not find support for the ...

  6. Building ties: social capital network analysis of a forest community in a biosphere reserve in Chiapas, Mexico

    Directory of Open Access Journals (Sweden)

    Luis Rico García-Amado

    2012-09-01

    Full Text Available Governance of the commons depends on the capacity to generate collective action. Networks and rules that foster that collective action have been defined as social capital. However, their causal link is still not fully understood. We use social network analysis to assess social capital, decision-making, and collective action in a forest-based common pool resource management in La Sepultura Biosphere Reserve (Chiapas, Mexico. Our research analyzes the productive networks and the evolution of coffee groups in one community. The network shows some centrality, with richer landholders tending to occupy core positions and poorer landless peasants occupying peripheral ones. This has fostered the community's environmentally oriented development but has also caused internal conflicts. Market requirements have shaped different but complementary productive networks, where organic coffee commercialization is the main source of bridging ties, which has resulted in more connectivity and resilience. Conservation attitudes, along with the institutional setting of the community, have promoted collective action. The unresolved conflicts, however, still leave some concerns about governance in the future.

  7. Role of Temporal Diversity in Inferring Social Ties Based on Spatio-Temporal Data

    OpenAIRE

    Desai, Deshana; Nisar, Harsh; Bhardawaj, Rishab

    2016-01-01

    The last two decades have seen a tremendous surge in research on social networks and their implications. The studies includes inferring social relationships, which in turn have been used for target advertising, recommendations, search customization etc. However, the offline experiences of human, the conversations with people and face-to-face interactions that govern our lives interactions have received lesser attention. We introduce DAIICT Spatio-Temporal Network (DSSN), a spatiotemporal data...

  8. The ties that bind: bonding versus bridging social capital and college student party attendance.

    Science.gov (United States)

    Buettner, Cynthia K; Debies-Carl, Jeffrey S

    2012-07-01

    This study explored the relationship between bonding and bridging social capital and college student attendance at alcohol-present parties, a common method for building informal social networks. A random sample of students (n = 6,291; 52% female) from a large public midwestern university completed a survey regarding their alcohol use and party-related behaviors on targeted weekends. The survey also included questions regarding students' living arrangements, romantic relationships, and membership in student and community organizations. Based on a dichotomous logistic regression analysis, we concluded that the act of attending parties largely serves as a complement to, rather than a substitute for, more conventional and formal social capital. Membership in bonding groups is associated with increased odds of party attendance, and bridging exerts no direct effect on party attendance. However, bridging capital does mitigate the effect of bonding capital, reducing its apparent tendency to promote or contribute to partying. Off-campus parties may offer an informal supplement to more conventional social capital as students establish themselves in their new context. These findings may have implications for structural decisions (e.g., number of roommates) as well as the design of context-based prevention programs that address students' need to quickly build social capital without exposing both themselves and the students around them to the harms associated with high-risk drinking.

  9. Infrastructure and social tie: Spatial model approach on understanding poverty in Malang regency, Indonesia

    Science.gov (United States)

    Ari, I. R. D.; Hasyim, A. W.; Pratama, B. A.; Helmy, M.; Sheilla, M. N.

    2017-06-01

    Poverty is a problem that requires attention from the government especially in developing countries such as Indonesia. This Research takes Place at Kasembon District because it has 53,19% family below poverty line in the region. The purpose of this research is to measure poverty based on 3 poverty indicators published by World Bank and 1 multidimensional poverty index. Furthermore, this research invesitigas the relationship between poverty with social and infrastructure in Kasembon District. This study using social network analysis, hot spots analysis, and regression analysis with ordinary least squares. From the poverty indicators known that Pondokagung Village has the highest poverty rate compared to another region. Results from regression model indicate that social and infrastructure affecting poverty in Kasembon District. Social parameter that affecting poverty is density. Infrastructure parameter that affecting poverty is length of paved road. Coefficient value of density is the largest in the model. Therefore it can be concluded that social factors can give more opportunity to reduce poverty rates in Kasembon District. In the local model of paved road coefficient, it is known that the coefficient for each village has not much different value from the global model.

  10. Social ties and psychological well-being in late life: the mediating role of relationship satisfaction.

    Science.gov (United States)

    Fuller-Iglesias, Heather R

    2015-01-01

    The current paper examines whether quantitative aspects of social support (i.e., support network characteristics) indirectly influence psychological well-being via older adults' qualitative perceptions of support (i.e., satisfaction with social relationships). A sample of 416 adults aged ≥60 was drawn from the Social Integration and Aging Study, a community-based survey conducted in a small US (Midwestern) city. The survey assessed social networks, social support, and physical and mental health among older adults. Bootstrapping was used to examine mediation models. Greater support network size predicted lower perceived stress, fewer depressive symptoms, and better life satisfaction, yet this association was fully mediated by relationship satisfaction. For support network composition, greater proportion kin was associated with lower stress and better life satisfaction, though not depressive symptoms, however, relationship satisfaction did not mediate this link. Findings highlight the complex interplay of support network characteristics and satisfaction, and suggest the greater import of support satisfaction for older adults' psychological well-being.

  11. "You Cannot Talk with All of the Strangers in a Pub": A Longitudinal Case Study of International Postgraduate Students' Social Ties at a British University

    Science.gov (United States)

    Schartner, Alina

    2015-01-01

    The formation of social ties is a major factor in the international student experience (Ramsay et al. in High Educ 54(2):247-265, 2007), influencing student wellbeing and adjustment to the new academic and sociocultural environment (Ward et al. in The psychology of culture shock. Routledge, Hove, 2001). Although a significant body of research in…

  12. Does the group leader matter? The impact of monitoring activities and social ties of group leaders on the repayment performance of groupbased lending Eritrea

    NARCIS (Netherlands)

    Hermes, Niels; Lensink, Robert; Mehrteab, Habteab T.

    2005-01-01

    This paper analyzes whether the effects of monitoring and social ties of the group leader and other group members on repayment performance of groups differ, using data from an extensive questionnaire held in Eritrea among participants of 102 groups. We hypothesize that the monitoring activities and

  13. Ties with Potential: Social Network Structure and Innovative Climate in Dutch Schools

    Science.gov (United States)

    Moolenaar, Nienke M.; Daly, Alan J.; Sleegers, Peter J. C.

    2011-01-01

    Background/Context: Similar to the United States, government efforts to improve education in the Netherlands are focused on innovation and the development of collaborative structures to support the generation of new knowledge. However, empirical evidence of the relationship between social linkages and innovation in education is scarce. Objective:…

  14. Ties with potential: Social network structure and innovative climate in Dutch schools

    NARCIS (Netherlands)

    Moolenaar, N.M.; Daly, A.J.; Sleegers, P.J.C.

    2011-01-01

    Background/Context: Similar to the United States, government efforts to improve education in the Netherlands are focused on innovation and the development of collaborative structures to support the generation of new knowledge. However, empirical evidence of the relationship between social linkages

  15. Ties that tear apart : the social embeddedness of strategic alliance termination

    NARCIS (Netherlands)

    Rooks, G.; Snijders, C.C.P.; Duysters, G.M.

    2013-01-01

    Strategic alliances between firms are inherently unstable, and many alliances fail before the planned termination date. Most studies of the instability of strategic alliances focus on internal factors, such as tensions between alliance partners. In the present study social networks, in particular

  16. Ties that tear apart. The social embeddedness of strategic alliance termination

    NARCIS (Netherlands)

    Rook, G.; Snijders, C.; Duijsters, G.M.

    2013-01-01

    Strategic alliances between firms are inherently unstable, and many alliances fail before the planned termination date. Most studies of the instability of strategic alliances focus on internal factors, such as tensions between alliance partners. In the present study social networks, in particular

  17. Ties That Bond: Youth Sport as a Vehicle for Social Identity and Positive Youth Development

    Science.gov (United States)

    Bruner, Mark W.; Balish, Shea M.; Forrest, Christopher; Brown, Sarah; Webber, Kristine; Gray, Emily; McGuckin, Matthew; Keats, Melanie R.; Rehman, Laurene; Shields, Christopher A.

    2017-01-01

    An emerging area of research has focused on understanding how the group dynamics of a sport team influence positive youth development (PYD). The identities that youth form through their membership in sport teams (i.e., social identities) have been found to influence teammate behavior and team performance. Yet, minimal work exists on social…

  18. Social network influences on technology acceptance : A matter of tie strength, centrality and density

    NARCIS (Netherlands)

    Ten Kate, Stephan; Haverkamp, Sophie; Mahmood, Fariha; Feldberg, Frans

    2010-01-01

    This study examines social network influences on the individual technology acceptance. Since it is believed that individuals' trust, opinions and behavior are influenced by their network, an analysis of that network may help to provide some explanations on technology acceptance. However, since

  19. The Ebb and Flow of Social Network Ties between District Leaders under High-Stakes Accountability

    Science.gov (United States)

    Daly, Alan J.; Finnigan, Kara S.

    2011-01-01

    Recent scholarship suggests the importance of school district offices in supporting reform. These studies provide strategies for building relations between central offices and sites in order to improve change efforts. However, what is frequently overlooked is that organizational reform efforts are socially constructed. Therefore, examining the…

  20. Social Network Perspectives Reveal Strength of Academic Developers as Weak Ties

    Science.gov (United States)

    Matthews, Kelly E.; Crampton, Andrea; Hill, Matthew; Johnson, Elizabeth D.; Sharma, Manjula D.; Varsavsky, Cristina

    2015-01-01

    Social network perspectives acknowledge the influence of disciplinary cultures on academics' teaching beliefs and practices with implications for academic developers. The contribution of academic developers in 18 scholarship of teaching and learning (SoTL) projects situated in the sciences are explored by drawing on data from a two-year national…

  1. Learning from Your Network of Friends: A Trajectory Representation Learning Model Based on Online Social Ties

    KAUST Repository

    Alharbi, Basma Mohammed; Zhang, Xiangliang

    2017-01-01

    Location-Based Social Networks (LBSNs) capture individuals whereabouts for a large portion of the population. To utilize this data for user (location)-similarity based tasks, one must map the raw data into a low-dimensional uniform feature space. However, due to the nature of LBSNs, many users have sparse and incomplete check-ins. In this work, we propose to overcome this issue by leveraging the network of friends, when learning the new feature space. We first analyze the impact of friends on individuals's mobility, and show that individuals trajectories are correlated with thoseof their friends and friends of friends (2-hop friends) in an online setting. Based on our observation, we propose a mixed-membership model that infers global mobility patterns from users' check-ins and their network of friends, without impairing the model's complexity. Our proposed model infers global patterns and learns new representations for both usersand locations simultaneously. We evaluate the inferred patterns and compare the quality of the new user representation against baseline methods on a social link prediction problem.

  2. Learning from Your Network of Friends: A Trajectory Representation Learning Model Based on Online Social Ties

    KAUST Repository

    Alharbi, Basma Mohammed

    2017-02-07

    Location-Based Social Networks (LBSNs) capture individuals whereabouts for a large portion of the population. To utilize this data for user (location)-similarity based tasks, one must map the raw data into a low-dimensional uniform feature space. However, due to the nature of LBSNs, many users have sparse and incomplete check-ins. In this work, we propose to overcome this issue by leveraging the network of friends, when learning the new feature space. We first analyze the impact of friends on individuals\\'s mobility, and show that individuals trajectories are correlated with thoseof their friends and friends of friends (2-hop friends) in an online setting. Based on our observation, we propose a mixed-membership model that infers global mobility patterns from users\\' check-ins and their network of friends, without impairing the model\\'s complexity. Our proposed model infers global patterns and learns new representations for both usersand locations simultaneously. We evaluate the inferred patterns and compare the quality of the new user representation against baseline methods on a social link prediction problem.

  3. Sensory response system of social behavior tied to female reproductive traits.

    Directory of Open Access Journals (Sweden)

    Jennifer M Tsuruda

    Full Text Available Honey bees display a complex set of anatomical, physiological, and behavioral traits that correlate with the colony storage of surplus pollen (pollen hoarding. We hypothesize that the association of these traits is a result of pleiotropy in a gene signaling network that was co-opted by natural selection to function in worker division of labor and foraging specialization. By acting on the gene network, selection can change a suite of traits, including stimulus/response relationships that affect individual foraging behavior and alter the colony level trait of pollen hoarding. The 'pollen-hoarding syndrome' of honey bees is the best documented syndrome of insect social organization. It can be exemplified as a link between reproductive anatomy (ovary size, physiology (yolk protein level, and foraging behavior in honey bee strains selected for pollen hoarding, a colony level trait. The syndrome gave rise to the forager-Reproductive Ground Plan Hypothesis (RGPH, which proposes that the regulatory control of foraging onset and foraging preference toward nectar or pollen was derived from a reproductive signaling network. This view was recently challenged. To resolve the controversy, we tested the associations between reproductive anatomy, physiology, and stimulus/response relationships of behavior in wild-type honey bees.Central to the stimulus/response relationships of honey bee foraging behavior and pollen hoarding is the behavioral trait of sensory sensitivity to sucrose (an important sugar in nectar. To test the linkage of reproductive traits and sensory response systems of social behavior, we measured sucrose responsiveness with the proboscis extension response (PER assay and quantified ovary size and vitellogenin (yolk precursor gene expression in 6-7-day-old bees by counting ovarioles (ovary filaments and by using semiquantitative real time RT-PCR. We show that bees with larger ovaries (more ovarioles are characterized by higher levels of

  4. Tie-Up Cycles in Long-Term Mating. Part II: Fictional Narratives and the Social Cognition of Mating

    Directory of Open Access Journals (Sweden)

    Lorenza Lucchi Basili

    2017-02-01

    Full Text Available In the first part of this paper, we have introduced a novel theoretical approach to mating dynamics, known as Tie-Up Theory (TU. In this second part, in the context of the bio-cultural approach to literature, that assigns to fictional narratives an important valence of social cognition, we apply the conceptual tools presented in the first part to the analysis of mating-related interaction dynamics in some blockbuster Hollywood movies from WWII to today. The interaction dynamics envisioned by our theory accurately reflect, to a significant level of detail, the narrative development of the movies under exam from the viewpoint of the mating dynamics of the couple of main characters, accounting for the specific reasons that lead them to react to certain situations via certain behaviors, and for the reasons why such behaviors lead to certain outcomes. Our analysis seems thus to bring some further legitimacy to the bio-cultural foundation of the narrative structure of the movies that we analyze, and moreover to the idea that it is possible to ‘inquire’ characters about their choices according to the narratological-experimental lines suggested by some proponents of the bio-cultural approach.

  5. Longitudinal analysis of large social networks: estimating the effect of health traits on changes in friendship ties.

    Science.gov (United States)

    O'Malley, A James; Christakis, Nicholas A

    2011-04-30

    We develop novel mixed effects models to examine the role of health traits on the status of peoples' close friendship nominations in the Framingham Heart Study. The health traits considered are both mutable (body mass index (BMI), smoking, blood pressure, body proportion, muscularity, and depression) and, for comparison, basically immutable (height, birth order, personality type, only child, and handedness); and the traits have varying degrees of observability. We test the hypotheses that existing ties (i.e. close friendship nominations) are more likely to dissolve between people with dissimilar (mutable and observable) health traits whereas new ties are more likely to form between those with similar (mutable and observable) traits while controlling for persons' age, gender, geographic separation, and education. The mixed effects models contain random effects for both the nominator (ego) and nominated (alter) persons in a tie to account for the fact that people were involved in multiple relationships and contributed observations at multiple exams. Results for BMI support the hypotheses that people of similar BMI are less likely to dissolve existing ties and more likely to form ties, while smoker to non-smoker ties were the least likely to dissolve and smoker to smoker ties were the most likely to form. We also validated previously known findings regarding homophily on age and gender, and found evidence that homophily also depends upon geographic separation. Copyright © 2011 John Wiley & Sons, Ltd.

  6. “Strength of Weak Ties,” Neighborhood Ethnic Heterogeneity, and Depressive Symptoms among Adults: A Multilevel Analysis of Korean General Social Survey (KGSS 2012

    Directory of Open Access Journals (Sweden)

    Harris Hyun-soo Kim

    2017-06-01

    Full Text Available A substantial body of research, based largely on North American and European contexts, demonstrates that social networks play a critical role in protecting and promoting mental, as well as physical, health. The purpose of this study is to examine how “weak” and “strong” network relations are differentially related to individual mental health (depressive symptoms based on a nationally representative sample of South Korean adults. Using multilevel analysis, the current research also investigates the extent to which contextual or neighborhood-level factors moderate the associations between depression and social network. Findings show that regular interaction with weaker ties (acquaintances, neighbors, coworkers, etc. are associated with better mental health. The number of strong ties (family members and friends, on the other hand, is not a significant predictor of psychological distress. In addition, a cross-level interaction term is observed: The negative relationship between weak ties and depressive symptoms is diminished in neighborhoods with more foreign-born residents or immigrants. General implications beyond the empirical case under investigation are discussed, as to why weak ties can be “strong” in relation to mental health and how this phenomenon can vary according to residential characteristics such as ethnic heterogeneity.

  7. New Tech, New Ties:

    DEFF Research Database (Denmark)

    Ling, Richard

    regardless of where they are. But when we are engaged in these intimate conversations with absent friends, what happens to our relationship with the people who are actually in the same room with us? In New Tech, New Ties, Rich Ling examines how the mobile telephone affects both kinds of interactions......The message of this book is simple: the mobile phone strengthens social bonds among family and friends. With a traditional land-line telephone, we place calls to a location and ask hopefully if someone is "there"; with a mobile phone, we have instant and perpetual access to friends and family......—those mediated by mobile communication and those that are face to face. Ling finds that through the use of various social rituals the mobile telephone strengthens social ties within the circle of friends and family—sometimes at the expense of interaction with those who are physically present—and creates what he...

  8. Tie Content in Professional Networks

    DEFF Research Database (Denmark)

    Zarzecka, Olga

    in resource exchanges and the effect of these differences on the number of, and extent to which, resources are provided by a network tie. Chapter 3 explores how firm underperfomance and social identity with corporate elite alter types of resources a network tie provides. Chapter 4 focuses on a tie’s internal......Professional networks of senior managers have indisputable value for them as well as for their organizations. In recent years, much attention has been given to the structure of these networks as it reflects senior managers’ opportunity to access valuable resources. Surprisingly, the actual...... resources that senior managers acquire through their network ties, i.e. the tie content, remain heavily understudied. Hence, the purpose of this dissertation is to answer the following question: What resources flow through informal ties in senior managers’ professional networks, and why? The first chapter...

  9. The role of strong-tie social networks in mediating food security of fish resources by a traditional riverine community in the Brazilian Amazon

    Directory of Open Access Journals (Sweden)

    Frédéric Mertens

    2015-09-01

    Full Text Available Social networks are a significant way through which rural communities that manage resources under common property regimes obtain food resources. Previous research on food security and social network analysis has mostly focused on egocentric network data or proxy variables for social networks to explain how social relations contribute to the different dimensions of food security. Whole-network approaches have the potential to contribute to former studies by revealing how individual social ties aggregate into complex structures that create opportunities or constraints to the sharing and distribution of food resources. We used a whole-network approach to investigate the role of network structure in contributing to the four dimensions of food security: food availability, access, utilization, and stability. For a case study of a riparian community from the Brazilian Amazon that is dependent on fish as a key element of food security, we mapped the community strong-tie network among 97% of the village population over 14 years old (n = 336 by integrating reciprocated friendship and occupational ties, as well as close kinship relationships. We explored how different structural properties of the community network contribute to the understanding of (1 the availability of fish as a community resource, (2 community access to fish as a dietary resource, (3 the utilization of fish for consumption in a way that allows the villagers to maximize nutrition while at the same time minimizing toxic risks associated with mercury exposure, and (4 the stability of the fish resources in local ecosystems as a result of cooperative behaviors and community-based management. The contribution of whole-network approaches to the study of the links between community-based natural resource management and food security were discussed in the context of recent social-ecological changes in the Amazonian region.

  10. No creative person is an island: Organisational culture, academic project-based creativity, and the mediating role of intra-organisational social ties

    Directory of Open Access Journals (Sweden)

    Leon AG Oerlemans

    2014-02-01

    Full Text Available This paper examines the relationship between perceptions of organizational culture, academics’ social embeddedness, and their creative paper project output. It argues that the extent to which researchers working on paper projects are socially embedded by having social ties with colleagues inside and outside their academic department (but within the same university is a causal step linking organizational values and norms to creative outputs. This study, however, does not find support for the proposed mediating effects. Instead, results indicate that three organizational culture dimensions – i.e. performance orientation, environmental orientation, and innovation support – affect employees’ creative project output through their social embeddedness outside the department (but within their own university. As the organizational culture and social embeddedness of employees outside the department are both contextual factors that (either indirectly or directly matter for the generation of creative project outputs by researchers, this study concludes that “no creative person and no project is an island”.

  11. The Strength of Direct Ties

    DEFF Research Database (Denmark)

    Claussen, Jörg; Falck, Oliver; Grosjean, Thorsten

    2012-01-01

    We analyze the economic effects of a developer's connectedness in the electronic game industry. Knowledge spillovers between developers are likely to be of special relevance in this knowledge-intensive and regionally concentrated industry. We calculate social network measures for a developer......'s connectedness to other developers at multiple points in time. In a regression in which we exploit within-career variation in social network measures, we find that the number of direct ties a developer has to other developers has a strong effect on both a game's revenues and critics' scores. The quality...... of indirect ties makes no additional contribution to the game's success....

  12. Senior Managers’ Network Tie Use

    DEFF Research Database (Denmark)

    Zarzecka, Olga; Villeseche, Florence

    While the importance or even necessity to build and maintain resourceful social networks appears as a forthright fact, there is still a lack of certainty as to who benefits from the resources that can be accessed through senior managers’ networks, and under what conditions. In this paper, we...... contribute to answering this puzzle with a sample constituted of senior managers from Denmark and their network ties, and investigate both economic and sociological conditions of senior managers’ tie use. Our results show that the greater the distance between aspiration level and actual firm performance......, the more likely it is that senior managers will use their network ties to access resources that benefit chiefly the individual rather than the organization. In addition, we demonstrate that this rapport is moderated by senior managers’ social identity as a member of the corporate elite, so that a strong...

  13. Family Ties and Civic Virtues

    DEFF Research Database (Denmark)

    Ljunge, Jan Martin

    I establish a positive relationship between family ties and civic virtues, as captured by disapproval of tax and benefit cheating, corruption, and a range of other dimensions of exploiting others for personal gain. I find that family ties are a complement to social capital, using within country...... evidence from 83 nations and data on second generation immigrants in 29 countries with ancestry in 85 nations. Strong families cultivate universalist values and produce more civic and altruistic individuals. The results provide a constructive role for families in promoting family values that support...

  14. The ties that bind: genetic relatedness predicts the fission and fusion of social groups in wild African elephants.

    Science.gov (United States)

    Archie, Elizabeth A; Moss, Cynthia J; Alberts, Susan C

    2006-03-07

    Many social animals live in stable groups. In contrast, African savannah elephants (Loxodonta africana) live in unusually fluid, fission-fusion societies. That is, 'core' social groups are composed of predictable sets of individuals; however, over the course of hours or days, these groups may temporarily divide and reunite, or they may fuse with other social groups to form much larger social units. Here, we test the hypothesis that genetic relatedness predicts patterns of group fission and fusion among wild, female African elephants. Our study of a single Kenyan population spans 236 individuals in 45 core social groups, genotyped at 11 microsatellite and one mitochondrial DNA (mtDNA) locus. We found that genetic relatedness predicted group fission; adult females remained with their first order maternal relatives when core groups fissioned temporarily. Relatedness also predicted temporary fusion between social groups; core groups were more likely to fuse with each other when the oldest females in each group were genetic relatives. Groups that shared mtDNA haplotypes were also significantly more likely to fuse than groups that did not share mtDNA. Our results suggest that associations between core social groups persist for decades after the original maternal kin have died. We discuss these results in the context of kin selection and its possible role in the evolution of elephant sociality.

  15. Ties That Bind: A Social Network Approach to Understanding Student Integration and Persistence. ASHE Annual Meeting Paper.

    Science.gov (United States)

    Thomas, Scott L.

    This study examined the social networks of college students and how such networks affect student commitment and persistence. The study's theoretical framework was based on application of the social network paradigm to Tinto's Student Integration Model, in which a student's initial commitment is modified over time as a result of the student's…

  16. Them That's Got: How Tie Formation in Partnership Networks Gives High Schools Differential Access to Social Capital

    Science.gov (United States)

    Bridwell-Mitchell, E. N.

    2017-01-01

    School partnerships are important sources of school social capital. Schools may have unequal access to social capital due to the pattern of relationships in the school-partner network. Using data on school resource needs, sociometric measures, and a set of multilevel logit models, the results of a study of 211 New York City public high schools and…

  17. The affective tie that binds: Examining the contribution of positive emotions and anxiety to relationship formation in social anxiety disorder.

    Science.gov (United States)

    Taylor, Charles T; Pearlstein, Sarah L; Stein, Murray B

    2017-06-01

    Individuals with social anxiety disorder (SAD) have difficulty forming social relationships. The prevailing clinical perspective is that negative emotions such as anxiety inhibit one's capacity to develop satisfying social connections. However, empirical findings from social psychology and affective neuroscience suggest that positive emotional experiences are fundamental to establishing new social bonds. To reconcile these perspectives, we collected repeated measurements of anxiety, positive emotions (pleasantness), and connectedness over the course of a controlled relationship formation encounter in 56 participants diagnosed with SAD (64% female; M age =23.3, SD=4.7). Participants experienced both increases in positive emotions and decreases in anxiety throughout the interaction. Change in positive emotions was the most robust predictor of subsequent increases in connectedness, as well as a greater desire to engage one's partner in future social activities, above and beyond reductions in anxiety (medium to large sized effects). Those findings suggest that anxiety-based models alone may not fully explain difficulties in relationship formation in SAD, and underscore the potential value of considering positive emotional experiences in conceptual and treatment models of SAD. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The ties that bind? Social networks of nursing staff and staff’s behaviour towards residents with dementia.

    NARCIS (Netherlands)

    Beek, A.P.A. van; Wagner, C.; Frijters, D.H.M.; Ribbe, M.W.; Groenewegen, P.P.

    2013-01-01

    This study investigated social networks of nursing staff and staff's behaviour towards residents with dementia. We focused on two types of networks: communication networks among staff, and networks between nursing staff and relatives/acquaintances of residents. Data was collected in 37 long-term

  19. The transcription factor Krüppel homolog 1 is linked to hormone mediated social organization in bees

    Directory of Open Access Journals (Sweden)

    Fan Yongliang

    2010-04-01

    Full Text Available Abstract Background Regulation of worker behavior by dominant queens or workers is a hallmark of insect societies, but the underlying molecular mechanisms and their evolutionary conservation are not well understood. Honey bee and bumble bee colonies consist of a single reproductive queen and facultatively sterile workers. The queens' influences on the workers are mediated largely via inhibition of juvenile hormone titers, which affect division of labor in honey bees and worker reproduction in bumble bees. Studies in honey bees identified a transcription factor, Krüppel-homolog 1 (Kr-h1, whose expression in worker brains is significantly downregulated in the presence of a queen or queen pheromone and higher in forager bees, making this gene an ideal candidate for examining the evolutionary conservation of socially regulated pathways in Hymenoptera. Results In contrast to honey bees, bumble bees foragers do not have higher Kr-h1 levels relative to nurses: in one of three colonies levels were similar in nurses and foragers, and in two colonies levels were higher in nurses. Similarly to honey bees, brain Kr-h1 levels were significantly downregulated in the presence versus absence of a queen. Furthermore, in small queenless groups, Kr-h1 levels were downregulated in subordinate workers with undeveloped ovaries relative to dominant individuals with active ovaries. Brain Kr-h1 levels were upregulated by juvenile hormone treatment relative to a vehicle control. Finally, phylogenetic analysis indicates that KR-H1 orthologs are presence across insect orders. Though this protein is highly conserved between honey bees and bumble bees, there are significant differences between orthologs of insects from different orders. Conclusions Our results suggest that Kr-h1 is associated with juvenile hormone mediated regulation of reproduction in bumble bees. The expression of this transcription factor is inhibited by the queen and associated with endocrine mediated

  20. The social nature of the mother's tie to her child: John Bowlby's theory of attachment in post-war America.

    Science.gov (United States)

    Vicedo, Marga

    2011-09-01

    This paper examines the development of British psychiatrist and psychoanalyst John Bowlby's views and their scientific and social reception in the United States during the 1950s. In a 1951 report for the World Health Organization Bowlby contended that the mother is the child's psychic organizer, as observational studies of children worldwide showed that absence of mother love had disastrous consequences for children's emotional health. By the end of the decade Bowlby had moved from observational studies of children in hospitals to animal research in order to support his thesis that mother love is a biological need. I examine the development of Bowlby's views and their scientific and social reception in the United States during the 1950s, a central period in the evolution of his views and in debates about the social implications of his work. I argue that Bowlby's view that mother love was a biological need for children influenced discussions about the desirability of mothers working outside the home during the early Cold War. By claiming that the future of a child's mind is determined by her mother's heart, Bowlby's argument exerted an unusually strong emotional demand on mothers and had powerful implications for the moral valuation of maternal care and love.

  1. Does it pay to have a network contact? Social network ties, workplace racial context, and pay outcomes.

    Science.gov (United States)

    Kmec, Julie A; Trimble, Lindsey B

    2009-06-01

    This article investigates how social network use to find work affects pay. Analyses using the Multi-City Study of Urban Inequality consider the extent to which a network contact's influence level affects a job applicant's pay, whether this effect differs for white, black, and Latino contacts, and how workplace racial context moderates this relationship. Three main findings emerge. First, having an influential contact--one with hiring authority--compared to having no contact yields higher pay. Second, white and minority contact influence on pay differs: among minority contacts, being an outsider (i.e., someone not employed by the firm to which the applicant applies) is associated with higher pay, but being an employee of the firm--an insider--is not. Third, regardless of workplace racial context, black and Latino contacts' influence is most beneficial when their race/ethnicity is not known to the hiring agent. We offer a new interpretation of the mixed findings with regard to the relationship between social network use and pay.

  2. Network ties and survival

    DEFF Research Database (Denmark)

    Acheampong, George; Narteh, Bedman; Rand, John

    2017-01-01

    Poultry farming has been touted as one of the major ways by which poverty can be reduced in low-income economies like Ghana. Yet, anecdotally there is a high failure rate among these poultry farms. This current study seeks to understand the relationship between network ties and survival chances...... of small commercial poultry farms (SCPFs). We utilize data from a 2-year network survey of SCPFs in rural Ghana. The survival of these poultry farms are modelled using a lagged probit model of farms that persisted from 2014 into 2015. We find that network ties are important to the survival chances...... but this probability reduces as the number of industry ties increases but moderation with dynamic capability of the firm reverses this trend. Our findings show that not all network ties aid survival and therefore small commercial poultry farmers need to be circumspect in the network ties they cultivate and develop....

  3. More ties than we thought

    Directory of Open Access Journals (Sweden)

    Dan Hirsch

    2015-05-01

    Full Text Available We extend the existing enumeration of neck tie-knots to include tie-knots with a textured front, tied with the narrow end of a tie. These tie-knots have gained popularity in recent years, based on reconstructions of a costume detail from The Matrix Reloaded, and are explicitly ruled out in the enumeration by Fink & Mao (2000. We show that the relaxed tie-knot description language that comprehensively describes these extended tie-knot classes is context free. It has a regular sub-language that covers all the knots that originally inspired the work. From the full language, we enumerate 266,682 distinct tie-knots that seem tie-able with a normal neck-tie. Out of these 266,682, we also enumerate 24,882 tie-knots that belong to the regular sub-language.

  4. Young adults, social networks, and addiction recovery: post treatment changes in social ties and their role as a mediator of 12-step participation.

    Directory of Open Access Journals (Sweden)

    John F Kelly

    Full Text Available Social factors play a key role in addiction recovery. Research with adults indicates individuals with substance use disorder (SUD benefit from mutual-help organizations (MHOs, such as Alcoholics Anonymous, via their ability to facilitate adaptive network changes. Given the lower prevalence of sobriety-conducive, and sobriety-supportive, social contexts in the general population during the life-stage of young adulthood, however, 12-step MHOs may play an even more crucial recovery-supportive social role for young adults, but have not been investigated. Greater knowledge could enhance understanding of recovery-related change and inform young adults' continuing care recommendations.Emerging adults (N = 302; 18-24 yrs; 26% female; 95% White enrolled in a study of residential treatment effectiveness were assessed at intake, 1, 3, 6, and 12 months on 12-step attendance, peer network variables ("high [relapse] risk" and "low [relapse] risk" friends, and treatment outcomes (Percent Days Abstinent; Percent Days Heavy Drinking. Hierarchical linear models tested for change in social risk over time and lagged mediational analyses tested whether 12-step attendance conferred recovery benefits via change in social risk.High-risk friends were common at treatment entry, but decreased during follow-up; low-risk friends increased. Contrary to predictions, while substantial recovery-supportive friend network changes were observed, this was unrelated to 12-step participation and, thus, not found to mediate its positive influence on outcome.Young adult 12-step participation confers recovery benefit; yet, while encouraging social network change, 12-step MHOs may be less able to provide social network change directly for young adults, perhaps because similar-aged peers are less common in MHOs. Findings highlight the importance of both social networks and 12-step MHOs and raise further questions as to how young adults benefit from 12-step MHOs.

  5. Young adults, social networks, and addiction recovery: post treatment changes in social ties and their role as a mediator of 12-step participation.

    Science.gov (United States)

    Kelly, John F; Stout, Robert L; Greene, M Claire; Slaymaker, Valerie

    2014-01-01

    Social factors play a key role in addiction recovery. Research with adults indicates individuals with substance use disorder (SUD) benefit from mutual-help organizations (MHOs), such as Alcoholics Anonymous, via their ability to facilitate adaptive network changes. Given the lower prevalence of sobriety-conducive, and sobriety-supportive, social contexts in the general population during the life-stage of young adulthood, however, 12-step MHOs may play an even more crucial recovery-supportive social role for young adults, but have not been investigated. Greater knowledge could enhance understanding of recovery-related change and inform young adults' continuing care recommendations. Emerging adults (N = 302; 18-24 yrs; 26% female; 95% White) enrolled in a study of residential treatment effectiveness were assessed at intake, 1, 3, 6, and 12 months on 12-step attendance, peer network variables ("high [relapse] risk" and "low [relapse] risk" friends), and treatment outcomes (Percent Days Abstinent; Percent Days Heavy Drinking). Hierarchical linear models tested for change in social risk over time and lagged mediational analyses tested whether 12-step attendance conferred recovery benefits via change in social risk. High-risk friends were common at treatment entry, but decreased during follow-up; low-risk friends increased. Contrary to predictions, while substantial recovery-supportive friend network changes were observed, this was unrelated to 12-step participation and, thus, not found to mediate its positive influence on outcome. Young adult 12-step participation confers recovery benefit; yet, while encouraging social network change, 12-step MHOs may be less able to provide social network change directly for young adults, perhaps because similar-aged peers are less common in MHOs. Findings highlight the importance of both social networks and 12-step MHOs and raise further questions as to how young adults benefit from 12-step MHOs.

  6. Inferring tie strength from online directed behavior.

    Directory of Open Access Journals (Sweden)

    Jason J Jones

    Full Text Available Some social connections are stronger than others. People have not only friends, but also best friends. Social scientists have long recognized this characteristic of social connections and researchers frequently use the term tie strength to refer to this concept. We used online interaction data (specifically, Facebook interactions to successfully identify real-world strong ties. Ground truth was established by asking users themselves to name their closest friends in real life. We found the frequency of online interaction was diagnostic of strong ties, and interaction frequency was much more useful diagnostically than were attributes of the user or the user's friends. More private communications (messages were not necessarily more informative than public communications (comments, wall posts, and other interactions.

  7. Ties That Bind: The Practice of Social Networks. Number Two in a Series of Reports on Social Networks from The Annie E. Casey Foundation

    Science.gov (United States)

    Bailey, Terri J.

    2006-01-01

    This report documents the Annie E. Casey Foundation's effort to learn from families, communities and organizations around the country about their experiences with social network strategies and approaches. Using the voices and experiences of the families and organizations visited, the report summarizes findings from these visits and helps lay the…

  8. When community ties lead to violent crimes | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2017-10-20

    Oct 20, 2017 ... Exploring social cohesion and mistrust of the state as drivers of urban ... Evidence suggests that these ties help communities to self-organize and .... acts while weakening social interactions and bonds between neighbours.

  9. All tied up: Tied staying and tied migration within the United States, 1997 to 2007

    Directory of Open Access Journals (Sweden)

    Thomas J. Cooke

    2013-10-01

    Full Text Available Background: The family migration literature presumes that women are cast into the role of the tied migrant. However, clearly identifying tied migrants is a difficult empirical task since it requires the identification of a counterfactual: Who moved but did not want to? Objective: This research develops a unique methodology to directly identify both tied migrants and tied stayers in order to investigate their frequency and determinants. Methods: Using data from the 1997 through 2009 U.S. Panel Study of Income Dynamics (PSID, propensity score matching is used to match married individuals with comparable single individuals to create counterfactual migration behaviors: who moved but would not have moved had they been single (tied migrants and who did not move but would have moved had they been single (tied stayers. Results: Tied migration is relatively rare and not limited just to women: rates of tied migration are similar for men and women. However, tied staying is both more common than tied migration and equally experienced by men and women. Consistent with the body of empirical evidence, an analysis of the determinants of tied migration and tied staying demonstrates that family migration decisions are imbued with gender. Conclusions: Additional research is warranted to validate the unique methodology developed in this paper and to confirm its results. One line of future research should be to examine the effects of tied staying, along with tied migration, on well-being, union stability, employment, and earnings.

  10. Strong Ties, Weak Ties, and Human Capital: Latino Immigrant Employment outside the Enclave

    Science.gov (United States)

    Pfeffer, Max J.; Parra, Pilar A.

    2009-01-01

    This study focuses on the role of social ties and human capital in the integration of Latino immigrants into the local economy. This analysis extends earlier research by focusing on more rural contexts with limited labor-market opportunities and less access to social resources provided by coethnics. We reconsider conclusions of previous studies by…

  11. The Tie retraction syndrome.

    Science.gov (United States)

    Geerling, Gerd; Neppert, Birte; Hemmant, Bridget

    2012-12-01

    Tissue retraction is implicated in the pathogenesis of various ophthalmic disorders. Here we describe the clinical characteristics, epidemiology and pathophysiology of a form of retraction syndrome which - to the best of our knowledge - has not been reported in the ophthalmic literature so far. We have termed this condition - consisting of a slowly progressive pseudovertical shortening of tie length due to a horizontal extension of girth length - the "Tie retraction syndrome" (TRS). Other pathognomonic features include an increased tie tip to belt buckle distance and a prolapse of the subumbilical fat pad (SUFP). The syndrome has a clear male to female preponderance and shows an increasing incidence with age and income before tax. Based on a newly proposed grading scheme we discuss and illustrate the diagnosis as well as the medical and surgical management options of this abundant, but often undiagnosed condition. The authors have no explanation for the apparent lack of awareness for this widely preponderant syndrome and its severe cosmetically disfiguring potential. We thus would like to invite all fellow colleagues with expertise in the field to comment or present their views.

  12. Redes sociais em comunidades de baixa renda: os efeitos diferenciais dos laços fracos e dos laços fortes Social networks in low-income communities: the differential effects of weak and strong ties

    Directory of Open Access Journals (Sweden)

    Antônio Augusto Pereira Prates

    2009-10-01

    Full Text Available Neste artigo demonstramos, a partir de uma replicação qualitativa de um estudo quantitativo, que os sistemas fechados de interação - aqui denominados capital social - e os abertos - laços fracos - são fenômenos de natureza distinta e, consequentemente, desempenham funções distintas na determinação da capacidade de articulação coletiva de indivíduos e no grau de eficácia de ações coletivas. A hipótese principal do artigo é que, enquanto capital social tem a ver com maior capacidade dos membros da comunidade para articular mobilização social, os laços fracos dizem respeito à capacidade de a comunidade conseguir benefícios, como saneamento básico, segurança pública, transporte coletivo, saúde e lazer - aqui denominada eficácia coletiva. A metodologia adotada baseia-se na replicação qualitativa de um survey, com três estudos de caso em comunidades periféricas da Região Metropolitana de Belo Horizonte, sobre a importância dos laços fracos para a ação eficaz da comunidade diante do poder público.This article demonstrates, through a qualitative replication of a quantitative research - a survey - that the concepts of closed interaction systems - social capital - and open ones - weak ties - refer to different kinds of social phenomena and, therefore, have independent roles in determining the individuals' capability of collective articulation as well as the effectiveness of the collective actions. The main hypothesis is that while social capital has to do with the people's ability to articulate social mobilization, weak ties have to do with the community's capability to obtain services such as sanitation, public safety, transportation, health care and leisure facilities - here called collective effectiveness. The study comprised a qualitative replication of a survey, with three case studies of low-income communities in the Belo Horizonte metropolitan area.

  13. Family ties and residential locations

    NARCIS (Netherlands)

    Mulder, C.H.; Cooke, T.J.

    2009-01-01

    In this paper, and in the Special Issue it introduces, the focus is on the role of family ties in residential location choice and, conversely, the role of residential locations in maintaining family ties. Not only do events in the nuclear family trigger residential relocations, but nearby family

  14. Why do leaf-tying caterpillars abandon their leaf ties?

    Directory of Open Access Journals (Sweden)

    Michelle Sliwinski

    2013-09-01

    Full Text Available Leaf-tying caterpillars act as ecosystem engineers by building shelters between overlapping leaves, which are inhabited by other arthropods. Leaf-tiers have been observed to leave their ties and create new shelters (and thus additional microhabitats, but the ecological factors affecting shelter fidelity are poorly known. For this study, we explored the effects of resource limitation and occupant density on shelter fidelity and assessed the consequences of shelter abandonment. We first quantified the area of leaf material required for a caterpillar to fully develop for two of the most common leaf-tiers that feed on white oak, Quercus alba. On average, Psilocorsis spp. caterpillars consumed 21.65 ± 0.67 cm2 leaf material to complete development. We also measured the area of natural leaf ties found in a Maryland forest, to determine the distribution of resources available to caterpillars in situ. Of 158 natural leaf ties examined, 47% were too small to sustain an average Psilocorsis spp. caterpillar for the entirety of its development. We also manipulated caterpillar densities within experimental ties on potted trees to determine the effects of cohabitants on the likelihood of a caterpillar to leave its tie. We placed 1, 2, or 4 caterpillars in ties of a standard size and monitored the caterpillars twice daily to track their movement. In ties with more than one occupant, caterpillars showed a significantly greater propensity to leave their tie, and left sooner and at a faster rate than those in ties as single occupants. To understand the consequences of leaf tie abandonment, we observed caterpillars searching a tree for a site to build a shelter in the field. This is a risky behavior, as 17% of the caterpillars observed died while searching for a shelter site. Caterpillars that successfully built a shelter traveled 110 ± 20 cm and took 28 ± 7 min to find a suitable site to build a shelter. In conclusion, leaf-tying caterpillars must frequently

  15. 23 CFR 635.111 - Tied bids.

    Science.gov (United States)

    2010-04-01

    ... MAINTENANCE Contract Procedures § 635.111 Tied bids. (a) The STD may tie or permit the tying of Federal-aid...-financed highway projects may be combined in one contract if the conditions of the projects are so similar...

  16. Account Managers Creation of Social Capital: Communal and Instrumental Investments and Performance Implications

    NARCIS (Netherlands)

    W.J.M.I. Verbeke (Willem); F.D. Belschak (Frank); S.H.K. Wuyts (Stefan); R.P. Bagozzi (Richard)

    2004-01-01

    textabstractAccount managers invest in two distinct, compensatory social ties to achieve social capital, namely peripheral knowledge ties and implementation support ties. The first ties require communal investments, which consist of organizational citizenship behaviors and peripheral information

  17. Pure homology of algebraic varieties

    OpenAIRE

    Weber, Andrzej

    2003-01-01

    We show that for a complete complex algebraic variety the pure component of homology coincides with the image of intersection homology. Therefore pure homology is topologically invariant. To obtain slightly more general results we introduce "image homology" for noncomplete varieties.

  18. Instability of ties in compression

    DEFF Research Database (Denmark)

    Buch-Hansen, Thomas Cornelius

    2013-01-01

    Masonry cavity walls are loaded by wind pressure and vertical load from upper floors. These loads results in bending moments and compression forces in the ties connecting the outer and the inner wall in a cavity wall. Large cavity walls are furthermore loaded by differential movements from...... the temperature gradient between the outer and the inner wall, which results in critical increase of the bending moments in the ties. Since the ties are loaded by combined compression and moment forces, the loadbearing capacity is derived from instability equilibrium equations. Most of them are iterative, since...... exact instability solutions are complex to derive, not to mention the extra complexity introducing dimensional instability from the temperature gradients. Using an inverse variable substitution and comparing an exact theory with an analytical instability solution a method to design tie...

  19. The Hazard of Teetering at the Top and Being Tied to the Bottom : The Interactive Relationship of Power, Stability, and Social Dominance Orientation with Work Stress

    NARCIS (Netherlands)

    Feenstra, Sanne; Jordan, Jennifer; Walter, Frank; Yan, Jin; Stoker, Janka I.

    2017-01-01

    This study examines the roles of power, stability, and social dominance orientation (SDO) for work stress. Initial laboratory research has demonstrated that power and the stability of one's power position interact to influence stress. Using a sample of Chinese managers, we replicate and extend this

  20. Lectures on functor homology

    CERN Document Server

    Touzé, Antoine

    2015-01-01

    This book features a series of lectures that explores three different fields in which functor homology (short for homological algebra in functor categories) has recently played a significant role. For each of these applications, the functor viewpoint provides both essential insights and new methods for tackling difficult mathematical problems. In the lectures by Aurélien Djament, polynomial functors appear as coefficients in the homology of infinite families of classical groups, e.g. general linear groups or symplectic groups, and their stabilization. Djament’s theorem states that this stable homology can be computed using only the homology with trivial coefficients and the manageable functor homology. The series includes an intriguing development of Scorichenko’s unpublished results. The lectures by Wilberd van der Kallen lead to the solution of the general cohomological finite generation problem, extending Hilbert’s fourteenth problem and its solution to the context of cohomology. The focus here is o...

  1. The Strength of the Strongest Ties in Collaborative Problem Solving

    DEFF Research Database (Denmark)

    de Montjoye, Yves-Alexandre; Stopczynski, Arkadiusz; Shmueli, Erez

    2014-01-01

    Complex problem solving in science, engineering, and business has become a highly collaborative endeavor. Teams of scientists or engineers collaborate on projects using their social networks to gather new ideas and feedback. Here we bridge the literature on team performance and information networks...... by studying teams' problem solving abilities as a function of both their within-team networks and their members' extended networks. We show that, while an assigned team's performance is strongly correlated with its networks of expressive and instrumental ties, only the strongest ties in both networks have...... an effect on performance. Both networks of strong ties explain more of the variance than other factors, such as measured or self-evaluated technical competencies, or the personalities of the team members. In fact, the inclusion of the network of strong ties renders these factors non...

  2. Social ties may play a critical role in mitigating sleep difficulties in disaster-affected communities: a cross-sectional study in the Ishinomaki area, Japan.

    Science.gov (United States)

    Matsumoto, Shoko; Yamaoka, Kazue; Inoue, Machiko; Muto, Shinsuke

    2014-01-01

    We examined the association between social factors and sleep difficulties among the victims remaining at home in the Ishinomaki area after the Great East Japan Earthquake and Tsunami and identified potentially modifiable factors that may mitigate vulnerability to sleep difficulties during future traumatic events or disasters. A cross-sectional household survey was conducted from October 2011 to March 2012 (6-12 mo after the disaster) in the Ishinomaki area, Japan. Univariate and multivariate logistic regression models were used to examine associations between social factors and sleep difficulties. We obtained data on 4,176 household members who remained in their homes after the earthquake and tsunami. N/A. Sleep difficulties were prevalent in 15.0% of the respondents (9.2% male, 20.2% female). Two potentially modifiable factors (lack of pleasure in life and lack of interaction with/visiting neighbors) and three nonmodifiable or hardly modifiable factors (sex, source of income, and number of household members) were associated with sleep difficulties. Nonmodifiable or hardly modifiable consequences caused directly by the disaster (severity of house damage, change in family structure, and change in working status) were not significantly associated with sleep difficulties. Our data suggest that the lack of pleasure in life and relatively strong networks in the neighborhood, which are potentially modifiable, might have stronger associations with sleep difficulties than do nonmodifiable or hardly modifiable consequences of the disaster (e.g., house damage, change in family structure, and change in work status).

  3. Homological stabilizer codes

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Jonas T., E-mail: jonastyleranderson@gmail.com

    2013-03-15

    In this paper we define homological stabilizer codes on qubits which encompass codes such as Kitaev's toric code and the topological color codes. These codes are defined solely by the graphs they reside on. This feature allows us to use properties of topological graph theory to determine the graphs which are suitable as homological stabilizer codes. We then show that all toric codes are equivalent to homological stabilizer codes on 4-valent graphs. We show that the topological color codes and toric codes correspond to two distinct classes of graphs. We define the notion of label set equivalencies and show that under a small set of constraints the only homological stabilizer codes without local logical operators are equivalent to Kitaev's toric code or to the topological color codes. - Highlights: Black-Right-Pointing-Pointer We show that Kitaev's toric codes are equivalent to homological stabilizer codes on 4-valent graphs. Black-Right-Pointing-Pointer We show that toric codes and color codes correspond to homological stabilizer codes on distinct graphs. Black-Right-Pointing-Pointer We find and classify all 2D homological stabilizer codes. Black-Right-Pointing-Pointer We find optimal codes among the homological stabilizer codes.

  4. The Ties That Bind

    Science.gov (United States)

    Gloyn, Liz; Crewe, Vicky; King, Laura; Woodham, Anna

    2018-01-01

    Using an interdisciplinary research methodology across three archaeological and historical case studies, this article explores “family archives.” Four themes illustrate how objects held in family archives, curation practices, and intergenerational narratives reinforce a family’s sense of itself: people–object interactions, gender, socialization and identity formation, and the “life course.” These themes provide a framework for professional archivists to assist communities and individuals working with their own family archives. We argue that the family archive, broadly defined, encourages a more egalitarian approach to history. We suggest a multiperiod analysis draws attention to historical forms of knowledge and meaning-making practices over time. PMID:29593371

  5. Tails and Ties. Editorial

    Science.gov (United States)

    Carbone, A.; Kaniadakis, G.; Scarfone, A. M.

    2007-05-01

    The study of behavioural and social phenomena has experienced a surge of interest over the last decade. One reason for this great attention is the huge amount of high quality data made available by the internet technologies. The many studies spanning concepts and problems belonging to economics, biology, ecology, physics and computer science, clearly indicates increasing interdisciplinary cross-fertilization, commonalities in the different approaches and communication across these disciplines. This issue of The European Physical Journal B is devoted to the interdisciplinary field of Sociophysics. The papers have been selected from the contributions presented at the 5th International Conference on “Applications of Physics in Financial Analysis" (APFA5) held in Torino from June 29th to July 1st 2006 ( http://www.polito.it/apfa5). The synergy and richness of results obtained from the investigation of problems belonging to the area of complexity science from different perspectives clearly indicates future directions and research methodologies in this field.

  6. Analysis of ILRS Site Ties

    Science.gov (United States)

    Husson, V. S.; Long, J. L.; Pearlman, M.

    2001-12-01

    By the end of 2000, 94% of ILRS stations had completed station and site information forms (i.e. site logs). These forms contain six types of information. These six categories include site identifiers, contact information, approximate coordinates, system configuration history, system ranging capabilities, and local survey ties. The ILRS Central Bureau, in conjunction with the ILRS Networks and Engineering Working Group, has developed procedures to quality control site log contents. Part of this verification entails data integrity checks of local site ties and is the primary focus of this paper. Local survey ties are critical to the combination of space geodetic network coordinate solutions (i.e. GPS, SLR, VLBI, DORIS) of the International Terrestrial Reference Frame (ITRF). Approximately 90% of active SLR sites are collocated with at least one other space geodetic technique. The process used to verify these SLR ties, at collocated sites, is identical to the approach used in ITRF2000. Local vectors (X, Y, Z) from each ILRS site log are differenced from its corresponding ITRF2000 position vectors (i.e. no transformations). These X, Y, and Z deltas are converted into North, East, and Up. Any deltas, in any component, larger than 5 millimeter is flagged for investigation. In the absence of ITRF2000 SLR positions, CSR positions were used. To further enhance this comparison and to fill gaps in information, local ties contained in site logs from the other space geodetic services (i.e. IGS, IVS, IDS) were used in addition to ITRF2000 ties. Case studies of two collocated sites (McDonald/Ft. Davis and Hartebeeshtoek) will be explored in-depth. Recommendations on how local site surveys should be conducted and how this information should be managed will also be presented.

  7. Do recruitment ties affect wages?

    DEFF Research Database (Denmark)

    Larsen, Anna Folke; Rand, John; Torm, Nina Elisabeth

    This paper examines the extent to which recruitment ties affect individual wage outcomes in small and medium scale manufacturing firms. Based on a unique matched employer-employee dataset from Vietnam we find that there is a significant positive wage premium associated with obtaining a job through...... an informal contact, when controlling for standard determinants of wage compensation. Moreover, we show that the mechanism through which informal contacts affect wages depends on the type of recruitment tie used. The findings are robust across location, firm size categories and different worker types....

  8. Leveraging strong social ties among young men in Dar es Salaam: A pilot intervention of microfinance and peer leadership for HIV and gender-based violence prevention.

    Science.gov (United States)

    Maman, Suzanne; Kajula, Lusajo; Balvanz, Peter; Kilonzo, Mrema; Mulawa, Marta; Yamanis, Thespina

    2016-12-01

    Gender inequality is at the core of the HIV patterns that are evident in sub-Saharan Africa. Gender-based violence (GBV) and lack of economic opportunity are important structural determinants of HIV risk. We piloted a microfinance and health promotion intervention among social networks of primarily young men in Dar es Salaam. Twenty-two individuals participated in the microfinance component and 30 peer leaders were recruited and trained in the peer health leadership component. We collected and analysed observational data from trainings, monitoring data on loan repayment, and reports of peer conversations to assess the feasibility and acceptability of the intervention. Eighteen of the loan recipients (82%) paid back their loans, and of these 15 (83%) received a second, larger loan. Among the loan defaulters, one died, one had chronic health problems, and two disappeared, one of whom was imprisoned for theft. The majority of conversations reported by peer health leaders focused on condoms, sexual partner selection, and HIV testing. Few peer leaders reported conversations about GBV. We demonstrated the feasibility and acceptability of this innovative HIV and GBV prevention intervention. The lessons learned from this pilot have informed the implementation of a cluster-randomised trial of the microfinance and peer health leadership intervention.

  9. The Impact of Strong Ties on Knowledge Acquisition of Enterprises: A View of Social Capital%强联结对企业知识获取绩效的影响研究——社会资本的视角

    Institute of Scientific and Technical Information of China (English)

    张晓棠; 荆心

    2012-01-01

    Researchers study a lot on the benefits and costs of the strength ties during the procession of knowledge acquisition form the Resource-Based View or Knowledge-based View, but the media role of social capital in the process seems to be ignored. This paper presents a view of social capital and study the impact of social capitals, such as trust, reciprocity, social interaction, network connection on knowledge acquisition under the context of strong ties. The paper proposes enterprises should build strong ties and accumulate social capitals in order to improve knowledge acquisition performance.%现有文献主要从资源基础观及知识基础观视角分析联结的强弱在企业知识获取中的利弊,却忽视了社会资本在此过程中的介质作用.本文从社会资本的新视角,研究强联结情境下,信任、互惠、社会化互动、网络联系等社会资本对企业知识获取绩效的影响路径.文章提出企业应该构建强关联网络,积累良好的社会资本,以提高知识获取绩效.

  10. PWR integral tie plate and locking mechanism

    International Nuclear Information System (INIS)

    Flora, B.S.; Osborne, J.L.

    1980-01-01

    A locking mechanism for securing an upper tie plate to the tie rods of a nuclear fuel bundle is described. The mechanism includes an upper tie plate assembly and locking sleeves fixed to the ends of the tie rods. The tie plate is part of the upper tie plate assembly and is secured to the fuel bundle by securing the entire upper tie plate assembly to the locking sleeves fixed to the tie rods. The assembly includes, in addition to the tie plate, locking nuts for engaging the locking sleeves, retaining sleeves to operably connect the locking nuts to the assembly, a spring biased reaction plate to restrain the locking nuts in the locked position and a means to facilitate the removal of the entire assembly as a unit from the fuel bundle

  11. Neural correlates of dynamically evolving interpersonal ties predict prosocial behaviour

    Directory of Open Access Journals (Sweden)

    Johannes Jacobus Fahrenfort

    2012-03-01

    Full Text Available There is a growing interest for the determinants of human choice behaviour in social settings. Upon initial contact, investment choices in social settings can be inherently risky, as the degree to which the other person will reciprocate is unknown. Nevertheless, people have been shown to exhibit prosocial behaviour even in one-shot laboratory settings where all interaction has been taken away. A logical step has been to link such behaviour to trait empathy-related neurobiological networks. However, as a social interaction unfolds, the degree of uncertainty with respect to the expected payoff of choice behaviour may change as a function of the interaction. Here we attempt to capture this factor. We show that the interpersonal tie one develops with another person during interaction - rather than trait empathy - motivates investment in a public good that is shared with an anonymous interaction partner. We examined how individual differences in trait empathy and interpersonal ties modulate neural responses to imposed monetary sharing. After, but not before interaction in a public good game, sharing prompted activation of neural systems associated with reward (striatum, empathy (anterior insular cortex [AIC] and anterior cingulate cortex [ACC] as well as altruism and social significance (posterior superior temporal sulcus [pSTS]. Although these activations could be linked to both empathy and interpersonal ties, only tie-related pSTS activation predicted prosocial behaviour during subsequent interaction, suggesting a neural substrate for keeping track of social relevance.

  12. Geometric homology revisited

    OpenAIRE

    Ruffino, Fabio Ferrari

    2013-01-01

    Given a cohomology theory, there is a well-known abstract way to define the dual homology theory using the theory of spectra. In [4] the author provides a more geometric construction of the homology theory, using a generalization of the bordism groups. Such a generalization involves in its definition the vector bundle modification, which is a particular case of the Gysin map. In this paper we provide a more natural variant of that construction, which replaces the vector bundle modification wi...

  13. Maintaining work-related personal ties following retirement

    NARCIS (Netherlands)

    Cozijnsen, M.R.; Stevens, N.L.; van Tilburg, T.G.

    2010-01-01

    This study examines the consequences of retirement for the continuation of work-related personal ties. The hypothesis is that their inclusion in personal networks after retirement has become more likely because these relationships have become less role based in today's social-cultural context. Data

  14. Social Ties and Coordination on Negative Reciprocity

    DEFF Research Database (Denmark)

    Reuben, Ernesto; van Winden, Frans

    This is an experimental study of a three-player power-to-take game where a proposer is matched with two responders. We compare a treatment in which subjects are anonymous to each other (strangers) with one in which responders know each other from outside the lab (friends). We focus on the respond...

  15. Personal Ties in the Writing of a Doctoral Dissertation

    Directory of Open Access Journals (Sweden)

    Laura Colombo

    2014-07-01

    Full Text Available The problem of low graduation rates at the graduate level has been linked to the challenges of dissertation work. Given that this is a process of “disciplinary enculturation”, where graduate students acquire the ways of being and doing of each discipline, the social relations of doctoral candidates should be analyzed. Several studies have explored the support provided by social ties within academia but have, nevertheless, ignored other spheres. This qualitative study, based on in-depth interviews, explores the personal-sphere social relations in the dissertation writing process from the point of view of doctoral candidates and recent graduates in the fields of Education and Linguistics. Results indicate that the emotional, financial, economic, and academic support offered by these social ties is a necessary, although not in itself, sufficient condition. Some strategies for increasing institutional support to facilitate the process of writing a dissertation are offered.

  16. The ties that bind: Ingroup ties are linked with diminished inflammatory immune responses and fewer mental health symptoms through less rumination.

    Science.gov (United States)

    Ysseldyk, Renate; McQuaid, Robyn J; McInnis, Opal A; Anisman, Hymie; Matheson, Kimberly

    2018-01-01

    The present research explored whether components of social identity, namely ingroup ties, affect, and centrality, were differentially linked to mental health and inflammatory immune responses, and whether rumination mediated those relations. Study 1 (N = 138) indicated that stronger ingroup ties were associated with fewer mental health (depressive and post-traumatic stress) symptoms; those relations were mediated by the tendency for individuals with strong ties to rely less on ruminative coping to deal with a stressful life event. Study 2 (N = 54) demonstrated that ingroup ties were negatively associated with depressive symptoms, dispositional rumination, as well as stress-linked inflammatory elements at the physiological level. Consistent associations for centrality and ingroup affect were absent, suggesting that ingroup ties may have unique health benefits.

  17. Peru turnaround tied to privatization

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Petroleos del Peru predicts a 10% increase in Peru's oil production this year and a further increase in 1994. Petroperu also forecasts a sharp increase in drilling in Peru this year. After several years of declining oil production, a gradual turnaround in the cash strapped country's petroleum industry is largely tied to its progress in privatization. The government last year began a campaign to privatize all state owned companies by the end of July 1995. The paper discusses forecasts by Petroperu; the contract of Occidental del Amazonas Inc.; the Petromar privatization; Great Western's contract; development of the Aguaytia gas field; and refinery contracts

  18. The Strength of the Strongest Ties in Collaborative Problem Solving

    Science.gov (United States)

    de Montjoye, Yves-Alexandre; Stopczynski, Arkadiusz; Shmueli, Erez; Pentland, Alex; Lehmann, Sune

    2014-06-01

    Complex problem solving in science, engineering, and business has become a highly collaborative endeavor. Teams of scientists or engineers collaborate on projects using their social networks to gather new ideas and feedback. Here we bridge the literature on team performance and information networks by studying teams' problem solving abilities as a function of both their within-team networks and their members' extended networks. We show that, while an assigned team's performance is strongly correlated with its networks of expressive and instrumental ties, only the strongest ties in both networks have an effect on performance. Both networks of strong ties explain more of the variance than other factors, such as measured or self-evaluated technical competencies, or the personalities of the team members. In fact, the inclusion of the network of strong ties renders these factors non-significant in the statistical analysis. Our results have consequences for the organization of teams of scientists, engineers, and other knowledge workers tackling today's most complex problems.

  19. Urban characteristics attributable to density-driven tie formation

    Science.gov (United States)

    Pan, Wei; Ghoshal, Gourab; Krumme, Coco; Cebrian, Manuel; Pentland, Alex

    2013-06-01

    Motivated by empirical evidence on the interplay between geography, population density and societal interaction, we propose a generative process for the evolution of social structure in cities. Our analytical and simulation results predict both super-linear scaling of social-tie density and information contagion as a function of the population. Here we demonstrate that our model provides a robust and accurate fit for the dependency of city characteristics with city-size, ranging from individual-level dyadic interactions (number of acquaintances, volume of communication) to population level variables (contagious disease rates, patenting activity, economic productivity and crime) without the need to appeal to heterogeneity, modularity, specialization or hierarchy.

  20. Mobile devices and weak ties: a study of vision impairments and workplace access in Bangalore.

    Science.gov (United States)

    Pal, Joyojeet; Lakshmanan, Meera

    2015-07-01

    To explore ways in which social and economic interactions are changed by access to mobile telephony. This is a mixed-methods study of mobile phone use among 52 urban professionals with vision impairments in Bangalore, India. Interviews and survey results indicated that mobile devices, specifically those with adaptive technology software, play a vital role as multi-purpose devices that enable people with disabilities to navigate economically and socially in an environment where accessibility remains a significant challenge. We found that mobile devices play a central role in enabling and sustaining weak ties, but also that these weak ties have important gender-specific implications. We found that women have less access to weak ties than men, which impacts women's access to assistive technology (AT). This has potential implications for women's sense of safety and independence, both of which are strongly related to AT access. Implications for Rehabilitation Adaptive technologies increase individuals' ability to keep in contact with casual connections or weak ties through phone calls or social media. Men tend to have stronger access to weak ties than women in India due to cultural impediments to independent access to public spaces. Weak ties are an important source of assistive technology (AT) due to the high rate of resale of used AT, typically through informal networks.

  1. Construction loads experienced by plastic composite ties.

    Science.gov (United States)

    2014-07-01

    Damage to plastic composite ties during handling and track installation has been reported by a number of railroads. Results from : a survey conducted to identify specific handling issues were used to develop field and laboratory tests to measure the ...

  2. "People Are Either Too Fake or Too Real": Opportunities and Challenges in Tie-Based Anonymity

    DEFF Research Database (Denmark)

    Ma, Xiao; Andabili, Nazanin; Barkhuus, Louise

    2017-01-01

    In recent years, several mobile applications allowed individuals to anonymously share information with friends and contacts, without any persistent identity marker. The functions of these “tie-based” anonymity services may be notably different than other social media services. We use semi-structu...... disclosure needs and social probing. Still, challenges for making such applications successful, for example the prevalence of negativity and bullying, are substantial.......In recent years, several mobile applications allowed individuals to anonymously share information with friends and contacts, without any persistent identity marker. The functions of these “tie-based” anonymity services may be notably different than other social media services. We use semi...

  3. Tying Trade Flows: A Theory of Countertrade

    OpenAIRE

    Marin, Dalia; Schnitzer, Monika

    1994-01-01

    A countertrade contract ties an export to an import. Usually, countertrade is seen as a form of bilateralism and reciprocity and thus as an inefficient form of international exchange. In this paper we argue that there are circumstances where the tying of two technologically unrelated trade flows may be efficiency enhancing. We show that countertrade can be seen as an efficient institution that solves moral hazard problems and restores creditworthiness of countries with large outstanding debt....

  4. Chemical shift homology in proteins

    International Nuclear Information System (INIS)

    Potts, Barbara C.M.; Chazin, Walter J.

    1998-01-01

    The degree of chemical shift similarity for homologous proteins has been determined from a chemical shift database of over 50 proteins representing a variety of families and folds, and spanning a wide range of sequence homologies. After sequence alignment, the similarity of the secondary chemical shifts of C α protons was examined as a function of amino acid sequence identity for 37 pairs of structurally homologous proteins. A correlation between sequence identity and secondary chemical shift rmsd was observed. Important insights are provided by examining the sequence identity of homologous proteins versus percentage of secondary chemical shifts that fall within 0.1 and 0.3 ppm thresholds. These results begin to establish practical guidelines for the extent of chemical shift similarity to expect among structurally homologous proteins

  5. Software With Strong Ties to Space

    Science.gov (United States)

    2003-01-01

    TieFlow is a simple but powerful business process improvement solution. It can automate and simplify any generic or industry-specific work process, helping organizations to transform work inefficiencies and internal operations involving people, paper, and procedures into a streamlined, well-organized, electronicbased process. TieFlow increases business productivity by improving process cycle times. The software can expedite generic processes in the areas of product design and development, purchase orders, expense reports, benefits enrollment, budgeting, hiring, and sales. It can also shore up vertical market processes such as claims processing, loan application and processing, health care administration, contract management, and advertising agency traffic. The processes can be easily and rapidly captured in a graphical manner and enforced together with rules pertaining to assignments that need to be performed. Aside from boosting productivity, TieFlow also reduces organizational costs and errors. TieFlow was developed with Small Business Innovation Research (SBIR) assistance from Johnson. The SBIR support entitles all Federal Government agencies to utilize the TieFlow software technology free of charge. Tietronix emphasizes that TieFlow is an outstanding workflow resource that could produce dramatic productivity and cost improvements for all agencies, just as it has done and continues to do for NASA. The Space Agency is currently using the software throughout several mission-critical offices, including the Mission Operations Directorate and the Flight Director s Office, for worldwide participation of authorized users in NASA processes. At the Flight Director s Office, TieFlow allows personnel to electronically submit and review changes to the flight rules carried out during missions.

  6. Analysis of ICPP fuel storage rack inner tie and corner tie substructures

    Energy Technology Data Exchange (ETDEWEB)

    Nitzel, M.E.; Rahl, R.G.

    1996-01-01

    Finite element models were developed and analyses performed for the tie plate, inner tie block assembly, and corner tie block assembly of a 25 port fuel rack assembly designed for installation in Pool 1 of Building 666 at the Idaho Chemical Processing Plant. These models were specifically developed to investigate the adequacy of certain welds joining components of the fuel storage rack assembly. The work scope for the task was limited to an investigation of the stress levels in the subject subassemblies when subjected to seismic loads. Structural acceptance criteria used for the elastic calculations performed were as found in the overall rack design report as issued by the rack`s designer, Holtec International. Structural acceptance criteria used for the plastic calculations performed as part of this effort were as defined in Subsection NF and Appendix F of the ASME Boiler & Pressure Vessel Code. The results of the analyses will also apply to the 30 port fuel storage rack design that is also scheduled for installation in Pool 1 of ICPP 666. The results obtained from the analyses performed for this task indicate that the welds joining the inner tie block and corner tie block to the surrounding rack structure meet the acceptance criteria. Further, the structural members (plates and blocks) were also found to be within the allowable stress limits established by the acceptance criteria. The separate analysis performed on the inner tie plate confirmed the structural adequacy for both the inner tie plate, corner tie plate, and tie block bolts. The analysis results verified that the inner tie and corner tie block should be capable of transferring the expected seismic load without structural failure.

  7. Mod two homology and cohomology

    CERN Document Server

    Hausmann, Jean-Claude

    2014-01-01

    Cohomology and homology modulo 2 helps the reader grasp more readily the basics of a major tool in algebraic topology. Compared to a more general approach to (co)homology this refreshing approach has many pedagogical advantages: It leads more quickly to the essentials of the subject, An absence of signs and orientation considerations simplifies the theory, Computations and advanced applications can be presented at an earlier stage, Simple geometrical interpretations of (co)chains. Mod 2 (co)homology was developed in the first quarter of the twentieth century as an alternative to integral homology, before both became particular cases of (co)homology with arbitrary coefficients. The first chapters of this book may serve as a basis for a graduate-level introductory course to (co)homology. Simplicial and singular mod 2 (co)homology are introduced, with their products and Steenrod squares, as well as equivariant cohomology. Classical applications include Brouwer's fixed point theorem, Poincaré duality, Borsuk-Ula...

  8. Open knot-tying skills: residents skills assessed

    NARCIS (Netherlands)

    van Empel, P.J.; Verdam, M.G.E.; Huirne, J.A.; Bonjer, H.J.; Meijerink, W.J.; Scheele, F.

    2013-01-01

    Aim: Open knot-tying and suturing skills are fundamental surgical skills, founding many alternative knot-tying techniques. It is therefore mandatory for residents to possess adequate basic open knot-tying skills. The aim of this study was to compare an objective assessment of open knot-tying skills

  9. Compositional Homology and Creative Thinking

    Directory of Open Access Journals (Sweden)

    Salvatore Tedesco

    2015-05-01

    Full Text Available The concept of homology is the most solid theoretical basis elaborated by the morphological thinking during its history. The enucleation of some general criteria for the interpretation of homology is today a fundamental tool for life sciences, and for restoring their own opening to the question of qualitative innovation that arose so powerfully in the original Darwinian project. The aim of this paper is to verify the possible uses of the concept of compositional homology in order to provide of an adequate understanding of the dynamics of creative thinking.

  10. Intergenerational family ties and the diffusion of cohabitation in Italy

    Directory of Open Access Journals (Sweden)

    Alessandro Rosina

    2007-05-01

    Full Text Available Cohabitation has been spreading in the population during the last thirty years, and this is one of the most striking aspects of wider social changes that have taken place throughout the industrialized world. However, this change did not take place uniformly across Europe. The purpose of this paper is to contribute to the current debate around the compatibility of cohabitation experiences with the Italian cultural context. Using an individual-level diffusion approach we obtain results that are consistent with the crucial role that family ties play in the choice of cohabitation in place of (or before marriage.

  11. Company Matters: Goal-Related Social Capital in the Transition to Working Life

    Science.gov (United States)

    Jokisaari, Markku; Nurmi, Jari-Erik

    2005-01-01

    Using longitudinal data on 343 young adults, the present study investigated the social ties involved in young adults' work-related goals, how these ties change during transition to working life, and whether social ties contribute to success in dealing with the transition. The results showed that goal-relevant social ties reflected changes in the…

  12. TIE: An Ability Test of Emotional Intelligence

    Science.gov (United States)

    Śmieja, Magdalena; Orzechowski, Jarosław; Stolarski, Maciej S.

    2014-01-01

    The Test of Emotional Intelligence (TIE) is a new ability scale based on a theoretical model that defines emotional intelligence as a set of skills responsible for the processing of emotion-relevant information. Participants are provided with descriptions of emotional problems, and asked to indicate which emotion is most probable in a given situation, or to suggest the most appropriate action. Scoring is based on the judgments of experts: professional psychotherapists, trainers, and HR specialists. The validation study showed that the TIE is a reliable and valid test, suitable for both scientific research and individual assessment. Its internal consistency measures were as high as .88. In line with theoretical model of emotional intelligence, the results of the TIE shared about 10% of common variance with a general intelligence test, and were independent of major personality dimensions. PMID:25072656

  13. TIE: an ability test of emotional intelligence.

    Science.gov (United States)

    Śmieja, Magdalena; Orzechowski, Jarosław; Stolarski, Maciej S

    2014-01-01

    The Test of Emotional Intelligence (TIE) is a new ability scale based on a theoretical model that defines emotional intelligence as a set of skills responsible for the processing of emotion-relevant information. Participants are provided with descriptions of emotional problems, and asked to indicate which emotion is most probable in a given situation, or to suggest the most appropriate action. Scoring is based on the judgments of experts: professional psychotherapists, trainers, and HR specialists. The validation study showed that the TIE is a reliable and valid test, suitable for both scientific research and individual assessment. Its internal consistency measures were as high as .88. In line with theoretical model of emotional intelligence, the results of the TIE shared about 10% of common variance with a general intelligence test, and were independent of major personality dimensions.

  14. TIE: an ability test of emotional intelligence.

    Directory of Open Access Journals (Sweden)

    Magdalena Śmieja

    Full Text Available The Test of Emotional Intelligence (TIE is a new ability scale based on a theoretical model that defines emotional intelligence as a set of skills responsible for the processing of emotion-relevant information. Participants are provided with descriptions of emotional problems, and asked to indicate which emotion is most probable in a given situation, or to suggest the most appropriate action. Scoring is based on the judgments of experts: professional psychotherapists, trainers, and HR specialists. The validation study showed that the TIE is a reliable and valid test, suitable for both scientific research and individual assessment. Its internal consistency measures were as high as .88. In line with theoretical model of emotional intelligence, the results of the TIE shared about 10% of common variance with a general intelligence test, and were independent of major personality dimensions.

  15. The Strength of Weak Ties in MBA Job Search: A Within–Person Test

    Directory of Open Access Journals (Sweden)

    Jason Greenberg

    2016-05-01

    Full Text Available Whether and how social ties create value has inspired substantial research in organizational theory, sociology, and economics. Scholars generally believe that social ties impact labor market outcomes. Two explanatory mechanisms have been identified, emphasizing access to better job offers in pecuniary terms and the efficacy of non-redundant information. The evidence informing each theory, however, has been inconsistent and circumstantial. We test predictions from both models using a rich set of job search data collected from an MBA student population, including detailed information about search channels and characteristics of job offers. Importantly, we can compare offers made to the same student derived via different search channels while accounting for industry, function, and non-pecuniary characteristics. We find that contrary to conventional wisdom, search through social networks typically results in job offers with lower total compensation (-17 percent for referrals through strong ties and -16 percent for referrals via weak ties vs. formal search. However, our models also show that students are considerably more likely to accept offers derived via weak ties. They do so because they are perceived to have greater growth potential and other non-pecuniary value. On balance, our tests are consistent with Granovetter’s argument that networks provide value by facilitating access to information that is otherwise difficult to obtain, rather than providing greater pecuniary compensation.

  16. Relationships: The Critical Ties That Bind Professionals.

    Science.gov (United States)

    Roper, Larry

    2002-01-01

    This article proposes that the success of student affairs professionals is more closely tied to their ability to construct and manage essential relationships during their careers than any other activity. The author discusses essential principles and skills in developing and managing professional relationships. (GCP)

  17. Weizmann ties with Cambridge in physics contest

    CERN Multimedia

    Siegel, J

    2004-01-01

    "Scientists and students from the Weizmann Institute of Science in Rehovot and Cambridge University in England have tied for first place in a physics competition aimed at simulating the future functioning of the particle accelerator being built at the European center CERN and due to open in 2007" (1/2 page)

  18. Commercial lumber, round timbers, and ties

    Science.gov (United States)

    David E. Kretschmann

    2010-01-01

    When sawn, a log yields round timber, ties, or lumber of varying quality. This chapter presents a general discussion of grading, standards, and specifications for these commercial products. In a broad sense, commercial lumber is any lumber that is bought or sold in the normal channels of commerce. Commercial lumber may be found in a variety of forms, species, and types...

  19. Ties That Bind: Creating and sustaining community-academic partnerships

    Directory of Open Access Journals (Sweden)

    Kynna N. Wright

    2011-11-01

    Full Text Available Growing interest among academics and health professionals in finding new ways to study and address complex health and social problems has manifested in recent years with increasing community demands for research and program implementation that is community-based, rather than merely community placed. In the United States, community-based participatory research (CBPR, with its emphasis on the creation and use of community-university or community-academic partnerships, is the prevailing paradigm to address these complex problems, especially those concerning racial/ethnic disparities in health and health care. While the need to strengthen the relationship between researchers and the community has been recognised, often from the viewpoint of the university partner, discussions on sustainability of partnerships have been few. The aim of this paper is to share reflections, through the eyes of the community members, on the core elements that tie community and academic members together and the challenges in understanding and nurturing those ties so that the community-academic partnership is sustained over time, and to offer possible recommendations for sustainability. This article speaks from the community’s perspective and reflects on the vital elements/components that tie together community-university partnerships and the challenges that may occur when trying to sustain and grow the partnership. It is based on a research CBPR study that was conducted to (1 evaluate the functioning and future sustainability of the community-university partnership of the Community Child Health Network Study Los Angeles (CCHN-LA community-university partnership, and (2 evaluate the experience and beliefs of the current CCHN-LA community-university partnership members in their understanding of current functioning. Keywords Community-academic partnerships; sustainability; challenges; solutions

  20. Persistent homology of complex networks

    International Nuclear Information System (INIS)

    Horak, Danijela; Maletić, Slobodan; Rajković, Milan

    2009-01-01

    Long-lived topological features are distinguished from short-lived ones (considered as topological noise) in simplicial complexes constructed from complex networks. A new topological invariant, persistent homology, is determined and presented as a parameterized version of a Betti number. Complex networks with distinct degree distributions exhibit distinct persistent topological features. Persistent topological attributes, shown to be related to the robust quality of networks, also reflect the deficiency in certain connectivity properties of networks. Random networks, networks with exponential connectivity distribution and scale-free networks were considered for homological persistency analysis

  1. Performance evaluation of concrete railroad ties on the northeast corridor.

    Science.gov (United States)

    2014-03-01

    Simpson Gumpertz & Heger Inc. conducted an investigation into the factors that caused widespread failure in prestressed concrete : railroad ties on the Northeast Corridor. The problem was apparent in ties manufactured and installed circa 19941998....

  2. Freeze-thaw performance testing of whole concrete railroad ties.

    Science.gov (United States)

    2013-10-01

    Freezing and thawing durability tests of prestressed concrete ties are normally performed according to ASTM C666 specifications. Small specimens are cut from the shoulders of concrete ties and tested through 300 cycles of freezing and thawing. Saw-cu...

  3. Homological stability of diffeomorphism groups

    DEFF Research Database (Denmark)

    Berglund, Alexander; Madsen, Ib Henning

    2013-01-01

    In this paper we prove a stability theorem for block diffeomorphisms of 2d -dimensional manifolds that are connected sums of S d ×S d . Combining this with a recent theorem of S. Galatius and O. Randal-Williams and Morlet’s lemma of disjunction, we determine the homology of the classifying space ...

  4. Network ties in the international opportunity recognition of family SMEs

    OpenAIRE

    Kontinen, Tanja; Ojala, Arto

    2011-01-01

    The importance of network ties is emphasized in the current literature on opportunity recognition. However, it is unclear how firms with limited bridging networks, such as family SMEs, recognize international opportunities through their network ties. In this case study we found that in gaining foreign market entry, those family SMEs that lack existing network ties recognize opportunities through weak ties formed in international exhibitions. The findings also indicate that rather than being p...

  5. Nonlinear Price Schedules and Tied Products.

    OpenAIRE

    Ormiston, Michael B; Phillips, Owen R

    1988-01-01

    Illegal tying often occurs when a monopolist jointly sells a product with a complementary requirement, also sold competitively. Along with selling the complement at its competi tive price, this paper shows that profit can increase when a monopoli st lets consumers bundle any amount of the requirement with the basic product at a fixed price. Examples illustrate demand conditions that enhance the profitability of this nonlinear price strategy and show that profits can approximate those earned f...

  6. China, Argentina agree to further strategic ties

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    According to Xinhua,China and Argentina have agreed to further enhance mutual trust and their strategic partnership as the two emerging economies are playing an increasingly important role in the world arena.“China will work with Argentina to strengthen strategic mutual trust,expand cooperation and coordination within multilateral frameworks in order to promote bilateral ties and benefit the two peoples,” Vice President Xi Jinping told Argentine Foreign Minister Hector Timerman on September 9.

  7. Grid-Tied Photovoltaic Power System

    Science.gov (United States)

    Eichenberg, Dennis J.

    2011-01-01

    A grid-tied photovoltaic (PV) power system is connected directly to the utility distribution grid. Facility power can be obtained from the utility system as normal. The PV system is synchronized with the utility system to provide power for the facility, and excess power is provided to the utility. Operating costs of a PV power system are low compared to conventional power technologies. This method can displace the highest-cost electricity during times of peak demand in most climatic regions, and thus reduce grid loading. Net metering is often used, in which independent power producers such as PV power systems are connected to the utility grid via the customers main service panels and meters. When the PV power system is generating more power than required at that location, the excess power is provided to the utility grid. The customer pays the net of the power purchased when the on-site power demand is greater than the onsite power production, and the excess power is returned to the utility grid. Power generated by the PV system reduces utility demand, and the surplus power aids the community. Modern PV panels are readily available, reliable, efficient, and economical, with a life expectancy of at least 25 years. Modern electronics have been the enabling technology behind grid-tied power systems, making them safe, reliable, efficient, and economical with a life expectancy equal to the modern PV panels. The grid-tied PV power system was successfully designed and developed, and this served to validate the basic principles developed, and the theoretical work that was performed. Grid-tied PV power systems are reliable, maintenance- free, long-life power systems, and are of significant value to NASA and the community. Of particular value are the analytical tools and capabilities that have been successfully developed. Performance predictions can be made confidently for grid-tied PV systems of various scales. The work was done under the NASA Hybrid Power Management (HPM

  8. Private support and social security.

    Science.gov (United States)

    Van Dijk, F

    1998-01-01

    "The issue is addressed whether assistance to persons in need can be left to the ¿family' and the ¿community'. In that case people depend on their social networks. The support a person receives through a given network of social ties is examined. However, ties are diverse and subject to change. By means of a model of the dynamics of social ties, the conditions for adequate private support are analyzed. The sustainability of private support over time is examined by incorporating the impact on social ties of lending and receiving support. It is shown that support is only an effective alternative in a limited number of situations." excerpt

  9. Homological algebra in -abelian categories

    Indian Academy of Sciences (India)

    Deren Luo

    2017-08-16

    Aug 16, 2017 ... Homological algebra in n-abelian categories. 627. We recall the Comparison lemma, together with its dual, plays a central role in the sequel. Lemma 2.1 [13, Comparison lemma 2.1]. Let C be an additive category and X ∈ Ch. ≥0(C) a complex such that for all k ≥ 0the morphism dk+1. X is a weak cokernel ...

  10. Vínculos organizacionais Organizational ties

    Directory of Open Access Journals (Sweden)

    Gustavo Garcez Kramer

    2007-02-01

    Full Text Available Este artigo é um estudo de caso único, realizado junto a uma organização pública municipal de Curitiba, e tem como objetivo investigar e compreender os vínculos organizacionais. O estudo dos vínculos é feito por meio dos seus elementos constitutivos: a identificação, o sentimento de pertença, a cooperação, a participação, a criação de inimigos, a idealização, o reconhecimento e valorização dos indivíduos, a solidariedade, a integração, o crescimento e desenvolvimento pessoal e profissional e a autonomia. Foram utilizados, como instrumentos de coleta, questionário fechado e análise documental. O resultado dessa pesquisa é a caracterização dos elementos que são importantes na formação e manutenção dos vínculos e, conseqüentemente, para o comprometimento dos empregados com os objetivos, políticas, problemas, desempenho e resultados da organização.This article presents a unique case study of the organizational ties in a public municipal organization in the city of Curitiba, Brazil. The ties are studied through their constitutive elements: identification, sense of belonging, cooperation, participation, creation of enemies, idealization, recognition and appreciation of individuals, solidarity, integration, professional and personal development and growth, and autonomy. Documental analysis and closed questionnaires were used for data collection. The research resulted in the characterization of the elements that are important in making and keeping ties, and consequently committing employees to the organization's objectives, policies, problems, performance and results.

  11. The Running Barbed Tie-over Dressing.

    Science.gov (United States)

    Joyce, Cormac W; Joyce, Kenneth M; Kennedy, Ann-Marie; Kelly, Jack L

    2014-04-01

    Barbed suture technology is becoming increasingly popular in plastic surgery and is now being used in body contouring surgery and facial rejuvenation. We describe the novel application of a barbed suture as a running tie-over dressing for skin grafts. The barbs act as anchors in the skin, so constant tensioning of the suture is not required. The bidirectional nature of the suture prevents any slippage, and the barbs even act as a grip on the underlying wool dressing. Furthermore, the method described is both quick and simple to learn and would be useful for the sole operator.

  12. The Running Barbed Tie-over Dressing

    Directory of Open Access Journals (Sweden)

    Cormac W. Joyce, MB, BCh, MRCSI

    2014-04-01

    Full Text Available Summary: Barbed suture technology is becoming increasingly popular in plastic surgery and is now being used in body contouring surgery and facial rejuvenation. We describe the novel application of a barbed suture as a running tie-over dressing for skin grafts. The barbs act as anchors in the skin, so constant tensioning of the suture is not required. The bidirectional nature of the suture prevents any slippage, and the barbs even act as a grip on the underlying wool dressing. Furthermore, the method described is both quick and simple to learn and would be useful for the sole operator.

  13. Homology and isomorphism: Bourdieu in conversation with New Institutionalism.

    Science.gov (United States)

    Wang, Yingyao

    2016-06-01

    Bourdieusian Field Theory (BFT) provided decisive inspiration for the early conceptual formulation of New Institutionalism (NI). This paper attempts to reinvigorate the stalled intellectual dialogue between NI and BFT by comparing NI's concept of isomorphism with BFT's notion of homology. I argue that Bourdieu's understanding of domination-oriented social action, transposable habitus, and a non-linear causality, embodied in his neglected concept of homology, provides an alternative theorization of field-level convergence to New Institutionalism's central idea of institutional isomorphism. To showcase how BFT can be useful for organizational research, I postulate a habitus-informed and field-conditioned theory of transference to enrich NI's spin-off thesis of 'diffusion'. I propose that while NI can benefit from BFT's potential of bringing social structure back into organizational research, BFT can enrich its social analysis by borrowing from NI's elaboration of the symbolic system of organizations. © London School of Economics and Political Science 2016.

  14. Rational Homological Stability for Automorphisms of Manifolds

    DEFF Research Database (Denmark)

    Grey, Matthias

    In this thesis we prove rational homological stability for the classifying spaces of the homotopy automorphisms and block di↵eomorphisms of iterated connected sums of products of spheres of a certain connectivity.The results in particular apply to the manifolds       Npg,q  = (#g(Sp x Sq)) - int...... with coefficients in the homology of the universal covering, which is studied using rational homology theory. The result for the block di↵eomorphisms is deduced from the homological stability for the homotopy automorphisms upon using Surgery theory. Themain theorems of this thesis extend the homological stability...

  15. Kuranishi homology and Kuranishi cohomology

    OpenAIRE

    Joyce, Dominic

    2007-01-01

    A Kuranishi space is a topological space with a Kuranishi structure, defined by Fukaya and Ono. Kuranishi structures occur naturally on moduli spaces of J-holomorphic curves in symplectic geometry. Let Y be an orbifold and R a commutative ring or Q-algebra. We define two kinds of Kuranishi homology KH_*(Y;R). The chain complex KC_*(Y;R) defining KH_*(Y;R) is spanned over R by [X,f,G], for X a compact oriented Kuranishi space with corners, f : X --> Y smooth, and G "gauge-fixing data" which ma...

  16. Social Networks and Technology Adoption

    OpenAIRE

    Hogset, Heidi

    2005-01-01

    This study analyzes social network effects on Kenyan smallholders' decision to adopt improved natural resource management techniques. These effects are decomposed into effects from social influence and learning through networks (strong ties), group effects, weak ties effects, informal finance, and conflicts arising from technological externalities, controlling for non-network effects.

  17. Language as Social Fabric: Ties That Bind and Separate.

    Science.gov (United States)

    Walters, Keith; And Others

    1991-01-01

    Asserts that speakers of Black English and their behavior evoke strong responses outside and inside their communities. Asserts that members of the black communities are rarely permitted to describe or defend their language or ways of using it. Offers the essays, comments, and class interactions of an African-American/Linguistics class on language…

  18. Gender differences and social ties effects in resource sharing

    NARCIS (Netherlands)

    d'Exelle, Ben; Riedl, Arno

    2016-01-01

    In rural areas in developing countries gender inequality tends to be severe which might have substantial welfare implications if it determines how scarce economic resources are shared between men and women. Therefore, it is important to know how gender influences resource sharing and - given the

  19. Persistent homology and string vacua

    Energy Technology Data Exchange (ETDEWEB)

    Cirafici, Michele [Center for Mathematical Analysis, Geometry and Dynamical Systems,Instituto Superior Técnico, Universidade de Lisboa,Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Institut des Hautes Études Scientifiques,Le Bois-Marie, 35 route de Chartres, F-91440 Bures-sur-Yvette (France)

    2016-03-08

    We use methods from topological data analysis to study the topological features of certain distributions of string vacua. Topological data analysis is a multi-scale approach used to analyze the topological features of a dataset by identifying which homological characteristics persist over a long range of scales. We apply these techniques in several contexts. We analyze N=2 vacua by focusing on certain distributions of Calabi-Yau varieties and Landau-Ginzburg models. We then turn to flux compactifications and discuss how we can use topological data analysis to extract physical information. Finally we apply these techniques to certain phenomenologically realistic heterotic models. We discuss the possibility of characterizing string vacua using the topological properties of their distributions.

  20. Equivariant ordinary homology and cohomology

    CERN Document Server

    Costenoble, Steven R

    2016-01-01

    Filling a gap in the literature, this book takes the reader to the frontiers of equivariant topology, the study of objects with specified symmetries. The discussion is motivated by reference to a list of instructive “toy” examples and calculations in what is a relatively unexplored field. The authors also provide a reading path for the first-time reader less interested in working through sophisticated machinery but still desiring a rigorous understanding of the main concepts. The subject’s classical counterparts, ordinary homology and cohomology, dating back to the work of Henri Poincaré in topology, are calculational and theoretical tools which are important in many parts of mathematics and theoretical physics, particularly in the study of manifolds. Similarly powerful tools have been lacking, however, in the context of equivariant topology. Aimed at advanced graduate students and researchers in algebraic topology and related fields, the book assumes knowledge of basic algebraic topology and group act...

  1. Homology in Electromagnetic Boundary Value Problems

    Directory of Open Access Journals (Sweden)

    Pellikka Matti

    2010-01-01

    Full Text Available We discuss how homology computation can be exploited in computational electromagnetism. We represent various cellular mesh reduction techniques, which enable the computation of generators of homology spaces in an acceptable time. Furthermore, we show how the generators can be used for setting up and analysis of an electromagnetic boundary value problem. The aim is to provide a rationale for homology computation in electromagnetic modeling software.

  2. Evolution of bow-tie architectures in biology.

    Directory of Open Access Journals (Sweden)

    Tamar Friedlander

    2015-03-01

    Full Text Available Bow-tie or hourglass structure is a common architectural feature found in many biological systems. A bow-tie in a multi-layered structure occurs when intermediate layers have much fewer components than the input and output layers. Examples include metabolism where a handful of building blocks mediate between multiple input nutrients and multiple output biomass components, and signaling networks where information from numerous receptor types passes through a small set of signaling pathways to regulate multiple output genes. Little is known, however, about how bow-tie architectures evolve. Here, we address the evolution of bow-tie architectures using simulations of multi-layered systems evolving to fulfill a given input-output goal. We find that bow-ties spontaneously evolve when the information in the evolutionary goal can be compressed. Mathematically speaking, bow-ties evolve when the rank of the input-output matrix describing the evolutionary goal is deficient. The maximal compression possible (the rank of the goal determines the size of the narrowest part of the network-that is the bow-tie. A further requirement is that a process is active to reduce the number of links in the network, such as product-rule mutations, otherwise a non-bow-tie solution is found in the evolutionary simulations. This offers a mechanism to understand a common architectural principle of biological systems, and a way to quantitate the effective rank of the goals under which they evolved.

  3. 27 CFR 6.72 - “Tie-in” sales.

    Science.gov (United States)

    2010-04-01

    ... OF THE TREASURY LIQUORS âTIED-HOUSEâ Unlawful Inducements Quota Sales § 6.72 “Tie-in” sales. The act by an industry member of requiring that a retailer purchase one product (as defined in § 6.11) in... and not individually. However, an industry member is not precluded from selling two or more kinds or...

  4. The Strength of the Strongest Ties in Collaborative Problem Solving

    DEFF Research Database (Denmark)

    de Montjoye, Yves-Alexandre; Stopczynski, Arkadiusz; Shmueli, Erez

    2014-01-01

    an effect on performance. Both networks of strong ties explain more of the variance than other factors, such as measured or self-evaluated technical competencies, or the personalities of the team members. In fact, the inclusion of the network of strong ties renders these factors non...

  5. Tie-breaking in games of perfect information

    DEFF Research Database (Denmark)

    Tranæs, Torben

    1998-01-01

    The paper suggests that ties in an extensive form game have strategic implications if they represent credible threats or promises. We consider a subset of subgame-perfect Nash equilibria obtained by breaking ties according to their strategic implications, and show that the subset is nonempty for ...

  6. Multiresolution persistent homology for excessively large biomolecular datasets

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Kelin; Zhao, Zhixiong [Department of Mathematics, Michigan State University, East Lansing, Michigan 48824 (United States); Wei, Guo-Wei, E-mail: wei@math.msu.edu [Department of Mathematics, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Electrical and Computer Engineering, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824 (United States)

    2015-10-07

    Although persistent homology has emerged as a promising tool for the topological simplification of complex data, it is computationally intractable for large datasets. We introduce multiresolution persistent homology to handle excessively large datasets. We match the resolution with the scale of interest so as to represent large scale datasets with appropriate resolution. We utilize flexibility-rigidity index to access the topological connectivity of the data set and define a rigidity density for the filtration analysis. By appropriately tuning the resolution of the rigidity density, we are able to focus the topological lens on the scale of interest. The proposed multiresolution topological analysis is validated by a hexagonal fractal image which has three distinct scales. We further demonstrate the proposed method for extracting topological fingerprints from DNA molecules. In particular, the topological persistence of a virus capsid with 273 780 atoms is successfully analyzed which would otherwise be inaccessible to the normal point cloud method and unreliable by using coarse-grained multiscale persistent homology. The proposed method has also been successfully applied to the protein domain classification, which is the first time that persistent homology is used for practical protein domain analysis, to our knowledge. The proposed multiresolution topological method has potential applications in arbitrary data sets, such as social networks, biological networks, and graphs.

  7. Multicentre randomised double bind crossover trial on contamination of conventional ties and bow ties in routine obstetric and gynaecological practice.

    Science.gov (United States)

    Biljan, M M; Hart, C A; Sunderland, D; Manasse, P R; Kingsland, C R

    1993-01-01

    OBJECTIVE--To assess level of contamination of neckwear worn by gynaecologists and obstetricians during routine working week. DESIGN--Multicentre randomised double blind crossover trial. Participants wore the same conventional ties for three days in one week and bow ties for the same period in second week. SETTING--Two teaching and three district general hospitals in the midlands, Wales, and north England. SUBJECTS--15 registrars and senior registrars. INTERVENTIONS--A swab soaked in sterile saline was taken from specific area on ties at end of first and third working days and sent in transport medium for culture on chocolatised blood and MacConkey agar for 48 hours. MAIN OUTCOME MEASURES--Level of bacteriological growth assessed semiquantitatively (0 for no contamination; for heavy contamination) after swabs had been cultured. At end of study the participants completed a questionnaire to assess their attitude toward wearing different types of necktie. RESULTS--12 doctors (80%) completed the study. Although bow ties were significantly less contaminated at end of first working day (z = -2.354, p = 0.019), this difference was not maintained; there was no difference in level of contamination on third day. Level of contamination did not increase between first and third day of wearing the same garment. One of the 10 doctors who returned the questionnaire found the bow tie very uncomfortable. All participants would consider wearing a bow tie if it proved to be less contaminated than a conventional tie. CONCLUSIONS--Although a significant difference in contamination was established between conventional and bow ties on first day of study, this difference was not confirmed on third day and there is unlikely to be any real association between tie type and bacterial contamination. Because of its negative image and difficulty to tie, the bow tie will probably remain a minority fashion. Images p1583-a PMID:8292945

  8. Resilience by solidary ties (Resiliencia por lazos de solidaridad

    Directory of Open Access Journals (Sweden)

    Antonio Alaminos

    2015-07-01

    Full Text Available This article considers an empirical approach to the relationships among three well known concepts: “Benevolence” (Schwartz, Solidarity and Resilience ("Subjective wellbeing scale" - SWB. The first concept refers to cultural values, the second one to social networks and the third to the ability to recover from crisis. The measurement of solidarity has been done from the point of view of supportive ties. The baseline hypothesis considers that the presence of a high value in Benevolence contributes to the involvements in solidarity networks. Participation in supportive relationships facilitates recovery from personal crisis. Using data from the European Social Survey (ESS6, we conclude from this structural analysis that the resilience reflected in a society is partly a consequence of the supportive networks shaped by the presence of benevolence values. | Tras introducir teóricamente los conceptos de "Benevolencia" (Schwartz, "Lazos de solidaridad" y "Resiliencia", se presenta su operativización en la Encuesta Social Europea de 2012. La hipótesis de partida plantea que la presencia de un valor alto en Benevolencia influye en la participación en interacciones solidarias y que la participación en redes solidarias facilita el recobrarse de las crisis. A partir de estos datos, y considerando varias sociedades europeas, se han testado dos modelos alternativos, según el efecto de la Benevolencia y los lazos de solidaridad sobre la resiliencia. Se concluye que existe un efecto directo de los valores de Benevolencia sobre la Solidaridad, y de esta sobre la Resiliencia. La influencia de los valores de Benevolencia sobre la Resiliencia se establece de forma indirecta mediante la activación de relaciones solidarias.

  9. Can TIE-2 expressing monocytes represent a novel marker for hepatocellular carcinoma?

    Science.gov (United States)

    Dapas, Barbara; Grassi, Mario; Grassi, Gabriele

    2014-08-01

    Hepatocellular carcinoma (HCC), the predominant form of primary liver cancer, is a global health problem representing the sixth most common cancer and the third cause of cancer related death worldwide. The number of deaths per year in HCC is comparable to the incidence number, underlying the aggressive behavior of HCC and the modest efficacy of available curative treatments. Effective HCC treatment is problematic also due to the lack of early and specific diagnostic markers. In this regard, particular interest has been put on the tyrosine kinase with Ig and endothelial growth factor (EGF) homology domains 2 (TIE2), a receptor of angiopoietins, predominantly present on endothelial cells but also observed on monocytes [TIE-2-expressing monocytes (TEMs)]. Recently, a work by Matsubara et al. showed that the amount of circulating TEMs is higher in hepatitis virus C (HCV)/HCC patients compared to HCV patients or healthy subjects. Additionally the authors showed that TEMs have a diagnostic potential for HCC. Whereas the molecular mechanisms responsible for this observation remain elusive and further studies are necessary to confirm this finding, the work of Matsubara et al. may contribute to the identification of a novel HCC prognostic and diagnostic marker.

  10. Homotopic Chain Maps Have Equal s-Homology and d-Homology

    Directory of Open Access Journals (Sweden)

    M. Z. Kazemi-Baneh

    2016-01-01

    Full Text Available The homotopy of chain maps on preabelian categories is investigated and the equality of standard homologies and d-homologies of homotopic chain maps is established. As a special case, if X and Y are the same homotopy type, then their nth d-homology R-modules are isomorphic, and if X is a contractible space, then its nth d-homology R-modules for n≠0 are trivial.

  11. The rational weakness of strong ties : Failure of group solidarity in a highly cohesive group of rational agents

    NARCIS (Netherlands)

    Flache, Andreas

    2002-01-01

    Recent research (Flache, 1996; Flache and Macy, 1996) suggests a "weakness of strong ties." Cohesive social networks may undermine group solidarity, rather than sustain it. In the original analysis, simulations showed that adaptive actors learn cooperation in bilateral exchanges faster than

  12. The rational weakness of strong ties : Failure of group solidarity in a highly cohesive group of rational agents

    NARCIS (Netherlands)

    Flache, A; Yamamoto, H

    2006-01-01

    Recent research (Flache 1996; Flache and Macy 1996) suggests a "weakness of strong ties." Cohesive social networks may undermine group solidarity, rather than sustain it. In the original analysis, simulations showed that adaptive actors learn cooperation in bilateral exchanges faster than

  13. Relative K-homology and normal operators

    DEFF Research Database (Denmark)

    Manuilov, Vladimir; Thomsen, Klaus

    2009-01-01

    -term exact sequence which generalizes the excision six-term exact sequence in the first variable of KK-theory. Subsequently we investigate the relative K-homology which arises from the group of relative extensions by specializing to abelian $C^*$-algebras. It turns out that this relative K-homology carries...

  14. Transnational Corporate Ties: A Synopsis of Theories and Empirical Findings

    Directory of Open Access Journals (Sweden)

    Michael Nollert

    2015-08-01

    Full Text Available In general, corporations are not isolated actors in an economic “war of all against all” but members of corporate networks of global reach. Although the literature on globalization emphasizes the increasing economic power of these networks and postulates the formation of a transnational capitalist class, there is still a lack of empirical findings. The article starts with a review of theoretical perspectives (resource dependence, social capital, coordination of markets, financial hegemony, class hegemony, inner circle, and transnational capitalist class which focuses on the functions and structures of corporate interlocks at the national and the transnational level. The subsequent section offers an outline of empirical studies concerning transnational corporate networks. These analyses of corporate ties (interlocking directorates, financial participations and policy group affiliations suggest the emergence of transnational economic elites whose members, however, have not lost their national identity. In the final section, the theoretical perspectives will be assessed and some prospects are sketched out. Finally, it will be argued that the disintegration of the world society, which is considerably driven by rent-seeking corporate networks, can only be restrained if a potential global regulatory agency will be anchored in a post-Washington consensus.

  15. Lectures on homology with internal symmetries

    International Nuclear Information System (INIS)

    Solovyov, Yu.

    1993-09-01

    Homology with internal symmetries is a natural generalization of cyclic homology introduced, independently, by Connes and Tsygan, which has turned out to be a very useful tool in a number of problems of algebra, geometry topology, analysis and mathematical physics. It suffices to say cycling homology and cohomology are successfully applied in the index theory of elliptic operators on foliations, in the description of the homotopy type of pseudoisotopy spaces, in the theory of characteristic classes in algebraic K-theory. They are also applied in noncommutative differential geometry and in the cohomology of Lie algebras, the branches of mathematics which brought them to life in the first place. Essentially, we consider dihedral homology, which was successfully applied for the description of the homology type of groups of homeomorphisms and diffeomorphisms of simply connected manifolds. (author). 27 refs

  16. Redoable Tie-Over Dressing Using Multiple Loop Silk Threads

    Directory of Open Access Journals (Sweden)

    Hyeon Jong Jo

    2013-05-01

    Full Text Available After skin grafting, to prevent hematoma or seroma collection at the graft site, a tie-over dressing has been commonly used. However, although the conventional tie-over dressing by suture is a useful method for securing a graft site, refixation is difficult when repeated tie-over dressing is needed. Therefore, we recommend a redoable tie-over dressing technique with multiple loops threads and connecting silk threads. After the raw surface of each of our cases was covered with a skin graft, multiple loop silk thread attached with nylon at the skin graft margin. We applied the ointment gauze and wet cotton/fluffy gauze over the skin graft, then fixed the dressing by connecting cross-counter multiple loop thread with connecting silk threads. When we opened the tie-over dressing by cutting the connecting silk threads, we repeated the tie-over dressing with the same method. The skin graft was taken successfully without hematoma or seroma collection or any other complications. In conclusion, we report a novel tie-over dressing enabling simple fixation of the dressing to maintain proper tension for wounds that require repetitive fixation. Further, with this reliable method, the skin grafts were well taken.

  17. Tyrosine phosphorylation of Grb14 by Tie2

    Directory of Open Access Journals (Sweden)

    Dumont Daniel J

    2010-10-01

    Full Text Available Abstract Background Growth factor receptor bound (Grb proteins 7, 10 and 14 are a family of structurally related multi-domain adaptor proteins involved in a variety of biological processes. Grb7, 10 and 14 are known to become serine and/or threonine phosphorylated in response to growth factor (GF stimulation. Grb7 and 10 have also been shown to become tyrosine phosphorylated under certain conditions. Under experimental conditions Grb7 is tyrosine phosphorylated by the Tie2/Tie-2/Tek angiogenic receptor tyrosine kinase (RTK. Furthermore, Grb14 has also been shown to interact with Tie2, however tyrosine phosphorylation of this Grb family member has yet to be reported. Results Here we report for the first time tyrosine phosphorylation of Grb14. This phosphorylation requires a kinase competent Tie2 as well as intact tyrosines 1100 and 1106 (Y1100 and Y1106 on the receptor. Furthermore, a complete SH2 domain on Grb14 is required for Grb14 tyrosine phosphorylation by Tie2. Grb14 was also able to become tyrosine phosphorylated in primary endothelial cells when treated with a soluble and potent variant of the Tie2 ligand, cartilage oligomeric matrix protein (COMP Ang1. Conclusion Our results show that Grb14, like its family members Grb7 and Grb10, is able to be tyrosine phosphorylated. Furthermore, our data indicate a role for Grb14 in endothelial signaling downstream of the Tie2 receptor.

  18. The Popularity of Picture Books with Television Tie-in

    Directory of Open Access Journals (Sweden)

    Patricia R. Ladd

    2011-06-01

    Full Text Available This study analyzes circulation statistics of television tie-in picture books from the Wake County Public Library System in North Carolina to determine their popularity among patrons. Caldecott winning picture books were used as a point of comparison. This study also examined OPAC holdings from North Carolina public libraries to determine television tie-in picture book popularity among collection builders. The findings of the study show that television tie-in picture books are found to some degree in the vast majority of North Carolina public libraries, and are more popular than award winners in the Wake County system.

  19. EXPORT PROMOTION: Export-Import Bank and Treasury Differ in Their Approaches to Using Tied Aid

    National Research Council Canada - National Science Library

    2002-01-01

    Under the tied aid program legislation,4 Treasury had the authority to direct and control the use of Ex-Im Bank's Tied Aid Capital Projects Fund, in effect allowing Treasury to veto individual tied aid proposals...

  20. Cross-border ties as a source of risk and resilience: Do cross-border ties moderate the relationship between migration-related stress and psychological distress among Latino migrants in the United States?

    Science.gov (United States)

    Torres, Jacqueline M.; Alcántara, Carmela; Rudolph, Kara E.; Viruell-Fuentes, Edna A.

    2017-01-01

    Few studies have examined the associations between health and the cross-border ties that migrants maintain with their family members in communities of origin. We draw on theory related to social ties, ethnic identity, and mental health to examine cross-border ties as potential moderators of the association between migration-related stress and psychological distress among Latino migrants. Using data from the National Latino and Asian American Survey, we find that remittance sending is associated with significantly lower levels of psychological distress for Cuban migrants, and difficulty visiting home is associated with significantly greater psychological distress for Puerto Rican migrants. There were significant associations between migration-related stressors and psychological distress, although these associations fell to non-significance after accounting for multiple testing. We found little evidence that cross-border ties either buffer or exacerbate the association between migration-related stressors and psychological distress. We consider the findings within the current political and historical context of cross-border ties and separation. PMID:27803264

  1. Cross-border Ties as Sources of Risk and Resilience: Do Cross-border Ties Moderate the Relationship between Migration-related Stress and Psychological Distress for Latino Migrants in the United States?

    Science.gov (United States)

    Torres, Jacqueline M; Alcántara, Carmela; Rudolph, Kara E; Viruell-Fuentes, Edna A

    2016-12-01

    Few studies have examined the associations between health and the cross-border ties that migrants maintain with their family members in communities of origin. We draw on theory related to social ties, ethnic identity, and mental health to examine cross-border ties as potential moderators of the association between migration-related stress and psychological distress among Latino migrants. Using data from the National Latino and Asian American Survey, we find that remittance sending is associated with significantly lower levels of psychological distress for Cuban migrants, and difficulty visiting home is associated with significantly greater psychological distress for Puerto Rican migrants. There were significant associations between migration-related stressors and psychological distress, although these associations fell to nonsignificance after accounting for multiple testing. We found little evidence that cross-border ties either buffer or exacerbate the association between migration-related stressors and psychological distress. We consider the findings within the current political and historical context of cross-border ties and separation. © American Sociological Association 2016.

  2. Differentiating weak ties and strong ties among external sources of influences for enterprise resource planning (ERP) adoption

    Science.gov (United States)

    Aubert, Benoit; Léger, Pierre-Majorique; Larocque, Denis

    2012-05-01

    Enterprise resource planning (ERP) systems represent a major IT adoption decision. ERP adoption decisions, in the chemicals and allied products sectors, were examined between 1994 and 2005. Networks of strong ties and weak ties partners are investigated. Results show that neighbouring companies linked with strong ties can have an influence on organisations making such adoption decision. Past decisions made by major trading partners have a significant influence on the decision to adopt an ERP system for a given organisation. This reflects the complex nature of the knowledge required for such adoption.

  3. High-speed passenger rail tie-ballast interaction.

    Science.gov (United States)

    2015-05-01

    This Research Results Report presents : evidence of poor tie support and increased : applied loads that were used to determine the : root cause of transient and permanent vertical : displacements at two Amtrak bridge transitions. : These result...

  4. Cracking and impact performance characteristics of plastic composite ties.

    Science.gov (United States)

    2012-03-01

    As followup to a workshop on Engineered Composite Ties sponsored by the American Railway Engineering and Maintenance-of-Way Association and the Federal Railroad Administration, the Transportation Technology Center, Inc., in Pueblo, CO, conducted a se...

  5. DO TIE LABORATORY BASED ASSESSMENT METHODS REALLY PREDICT FIELD EFFECTS?

    Science.gov (United States)

    Sediment Toxicity Identification and Evaluation (TIE) methods have been developed for both porewaters and whole sediments. These relatively simple laboratory methods are designed to identify specific toxicants or classes of toxicants in sediments; however, the question of whethe...

  6. DO TIE LABORATORY BASED METHODS REALLY REFLECT FIELD CONDITIONS

    Science.gov (United States)

    Sediment Toxicity Identification and Evaluation (TIE) methods have been developed for both interstitial waters and whole sediments. These relatively simple laboratory methods are designed to identify specific toxicants or classes of toxicants in sediments; however, the question ...

  7. Vibration Analysis for Monitoring of Ancient Tie-Rods

    Directory of Open Access Journals (Sweden)

    L. Collini

    2017-01-01

    Full Text Available This paper presents an application of vibration analysis to the monitoring of tie-rods. An algorithm for the axial load estimation based on experimentally measured natural frequencies is introduced and its application to a case study is reported. The proposed model of a tie-rod incorporates elastic bed-type boundary conditions that represent the contact between stonework and the tie-rod. The weighed differences between experimentally and numerically determined frequencies are minimized with respect to the parameters of the model, the main being the axial load and the stiffness at the tie-rod/wall interface. Thus, the multidimensional optimization problem is solved. Results are analysed in comparison to a model with simple fixed-end boundary conditions. In addition, the analytical formulation of the problem is delivered.

  8. Family ties and depression across the life course: An Overview

    Directory of Open Access Journals (Sweden)

    Nienke Moor

    2012-08-01

    Full Text Available BACKGROUND Family ties in Europe are affected by demographic trends associated with parenting and partnering, such as a decline in fertility, an increase in childlessness, postponement of parenthood and of partnership formation, the rise of "new" relationship forms and divorce rates. It is unclear how the contemporary family structure and composition are associated with people's mental wellbeing. OBJECTIVE This article examines how ties with parents, siblings, a partner and children are associated with depressive mood of men and women in seven Eastern and Western European countries. METHODS To test our hypotheses we made use of data from the Generations and Gender Surveys. We performed logistic regression analyses to study the associations between people's family ties and depressive mood. RESULTS Our research findings show that family ties can diminish people's depressive feelings. Although we find some gender differences in these associations, we do not find support for the argument that family ties are more important for the mental wellbeing of women than of men. Moreover, our findings support the hierarchical model of family relations in which new ties with partner and children in adulthood gain precedence over the original primary ties with parents and siblings. Finally, we find that the association between family ties and depressive mood is quite similar in Eastern and Western Europe, but being married or having a partner more strongly reduces depressive feelings in Eastern than in Western Europe. CONCLUSIONS Although we did not dispose of longitudinal data, our research results do provide some indications about how demographic changes, for instance, those affecting family size -- the number of children or siblings -- might be associated with mental wellbeing. Our findings also suggest that the demographic trend of increasing partnership dissolution may have larger consequences for people's mental wellbeing in Eastern

  9. Redoable Tie-Over Dressing Using Multiple Loop Silk Threads

    Directory of Open Access Journals (Sweden)

    Hyeon Jong Jo

    2013-05-01

    Full Text Available After skin grafting, to prevent hematoma or seroma collection at the graft site, a tie-over dressing has been commonly used. However, although the conventional tie-over dressing by suture is a useful method for securing a graft site, refixation is difficult when repeated tieover dressing is needed. Therefore, we recommend a redoable tie-over dressing technique with multiple loops threads and connecting silk threads. After the raw surface of each of our cases was covered with a skin graft, multiple loop silk thread attached with nylon at the skin graft margin. We applied the ointment gauze and wet cotton/fluffy gauze over the skin graft, then fixed the dressing by connecting cross-counter multiple loop thread with connecting silk threads. When we opened the tie-over dressing by cutting the connecting silk threads, we repeated the tie-over dressing with the same method. The skin graft was taken successfully without hematoma or seroma collection or any other complications. In conclusion, we report a novel tie-over dressing enabling simple fixation of the dressing to maintain proper tension for wounds that require repetitive fixation. Further, with this reliable method, the skin grafts were well taken.

  10. Localization of the angiopoietin receptors Tie-1 and Tie-2 on the primary cilia in the female reproductive organs

    DEFF Research Database (Denmark)

    Teilmann, Stefan C; Christensen, Søren T

    2005-01-01

    Blood vessel homeostasis and endothelial cell survival depend on proper signalling through angiopoietin receptors such as the receptor tyrosine kinases Tie-1 and Tie-2. We have studied the presence and subcellular localization of these receptors in murine female reproductive organs using confocal...... organs play a novel and important sensory role in relaying physiochemical changes from the extracellular environment to epithelial cells of the oviduct, the ovary and extra-ovarian tissues.......Blood vessel homeostasis and endothelial cell survival depend on proper signalling through angiopoietin receptors such as the receptor tyrosine kinases Tie-1 and Tie-2. We have studied the presence and subcellular localization of these receptors in murine female reproductive organs using confocal...

  11. Preserved irradiated homologous cartilage for orbital reconstruction

    International Nuclear Information System (INIS)

    Linberg, J.V.; Anderson, R.L.; Edwards, J.J.; Panje, W.R.; Bardach, J.

    1980-01-01

    Human costal cartilage is an excellent implant material for orbital and periorbital reconstruction because of its light weight, strength, homogeneous consistency and the ease with which it can be carved. Its use has been limited by the necessity of a separate surgical procedure to obtain the material. Preserved irradiated homologous cartilage has been shown to have almost all the autogenous cartilage and is convenient to use. Preserved irradiated homologous cartilage transplants do not elicit rejection reactions, resist infection and rarely undergo absorption

  12. Dualities in persistent (co)homology

    International Nuclear Information System (INIS)

    De Silva, Vin; Morozov, Dmitriy; Vejdemo-Johansson, Mikael

    2011-01-01

    We consider sequences of absolute and relative homology and cohomology groups that arise naturally for a filtered cell complex. We establish algebraic relationships between their persistence modules, and show that they contain equivalent information. We explain how one can use the existing algorithm for persistent homology to process any of the four modules, and relate it to a recently introduced persistent cohomology algorithm. We present experimental evidence for the practical efficiency of the latter algorithm

  13. Effect of summer grazing on welfare of dairy cows reared in mountain tie-stall barns

    Directory of Open Access Journals (Sweden)

    Simonetta Dovier

    2010-09-01

    Full Text Available Traditional mountain farms have an important economic, social and environmental role. The Alps management system for dairy cows consists of animals kept indoors from autumn to spring, mostly in tie-stalls, and moved to mountain pasture in summer. The aim of our study was to assess the effect of mountain summer grazing on the welfare of dairy cows housed in tie-stall barns. Twenty-four farms were considered. In twelve of them, animals were reared in tie-stalls and moved to mountain pasture for three months in summer; they were visited three times: (i four weeks before grazing during the indoor period in the stall; (ii about three weeks after the start of grazing; and (iii in the stall, in autumn, at least three weeks after returning from grazing. The other twelve farms kept the animals in tie-stalls all year; they were visited once in autumn. Data were collected following a protocol that considers animal-based measures and structure information on the basis of Quality Welfare Consortium® indications. Data allowed the calculation of both the Animal Needs Index score (ANI 35L and an overall assessment of the cows’ welfare obtained from three general aspects: housing, animal’s physical condition, and animal’s behaviour. Summer grazing had a significant positive effect on injuries, lameness and animal’s rising duration but a negative effect on faeces consistency. Moreover, a reduction of tongue playing was observed. The ANI 35L and the overall assessment did not show significant differences linked to summer grazing, which tended to have a positive but temporary effect on animal behaviour.

  14. SURVEY ON SOCIAL ENTREPRENEURS

    DEFF Research Database (Denmark)

    Persson, H Thomas R; Rakar, Fredrik

    of social enterprises and highlights the diversity of the social entrepreneurship sector in Sweden. The image of social entrepreneurship in Sweden as being dominated by a well-educated middle class and tied to the university environments – rather than being sprung out of bottom-up organising...

  15. Close encounters: Analyzing how social similarity and propinquity contribute to strong network connections.

    OpenAIRE

    Reagans, Ray Eugene

    2010-01-01

    Models of network formation emphasize the importance of social similarity and propinquity in producing strong interpersonal connections. The positive effect each factor can have on tie strength has been documented across a number of studies, and yet we know surprisingly very little about how the two factors combine to produce strong ties. Being in close proximity could either amplify or dampen the positive effect that social similarity can have on tie strength. Data on tie strength among teac...

  16. 78 FR 75545 - Prestressed Concrete Steel Rail Tie Wire From the People's Republic of China: Preliminary...

    Science.gov (United States)

    2013-12-12

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-990] Prestressed Concrete Steel... (``Department'') preliminarily determines that prestressed concrete steel rail tie wire (``PC tie wire'') from... prestressed tendons in concrete railroad ties (``PC tie wire''). High carbon steel is defined as steel that...

  17. Investigating homology between proteins using energetic profiles.

    Science.gov (United States)

    Wrabl, James O; Hilser, Vincent J

    2010-03-26

    Accumulated experimental observations demonstrate that protein stability is often preserved upon conservative point mutation. In contrast, less is known about the effects of large sequence or structure changes on the stability of a particular fold. Almost completely unknown is the degree to which stability of different regions of a protein is generally preserved throughout evolution. In this work, these questions are addressed through thermodynamic analysis of a large representative sample of protein fold space based on remote, yet accepted, homology. More than 3,000 proteins were computationally analyzed using the structural-thermodynamic algorithm COREX/BEST. Estimated position-specific stability (i.e., local Gibbs free energy of folding) and its component enthalpy and entropy were quantitatively compared between all proteins in the sample according to all-vs.-all pairwise structural alignment. It was discovered that the local stabilities of homologous pairs were significantly more correlated than those of non-homologous pairs, indicating that local stability was indeed generally conserved throughout evolution. However, the position-specific enthalpy and entropy underlying stability were less correlated, suggesting that the overall regional stability of a protein was more important than the thermodynamic mechanism utilized to achieve that stability. Finally, two different types of statistically exceptional evolutionary structure-thermodynamic relationships were noted. First, many homologous proteins contained regions of similar thermodynamics despite localized structure change, suggesting a thermodynamic mechanism enabling evolutionary fold change. Second, some homologous proteins with extremely similar structures nonetheless exhibited different local stabilities, a phenomenon previously observed experimentally in this laboratory. These two observations, in conjunction with the principal conclusion that homologous proteins generally conserved local stability, may

  18. Investigating homology between proteins using energetic profiles.

    Directory of Open Access Journals (Sweden)

    James O Wrabl

    2010-03-01

    Full Text Available Accumulated experimental observations demonstrate that protein stability is often preserved upon conservative point mutation. In contrast, less is known about the effects of large sequence or structure changes on the stability of a particular fold. Almost completely unknown is the degree to which stability of different regions of a protein is generally preserved throughout evolution. In this work, these questions are addressed through thermodynamic analysis of a large representative sample of protein fold space based on remote, yet accepted, homology. More than 3,000 proteins were computationally analyzed using the structural-thermodynamic algorithm COREX/BEST. Estimated position-specific stability (i.e., local Gibbs free energy of folding and its component enthalpy and entropy were quantitatively compared between all proteins in the sample according to all-vs.-all pairwise structural alignment. It was discovered that the local stabilities of homologous pairs were significantly more correlated than those of non-homologous pairs, indicating that local stability was indeed generally conserved throughout evolution. However, the position-specific enthalpy and entropy underlying stability were less correlated, suggesting that the overall regional stability of a protein was more important than the thermodynamic mechanism utilized to achieve that stability. Finally, two different types of statistically exceptional evolutionary structure-thermodynamic relationships were noted. First, many homologous proteins contained regions of similar thermodynamics despite localized structure change, suggesting a thermodynamic mechanism enabling evolutionary fold change. Second, some homologous proteins with extremely similar structures nonetheless exhibited different local stabilities, a phenomenon previously observed experimentally in this laboratory. These two observations, in conjunction with the principal conclusion that homologous proteins generally conserved

  19. The Spontaneous Combustion of Railway Ties and Asphalt Shingles

    Science.gov (United States)

    Leslie, Geoffrey

    Many Low Carbon Fuels (LCFs) present unknown spontaneous combustion risks, which must be quantified before their use as fossil fuel replacements. Wood and coal spontaneous combustion is well understood; however, LCFs weather, and subsequent chemical changes could affect their spontaneous combustion properties. LCF spontaneous combustion could lead to accidental fires with possible loss of life, limb and property. The spontaneous combustion risks of two LCFs, discarded creosote-treated wooden railway ties and roofing asphalt shingles, were investigated with calorimetry and heat transfer experiments. Chemical changes due to weathering were studied with pyrolysis-Gas Chromatography/Mass Spectrometry (py-GC/MS). Creosote-treated wooden railway tie dust, roofing asphalt shingle particles, poplar wood pellets, and petroleum coke self-heating were studied with isothermal calorimetry. Railway tie dust and asphalt shingle heat transfer were characterized with a guarded hot plate. Petroleum coke self-heating was consistent with coal, while both poplar pellets and railway tie dust were found to be more reactive compared to oven test results of similar materials. The observed increase in reactivity was probably a result of significant moisture contenint in the pellet and railway tie dust. Critical conditions for spontaneous combustion were evaluated with the Frank-Kamenetskii parameter, assuming an ambient temperature of 40°C and constant moisture content. Kamenetskii calculations indicate that a 1.6 m cube of railway tie dust, or a 58 m cube of asphalt particles, would be unstable and combust. LCF chemistry may have been affected by weathering, which would cause chemical changes that affect their spontaneous combustion properties. Therefore, railway tie wood and roofing asphalt shingle chemistry were investigated by identifying products of 250° and 550°C pyrolysis with py-GC/MS. Railway tie wood pyrolyzates did not show signs of weathering; in contrast, asphalt pyrolysis

  20. Robust tie points selection for InSAR image coregistration

    Science.gov (United States)

    Skanderi, Takieddine; Chabira, Boulerbah; Afifa, Belkacem; Belhadj Aissa, Aichouche

    2013-10-01

    Image coregistration is an important step in SAR interferometry which is a well known method for DEM generation and surface displacement monitoring. A practical and widely used automatic coregistration algorithm is based on selecting a number of tie points in the master image and looking for the correspondence of each point in the slave image using correlation technique. The characteristics of these points, their number and their distribution have a great impact on the reliability of the estimated transformation. In this work, we present a method for automatic selection of suitable tie points that are well distributed over the common area without decreasing the desired tie points' number. First we select candidate points using Harris operator. Then from these points we select tie points depending on their cornerness measure (the highest first). Once a tie point is selected, its correspondence is searched for in the slave image, if the similarity measure maximum is less than a given threshold or it is at the border of the search window, this point is discarded and we proceed to the next Harris point, else, the cornerness of the remaining candidates Harris points are multiplied by a spatially radially increasing function centered at the selected point to disadvantage the points in a neighborhood of a radius determined from the size of the common area and the desired number of points. This is repeated until the desired number of points is selected. Results of an ERS1/2 tandem pair are presented and discussed.

  1. On the Directionality Test of Peer Effects in Social Networks

    Science.gov (United States)

    An, Weihua

    2016-01-01

    One interesting idea in social network analysis is the directionality test that utilizes the directions of social ties to help identify peer effects. The null hypothesis of the test is that if contextual factors are the only force that affects peer outcomes, the estimated peer effects should not differ, if the directions of social ties are…

  2. Social Networks in the Classroom: Personality Factors as Antecedents of Student Social Capital

    Science.gov (United States)

    Seevers, Matthew T.; Johnson, Bryan R.; Darnold, Todd C.

    2015-01-01

    This study examines personality factors as antecedents of student social capital. We hypothesize relationships between two constructs taken from the five-factor model of personality (agreeableness and extraversion) and two variables that reflect a student's social capital (quantity of ties and strength of ties) in an academic setting. Analysis of…

  3. Heider balance, asymmetric ties, and gender segregation

    Science.gov (United States)

    Krawczyk, Małgorzata J.; del Castillo-Mussot, Marcelo; Hernández-Ramírez, Eric; Naumis, Gerardo G.; Kułakowski, Krzysztof

    2015-12-01

    To remove a cognitive dissonance in interpersonal relations, people tend to divide their acquaintances into friendly and hostile parts, both groups internally friendly and mutually hostile. This process is modeled as an evolution toward the Heider balance. A set of differential equations have been proposed and validated (Kułakowski et al., 2005) to model the Heider dynamics of this social and psychological process. Here we generalize the model by including the initial asymmetry of the interpersonal relations and the direct reciprocity effect which removes this asymmetry. Our model is applied to the data on enmity and friendship in 37 school classes and 4 groups of teachers in México. For each class, a stable balanced partition is obtained into two groups. The gender structure of the groups reveals stronger gender segregation in younger classes, i.e. of age below 12 years, a fact consistent with other general empirical results.

  4. Stability and failure analysis of steering tie-rod

    Science.gov (United States)

    Jiang, GongFeng; Zhang, YiLiang; Xu, XueDong; Ding, DaWei

    2008-11-01

    A new car in operation of only 8,000 km, because of malfunction, resulting in lost control and rammed into the edge of the road, and then the basic vehicle scrapped. According to the investigation of the site, it was found that the tie-rod of the car had been broken. For the subjective analysis of the accident and identifying the true causes of rupture of the tierod, a series of studies, from the angle of theory to experiment on the bended broken tie-rod, were conducted. The mechanical model was established; the stability of the defective tie-rod was simulated based on ANSYS software. Meanwhile, the process of the accident was simulated considering the effect of destabilization of different vehicle speed and direction of the impact. Simultaneously, macro graphic test, chemical composition analysis, microstructure analysis and SEM analysis of the fracture were implemented. The results showed that: 1) the toughness of the tie-rod is at a normal level, but there is some previous flaws. One quarter of the fracture surface has been cracked before the accident. However, there is no relationship between the flaw and this incident. The direct cause is the dynamic instability leading to the large deformation of impact loading. 2) The declining safety factor of the tie-rod greatly due to the previous flaws; the result of numerical simulation shows that previous flaw is the vital factor of structure instability, on the basis of the comparison of critical loads of the accident tie-rod and normal. The critical load can decrease by 51.3% when the initial defect increases 19.54% on the cross-sectional area, which meets the Theory of Koiter.

  5. Family ties: the multilevel effects of households and kinship on the networks of individuals.

    Science.gov (United States)

    Koster, Jeremy

    2018-04-01

    Among social mammals, humans uniquely organize themselves into communities of households that are centred around enduring, predominantly monogamous unions of men and women. As a consequence of this social organization, individuals maintain social relationships both within and across households, and potentially there is conflict among household members about which social ties to prioritize or de-emphasize. Extending the logic of structural balance theory, I predict that there will be considerable overlap in the social networks of individual household members, resulting in a pattern of group-level reciprocity. To test this prediction, I advance the Group-Structured Social Relations Model, a generalized linear mixed model that tests for group-level effects in the inter-household social networks of individuals. The empirical data stem from social support interviews conducted in a community of indigenous Nicaraguan horticulturalists, and model results show high group-level reciprocity among households. Although support networks are organized around kinship, covariates that test predictions of kin selection models do not receive strong support, potentially because most kin-directed altruism occurs within households, not between households. In addition, the models show that households with high genetic relatedness in part from children born to adulterous relationships are less likely to assist each other.

  6. Homological methods, representation theory, and cluster algebras

    CERN Document Server

    Trepode, Sonia

    2018-01-01

    This text presents six mini-courses, all devoted to interactions between representation theory of algebras, homological algebra, and the new ever-expanding theory of cluster algebras. The interplay between the topics discussed in this text will continue to grow and this collection of courses stands as a partial testimony to this new development. The courses are useful for any mathematician who would like to learn more about this rapidly developing field; the primary aim is to engage graduate students and young researchers. Prerequisites include knowledge of some noncommutative algebra or homological algebra. Homological algebra has always been considered as one of the main tools in the study of finite-dimensional algebras. The strong relationship with cluster algebras is more recent and has quickly established itself as one of the important highlights of today’s mathematical landscape. This connection has been fruitful to both areas—representation theory provides a categorification of cluster algebras, wh...

  7. Endothelial Activation: The Ang/Tie Axis in Sepsis

    Directory of Open Access Journals (Sweden)

    Aleksandra Leligdowicz

    2018-04-01

    Full Text Available Sepsis, a dysregulated host response to infection that causes life-threatening organ dysfunction, is a highly heterogeneous syndrome with no specific treatment. Although sepsis can be caused by a wide variety of pathogenic organisms, endothelial dysfunction leading to vascular leak is a common mechanism of injury that contributes to the morbidity and mortality associated with the syndrome. Perturbations to the angiopoietin (Ang/Tie2 axis cause endothelial cell activation and contribute to the pathogenesis of sepsis. In this review, we summarize how the Ang/Tie2 pathway is implicated in sepsis and describe its prognostic as well as therapeutic utility in life-threatening infections.

  8. Dairy cows welfare quality in tie-stall housing system with or without access to exercise

    Science.gov (United States)

    2013-01-01

    Background Tie-stall housing of dairy cows is used extensively worldwide, despite of the welfare concerns regarding the restriction of voluntary movement and limitation of expression of the cows’ natural behaviour. The aim of this study was to compare the welfare quality of dairy cows kept in two types of tie-stall housing systems: with regular outdoor exercise and without access to exercise. In addition, the study investigated the relationship between different welfare measures of dairy cows kept in tie-stalls. Methods 3,192 lactating cows were assessed using the Welfare Quality® assessment protocol for cattle in 80 commercial dairy farms, half of the farms providing outdoor access for the animals to exercise. The descriptive statistical indicators were determined for the assessed measures and for the welfare criteria and principle scores. The data obtained in the two housing types were compared and the correlation coefficients were calculated between the different welfare measures. Results The significant differences found between the two housing systems for the majority of the animal based measures indicate the positive effect of exercise on the welfare of tethered cows. Many of the animal welfare parameters correlated with each other. For the farms allowing the cows’ turnout in a paddock, pasture or both, the mean scores for the welfare criteria and principles were higher than for the farms with permanent tethering of the cows, except the criteria absence of prolonged hunger and expression of social behaviours. The lowest scores were obtained for the criterion positive emotional state, in both housing systems. With regard to the overall classification, none of the farms were considered excellent. In the not classified category were only farms with all-year-round tethering of the animals and in the enhanced category only farms where the cows had outdoor access. Conclusions The welfare quality of the investigated dairy cows was significantly better in the

  9. Beyond Getting in and Fitting in: An Examination of Social Networks and Professionally Relevant Social Capital among Latina/o University Students

    Science.gov (United States)

    Rios-Aguilar, Cecilia; Deil-Amen, Regina

    2012-01-01

    Social network analyses, combined with qualitative analyses, are examined to understand key components of the college trajectories of 261 Latina/o students. Their social network ties reveal variation in extensity and the relevance. Most ties facilitate social capital relevant to getting into college, fewer engage social capital relevant to…

  10. A homology theory for smale spaces

    CERN Document Server

    Putnam, Ian F

    2014-01-01

    The author develops a homology theory for Smale spaces, which include the basics sets for an Axiom A diffeomorphism. It is based on two ingredients. The first is an improved version of Bowen's result that every such system is the image of a shift of finite type under a finite-to-one factor map. The second is Krieger's dimension group invariant for shifts of finite type. He proves a Lefschetz formula which relates the number of periodic points of the system for a given period to trace data from the action of the dynamics on the homology groups. The existence of such a theory was proposed by Bowen in the 1970s.

  11. TIE-2 and VEGFR kinase activities drive immunosuppressive function of TIE-2-expressing monocytes in human breast tumors.

    Science.gov (United States)

    Ibberson, Mark; Bron, Sylvian; Guex, Nicolas; Faes-van't Hull, Eveline; Ifticene-Treboux, Assia; Henry, Luc; Lehr, Hans-Anton; Delaloye, Jean-François; Coukos, George; Xenarios, Ioannis; Doucey, Marie-Agnès

    2013-07-01

    Tumor-associated TIE-2-expressing monocytes (TEM) are highly proangiogenic cells critical for tumor vascularization. We previously showed that, in human breast cancer, TIE-2 and VEGFR pathways control proangiogenic activity of TEMs. Here, we examine the contribution of these pathways to immunosuppressive activity of TEMs. We investigated the changes in immunosuppressive activity of TEMs and gene expression in response to specific kinase inhibitors of TIE-2 and VEGFR. The ability of tumor TEMs to suppress tumor-specific T-cell response mediated by tumor dendritic cells (DC) was measured in vitro. Characterization of TEM and DC phenotype in addition to their interaction with T cells was done using confocal microscopic images analysis of breast carcinomas. TEMs from breast tumors are able to suppress tumor-specific immune responses. Importantly, proangiogenic and suppressive functions of TEMs are similarly driven by TIE-2 and VEGFR kinase activity. Furthermore, we show that tumor TEMs can function as antigen-presenting cells and elicit a weak proliferation of T cells. Blocking TIE-2 and VEGFR kinase activity induced TEMs to change their phenotype into cells with features of myeloid dendritic cells. We show that immunosuppressive activity of TEMs is associated with high CD86 surface expression and extensive engagement of T regulatory cells in breast tumors. TIE-2 and VEGFR kinase activity was also necessary to maintain high CD86 surface expression levels and to convert T cells into regulatory cells. These results suggest that TEMs are plastic cells that can be reverted from suppressive, proangiogenic cells into cells that are able to mediate an antitumoral immune response. ©2013 AACR.

  12. Transnational ties and the health of sub-Saharan African migrants: The moderating role of gender and family separation.

    Science.gov (United States)

    Afulani, Patience A; Torres, Jacqueline M; Sudhinaraset, May; Asunka, Joseph

    2016-11-01

    Recent scholarship has focused on the role that cross-border social and economic ties play in shaping health outcomes for migrant populations. Nevertheless, the extant empirical work on this topic has paid little attention to the health impacts of cross-border separation from close family members. In this paper we examine the association between cross-border ties-and cross-border separation-with the health of sub-Saharan African (SSA) migrant adults living in metropolitan France using data from the nationally representative "Trajectoire et Origines" survey (n = 1980 SSA migrants). In logistic regression analyses we find that remitting money and having a child abroad are each associated with poor health among women, but not men. The effect of remittances on health is also modified by the location of one's children: remittance sending is associated with poor health only for SSA-migrants separated from their children. These findings underscore the importance of examining both cross-border connection and cross-border separation in studies of immigrant health, and also underscore the heterogeneous relationships between cross-border ties and health for men and women. This is the first study to our knowledge that examines the relationship between cross-border ties and health for migrants in Europe, with a focus on SSA-migrants in France. These findings have important implications for the health of the growing immigrant and refugee populations in Europe and around the globe. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Changes of Personal Network Composition and Inter-Group Ties from 1987 to 2005 in Hungary

    Directory of Open Access Journals (Sweden)

    VARGA V., Attila

    2014-04-01

    Full Text Available The following paper presents the changes and stability of assortative mixing, and inter-group ties in Hungary from 1987 to 2005. The demographic categories under investigation are age, sex, and education. The analysis has a special focus on the rearrangement of the context of tie formation, and the inequality of receiving choices into personal networks along social categories. The most substantial change during the period, is the strong decrease in gender homophily, and some strengthening of intergenerationalties. Both of these findings are in line with the observation that personal networks are recruited more often among the members of the nuclear-family. This latter phenomenon is probably due to the shrinking network size. However, this set of finding is prone to the methodological criticism formulated in the US context, that these observations are in fact the result of the interviewer effect. Finally, the study found stable patterns of educational network prestige, and describes the changes of social capital attached to categories of gender and age.

  14. The effects of individual status and group performance on network ties among teammates in the National Basketball Association.

    Directory of Open Access Journals (Sweden)

    Jeremy Koster

    Full Text Available For individuals, status is derived both from their personal attributes and the groups with whom they are affiliated. Depending on the performance of their groups, the status of individuals may benefit or suffer from identifying closely with the group. When the group excels, high-status members potentially receive much of the credit and increased status. Conversely, high-status members of underperforming groups potentially suffer disproportionate declines in their status relative to the low-status group members. We therefore predict an interaction between group performance and individual status on the willingness to associate with the group and its members. We test our prediction by examining social media ties among teammates in the National Basketball Association. Specifically, we investigate the "following" ties of teammates on Twitter at the end of the 2014-2015 season. Elections to All-Star games are used to measure the status of players, and team performance is measured by recent success in the postseason playoffs. The results show that compared to high-status players on successful teams, high-status players on underperforming teams are less likely to follow their teammates. This result aligns with research on status inconsistency, suggesting that individuals deemphasize their group affiliation when it jeopardizes their individual status. An additional contribution is the advancement of the probit Social Relations Model for the analysis of binary ties in social networks.

  15. The effects of individual status and group performance on network ties among teammates in the National Basketball Association.

    Science.gov (United States)

    Koster, Jeremy; Aven, Brandy

    2018-01-01

    For individuals, status is derived both from their personal attributes and the groups with whom they are affiliated. Depending on the performance of their groups, the status of individuals may benefit or suffer from identifying closely with the group. When the group excels, high-status members potentially receive much of the credit and increased status. Conversely, high-status members of underperforming groups potentially suffer disproportionate declines in their status relative to the low-status group members. We therefore predict an interaction between group performance and individual status on the willingness to associate with the group and its members. We test our prediction by examining social media ties among teammates in the National Basketball Association. Specifically, we investigate the "following" ties of teammates on Twitter at the end of the 2014-2015 season. Elections to All-Star games are used to measure the status of players, and team performance is measured by recent success in the postseason playoffs. The results show that compared to high-status players on successful teams, high-status players on underperforming teams are less likely to follow their teammates. This result aligns with research on status inconsistency, suggesting that individuals deemphasize their group affiliation when it jeopardizes their individual status. An additional contribution is the advancement of the probit Social Relations Model for the analysis of binary ties in social networks.

  16. TIE - DYE (ADIRE) AMONG THE JUKUN PEOPLE Gausa Solomon ...

    African Journals Online (AJOL)

    SO

    clothing scraps or fibrous materials from municipal waste stream (Wikipedia, 2014). ... example fabric that has been tie-dyed can be recycled and used as lamp shades, .... Dye colour is used in the manufacture of plastic products, but their most ...

  17. The Ties That Bind Exhibition Science Bringing Nations Together

    CERN Document Server

    1997-01-01

    Scientific ties between JINR and CERN date back to 1957, when JINR Vice-Director Marian Danysz, a Polish professor, visited CERN and agreed with CERN Director-General C.J. Bakker on the exchange of scientists and on joint experiments. Since that time to progress and now JINR takes an active part in the Large Hadron Collider, LHC, project at CERN.

  18. Matrilineal Family Ties and Marital Dissolution in Ghana

    Science.gov (United States)

    Takyi, Baffour K.; Gyimah, Stephen Obeng

    2007-01-01

    Although previous work has attributed the instability of African marriages to the diffusion of Western norms and values in the region, fewer attempts have been made to empirically assess how Africa's internal institutional structures, such as extended kinship ties, impact marital outcomes. Guided by rational choice and exchange theories, we argue…

  19. Knotcraft the practical and entertaining art of tying knots

    CERN Document Server

    Macfarlan, Allan and Paulette

    1983-01-01

    Comprehensive reference work explains how to tie hundreds of practical (and decorative) knots in clear illustrations and precisely worded written instructions. Ideal for boaters and campers. Also covers knots in history, knot mystery and magic, and games, stunts and tricks with rope. Introduction. Index. 166 black-and-white illustrations.

  20. Application of Bow-tie methodology to improve patient safety.

    Science.gov (United States)

    Abdi, Zhaleh; Ravaghi, Hamid; Abbasi, Mohsen; Delgoshaei, Bahram; Esfandiari, Somayeh

    2016-05-09

    Purpose - The purpose of this paper is to apply Bow-tie methodology, a proactive risk assessment technique based on systemic approach, for prospective analysis of the risks threatening patient safety in intensive care unit (ICU). Design/methodology/approach - Bow-tie methodology was used to manage clinical risks threatening patient safety by a multidisciplinary team in the ICU. The Bow-tie analysis was conducted on incidents related to high-alert medications, ventilator associated pneumonia, catheter-related blood stream infection, urinary tract infection, and unwanted extubation. Findings - In total, 48 potential adverse events were analysed. The causal factors were identified and classified into relevant categories. The number and effectiveness of existing preventive and protective barriers were examined for each potential adverse event. The adverse events were evaluated according to the risk criteria and a set of interventions were proposed with the aim of improving the existing barriers or implementing new barriers. A number of recommendations were implemented in the ICU, while considering their feasibility. Originality/value - The application of Bow-tie methodology led to practical recommendations to eliminate or control the hazards identified. It also contributed to better understanding of hazard prevention and protection required for safe operations in clinical settings.

  1. Competition increases in the face of strong regional ties

    International Nuclear Information System (INIS)

    Knoetgen, P.M.

    1987-01-01

    The current fuel market exhibits a large surplus production capacity and is strongly influenced by regional ties, with imports of fabricated fuel serving to supplement domestic production or to keep domestic vendors competitive. In the future, the market is set to become increasingly competitive, especially in Europe and the United States. (author)

  2. Children's Books in Review: Books on Strengthening Family Ties.

    Science.gov (United States)

    Winfield, Evelyn T.

    1991-01-01

    Reviews children's books that emphasize the strengthening of family ties. Characters in the books realize the importance and influence of family relationships as they struggle with sibling rivalry, self-discovery, peer relationships, a search for heritage, adoption, and death. (SM)

  3. Measurement of the location of tie-bar shoulders

    CERN Multimedia

    Hubert Gerwig

    2001-01-01

    The inner vactank is machined on a length of 13m at the location of the rails for HCAL. in addition at one side the inner vactank has shoulders to lodge the M48 tie-bars that will guarantee the fixation to the swivelling platform actually produced at HANJUNG Company in South Korea

  4. Urban violence and displacement, gender, and community ties ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2017-10-20

    Oct 20, 2017 ... SAIC experts explored poverty, violence, and inequality in 40 cities across Latin America, South Asia, and sub-Saharan Africa. The 15 research ... Urban violence and displacement, gender, and community ties. October 20 ... in urban spaces. Return to main page: Solutions to make cities safe and inclusive.

  5. Preventing Cauliflower Ear with a Modified Tie-Through Technique.

    Science.gov (United States)

    Dimeff, Robert J.; Hough, David O.

    1989-01-01

    Describes a quick, simple tie-through suture technique (in which a collodion packing is secured to the auricle with two buttons) for preventing cauliflower ear following external ear trauma in wrestlers and boxers. The technique ensures constant compression; multiple treatments for fluid reaccumulation are rarely necessary. (SM)

  6. Homology and cohomology of Rees semigroup algebras

    DEFF Research Database (Denmark)

    Grønbæk, Niels; Gourdeau, Frédéric; White, Michael C.

    2011-01-01

    Let S by a Rees semigroup, and let 1¹(S) be its convolution semigroup algebra. Using Morita equivalence we show that bounded Hochschild homology and cohomology of l¹(S) is isomorphic to those of the underlying discrete group algebra....

  7. Induction of homologous recombination in Saccharomyces cerevisiae.

    Science.gov (United States)

    Simon, J R; Moore, P D

    1988-09-01

    We have investigated the effects of UV irradiation of Saccharomyces cerevisiae in order to distinguish whether UV-induced recombination results from the induction of enzymes required for homologous recombination, or the production of substrate sites for recombination containing regions of DNA damage. We utilized split-dose experiments to investigate the induction of proteins required for survival, gene conversion, and mutation in a diploid strain of S. cerevisiae. We demonstrate that inducing doses of UV irradiation followed by a 6 h period of incubation render the cells resistant to challenge doses of UV irradiation. The effects of inducing and challenge doses of UV irradiation upon interchromosomal gene conversion and mutation are strictly additive. Using the yeast URA3 gene cloned in non-replicating single- and double-stranded plasmid vectors that integrate into chromosomal genes upon transformation, we show that UV irradiation of haploid yeast cells and homologous plasmid DNA sequences each stimulate homologous recombination approximately two-fold, and that these effects are additive. Non-specific DNA damage has little effect on the stimulation of homologous recombination, as shown by studies in which UV-irradiated heterologous DNA was included in transformation/recombination experiments. We further demonstrate that the effect of competing single- and double-stranded heterologous DNA sequences differs in UV-irradiated and unirradiated cells, suggesting an induction of recombinational machinery in UV-irradiated S. cerevisiae cells.

  8. Threading homology through algebra selected patterns

    CERN Document Server

    Boffi, Giandomenico

    2006-01-01

    Aimed at graduate students and researchers in mathematics, this book takes homological themes, such as Koszul complexes and their generalizations, and shows how these can be used to clarify certain problems in selected parts of algebra, as well as their success in solving a number of them.

  9. Cell biology of homologous recombination in yeast

    DEFF Research Database (Denmark)

    Eckert-Boulet, Nadine Valerie; Rothstein, Rodney; Lisby, Michael

    2011-01-01

    Homologous recombination is an important pathway for error-free repair of DNA lesions, such as single- and double-strand breaks, and for rescue of collapsed replication forks. Here, we describe protocols for live cell imaging of single-lesion recombination events in the yeast Saccharomyces...

  10. Polar representation of centrifugal pump homologous curves

    International Nuclear Information System (INIS)

    Veloso, Marcelo Antonio; Mattos, Joao Roberto Loureiro de

    2008-01-01

    Essential for any mathematical model designed to simulate flow transient events caused by pump operations is the pump performance data. The performance of a centrifugal pump is characterized by four basic parameters: the rotational speed, the volumetric flow rate, the dynamic head, and the hydraulic torque. Any one of these quantities can be expressed as a function of any two others. The curves showing the relationships between these four variables are called the pump characteristic curves, also referred to as four-quadrant curves. The characteristic curves are empirically developed by the pump manufacturer and uniquely describe head and torque as functions of volumetric flow rate and rotation speed. Because of comprising a large amount of points, the four-quadrant configuration is not suitable for computational purposes. However, it can be converted to a simpler form by the development of the homologous curves, in which dynamic head and hydraulic torque ratios are expressed as functions of volumetric flow and rotation speed ratios. The numerical use of the complete set of homologous curves requires specification of sixteen partial curves, being eight for the dynamic head and eight for the hydraulic torque. As a consequence, the handling of homologous curves is still somewhat complicated. In solving flow transient problems that require the pump characteristic data for all the operation zones, the polar form appears as the simplest way to represent the homologous curves. In the polar method, the complete characteristics of a pump can be described by only two closed curves, one for the dynamic head and other for the hydraulic torque, both in function of a single angular coordinate defined adequately in terms of the quotient between volumetric flow ratio and rotation speed ratio. The usefulness and advantages of this alternative method are demonstrated through a practical example in which the homologous curves for a pump of the type used in the main coolant loops of a

  11. Parametric representation of centrifugal pump homologous curves

    International Nuclear Information System (INIS)

    Veloso, Marcelo A.; Mattos, Joao R.L. de

    2015-01-01

    Essential for any mathematical model designed to simulate flow transient events caused by pump operations is the pump performance data. The performance of a centrifugal pump is characterized by four basic quantities: the rotational speed, the volumetric flow rate, the dynamic head, and the hydraulic torque. The curves showing the relationships between these four variables are called the pump characteristic curves. The characteristic curves are empirically developed by the pump manufacturer and uniquely describe head and torque as functions of volumetric flow rate and rotation speed. Because of comprising a large amount of points, this configuration is not suitable for computational purposes. However, it can be converted to a simpler form by the development of the homologous curves, in which dynamic head and hydraulic torque ratios are expressed as functions of volumetric flow and rotation speed ratios. The numerical use of the complete set of homologous curves requires specification of sixteen partial curves, being eight for the dynamic head and eight for the hydraulic torque. As a consequence, the handling of homologous curves is still somewhat complicated. In solving flow transient problems that require the pump characteristic data for all the operation zones, the parametric form appears as the simplest way to deal with the homologous curves. In this approach, the complete characteristics of a pump can be described by only two closed curves, one for the dynamic head and other for the hydraulic torque, both in function of a single angular coordinate defined adequately in terms of the quotient between volumetric flow ratio and rotation speed ratio. The usefulness and advantages of this alternative method are demonstrated through a practical example in which the homologous curves for a pump of the type used in the main coolant loops of a pressurized water reactor (PWR) are transformed to the parametric form. (author)

  12. High tie versus low tie of the inferior mesenteric artery in colorectal cancer: A meta-analysis.

    Science.gov (United States)

    Yang, Yafan; Wang, Guiying; He, Jingli; Zhang, Jianfeng; Xi, Jinchuan; Wang, Feifei

    2018-04-01

    Colorectal cancer surgery includes "high tie" and "low tie"of the inferior mesenteric artery(IMA). However, different ligation level is closely related to the blood supply of anastomosis, which may increase the leakage rate, and it is unclear which technique confers a lower anastomotic leakage rate(AL) and survival advantage. To compare the effectiveness and impact of inferior mesenteric artery (IMA) high ligation versus IMA low ligation on anastomotic leakage, lymph nodes yield rates and 5-year survival. A list of these studies, published in English from 1990 to 2017, was obtained independently by two reviewers from databases such as PubMed, Medline, ScienceDirect and Web of Science. Anastomotic leakage rate, the yield of lymph nodes and 5-year survival were compared using Review Manager 5.3. There was no significant difference in anastomotic leakage, number of lymph nodes retrieved and 5-year survival rate for both techniques. Neither the high tie nor the low tie strategy has an evidence in terms of anastomotic leakage rate, harvested lymph nodes, and the 5-year survival rate. Further RCT is needed. Copyright © 2018 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

  13. Sources of Segregation in Social Networks : A Novel Approach Using Facebook

    NARCIS (Netherlands)

    Hofstra, B.; Corten, R.; van Tubergen, F.A.; Ellison, Nicole

    2017-01-01

    Most research on segregation in social networks considers small circles of strong ties, and little is known about segregation among the much larger number of weaker ties. This article proposes a novel approach to the study of these more extended networks, through the use of data on personal ties in

  14. SOCIAL RELATIONSHIPS AND SLEEP QUALITY

    Science.gov (United States)

    Kent, Robert G.; Uchino, Bert N.; Cribbet, Matthew R.; Bowen, Kimberly; Smith, Timothy W.

    2015-01-01

    Background The quality of social relationships and social support appears to be associated with physical health outcomes and sleep quality. Almost all previous research in this area focuses on positive aspects of relationships. Purpose The present study thus intended to examine the links between supportive, aversive, ambivalent, and indifferent network ties and sleep quality. Methods Relationship data, PSQI-assessed sleep quality, and depression were examined in 175 middle-aged and older adults. Results Consistent with hypotheses, supportive ties were positively related to sleep quality, while aversive ties predicted worse sleep quality; associations that were primarily seen for close relationships. Ambivalent and indifferent ties were not significant predictors of sleep quality. Importantly, depression was found to mediate the link between relationship quality and sleep quality. Conclusions These data suggest the more specific types of social relationships that may be linked to poor sleep quality, and that depression appears to underlie these associations. PMID:25976874

  15. Four- year thyroidectomy procedures: Ligasure Vs. clamp & tie

    Directory of Open Access Journals (Sweden)

    Pazoki AR

    2010-01-01

    Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: The electrothermal bipolar vessel sealing system is an adjunct to the hemostatic technique, which has been successfully used in many abdominal operation, recently made available to thyroid surgery. The purpose of this was compare the outcomes of new hemostatic technique with traditional method of clamp and tie."n"nMethods: In this retrospective cross-sectional study has been done in surgery's wards of Milad & Rasul- Akram hospitals in Tehran, Iran. During three- year period between 2005-2008 all patients with different kind of pathology that need operation were assessed. Time duration of surgery and hospital stay and post surgery complication in two group, ligasure (n=45 and clamp & tie (n=145 were compared with each others."n"nResults: No difference was seen between two groups in time duration of surgery. Significant difference was seen in hospital stay and complications of surgery. Time of operation in Ligasure group was 132/22 minute and in clamp and tie group was 130/10 minute. There was found significant difference in duration of hospital stay and postoperative complication. Hypocalcemia were seen in two and 24 cases in Ligasure and Clamp & Tie group, respectively (p<0.05. Hospital stay was 2

  16. Homologation Reaction of Ketones with Diazo Compounds.

    Science.gov (United States)

    Candeias, Nuno R; Paterna, Roberta; Gois, Pedro M P

    2016-03-09

    This review covers the addition of diazo compounds to ketones to afford homologated ketones, either in the presence or in the absence of promoters or catalysts. Reactions with diazoalkanes, aryldiazomethanes, trimethylsilyldiazomethane, α-diazo esters, and disubstituted diazo compounds are covered, commenting on the complex regiochemistry of the reaction and the nature of the catalysts and promoters. The recent reports on the enantioselective version of ketone homologation reactions are gathered in one section, followed by reports on the use of cyclic ketones ring expansion in total synthesis. Although the first reports of this reaction appeared in the literature almost one century ago, the recent achievements, in particular, for the asymmetric version, forecast the development of new breakthroughs in the synthetically valuable field of diazo chemistry.

  17. Homological mirror symmetry and tropical geometry

    CERN Document Server

    Catanese, Fabrizio; Kontsevich, Maxim; Pantev, Tony; Soibelman, Yan; Zharkov, Ilia

    2014-01-01

    The relationship between Tropical Geometry and Mirror Symmetry goes back to the work of Kontsevich and Y. Soibelman (2000), who applied methods of non-archimedean geometry (in particular, tropical curves) to Homological Mirror Symmetry. In combination with the subsequent work of Mikhalkin on the “tropical” approach to Gromov-Witten theory, and the work of Gross and Siebert, Tropical Geometry has now become a powerful tool. Homological Mirror Symmetry is the area of mathematics concentrated around several categorical equivalences connecting symplectic and holomorphic (or algebraic) geometry. The central ideas first appeared in the work of Maxim Kontsevich (1993). Roughly speaking, the subject can be approached in two ways: either one uses Lagrangian torus fibrations of Calabi-Yau manifolds (the so-called Strominger-Yau-Zaslow picture, further developed by Kontsevich and Soibelman) or one uses Lefschetz fibrations of symplectic manifolds (suggested by Kontsevich and further developed by Seidel). Tropical Ge...

  18. Homological stability for unordered configuration spaces

    DEFF Research Database (Denmark)

    Randal-Williams, Oscar

    2013-01-01

    This paper consists of two related parts. In the first part we give a self-contained proof of homological stability for the spaces C_n(M;X) of configurations of n unordered points in a connected open manifold M with labels in a path-connected space X, with the best possible integral stability range...... of the spaces C_n(M) can be considered stable when M is a closed manifold. In this case there are no stabilisation maps, but one may still ask if the dimensions of the homology groups over some field stabilise with n. We prove that this is true when M is odd-dimensional, or when the field is F_2 or Q...

  19. Linkage of genomic biomarkers to whole organism endpoints in a Toxicity Identification Evaluation (TIE).

    Science.gov (United States)

    Aquatic organisms are exposed to many toxic chemicals and interpreting the cause and effect relationships between occurrence and impairment is difficult. Toxicity Identification Evaluation (TIE) provides a systematic approach for identifying responsible toxicants. TIE relies on ...

  20. Regulation of homologous recombination in eukaryotes

    OpenAIRE

    Heyer, Wolf-Dietrich; Ehmsen, Kirk T.; Liu, Jie

    2010-01-01

    Homologous recombination is required for accurate chromosome segregation during the first meiotic division and constitutes a key repair and tolerance pathway for complex DNA damage including DNA double-stranded breaks, interstrand crosslinks, and DNA gaps. In addition, recombination and replication are inextricably linked, as recombination recovers stalled and broken replication forks enabling the evolution of larger genomes/replicons. Defects in recombination lead to genomic instability and ...

  1. Khovanov homology of graph-links

    Energy Technology Data Exchange (ETDEWEB)

    Nikonov, Igor M [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation)

    2012-08-31

    Graph-links arise as the intersection graphs of turning chord diagrams of links. Speaking informally, graph-links provide a combinatorial description of links up to mutations. Many link invariants can be reformulated in the language of graph-links. Khovanov homology, a well-known and useful knot invariant, is defined for graph-links in this paper (in the case of the ground field of characteristic two). Bibliography: 14 titles.

  2. Quandle and Biquandle Homology Calculation in R

    Directory of Open Access Journals (Sweden)

    Roger Fenn

    2018-01-01

    Full Text Available In knot theory several knot invariants have been found over the last decades. This paper concerns itself with invariants of several of those invariants, namely the Homology of racks, quandles, biracks and biquandles. The software described in this paper calculates the rack, quandle and degenerate homology groups of racks and biracks. It works for any rack/quandle with finite elements where there are homology coefficients in 'Z'k. The up and down actions can be given either as a function of the elements of 'Z'k or provided as a matrix. When calculating a rack, the down action should coincide with the identity map. We have provided actions for both the general dihedral quandle and the group quandle over 'S'3. We also provide a second function to test if a set with a given action (or with both actions gives rise to a quandle or biquandle. The program is provided as an R package and can be found at https://github.com/ansgarwenzel/quhomology.   AMS subject classification: 57M27; 57M25

  3. Several aspects of some techniques avoiding homologous blood transfusions

    NARCIS (Netherlands)

    E.C.S.M. van Woerkens (Liesbeth)

    1998-01-01

    textabstractThe use of homologous blood products during anesthesia and surgery is not without risks. Complications due to homologous blood transfusions include transfusion reactions, isosensitization, transmission of infections (including HIV, hepatitis, CMV) and immunosuppression (resuiting in

  4. Are You Your Friends’ Friend? Poor Perception of Friendship Ties Limits the Ability to Promote Behavioral Change

    Science.gov (United States)

    Almaatouq, Abdullah; Radaelli, Laura; Pentland, Alex; Shmueli, Erez

    2016-01-01

    Persuasion is at the core of norm creation, emergence of collective action, and solutions to ‘tragedy of the commons’ problems. In this paper, we show that the directionality of friendship ties affect the extent to which individuals can influence the behavior of each other. Moreover, we find that people are typically poor at perceiving the directionality of their friendship ties and that this can significantly limit their ability to engage in cooperative arrangements. This could lead to failures in establishing compatible norms, acting together, finding compromise solutions, and persuading others to act. We then suggest strategies to overcome this limitation by using two topological characteristics of the perceived friendship network. The findings of this paper have significant consequences for designing interventions that seek to harness social influence for collective action. PMID:27002530

  5. Are You Your Friends' Friend? Poor Perception of Friendship Ties Limits the Ability to Promote Behavioral Change.

    Science.gov (United States)

    Almaatouq, Abdullah; Radaelli, Laura; Pentland, Alex; Shmueli, Erez

    2016-01-01

    Persuasion is at the core of norm creation, emergence of collective action, and solutions to 'tragedy of the commons' problems. In this paper, we show that the directionality of friendship ties affect the extent to which individuals can influence the behavior of each other. Moreover, we find that people are typically poor at perceiving the directionality of their friendship ties and that this can significantly limit their ability to engage in cooperative arrangements. This could lead to failures in establishing compatible norms, acting together, finding compromise solutions, and persuading others to act. We then suggest strategies to overcome this limitation by using two topological characteristics of the perceived friendship network. The findings of this paper have significant consequences for designing interventions that seek to harness social influence for collective action.

  6. The Ties That Bind Exhibition Science Bringing Nations Together

    CERN Document Server

    2000-01-01

    Scientific ties between JINR and CERN date back to 1957, when JINR Vice-Director Marian Danysz, a Polish professor, visited CERN and agreed with CERN Director-General C.J. Bakker on the exchange of scientists and on joint experiments. Political confrontation did not affect extensive contacts between scientists. By the early 1970s, the meetings of the heads of two international centres, JINR and CERN, had become regular occurrences.

  7. The ties between natural gas and oil prices

    International Nuclear Information System (INIS)

    Maisonnier, G.

    2006-01-01

    On the European continent, the price of natural gas is still tied directly and to a great extent to the price of competing energies, especially heavy fuel oil and home heating oil. In other words, the gas market is linked to the oil market. Under the effect of deregulation, this model is likely to change in the future, making a shift like that which took place on the American market in the past. (author)

  8. Computing Homology Group Generators of Images Using Irregular Graph Pyramids

    OpenAIRE

    Peltier , Samuel; Ion , Adrian; Haxhimusa , Yll; Kropatsch , Walter; Damiand , Guillaume

    2007-01-01

    International audience; We introduce a method for computing homology groups and their generators of a 2D image, using a hierarchical structure i.e. irregular graph pyramid. Starting from an image, a hierarchy of the image is built, by two operations that preserve homology of each region. Instead of computing homology generators in the base where the number of entities (cells) is large, we first reduce the number of cells by a graph pyramid. Then homology generators are computed efficiently on...

  9. Automated Simultaneous Local Ties with GNSS and Robot Tacheometer

    Science.gov (United States)

    Kallio, Ulla; Lösler, Michael; Bergstrand, Sten; Haas, Rüdiger; Eschelbach, Cornelia

    2016-12-01

    We have used GPS-based local-tie measurements simultaneously with geo-VLBI observations since 2008 during every geodetic VLBI session at Metsähovi. This system uses gimbal-mounted GNSS antennas that are mounted on the reflector of the Metsähovi 14-m radio telescope. A similar system was installed in 2013 at the Onsala 20-m radio telescope and has been used for a large number of VLBI sessions, including, e.g., the 15-day-long CONT14 campaign. In order to verify the results of the two systems, we performed a dedicated measurement campaign in the framework of the SIB60 project, involving both Metsähovi and Onsala. During this campaign the local ties at the two stations were measured simultaneously during two VLBI sessions in August and September 2015 where both stations participated. The robot tacheometer monitoring system HEIMDALL was used for the automated classical monitoring of the telescopes at both stations. Moreover, additional local terrestrial measurements were performed several times to derive the full IVS-IGS local ties at both sites. The kinematic GPS measurements at the two stations were analyzed with two independently developed analysis programs. We present here the preparations of the campaign, the measurement process, and preliminary results.

  10. The emergence of cooperation in tie strength models

    International Nuclear Information System (INIS)

    Xu, Bo; Yue, Yunpeng

    2016-01-01

    In this paper, we propose a tie strength model to explain the emergence of cooperation in spatial prisoner's dilemma games, assuming that cooperators preferentially allocate their investments to friends with strong ties. Two types of prisoner's dilemma models are examined in this study: the traditional two-strategy model considering only cooperators and defectors; the expanded three-strategy model consisting cooperators, defectors and extortioners. The results show that tie strength model contributes to the promotion of cooperation in both types of prisoner's dilemma games. However, we point out that the influence of the investment preference is quite different in the two prisoner's dilemma game settings. In the two-strategy prisoner's dilemma game, only small preference contributes to the promotion of cooperation. Once this preference exceeds a critical value, cooperation will be prohibited. We explain this phenomenon by arguing that extremely strong investment preference undermines the ability of cooperative clusters to resist defectors. Moreover, we extend the analysis into the three-strategy case and discover that the catalytic effect of extortioners can eliminate this first up and then down trend in the two-strategy model. The equilibrium fraction of cooperators is always positively correlated to the level of investment preference in three-strategy models.

  11. ERT and Well Data Tie for Nickel Laterite Characterization

    Science.gov (United States)

    Aswad, Sabrianto; Mamela Mais, Difar; Syamsuddin; Wanni

    2018-03-01

    The need of ERT method in nickel latentes exploration can’t be deny. This method have capability to make exploration more effective and efficient. In reality this method still remain ambiguity in its application, especially for geologist and mining expert. These ambiguity related with layer zone determination (limonite, saprolite and bedrock), the same resistivity values in the different zones and determination of bedrock. This paper try to expose interesting fact to overcome this ambiguity by using ERT data and drill data tie. This tie will show characteristic of nickel lateric based on resisitivity value and the contribution of chemistry element for resistivity value. Data ERT was collected by using gradient configuration and well data consist of mayor element and minor element. Tie result showed difference resistivity value in limonite layer influence by Fe, H2O and Ni, where resistivity value from saprolite layer influenced by Fe, H2O, Si02, MgO, Al, Cr, and Ni in certain accumulation. In bedrock layer, almost all drill data did not reach bedrock but only reached the boulder alone, it is supported by the value of the resistivity of rock unserpentinized peridotite which should show a relatively large resistivity value

  12. 77 FR 21620 - Notice of the Buy America Waiver Request for Vossloh 101-LV Concrete Ties

    Science.gov (United States)

    2012-04-10

    ... the Buy America Waiver Request for Vossloh 101-LV Concrete Ties AGENCY: Federal Railroad... concrete ties, which contain certain components not manufactured in the United States. In furtherance of... concrete ties. FRA has received this request from the four States for the following projects: (a) The...

  13. Ties that Blind: Perpetuation of Racial Comfort and Discomfort at a Community College

    Science.gov (United States)

    Price, Douglas B.; Hyle, Adrienne E.; Jordan, Kitty V.

    2009-01-01

    Interviews with 17 African American students and 19 White students were employed to examine interracial relations at a predominantly White community college campus. Seen through the lens of Granovetter's strength of ties theory, the interview findings revealed that strong intraracial ties and the absence of weak interracial ties inhibited…

  14. Urbanism, Neighborhood Context, and Social Networks.

    Science.gov (United States)

    Cornwell, Erin York; Behler, Rachel L

    2015-09-01

    Theories of urbanism suggest that the urban context erodes individuals' strong social ties with friends and family. Recent research has narrowed focus to the neighborhood context, emphasizing how localized structural disadvantage affects community-level cohesion and social capital. In this paper, we argue that neighborhood context also shapes social ties with friends and family- particularly for community-dwelling seniors. We hypothesize that neighborhood disadvantage, residential instability, and disorder restrict residents' abilities to cultivate close relationships with neighbors and non-neighbor friends and family. Using data from the National Social Life, Health, and Aging Project (NSHAP), we find that older adults who live in disadvantaged neighborhoods have smaller social networks. Neighborhood disadvantage is also associated with less close network ties and less frequent interaction - but only among men. Furthermore, residents of disordered neighborhoods have smaller networks and weaker ties. We urge scholars to pay greater attention to how neighborhood context contributes to disparities in network-based access to resources.

  15. TIES for Dummies 3rd Edition (Technology Identification, Evaluation, and Selection) Basic how to's to implement the TIES method

    Science.gov (United States)

    Kirby, Michelle R.

    2002-01-01

    The TIES method is a forecasting environment whereby the decision-maker has the ability to easily assess and trade-off the impact of various technologies without sophisticated and time-consuming mathematical formulations. TIES provides a methodical approach where technically feasible alternatives can be identified with accuracy and speed to reduce design cycle time, and subsequently, life cycle costs, and was achieved through the use of various probabilistic methods, such as Response Surface Methodology and Monte Carlo Simulations. Furthermore, structured and systematic techniques are utilized from other fields to identify possible concepts and evaluation criteria by which comparisons can be made. This objective is achieved by employing the use of Morphological Matrices and Multi-Attribute Decision Making techniques. Through the execution of each step, a family of design alternatives for a given set of customer requirements can be identified and assessed subjectively or objectively. This methodology allows for more information (knowledge) to be brought into the earlier phases of the design process and will have direct implications on the affordability of the system. The increased knowledge allows for optimum allocation of company resources and quantitative justification for program decisions. Finally, the TIES method provided novel results and quantitative justification to facilitate decision making in the early stages of design so as to produce affordable and quality products.

  16. A PHF8 homolog in C. elegans promotes DNA repair via homologous recombination.

    Directory of Open Access Journals (Sweden)

    Changrim Lee

    Full Text Available PHF8 is a JmjC domain-containing histone demethylase, defects in which are associated with X-linked mental retardation. In this study, we examined the roles of two PHF8 homologs, JMJD-1.1 and JMJD-1.2, in the model organism C. elegans in response to DNA damage. A deletion mutation in either of the genes led to hypersensitivity to interstrand DNA crosslinks (ICLs, while only mutation of jmjd-1.1 resulted in hypersensitivity to double-strand DNA breaks (DSBs. In response to ICLs, JMJD-1.1 did not affect the focus formation of FCD-2, a homolog of FANCD2, a key protein in the Fanconi anemia pathway. However, the dynamic behavior of RPA-1 and RAD-51 was affected by the mutation: the accumulations of both proteins at ICLs appeared normal, but their subsequent disappearance was retarded, suggesting that later steps of homologous recombination were defective. Similar changes in the dynamic behavior of RPA-1 and RAD-51 were seen in response to DSBs, supporting a role of JMJD-1.1 in homologous recombination. Such a role was also supported by our finding that the hypersensitivity of jmjd-1.1 worms to ICLs was rescued by knockdown of lig-4, a homolog of Ligase 4 active in nonhomologous end-joining. The hypersensitivity of jmjd-1.1 worms to ICLs was increased by rad-54 knockdown, suggesting that JMJD-1.1 acts in parallel with RAD-54 in modulating chromatin structure. Indeed, the level of histone H3 Lys9 tri-methylation, a marker of heterochromatin, was higher in jmjd-1.1 cells than in wild-type cells. We conclude that the histone demethylase JMJD-1.1 influences homologous recombination either by relaxing heterochromatin structure or by indirectly regulating the expression of multiple genes affecting DNA repair.

  17. In stressful company – Changes in stress and work ties over time

    DEFF Research Database (Denmark)

    Waldstrøm, Christian; Parker, Andrew; Shah, Neha P.

    Recent research on stress and burnout has highlighted the collective aspects of stress symptoms, perceived stress, and coping mechanisms. Much of this work, however, is focused on group and team dynamics rather than how network factors shape individuals’ feelings of stress and burnout. We use...... a stress questionnaire and social network analysis at three time points in a Scandinavian biotechnology company to examine the interactions between stress and relationship development and maintenance over time. We show that individuals tend to form and maintain ties to people who are less stressed than...... they are, indicating that while misery might love company, stress does not. Given the longitudinal nature of the study, we’re able to disentangle the causal effects....

  18. The strength-of-weak-ties perspective on creativity: a comprehensive examination and extension.

    Science.gov (United States)

    Baer, Markus

    2010-05-01

    Disentangling the effects of weak ties on creativity, the present study separated, both theoretically and empirically, the effects of the size and strength of actors' idea networks and examined their joint impact while simultaneously considering the separate, moderating role of network diversity. I hypothesized that idea networks of optimal size and weak strength were more likely to boost creativity when they afforded actors access to a wide range of different social circles. In addition, I examined whether the joint effects of network size, strength, and diversity on creativity were further qualified by the openness to experience personality dimension. As expected, results indicated that actors were most creative when they maintained idea networks of optimal size, weak strength, and high diversity and when they scored high on the openness dimension. The implications of these results are discussed. PsycINFO Database Record (c) 2010 APA, all rights reserved.

  19. Research on the network structure of the urban economic ties in Shanghai

    Directory of Open Access Journals (Sweden)

    CHEN Wenyan

    2015-04-01

    Full Text Available Assessing the network structure of the urban economic ties (NSUET of a city can help us understand its development level.Using the gravity model,the social network analysis method and the Arcgis tool,this paper has done some researches about the NSUET in Shanghai.The research results show that the NSUET in Shanghai was improved gradually from 2000 to 2010 and is in a stable status now.In the future,the NSUET in Shanghai should be adjusted to meet the need of urban development;the more focuses should be placed on the districts with better infrastructure,while the other areas are also considered to develop the NSUET.

  20. When he is "tied": power, vulnerability, and embodied masculinity in Egypt.

    Science.gov (United States)

    Ghannam, Farha

    2017-10-01

    This paper looks at the notion of rabt [tying], the inability of the groom to engage in penetrative intercourse on the wedding night, to explore the relationship between masculinity, embodiment, and sexual performance. Drawing on ethnographic fieldwork in Egypt between 1993 and 2015, this paper explores the notion of groom rabt, how it is socially defined and managed. After presenting my conceptual framework for the study of sexuality and embodiment, the paper moves to discuss the meaning of the wedding night; the social clues people draw on when they identify rabt; how these clues relate different events to the (in)abilities of the groom; and how women, particularly mothers, work to protect and heal their male relatives from this affliction. To understand moments when individuals are unable, or "fail," to produce desirable physical and social effects, it is important that we do not exclusively consider the individual sexed body - the body that is clearly defined, bounded, and invested with unique desires and feelings. We must also consider the broader configurations that connect different bodies, endow them with certain meanings, and produce their materiality. My discussion shows that our understanding of sexuality and reproductive health will continue to be limited if we consider only men or women as separate individuals or as autonomous couples. Exploring moments of biological-social vulnerability, such as rabt, and how they relate to broader projects of gendering helps us understand issues linked to reproductive health and sexual rights in a deeper sense.

  1. Hochschild Homology and Cohomology of Klein Surfaces

    Directory of Open Access Journals (Sweden)

    Frédéric Butin

    2008-09-01

    Full Text Available Within the framework of deformation quantization, a first step towards the study of star-products is the calculation of Hochschild cohomology. The aim of this article is precisely to determine the Hochschild homology and cohomology in two cases of algebraic varieties. On the one hand, we consider singular curves of the plane; here we recover, in a different way, a result proved by Fronsdal and make it more precise. On the other hand, we are interested in Klein surfaces. The use of a complex suggested by Kontsevich and the help of Groebner bases allow us to solve the problem.

  2. Homology in vertebrates bone mineral structure

    International Nuclear Information System (INIS)

    Batdehmbehrehl, G.; Chultehm, D.; Sangaa, D.

    1999-01-01

    Using the neutron diffraction method a domination of low crystal syngonic (sp. gr. P63/m) phase Ca 5 [PO 4 ] 3 (OH, F, Cl) in bull and sheep bones as well as in the fossil dinosaur bone has been established and crystal phases in all the bones have identical structure (homology). The result becomes to be an important contribution to fundamental science such as biological evolution and to be useful in medical practice and solution of radiobiological problems connected with vertebrates and man. (author)

  3. Homological Perturbation Theory for Nonperturbative Integrals

    Science.gov (United States)

    Johnson-Freyd, Theo

    2015-11-01

    We use the homological perturbation lemma to produce explicit formulas computing the class in the twisted de Rham complex represented by an arbitrary polynomial. This is a non-asymptotic version of the method of Feynman diagrams. In particular, we explain that phenomena usually thought of as particular to asymptotic integrals in fact also occur exactly: integrals of the type appearing in quantum field theory can be reduced in a totally algebraic fashion to integrals over an Euler-Lagrange locus, provided this locus is understood in the scheme-theoretic sense, so that imaginary critical points and multiplicities of degenerate critical points contribute.

  4. Topic Detection Based on Weak Tie Analysis: A Case Study of LIS Research

    Directory of Open Access Journals (Sweden)

    Ling Wei

    2016-11-01

    Full Text Available Purpose: Based on the weak tie theory, this paper proposes a series of connection indicators of weak tie subnets and weak tie nodes to detect research topics, recognize their connections, and understand their evolution. Design/methodology/approach: First, keywords are extracted from article titles and preprocessed. Second, high-frequency keywords are selected to generate weak tie co-occurrence networks. By removing the internal lines of clustered sub-topic networks, we focus on the analysis of weak tie subnets' composition and functions and the weak tie nodes' roles. Findings: The research topics' clusters and themes changed yearly; the subnets clustered with technique-related and methodology-related topics have been the core, important subnets for years; while close subnets are highly independent, research topics are generally concentrated and most topics are application-related; the roles and functions of nodes and weak ties are diversified. Research limitations: The parameter values are somewhat inconsistent; the weak tie subnets and nodes are classified based on empirical observations, and the conclusions are not verified or compared to other methods. Practical implications: The research is valuable for detecting important research topics as well as their roles, interrelations, and evolution trends. Originality/value: To contribute to the strength of weak tie theory, the research translates weak and strong ties concepts to co-occurrence strength, and analyzes weak ties' functions. Also, the research proposes a quantitative method to classify and measure the topics' clusters and nodes.

  5. Private support and social securityPrivate support and social security

    OpenAIRE

    Frans van Dijk

    1998-01-01

    The issue is addressed whether assistance to persons in need can be left to the `family' and the `community'. In that case people depend on their social networks. The support a person receives through a given network of social ties is examined. However, ties are diverse and subject to change. By means of a model of the dynamics of social ties, the conditions for adequate private support are analyzed. The sustainability of private support over time is examined by incorporating the impact on so...

  6. A small world of weak ties provides optimal global integration of self-similar modules in functional brain networks.

    Science.gov (United States)

    Gallos, Lazaros K; Makse, Hernán A; Sigman, Mariano

    2012-02-21

    The human brain is organized in functional modules. Such an organization presents a basic conundrum: Modules ought to be sufficiently independent to guarantee functional specialization and sufficiently connected to bind multiple processors for efficient information transfer. It is commonly accepted that small-world architecture of short paths and large local clustering may solve this problem. However, there is intrinsic tension between shortcuts generating small worlds and the persistence of modularity, a global property unrelated to local clustering. Here, we present a possible solution to this puzzle. We first show that a modified percolation theory can define a set of hierarchically organized modules made of strong links in functional brain networks. These modules are "large-world" self-similar structures and, therefore, are far from being small-world. However, incorporating weaker ties to the network converts it into a small world preserving an underlying backbone of well-defined modules. Remarkably, weak ties are precisely organized as predicted by theory maximizing information transfer with minimal wiring cost. This trade-off architecture is reminiscent of the "strength of weak ties" crucial concept of social networks. Such a design suggests a natural solution to the paradox of efficient information flow in the highly modular structure of the brain.

  7. Tongue-tie, from embriology to treatment: a literature review

    Directory of Open Access Journals (Sweden)

    Maria Dezio

    2015-03-01

    Full Text Available The aim of this review is to create a complete analysis about tongue-tie (or short lingual frenum or ankyloglossia according to the most important works published in literature. The analysis allowed us to do a complete evaluation of this problem, from embriology to the therapeutic approach we could use today, focusing our attention on laser-assisted therapy. This review is based on the research on the PubMed Database (www.ncbi.nlm.nih.gov of studies about lingual frenum written in English between January 1980 and May 2014. The keywords inserted were “lingual frenum”, “frenectomy”, “laser therapy”. We have analyzed: case series, case reports, clinical studies, and also literature reviews in which embryology, physiology, diagnosis and treatment of ankyloglossia were described. We excluded laboratory studies, studies based on animal tests and studies about patients with particular syndromes in which we can also find tongue-tie. The selection criteria allowed us to select 42 articles. The treatment options for the releasing of the frenum are surgically represented by frenotomy (i.e. simple horizontal cut of this training and frenectomy (i.e. removal. In both cases, the intervention on the short lingual frenum is simple, short-lasting, and without particular complications. Furthermore, this kind of treatment can be carried out with different devices: with the typical cold blade scalpel or by the use of laser, a new method that shows more advantages over the prior art. Laser-assisted therapy permits to intervene on newborns (from 0 to 20 days, when there are breastfeeding problems without total anesthesia and suture. The Er:YAG, CO2 laser (according to literature data and Diode laser (according to our experience are advantageous, safe and effective in tongue-tie treatment.

  8. SANSparallel: interactive homology search against Uniprot.

    Science.gov (United States)

    Somervuo, Panu; Holm, Liisa

    2015-07-01

    Proteins evolve by mutations and natural selection. The network of sequence similarities is a rich source for mining homologous relationships that inform on protein structure and function. There are many servers available to browse the network of homology relationships but one has to wait up to a minute for results. The SANSparallel webserver provides protein sequence database searches with immediate response and professional alignment visualization by third-party software. The output is a list, pairwise alignment or stacked alignment of sequence-similar proteins from Uniprot, UniRef90/50, Swissprot or Protein Data Bank. The stacked alignments are viewed in Jalview or as sequence logos. The database search uses the suffix array neighborhood search (SANS) method, which has been re-implemented as a client-server, improved and parallelized. The method is extremely fast and as sensitive as BLAST above 50% sequence identity. Benchmarks show that the method is highly competitive compared to previously published fast database search programs: UBLAST, DIAMOND, LAST, LAMBDA, RAPSEARCH2 and BLAT. The web server can be accessed interactively or programmatically at http://ekhidna2.biocenter.helsinki.fi/cgi-bin/sans/sans.cgi. It can be used to make protein functional annotation pipelines more efficient, and it is useful in interactive exploration of the detailed evidence supporting the annotation of particular proteins of interest. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  9. Contact dermatitis in tie and dye industry workers

    Energy Technology Data Exchange (ETDEWEB)

    Mathur, N K; Mathur, A; Banerjee, K

    1985-01-01

    A survey of the Tie and Dye industry of Jodhpur City in India was made to investigate occupational dermatoses. 49 (16.6%) of 250 workers had incapacitating dermatitis. Skin lesions were seen mostly over the dorsa of the hands and fingers. 26 patients were patch tested with various dyes and chemicals; 14 were positive. Fast Red RC salt was the most potent sensitizer. Other dyes showing positive reactions were Orange GC salt, Bordeaux GP salt, Blue B salt, Red B base and naphthol.

  10. ‘Not a Problem Until it Becomes a Problem’: A Qualitative Study of Values and Risks of In-house Family Ties in Swedish Workplaces

    Directory of Open Access Journals (Sweden)

    Katarina Haugen

    2016-12-01

    Full Text Available In-house family ties at workplaces occur in most contexts, and are associated with both advantages and disadvantages. On the basis of 40 interviews with human resource managers at Swedish workplaces, the values and risks of in-house family ties and their importance within the workplace are analyzed jointly, thus allowing for a holistic perspective. The interviews reveal values and risks on a strategic level, for day-to-day operations, for the social work environment, and on the level of individuals. Crucially, even when in-house family ties are perceived as uncomplicated, there is a latent risk that problems might arise. The interpretation of the role of in-house family ties is also strongly related to whether they are paired with asymmetrical (vertical power relations. It also depends heavily on the chosen perspective—that of the organization, the social work environment, the individual, or the broader society—and the perceived advantages tend to come with corresponding inverted disadvantages.

  11. Homologous Recombination—Experimental Systems, Analysis and Significance

    Science.gov (United States)

    Kuzminov, Andrei

    2014-01-01

    Homologous recombination is the most complex of all recombination events that shape genomes and produce material for evolution. Homologous recombination events are exchanges between DNA molecules in the lengthy regions of shared identity, catalyzed by a group of dedicated enzymes. There is a variety of experimental systems in E. coli and Salmonella to detect homologous recombination events of several different kinds. Genetic analysis of homologous recombination reveals three separate phases of this process: pre-synapsis (the early phase), synapsis (homologous strand exchange) and post-synapsis (the late phase). In E. coli, there are at least two independent pathway of the early phase and at least two independent pathways of the late phase. All this complexity is incongruent with the originally ascribed role of homologous recombination as accelerator of genome evolution: there is simply not enough duplication and repetition in enterobacterial genomes for homologous recombination to have a detectable evolutionary role, and therefore not enough selection to maintain such a complexity. At the same time, the mechanisms of homologous recombination are uniquely suited for repair of complex DNA lesions called chromosomal lesions. In fact, the two major classes of chromosomal lesions are recognized and processed by the two individual pathways at the early phase of homologous recombination. It follows, therefore, that homologous recombination events are occasional reflections of the continual recombinational repair, made possible in cases of natural or artificial genome redundancy. PMID:26442506

  12. Organizing learning processes on risks by using the bow-tie representation

    Energy Technology Data Exchange (ETDEWEB)

    Chevreau, F.R. [Ecole des Mines de Paris, 06904 Sophia-Antipolis (France)]. E-mail: chevreau@cindy.ensmp.fr; Wybo, J.L. [Ecole des Mines de Paris, 06904 Sophia-Antipolis (France)]. E-mail: wybo@cindy.ensmp.fr; Cauchois, D. [Process Safety Department, Sanofi-Aventis, Site de Production de Vitry sur Seine, 9 Quai Jules Guesdes, 94400 Vitry sur Seine (France)]. E-mail: didier.cauchois@sanofi-aventis.com

    2006-03-31

    The Aramis method proposes a complete and efficient way to manage risk analysis by using the bow-tie representation. This paper shows how the bow-tie representation can also be appropriate for experience learning. It describes how a pharmaceutical production plant uses bow-ties for incident and accident analysis. Two levels of bow-ties are constructed: standard bow-ties concern generic risks of the plant whereas local bow-ties represent accident scenarios specific to each workplace. When incidents or accidents are analyzed, knowledge that is gained is added to existing local bow-ties. Regularly, local bow-ties that have been updated are compared to standard bow-ties in order to revise them. Knowledge on safety at the global and at local levels is hence as accurate as possible and memorized in a real time framework. As it relies on the communication between safety experts and local operators, this use of the bow-ties contributes therefore to organizational learning for safety.

  13. Organizing learning processes on risks by using the bow-tie representation

    International Nuclear Information System (INIS)

    Chevreau, F.R.; Wybo, J.L.; Cauchois, D.

    2006-01-01

    The Aramis method proposes a complete and efficient way to manage risk analysis by using the bow-tie representation. This paper shows how the bow-tie representation can also be appropriate for experience learning. It describes how a pharmaceutical production plant uses bow-ties for incident and accident analysis. Two levels of bow-ties are constructed: standard bow-ties concern generic risks of the plant whereas local bow-ties represent accident scenarios specific to each workplace. When incidents or accidents are analyzed, knowledge that is gained is added to existing local bow-ties. Regularly, local bow-ties that have been updated are compared to standard bow-ties in order to revise them. Knowledge on safety at the global and at local levels is hence as accurate as possible and memorized in a real time framework. As it relies on the communication between safety experts and local operators, this use of the bow-ties contributes therefore to organizational learning for safety

  14. Poor textural image tie point matching via graph theory

    Science.gov (United States)

    Yuan, Xiuxiao; Chen, Shiyu; Yuan, Wei; Cai, Yang

    2017-07-01

    Feature matching aims to find corresponding points to serve as tie points between images. Robust matching is still a challenging task when input images are characterized by low contrast or contain repetitive patterns, occlusions, or homogeneous textures. In this paper, a novel feature matching algorithm based on graph theory is proposed. This algorithm integrates both geometric and radiometric constraints into an edge-weighted (EW) affinity tensor. Tie points are then obtained by high-order graph matching. Four pairs of poor textural images covering forests, deserts, bare lands, and urban areas are tested. For comparison, three state-of-the-art matching techniques, namely, scale-invariant feature transform (SIFT), speeded up robust features (SURF), and features from accelerated segment test (FAST), are also used. The experimental results show that the matching recall obtained by SIFT, SURF, and FAST varies from 0 to 35% in different types of poor textures. However, through the integration of both geometry and radiometry and the EW strategy, the recall obtained by the proposed algorithm is better than 50% in all four image pairs. The better matching recall improves the number of correct matches, dispersion, and positional accuracy.

  15. Dynamic risk analysis using bow-tie approach

    International Nuclear Information System (INIS)

    Khakzad, Nima; Khan, Faisal; Amyotte, Paul

    2012-01-01

    Accident probability estimation is a common and central step to all quantitative risk assessment methods. Among many techniques available, bow-tie model (BT) is very popular because it represent the accident scenario altogether including causes and consequences. However, it suffers a static structure limiting its application in real-time monitoring and probability updating which are key factors in dynamic risk analysis. The present work is focused on using BT approach in a dynamic environment in which the occurrence probability of accident consequences changes. In this method, on one hand, failure probability of primary events of BT, leading to the top event, are developed using physical reliability models, and constantly revised as physical parameters (e.g., pressure, velocity, dimension, etc) change. And, on the other hand, the failure probability of safety barriers of the BT are periodically updated using Bayes’ theorem as new information becomes available over time. Finally, the resulting, updated BT is used to estimate the posterior probability of the consequences which in turn results in an updated risk profile. - Highlights: ► A methodology is proposed to make bow-tie method adapted for dynamic risk analysis. ► Physical reliability models are used to revise the top event. ► Bayes’ theorem is used to update the probability of safety barriers. ► The number of accidents in sequential time intervals is used to form likelihood function. ► The risk profile is updated for varying physical parameters and for different times.

  16. Infectious disease research investments follow colonial ties: questionable ethics.

    Science.gov (United States)

    Fitchett, Joseph R; Head, Michael G; Atun, Rifat

    2014-03-01

    International funding for global health research is not systematically documented. We have assessed the level of research funding awarded by UK funders of international research to low- and middle-income countries or research institutions in these countries. We analysed 6165 studies; from these we selected 522 that matched our criteria and used them to evaluate research funding by pathogen, disease, research and development value chain, funding organisation and country. Investment in infectious disease research in the countries studied totalled £264 million. Distribution of research investments closely mirrored that of the UK's former colonial territories; the top five countries, and eight of the top 10, have historical links with the UK, being current or former members of the Commonwealth of Nations. HIV, malaria and neglected tropical diseases attracted the greatest investment (£219 million; 82.8%), with most studies focussing on operational and epidemiological research (£109 million; 41.3%). International financing of infectious disease research by UK funding organisations follows former colonial ties. Funding institutions should review their funding policies to ensure that they also assist low- and middle-income countries without colonial ties to address their disease burden. A global investment surveillance system is needed to map and monitor funding for international research and guide the allocation of scarce resources to reduce the global disease burden.

  17. The Weakening of Kin Ties: Exploring the Need for Life-World Led Interventions.

    Science.gov (United States)

    Schout, Gert; de Jong, Gideon

    2018-01-25

    The protective features that families and wider social relationships can have are required to meet the demands of life in contemporary Western societies. Choice and detraditionalization, however; impede this source of solidarity. Family Group Conferencing (FGC) and other life-world led interventions have the potential to strengthen primary groups. This paper explores the need for such a social intervention, using insights from sociological and philosophical theories and empirical findings from a case study of the research project 'FGC in mental health'. This need is understandable considering the weakening of kin ties, the poor qualities of state agencies to mobilise self-care and informal care, its capacity to produce a shift of power from public to private spheres and its capacity to mitigate the co-isolation of individuals, families and communities. A life-world led intervention like FGC with a specific and modest ambition contributes to small-scale solidarity. This ambition is not inclined to establish a broad social cohesion within society but to restore; in terms of the German philosopher Peter Sloterdijk; immunity (protection) and solidarity in primary groups, and consequently, resolve issues with those (family, neighbours, colleagues) who share a sphere (a situation, a process, a fate).

  18. The influence of tie strength on evolutionary games on networks: An empirical investigation

    Science.gov (United States)

    Buesser, Pierre; Peña, Jorge; Pestelacci, Enea; Tomassini, Marco

    2011-11-01

    Extending previous work on unweighted networks, we present here a systematic numerical investigation of standard evolutionary games on weighted networks. In the absence of any reliable model for generating weighted social networks, we attribute weights to links in a few ways supported by empirical data ranging from totally uncorrelated to weighted bipartite networks. The results of the extensive simulation work on standard complex network models show that, except in a case that does not seem to be common in social networks, taking the tie strength into account does not change in a radical manner the long-run steady-state behavior of the studied games. Besides model networks, we also included a real-life case drawn from a coauthorship network. In this case also, taking the weights into account only changes the results slightly with respect to the raw unweighted graph, although to draw more reliable conclusions on real social networks many more cases should be studied as these weighted networks become available.

  19. 78 FR 75544 - Prestressed Concrete Steel Rail Tie Wire From Mexico: Preliminary Determination of Sales at Less...

    Science.gov (United States)

    2013-12-12

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-201-843] Prestressed Concrete Steel...'') preliminarily determines that prestressed concrete steel rail tie wire (``PC tie wire'') from Mexico is being... element levels; suitable for use as prestressed tendons in concrete railroad ties (``PC tie wire''). High...

  20. 78 FR 29325 - Prestressed Concrete Steel Rail Tie Wire From Mexico, the People's Republic of China, and...

    Science.gov (United States)

    2013-05-20

    ...] Prestressed Concrete Steel Rail Tie Wire From Mexico, the People's Republic of China, and Thailand: Initiation... of prestressed concrete steel rail tie wire (``PC tie wire'') from Mexico, the PRC, and Thailand... Prestressed Concrete Steel Rail Tie Wire from the PRC, Mexico, and Thailand, filed on April 23, 2013 (the...

  1. Acetylcholine Receptor: Complex of Homologous Subunits

    Science.gov (United States)

    Raftery, Michael A.; Hunkapiller, Michael W.; Strader, Catherine D.; Hood, Leroy E.

    1980-06-01

    The acetylcholine receptor from the electric ray Torpedo californica is composed of five subunits; two are identical and the other three are structurally related to them. Microsequence analysis of the four polypeptides demonstrates amino acid homology among the subunits. Further sequence analysis of both membrane-bound and Triton-solubilized, chromatographically purified receptor gave the stoichiometry of the four subunits (40,000:50,000:60,000:65,000 daltons) as 2:1:1:1, indicating that this protein is a pentameric complex with a molecular weight of 255,000 daltons. Genealogical analysis suggests that divergence from a common ancestral gene occurred early in the evolution of the receptor. This shared ancestry argues that each of the four subunits plays a functional role in the receptor's physiological action.

  2. Regulation of Homologous Recombination by SUMOylation

    DEFF Research Database (Denmark)

    Pinela da Silva, Sonia Cristina

    factors such as the homologous recombination (HR) machinery. HR constitutes the main DSB repair pathway in Saccharomyces cerevisiae and despite being largely considered an error-free process and essential for genome stability, uncontrolled recombination can lead to loss of heterozygosity, translocations......, deletions, and genome rearrangements that can lead to cell death or cancer in humans. The post-translational modification by SUMO (small ubiquitinlike modifier) has proven to be an important regulator of HR and genome integrity, but the molecular mechanisms responsible for these roles are still unclear....... In this study I present new insights for the role of SUMOylation in regulating HR by dissecting the role of SUMO in the interaction between the central HR-mediator protein Rad52 and its paralogue Rad59 and the outcome of recombination. This data provides evidence for the importance of SUMO in promoting protein...

  3. Homological mirror symmetry. New developments and perspectives

    International Nuclear Information System (INIS)

    Kapustin, Anton; Kreuzer, Maximilian; Schlesinger, Karl-Georg

    2009-01-01

    Homological Mirror Symmetry, the study of dualities of certain quantum field theories in a mathematically rigorous form, has developed into a flourishing subject on its own over the past years. The present volume bridges a gap in the literature by providing a set of lectures and reviews that both introduce and representatively review the state-of-the art in the field from different perspectives. With contributions by K. Fukaya, M. Herbst, K. Hori, M. Huang, A. Kapustin, L. Katzarkov, A. Klemm, M. Kontsevich, D. Page, S. Quackenbush, E. Sharpe, P. Seidel, I. Smith and Y. Soibelman, this volume will be a reference on the topic for everyone starting to work or actively working on mathematical aspects of quantum field theory. (orig.)

  4. HOMOLOGOUS CYCLONES IN THE QUIET SUN

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xinting; Zhang, Jun; Li, Ting; Zhang, Yuzong; Yang, Shuhong, E-mail: yxt27272@mail.ustc.edu.cn, E-mail: zjun@nao.cas.cn, E-mail: liting@nao.cas.cn, E-mail: yuzong@nao.cas.cn, E-mail: shuhongyang@nao.cas.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2014-02-20

    Through observations with the Solar Dynamics Observatory Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager, we tracked one rotating network magnetic field (RNF) near the solar equator. It lasted for more than 100 hr, from 2013 February 23 to 28. During its evolution, three cyclones were found to be rooted in this structure. Each cyclone event lasted for about 8 to 10 hr. While near the polar region, another RNF was investigated. It lasted for a shorter time (∼70 hr), from 2013 July 7 to 9. There were two cyclones rooted in the RNF and each lasted for 8 and 11 hr, respectively. For the two given examples, the cyclones have a similar dynamic evolution, and thus we put forward a new term: homologous cyclones. The detected brightening in AIA 171 Å maps indicates the release of energy, which is potentially available to heat the corona.

  5. Human communication dynamics in digital footsteps: a study of the agreement between self-reported ties and email networks.

    Directory of Open Access Journals (Sweden)

    Stefan Wuchty

    Full Text Available Digital communication data has created opportunities to advance the knowledge of human dynamics in many areas, including national security, behavioral health, and consumerism. While digital data uniquely captures the totality of a person's communication, past research consistently shows that a subset of contacts makes up a person's "social network" of unique resource providers. To address this gap, we analyzed the correspondence between self-reported social network data and email communication data with the objective of identifying the dynamics in e-communication that correlate with a person's perception of a significant network tie. First, we examined the predictive utility of three popular methods to derive social network data from email data based on volume and reciprocity of bilateral email exchanges. Second, we observed differences in the response dynamics along self-reported ties, allowing us to introduce and test a new method that incorporates time-resolved exchange data. Using a range of robustness checks for measurement and misreporting errors in self-report and email data, we find that the methods have similar predictive utility. Although e-communication has lowered communication costs with large numbers of persons, and potentially extended our number of, and reach to contacts, our case results suggest that underlying behavioral patterns indicative of friendship or professional contacts continue to operate in a classical fashion in email interactions.

  6. Human communication dynamics in digital footsteps: a study of the agreement between self-reported ties and email networks.

    Science.gov (United States)

    Wuchty, Stefan; Uzzi, Brian

    2011-01-01

    Digital communication data has created opportunities to advance the knowledge of human dynamics in many areas, including national security, behavioral health, and consumerism. While digital data uniquely captures the totality of a person's communication, past research consistently shows that a subset of contacts makes up a person's "social network" of unique resource providers. To address this gap, we analyzed the correspondence between self-reported social network data and email communication data with the objective of identifying the dynamics in e-communication that correlate with a person's perception of a significant network tie. First, we examined the predictive utility of three popular methods to derive social network data from email data based on volume and reciprocity of bilateral email exchanges. Second, we observed differences in the response dynamics along self-reported ties, allowing us to introduce and test a new method that incorporates time-resolved exchange data. Using a range of robustness checks for measurement and misreporting errors in self-report and email data, we find that the methods have similar predictive utility. Although e-communication has lowered communication costs with large numbers of persons, and potentially extended our number of, and reach to contacts, our case results suggest that underlying behavioral patterns indicative of friendship or professional contacts continue to operate in a classical fashion in email interactions.

  7. Human Communication Dynamics in Digital Footsteps: A Study of the Agreement between Self-Reported Ties and Email Networks

    Science.gov (United States)

    Wuchty, Stefan; Uzzi, Brian

    2011-01-01

    Digital communication data has created opportunities to advance the knowledge of human dynamics in many areas, including national security, behavioral health, and consumerism. While digital data uniquely captures the totality of a person's communication, past research consistently shows that a subset of contacts makes up a person's “social network” of unique resource providers. To address this gap, we analyzed the correspondence between self-reported social network data and email communication data with the objective of identifying the dynamics in e-communication that correlate with a person's perception of a significant network tie. First, we examined the predictive utility of three popular methods to derive social network data from email data based on volume and reciprocity of bilateral email exchanges. Second, we observed differences in the response dynamics along self-reported ties, allowing us to introduce and test a new method that incorporates time-resolved exchange data. Using a range of robustness checks for measurement and misreporting errors in self-report and email data, we find that the methods have similar predictive utility. Although e-communication has lowered communication costs with large numbers of persons, and potentially extended our number of, and reach to contacts, our case results suggest that underlying behavioral patterns indicative of friendship or professional contacts continue to operate in a classical fashion in email interactions. PMID:22114665

  8. Modeling Non-homologous End Joining

    Science.gov (United States)

    Li, Yongfeng

    2013-01-01

    Non-homologous end joining (NHEJ) is the dominant DNA double strand break (DSB) repair pathway and involves several NHEJ proteins such as Ku, DNA-PKcs, XRCC4, Ligase IV and so on. Once DSBs are generated, Ku is first recruited to the DNA end, followed by other NHEJ proteins for DNA end processing and ligation. Because of the direct ligation of break ends without the need for a homologous template, NHEJ turns out to be an error-prone but efficient repair pathway. Some mechanisms have been proposed of how the efficiency of NHEJ repair is affected. The type of DNA damage is an important factor of NHEJ repair. For instance, the length of DNA fragment may determine the recruitment efficiency of NHEJ protein such as Ku [1], or the complexity of the DNA breaks [2] is accounted for the choice of NHEJ proteins and subpathway of NHEJ repair. On the other hand, the chromatin structure also plays a role of the accessibility of NHEJ protein to the DNA damage site. In this talk, some mathematical models of NHEJ, that consist of series of biochemical reactions complying with the laws of chemical reaction (e.g. mass action, etc.), will be introduced. By mathematical and numerical analysis and parameter estimation, the models are able to capture the qualitative biological features and show good agreement with experimental data. As conclusions, from the viewpoint of modeling, how the NHEJ proteins are recruited will be first discussed for connection between the classical sequential model [4] and recently proposed two-phase model [5]. Then how the NHEJ repair pathway is affected, by the length of DNA fragment [6], the complexity of DNA damage [7] and the chromatin structure [8], will be addressed

  9. More on homological supersymmetric quantum mechanics

    Science.gov (United States)

    Behtash, Alireza

    2018-03-01

    In this work, we first solve complex Morse flow equations for the simplest case of a bosonic harmonic oscillator to discuss localization in the context of Picard-Lefschetz theory. We briefly touch on the exact non-BPS solutions of the bosonized supersymmetric quantum mechanics on algebraic geometric grounds and report that their complex phases can be accessed through the cohomology of WKB 1-form of the underlying singular spectral curve subject to necessary cohomological corrections for nonzero genus. Motivated by Picard-Lefschetz theory, we write down a general formula for the index of N =4 quantum mechanics with background R -symmetry gauge fields. We conjecture that certain symmetries of the refined Witten index and singularities of the moduli space may be used to determine the correct intersection coefficients. A few examples, where this conjecture holds, are shown in both linear and closed quivers with rank-one quiver gauge groups. The R -anomaly removal along the "Morsified" relative homology cycles also called "Lefschetz thimbles" is shown to lead to the appearance of Stokes lines. We show that the Fayet-Iliopoulos parameters appear in the intersection coefficients for the relative homology of the quiver quantum mechanics resulting from dimensional reduction of 2 d N =(2 ,2 ) gauge theory on a circle and explicitly calculate integrals along the Lefschetz thimbles in N =4 C Pk -1 model. The Stokes jumping of coefficients and its relation to wall crossing phenomena is briefly discussed. We also find that the notion of "on-the-wall" index is related to the invariant Lefschetz thimbles under Stokes phenomena. An implication of the Lefschetz thimbles in constructing knots from quiver quantum mechanics is indicated.

  10. Clustering evolving proteins into homologous families.

    Science.gov (United States)

    Chan, Cheong Xin; Mahbob, Maisarah; Ragan, Mark A

    2013-04-08

    Clustering sequences into groups of putative homologs (families) is a critical first step in many areas of comparative biology and bioinformatics. The performance of clustering approaches in delineating biologically meaningful families depends strongly on characteristics of the data, including content bias and degree of divergence. New, highly scalable methods have recently been introduced to cluster the very large datasets being generated by next-generation sequencing technologies. However, there has been little systematic investigation of how characteristics of the data impact the performance of these approaches. Using clusters from a manually curated dataset as reference, we examined the performance of a widely used graph-based Markov clustering algorithm (MCL) and a greedy heuristic approach (UCLUST) in delineating protein families coded by three sets of bacterial genomes of different G+C content. Both MCL and UCLUST generated clusters that are comparable to the reference sets at specific parameter settings, although UCLUST tends to under-cluster compositionally biased sequences (G+C content 33% and 66%). Using simulated data, we sought to assess the individual effects of sequence divergence, rate heterogeneity, and underlying G+C content. Performance decreased with increasing sequence divergence, decreasing among-site rate variation, and increasing G+C bias. Two MCL-based methods recovered the simulated families more accurately than did UCLUST. MCL using local alignment distances is more robust across the investigated range of sequence features than are greedy heuristics using distances based on global alignment. Our results demonstrate that sequence divergence, rate heterogeneity and content bias can individually and in combination affect the accuracy with which MCL and UCLUST can recover homologous protein families. For application to data that are more divergent, and exhibit higher among-site rate variation and/or content bias, MCL may often be the better

  11. Social networks, personal values, and creativity: evidence for curvilinear and interaction effects.

    Science.gov (United States)

    Zhou, Jing; Shin, Shung Jae; Brass, Daniel J; Choi, Jaepil; Zhang, Zhi-Xue

    2009-11-01

    Taking an interactional perspective on creativity, the authors examined the influence of social networks and conformity value on employees' creativity. They theorized and found a curvilinear relationship between number of weak ties and creativity such that employees exhibited greater creativity when their number of weak ties was at intermediate levels rather than at lower or higher levels. In addition, employees' conformity value moderated the curvilinear relationship between number of weak ties and creativity such that employees exhibited greater creativity at intermediate levels of number of weak ties when conformity was low than when it was high. A proper match between personal values and network ties is critical for understanding creativity.

  12. K-homology and K-cohomology constructions of relations

    International Nuclear Information System (INIS)

    Abd El-Sattar, A. Dabbour; Bayoumy, F.M.

    1990-08-01

    One of the important homology (cohomology) theories, based on systems of covering of the space, is the homology (cohomology) theory of relations. In the present work, by using the idea of K-homology and K-cohomology groups different varieties of the Dowker's theory are introduced and studied. These constructions are defined on the category of pairs of topological spaces and over a pair of coefficient groups. (author). 14 refs

  13. A local homology theory for linearly compact modules

    International Nuclear Information System (INIS)

    Nguyen Tu Cuong; Tran Tuan Nam

    2004-11-01

    We introduce a local homology theory for linearly modules which is in some sense dual to the local cohomology theory of A. Grothendieck. Some basic properties of local homology modules are shown such as: the vanishing and non-vanishing, the noetherianness of local homology modules. By using duality, we extend some well-known results in theory of local cohomology of A. Grothendieck. (author)

  14. On (co)homology of Frobenius Poisson algebras

    OpenAIRE

    Zhu, Can; Van Oystaeyen, Fred; ZHANG, Yinhuo

    2014-01-01

    In this paper, we study Poisson (co)homology of a Frobenius Poisson algebra. More precisely, we show that there exists a duality between Poisson homology and Poisson cohomology of Frobenius Poisson algebras, similar to that between Hochschild homology and Hochschild cohomology of Frobenius algebras. Then we use the non-degenerate bilinear form on a unimodular Frobenius Poisson algebra to construct a Batalin-Vilkovisky structure on the Poisson cohomology ring making it into a Batalin-Vilkovisk...

  15. A geometric model for Hochschild homology of Soergel bimodules

    DEFF Research Database (Denmark)

    Webster, Ben; Williamson, Geordie

    2008-01-01

    An important step in the calculation of the triply graded link homology of Khovanov and Rozansky is the determination of the Hochschild homology of Soergel bimodules for SL(n). We present a geometric model for this Hochschild homology for any simple group G, as B–equivariant intersection cohomology...... on generators whose degree is explicitly determined by the geometry of the orbit closure, and to describe its Hilbert series, proving a conjecture of Jacob Rasmussen....

  16. Heteromorphic Sex Chromosomes: Navigating Meiosis without a Homologous Partner

    OpenAIRE

    Checchi, Paula M.; Engebrecht, JoAnne

    2011-01-01

    Accurate chromosome segregation during meiosis relies on homology between the maternal and paternal chromosomes. Yet by definition, sex chromosomes of the heterogametic sex lack a homologous partner. Recent studies in a number of systems have shed light on the unique meiotic behavior of heteromorphic sex chromosomes, and highlight both the commonalities and differences in divergent species. During meiotic prophase, the homology-dependent processes of pairing, synapsis, and recombination have ...

  17. Studi Tentang Political Tie, Pengaruhnya Terhadap Keputusan Pemberian Kredit Bank di Indonesia

    Directory of Open Access Journals (Sweden)

    Elisa Tjondro

    2012-01-01

    Full Text Available This study uses bank loan data to examine the effect of (political tie between the company and the government to on the assessment of companies financial leverage and profitability in the bank lending decisions in Indonesia. The numbers of samples are 1465 observations. This study uses moderated regression analysis (MRA. The study finds that a political tie affect corporate profitability assessment in bank lending decisions. Firms with lower profitability receive larger bank loan because their political tie (rent-seeking hypothesis. However, this study inds that a political tie does not affect the assessment of financial leverage in bank's lending decisions. This finding also supports Faccio (2010, Fisman (2001, and Backman (2001. Indonesia condition which has a weak institutional regulation and high information asymmetry is beneficial for companies that have a political tie. This leads to more trusted political tie as an indicator of the profitability.

  18. Colored Kauffman homology and super-A-polynomials

    International Nuclear Information System (INIS)

    Nawata, Satoshi; Ramadevi, P.; Zodinmawia

    2014-01-01

    We study the structural properties of colored Kauffman homologies of knots. Quadruple-gradings play an essential role in revealing the differential structure of colored Kauffman homology. Using the differential structure, the Kauffman homologies carrying the symmetric tensor products of the vector representation for the trefoil and the figure-eight are determined. In addition, making use of relations from representation theory, we also obtain the HOMFLY homologies colored by rectangular Young tableaux with two rows for these knots. Furthermore, the notion of super-A-polynomials is extended in order to encompass two-parameter deformations of PSL(2,ℂ) character varieties

  19. Protective or harmful? Exploring the ambivalent role of social identification as a moderator of intergroup stress in sojourners

    NARCIS (Netherlands)

    Bierwiaczonek, Kinga; Waldzus, Sven; van der Zee, Karen

    2017-01-01

    Living outside one's home country may be stressful, and having strong social ties should help deal with this stress. However, social ties may be protective or harmful depending on whether the social group they evoke belongs to the host- or the home country context. The current study examines how

  20. Financial and Emotional Support in Close Personal Ties among Central Asian Migrant Women in Russia.

    Science.gov (United States)

    Kornienko, Olga; Agadjanian, Victor; Menjívar, Cecilia; Zotova, Natalia

    2018-05-01

    This study advances research on the role of personal networks as sources of financial and emotional support in immigrants' close personal ties beyond the immediate family. Because resource scarcity experienced by members of immigrant communities is likely to disrupt normatively expected reciprocal support, we explored multi-level predictors of exchange processes with personal network members that involve (1) only receiving support, (2) only providing support, and (3) reciprocal support exchanges. We focus on an understudied case of Central Asian migrant women in the Russian Federation using a sample of 607 women from three ethnic groups-Kyrgyz, Tajik, Uzbek-who were surveyed in two large Russian cities-Nizhny Novgorod and Kazan. The survey collected information on respondents' demographic, socioeconomic, and migration-related characteristics, as well as characteristics of up to five individuals with whom they had a close relationship. Multi-level multinomial regression analyses were used to account for the nested nature of the data. Our results revealed that closer social relationships (siblings and friends) and greater levels of resources (income and regularized legal status) at both ego and alter levels were positively related to providing, receiving, and reciprocally exchanging financial and emotional support. Egos were more likely to provide financial assistance to transnational alters, whereas they were more likely to engage in mutual exchanges of emotional support with their network members from other countries. Personal network size and density showed no relationship with support exchanges. These findings provide a nuanced picture of close personal ties as conduits for financial and emotional support in migrant communities in a major, yet understudied, migrant-receiving context.

  1. Representation of Women With Industry Ties in Ophthalmology.

    Science.gov (United States)

    Reddy, Ashvini K; Bounds, Gregory W; Bakri, Sophie J; Gordon, Lynn K; Smith, Justine R; Haller, Julia A; Thorne, Jennifer E

    2016-06-01

    Women in ophthalmology are growing in number and have made strides in traditional metrics of professional achievement. Professional ties to industry represent another potential means of career advancement, recognition, and income. To report the representation of women among ophthalmologists receiving industry remuneration for research, consulting, honoraria, grants, royalties, and faculty/speaker roles. In this observational, retrospective study, the Centers for Medicare and Medicaid Services Open Payments database for payments to ophthalmologists by biomedical companies was reviewed for representation, median payments, and mean payments by women and men for industry relationships in 2013 and 2014. The analysis was performed from July 2015 to November 2015. The primary outcome measures were percentage representation of women vs men overall and in industry research, consulting, speaking roles, royalties and licenses, grants, services other than consulting, and honoraria. Secondary outcome measures included mean and median payments from industry to female vs male ophthalmologists. In 2013, 4164 of 21 380 (19.5%) ophthalmologists were women, and of 1204 ophthalmologists analyzed for industry payments, 176 (4.2%) women had industry ties compared with 1028 (6%) men (P women were $11 419 compared with $20 957 for men (P = .001), and median payments to women were $3000 compared with $4787 for men (P = .007). In 2013, women were underrepresented among ophthalmologists receiving industry payments for research (49 of 462 [10.6%]), consulting (96 of 610 [15.7%]), honoraria (3 of 47 [6.4%]), industry grants (1 of 7 [14.3%]), royalties and licenses (1 of 13 [7.7%]), and faculty/speaker roles (2 of 48 [4.2%]). In 2014, 4352 of 21 531 (20.2%) of ophthalmologists were women. Of 1518 ophthalmologists analyzed for industry payments, 255 (6%) women had industry ties compared with 1263 (7.4%) men (P women were $14 848 compared with $30 513 for men (P = .004

  2. Risk aversion and social networks

    NARCIS (Netherlands)

    Kovářík, J.; van der Leij, M.J.

    2014-01-01

    This paper first investigates empirically the relationship between risk aversion and social network structure in a large group of undergraduate students. We find that risk aversion is strongly correlated to local network clustering, that is, the probability that one has a social tie to friends of

  3. Performance and Characterization of Shear Ties for Use in Insulated Precast Concrete Sandwich Wall Panels

    Science.gov (United States)

    2010-11-01

    stainless 14 steel, galvanized carbon steel, carbon- fiber -reinforced polymer (CFRP), glass- fiber -reinforced polymer 15 (GFRP), and basalt - fiber ...CFRP Grid, (E) Universal Building Products GFRP Teplo Tie, and (F) Universal Building Products 6 Basalt FRP RockBar. Traditional steel connections...1.6 E Universal Building Products TeploTie GFRP Tie 10 mm dia. x 150 mm F RockBar Basalt FRP Bar 7 in. x 5/16 in. G TSA Manufacturing C-Clip

  4. Military Social Work as an Exemplar in Teaching Social Work Competencies

    Science.gov (United States)

    Daley, James G.; Carlson, Joan; Evans, Pinkie

    2015-01-01

    This article is for social work educators unfamiliar with military social work and receptive to a number of exemplars to enhance teaching strategies within their courses. Because examples of military social work are directly tied to the Council on Social Work Education competencies, this article offers a number of suggested teaching strategies…

  5. Risk Factors for Social Isolation in Older Korean Americans.

    Science.gov (United States)

    Jang, Yuri; Park, Nan Sook; Chiriboga, David A; Yoon, Hyunwoo; Ko, Jisook; Lee, Juyoung; Kim, Miyong T

    2016-02-01

    Given the importance of social ties and connectedness in the lives of older ethnic immigrants, the present study examined the prevalence of social isolation and its risk factors in older Korean Americans. Using survey data from 1,301 participants (Mage = 70.5, SD = 7.24), risk groups for marginal social ties with family and friends were identified and predictors of each type of social isolation explored. Male gender and poorer rating of health were identified as common risk factors for marginal ties to both family and friends. Findings also present specific risk factors for each type of social isolation. For example, an increased risk of having marginal ties with friends was observed among individuals with perceived financial strain, greater functional impairment, and a shorter stay in the United States. The common and specific risk factors should be incorporated in programs to reduce social isolation in older immigrant populations. © The Author(s) 2015.

  6. Temperature Profile in Fuel and Tie-Tubes for Nuclear Thermal Propulsion Systems

    Energy Technology Data Exchange (ETDEWEB)

    Vishal Patel

    2015-02-01

    A finite element method to calculate temperature profiles in heterogeneous geometries of tie-tube moderated LEU nuclear thermal propulsion systems and HEU designs with tie-tubes is developed and implemented in MATLAB. This new method is compared to previous methods to demonstrate shortcomings in those methods. Typical methods to analyze peak fuel centerline temperature in hexagonal geometries rely on spatial homogenization to derive an analytical expression. These methods are not applicable to cores with tie-tube elements because conduction to tie-tubes cannot be accurately modeled with the homogenized models. The fuel centerline temperature directly impacts safety and performance so it must be predicted carefully. The temperature profile in tie-tubes is also important when high temperatures are expected in the fuel because conduction to the tie-tubes may cause melting in tie-tubes, which may set maximum allowable performance. Estimations of maximum tie-tube temperature can be found from equivalent tube methods, however this method tends to be approximate and overly conservative. A finite element model of heat conduction on a unit cell can model spatial dependence and non-linear conductivity for fuel and tie-tube systems allowing for higher design fidelity of Nuclear Thermal Propulsion.

  7. Strengthening weak ties through on-line gaming

    DEFF Research Database (Denmark)

    Sudzina, Frantisek; Razmerita, Liana Virginia; Kirchner, Kathrin

    On-line gaming became widespread in the last couple of years. The aim of the research presented in the paper is to figure out to what extent does game playing helps to strengthen weak ties and what additional factors influence this process. The approach is rather exploratory – some factors...... are grounded in theory, some are new. These factors are age, gender, place of origin, number of their Facebook connections (friends in Facebook terminology), the amount of time they are on Facebook, the amount of time they keep the Facebook site open, the amount of time they play on-line games, and the reasons...... for starting to play on-line games. Regarding the latter, we chose to focus only on escapist reasons....

  8. Semantic mining of social networks

    CERN Document Server

    Tang, Jie

    2015-01-01

    The first kinds of questions we try to answer are: What are the fundamental factors that form the different categories of social ties? How have reciprocal relationships been developed fro parasocial relationships? How do connected users further form groups? Another theme addressed in this book is the study of social influence. Social influence occurs when one's opinions, emotions, or behaviors are affected by others, intentionally or unintentionally. Considerable research has been conducted to verify the existence of social influence in various networks.

  9. Parent-Implemented Behavioral Skills Training of Social Skills

    Science.gov (United States)

    Dogan, Rebecca K.; King, Melissa L.; Fischetti, Anthony T.; Lake, Candice M.; Mathews, Therese L.; Warzak, William J.

    2017-01-01

    Impairment in social skills is a primary feature of Autism Spectrum Disorders (ASDs). Research indicates that social skills are intimately tied to social development and negative social consequences can persist if specific social behaviors are not acquired. The present study evaluated the effects of behavioral skills training (BST) on teaching…

  10. The Role of School Board Social Capital in District Governance: Effects on Financial and Academic Outcomes

    Science.gov (United States)

    Saatcioglu, Argun; Moore, Suzanne; Sargut, Gokce; Bajaj, Aarti

    2011-01-01

    Social capital refers to the nature of ties within a social unit, as well as the unit's external relationships. We draw from organizational sociology and political science, and also build upon existing insights in school board research, to offer an approach that address the effects of "bonding" (internal ties) and "bridging"…

  11. Cohorts, "Siblings," and Mentors: Organizational Structures and the Creation of Social Capital

    Science.gov (United States)

    Cox, Amanda Barrett

    2017-01-01

    How can an organization help participants increase their social capital? Using data from an ethnographic study of Launch, an organization that prepares low-income students of color to attend elite boarding schools, I analyze how the organization's structures not only generate social ties among students but also stratify those ties horizontally and…

  12. Acculturation Versus Cultural Retention: The Interactive Impact of Acculturation and Co-ethnic Ties on Substance Use Among Chinese Students in the United States.

    Science.gov (United States)

    Yang, Xiaozhao Yousef; Yang, Fenggang

    2018-06-01

    Acculturation is often found to increase substance use among immigrants in the U.S., but such effect may depend on how immigrants are attached to their co-ethnic community. Meanwhile, the high socioeconomic status of some new immigrant groups also challenges the classical assumption that ties to co-ethnic community are associated with deviance. With a sample (n = 960) collected from a population of Chinese students in a large public university in the U.S., we tested how do the interplays between acculturation and co-ethnic ties affect substance use. This study establishes that: (1) different dimensions of acculturation have opposite effects on substance use; (2) acculturative stress does not explain the association between acculturation and substance use; (3) acculturation increases the likelihood of substance use only when one has weak attachment to their co-ethnic community. The findings are consistent for three dependent variables: smoking, drinking, and drunkenness, and for the different constructs of acculturation and co-ethnic ties. Ties to co-ethnic community may provide important social support for immigrants, while acculturation may alleviate the insular subculture that promotes at-risk behaviors. We encourage policy makers to consider the cooperative nature of acculturation and cultural retention for the improvement of health among this growing population.

  13. CBH1 homologs and varian CBH1 cellulase

    Energy Technology Data Exchange (ETDEWEB)

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Neefe, Paulien

    2014-07-01

    Disclosed are a number of homologs and variants of Hypocrea jecorina Cel7A (formerly Trichoderma reesei cellobiohydrolase I or CBH1), nucleic acids encoding the same and methods for producing the same. The homologs and variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted and/or deleted.

  14. The Causes of Quasi-homologous CMEs

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lijuan; Wang, Yuming; Liu, Rui; Zhou, Zhenjun; Liu, Jiajia; Liu, Kai; Shen, Chenglong; Zhang, Quanhao [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui, 230026 (China); Temmer, M.; Thalmann, J. K.; Veronig, A. M., E-mail: ymwang@ustc.edu.cn, E-mail: ljliu@mail.ustc.edu.cn [Institute of Physics/IGAM, University of Graz, Universitätsplatz 5/II, A-8010 Graz (Austria)

    2017-08-01

    In this paper, we identified the magnetic source locations of 142 quasi-homologous (QH) coronal mass ejections (CMEs), of which 121 are from solar cycle (SC) 23 and 21 from SC 24. Among those CMEs, 63% originated from the same source location as their predecessor (defined as S-type), while 37% originated from a different location within the same active region as their predecessor (defined as D-type). Their distinctly different waiting time distributions, peaking around 7.5 and 1.5 hr for S- and D-type CMEs, suggest that they might involve different physical mechanisms with different characteristic timescales. Through detailed analysis based on nonlinear force-free coronal magnetic field modeling of two exemplary cases, we propose that the S-type QH CMES might involve a recurring energy release process from the same source location (by magnetic free energy replenishment), whereas the D-type QH CMEs can happen when a flux tube system is disturbed by a nearby CME.

  15. Torus actions, combinatorial topology, and homological algebra

    International Nuclear Information System (INIS)

    Bukhshtaber, V M; Panov, T E

    2000-01-01

    This paper is a survey of new results and open problems connected with fundamental combinatorial concepts, including polytopes, simplicial complexes, cubical complexes, and arrangements of subspaces. Attention is concentrated on simplicial and cubical subdivisions of manifolds, and especially on spheres. Important constructions are described that enable one to study these combinatorial objects by using commutative and homological algebra. The proposed approach to combinatorial problems is based on the theory of moment-angle complexes recently developed by the authors. The crucial construction assigns to each simplicial complex K with m vertices a T m -space Z K with special bigraded cellular decomposition. In the framework of this theory, well-known non-singular toric varieties arise as orbit spaces of maximally free actions of subtori on moment-angle complexes corresponding to simplicial spheres. It is shown that diverse invariants of simplicial complexes and related combinatorial-geometric objects can be expressed in terms of bigraded cohomology rings of the corresponding moment-angle complexes. Finally, it is shown that the new relationships between combinatorics, geometry, and topology lead to solutions of some well-known topological problems

  16. Statistical Inference for Porous Materials using Persistent Homology.

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Chul [Univ. of Georgia, Athens, GA (United States); Heath, Jason E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mitchell, Scott A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-12-01

    We propose a porous materials analysis pipeline using persistent homology. We rst compute persistent homology of binarized 3D images of sampled material subvolumes. For each image we compute sets of homology intervals, which are represented as summary graphics called persistence diagrams. We convert persistence diagrams into image vectors in order to analyze the similarity of the homology of the material images using the mature tools for image analysis. Each image is treated as a vector and we compute its principal components to extract features. We t a statistical model using the loadings of principal components to estimate material porosity, permeability, anisotropy, and tortuosity. We also propose an adaptive version of the structural similarity index (SSIM), a similarity metric for images, as a measure to determine the statistical representative elementary volumes (sREV) for persistence homology. Thus we provide a capability for making a statistical inference of the uid ow and transport properties of porous materials based on their geometry and connectivity.

  17. Measuring Social Capital Accumulation in Rural Development

    Science.gov (United States)

    Teilmann, Kasper

    2012-01-01

    Using a theoretical framework, the study proposes an index that can measure the social capital of local action group (LAG) projects. The index is founded on four indicators: number of ties, bridging social capital, recognition, and diversity, which are aggregated into one social capital index. The index has been tested in LAG-Djursland, Denmark,…

  18. Enfrentando a pobreza, reconstruindo vínculos sociais: as lições da Ação da Cidadania contra a Fome, a Miséria e pela Vida Combating poverty and rebuilding social ties: the lessons of Citizens' Action in the Struggle Against Hunger and Destitution and in Defense of Life

    Directory of Open Access Journals (Sweden)

    Rosana Magalhães

    2002-01-01

    Full Text Available Refletir sobre a Ação da Cidadania contra a Fome e a Miséria e pela Vida é buscar uma aproximação com os dilemas e desafios que envolvem a consolidação da cidadania e da justiça social e, também, com as forças em ação na sociedade brasileira contemporânea. Neste esforço, porém, muitas interrogações ficam em aberto. O entrelaçamento dos temas da pobreza, da política e da solidariedade, os contornos concretos e os múltiplos desdobramentos sociais da chamada "Campanha da Fome" dão margem a diferentes possibilidades interpretativas. Dessa forma, considerando por uma lado, a amplitude do tema e, por outro, as limitações deste artigo, o objetivo é explorar algumas questões relevantes em torno do debate sobre a miséria, a exclusão e o processo de construção de novos perfis de intervenção pública e participação cívica, suscitadas ao longo da pesquisa realizada junto aos "Comitês da Ação da Cidadania" no Rio de Janeiro, entre 1996 e 1997. Em linhas gerais, a idéia é discutir, a partir das práticas dos voluntários, os dilemas postos para o equacionamento da pobreza e da fragmentação social por meio de ações de cooperação e ajuda mútua no país.To reflect on Citizens' Action in the Struggle Against Hunger and Destitution and in Defense of Life is to seek to approach the dilemmas and challenges involving the consolidation of citizenship and social justice, as well as the forces in action in contemporary Brazilian society. However, many questions remain open in this effort. The intertwining issues of poverty, politics, and solidarity and the concrete shapes and multiple social developments of Brazil's "Campaign Against Hunger" leave room for various possible interpretations. Thus, considering the breadth of the theme on the one hand and the limits of this article on the other, the objective is to explore some relevant issues in the debate on destitution and exclusion and the process of constructing new kinds

  19. Homologous series of induced early mutants in indican rice. Pt.1. The production of homologous series of early mutants

    International Nuclear Information System (INIS)

    Chen Xiulan; Yang Hefeng; He Zhentian; Han Yuepeng; Liu Xueyu

    1999-01-01

    The percentage of homologous series of early mutants induced from the same Indican rice variety were almost the same (1.37%∼1.64%) in 1983∼1993, but the ones from the different eco-typical varieties were different. The early variety was 0.73%, the mid variety was 1.51%, and the late variety was 1.97%. The percentage of homologous series of early mutants from the varieties with the same pedigree and relationship were similar, but the one from the cog nation were lower than those from distant varieties. There are basic laws and characters in the homologous series of early mutants: 1. The inhibited phenotype is the basic of the homologous series of early mutants; 2. The production of the homologous series of early mutants is closely related with the growing period of the parent; 3. The parallel mutation of the stem and leaves are simultaneously happened with the variation of early or late maturing; 4. The occurrence of the homologous series of early mutants is in a state of imbalance. According to the law of parallel variability, the production of homologous series of early mutants can be predicted as long as the parents' classification of plant, pedigree and ecological type are identified. Therefore, the early breeding can be guided by the law of homologous series of early mutants

  20. Effects of a Group Intervention on the Career Network Ties of Finnish Adolescents

    Science.gov (United States)

    Jokisaari, Markku; Vuori, Jukka

    2011-01-01

    The authors evaluated how a group-based career intervention affected career network ties among Finnish adolescents as they made educational choices and prepared for their transition to secondary education. They examined the career-related network ties of 868 students during their last year in comprehensive school (junior high school) in a…

  1. Polycyclic aromatic hydrocarbon migration from creosote-treated railway ties into ballast and adjacent wetlands

    Science.gov (United States)

    Kenneth M. Brooks

    2004-01-01

    Occasionally, creosote-treated railroad ties need to be replaced, sometimes in sensitive environments such as wetlands. To help determine if this is detrimental to the surrounding environment, more information is needed on the extent and pattern of creosote, or more specifically polycyclic aromatic hydrocarbon (PAH), migration from railroad ties and what effects this...

  2. The Bright Side and Dark Side of Embedded Ties In Business-to-Business Innovation

    NARCIS (Netherlands)

    C.S. Noordhoff (Corine); K. Kyriakopoulos (Kyriakos); C. Moorman (Christina); P. Pauwels (Pieter); B.G.C. Dellaert (Benedict)

    2011-01-01

    textabstractWhile the number and importance of joint innovation projects between suppliers and their customers continue to rise, the literature has yet to resolve a key question—do embedded ties with customers help or hurt supplier innovation? Drawing on both the tie strength and knowledge

  3. The bright side and dark side of embedded ties in business-to-business innovation

    NARCIS (Netherlands)

    C.S. Noordhoff (Corine); K. Kyriakopoulos (Kyriakos); C. Moorman (Christina); P. Pauwels (Pieter); B.G.C. Dellaert (Benedict)

    2011-01-01

    textabstractAlthough the number and importance of joint innovation projects between suppliers and their customers continue to rise, the literature has yet to resolve a key question: Do embedded ties with customers help or hurt supplier innovation? Drawing on both the tie strength and knowledge

  4. The use of nylon cable ties to repair rib fractures in neonatal foals

    OpenAIRE

    Downs, Chris; Rodgerson, Dwayne

    2011-01-01

    Commercially available nylon cable ties were used as a method of internal fixation for displaced rib fractures in 8 equine neonates. The procedure was effective, well-tolerated, rapid, and inexpensive. The use of nylon cable ties as internal fixation for displaced rib fractures in foals is an effective surgical procedure.

  5. 78 FR 25303 - Prestressed Concrete Steel Rail Tie Wire From China, Mexico, and Thailand

    Science.gov (United States)

    2013-04-30

    ... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 731-TA-1207-1209 (Preliminary)] Prestressed Concrete Steel Rail Tie Wire From China, Mexico, and Thailand Institution of antidumping duty..., by reason of imports from prestressed concrete steel rail tie wire from China, Mexico, and Thailand...

  6. 78 FR 37236 - Prestressed Concrete Steel Rail Tie Wire From China, Mexico, and Thailand

    Science.gov (United States)

    2013-06-20

    ... Concrete Steel Rail Tie Wire From China, Mexico, and Thailand Determinations On the basis of the record \\1... imports from China, Mexico, and Thailand of prestressed concrete steel rail tie wire, provided for in... China, Mexico, and Thailand. Accordingly, effective April 23, 2013, the Commission instituted...

  7. The VEGF system and tie-2 are spatio-temporal expressed during tayassu placentation

    DEFF Research Database (Denmark)

    Miglino, M.A.; Santos, T.C.; Papa, P.C.

    Objectives: The vascular endothelial growth factor (VEGF) is one of the most important vascular mitogens, while the angiotensin receptor Tie-2 binds to the angiopoietin and stabilizes newly formed vessels. We therefore wanted to localize VEGF and its receptors VEGF-R1, VEGF-R2 and the Tie-2 recep...

  8. 75 FR 34941 - Review of the Commission's Program Access Rules and Examination of Programming Tying Arrangements

    Science.gov (United States)

    2010-06-21

    ... Commission's Program Access Rules and Examination of Programming Tying Arrangements AGENCY: Federal... Program Access Rules and Examination of Programming Tying Arrangements, MB Docket No. 07-198, FCC 10-17... information collection is contained in Sections 4(i), 303(r), and 628 of the Communications Act of 1934, as...

  9. Dual market structures and the likelihood of repeated ties - evidence from pharmaceutical biotechnology

    NARCIS (Netherlands)

    Roijakkers, A.H.W.M.; Hagedoorn, J.; Kranenburg, van H.

    2005-01-01

    This paper analyses the role of repeated ties in the high-tech pharmaceutical biotechnology industry, a sector that is characterized by a strong dual market structure. Our most important finding is that previous ties in pairs of large pharmaceutical companies and small biotechnology firms have a

  10. Weak Ties and Self-Regulation in Job Search: The Effects of Goal Orientation on Networking

    Science.gov (United States)

    Hatala, John-Paul; Yamkovenko, Bogdan

    2016-01-01

    The purpose of this study is to empirically investigate the relationship between the self-regulatory variable of goal orientation and the extent to which job seekers reach out to and use weak ties in their job search. Weak ties, as defined by Granovettor, are connections to densely knit networks outside the individual's direct contacts who could…

  11. Finite element analyses of continuous filament ties for masonry applications: final report for the Arquin Corporation

    Energy Technology Data Exchange (ETDEWEB)

    Quinones, Sr., Armando [Arquin Corporation, La Luz, NM (United States); Bibeau, Tiffany A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ho, Clifford Kuofei

    2006-06-01

    Finite-element analyses were performed to simulate the response of a hypothetical masonry shear wall with and without continuous filament ties to various lateral loads. The loads represented three different scenarios: (1) 100 mph wind, (2) explosive attack, and (3) an earthquake. In addition, a static loading analysis and cost comparison were performed to evaluate optimal materials and designs for the spacers affixed to the filaments. Results showed that polypropylene, ABS, and polyethylene (high density) were suitable materials for the spacers based on performance and cost, and the short T-spacer design was optimal based on its performance and functionality. Results of the shear-wall loading simulations revealed that simulated walls with the continuous filament ties yielded factors of safety that were at least ten times greater than those without the ties. In the explosive attack simulation (100 psi), the simulated wall without the ties failed (minimum factor of safety was less than one), but the simulated wall with the ties yielded a minimum factor of safety greater than one. Simulations of the walls subject to lateral loads caused by 100 mph winds (0.2 psi) and seismic events with a peak ground acceleration of 1 ''g'' (0.66 psi) yielded no failures with or without the ties. Simulations of wall displacement during the seismic scenarios showed that the wall with the ties resulted in a maximum displacement that was 20% less than the wall without the ties.

  12. Quality resource networks for young women in science: The role of Internet-facilitated ties

    Science.gov (United States)

    Gillette, Shana Cecile

    In communications, a new approach to the study of online interaction has been suggested by social network analysts. Garton, Haythornthwaite, and Wellman (1997) have outlined the importance of using network analysis to study how media are interconnected with other social aspects of a media user's world. As applied here, this approach to communication when combined with recent network studies from the fields of education and rural development, provides a method for looking at the role of Internet-facilitated ties in the development of resource networks in the learning communities of young women from seven rural schools across the state of Washington. Twenty-six young women (ages 14-16) from diverse cultural and ethnic backgrounds (approximately half of the participants are Hispanic or Native American, the other half are White) participated in the research. Participants were selected because they shared a common educational orientation through Rural Girls in Science, a NSF-funded program at the Northwest Center for Research on Women at the University of Washington. As part of the school-based component of the Rural Girls in Science program, all 26 participants designed and conducted year-long, community-based research projects in science. Each school in the program was provided an Internet workstation for communication and research. Through the Internet, students could conceivably maintain distant ties with mentors and research scientists whom they met at summer camp as well as seek additional information resources. Toward the conclusion of the long-term research projects, each student participant was interviewed using a participatory form of network analysis that included a combined qualitative and quantitative approach. Given the small number of participants and schools in the sample, the results from the analysis can not be generalized to a larger population. However the study of the structure and composition of networks among individuals and school groups provided

  13. Productive Homologous and Non-homologous Recombination of Hepatitis C Virus in Cell Culture

    Science.gov (United States)

    Li, Yi-Ping; Mikkelsen, Lotte S.; Gottwein, Judith M.; Bukh, Jens

    2013-01-01

    Genetic recombination is an important mechanism for increasing diversity of RNA viruses, and constitutes a viral escape mechanism to host immune responses and to treatment with antiviral compounds. Although rare, epidemiologically important hepatitis C virus (HCV) recombinants have been reported. In addition, recombination is an important regulatory mechanism of cytopathogenicity for the related pestiviruses. Here we describe recombination of HCV RNA in cell culture leading to production of infectious virus. Initially, hepatoma cells were co-transfected with a replicating JFH1ΔE1E2 genome (genotype 2a) lacking functional envelope genes and strain J6 (2a), which has functional envelope genes but does not replicate in culture. After an initial decrease in the number of HCV positive cells, infection spread after 13–36 days. Sequencing of recovered viruses revealed non-homologous recombinants with J6 sequence from the 5′ end to the NS2–NS3 region followed by JFH1 sequence from Core to the 3′ end. These recombinants carried duplicated sequence of up to 2400 nucleotides. HCV replication was not required for recombination, as recombinants were observed in most experiments even when two replication incompetent genomes were co-transfected. Reverse genetic studies verified the viability of representative recombinants. After serial passage, subsequent recombination events reducing or eliminating the duplicated region were observed for some but not all recombinants. Furthermore, we found that inter-genotypic recombination could occur, but at a lower frequency than intra-genotypic recombination. Productive recombination of attenuated HCV genomes depended on expression of all HCV proteins and tolerated duplicated sequence. In general, no strong site specificity was observed. Non-homologous recombination was observed in most cases, while few homologous events were identified. A better understanding of HCV recombination could help identification of natural recombinants

  14. Productive homologous and non-homologous recombination of hepatitis C virus in cell culture

    DEFF Research Database (Denmark)

    Scheel, Troels K H; Galli, Andrea; Li, Yi-Ping

    2013-01-01

    . In addition, recombination is an important regulatory mechanism of cytopathogenicity for the related pestiviruses. Here we describe recombination of HCV RNA in cell culture leading to production of infectious virus. Initially, hepatoma cells were co-transfected with a replicating JFH1ΔE1E2 genome (genotype 2a......) lacking functional envelope genes and strain J6 (2a), which has functional envelope genes but does not replicate in culture. After an initial decrease in the number of HCV positive cells, infection spread after 13-36 days. Sequencing of recovered viruses revealed non-homologous recombinants with J6...

  15. The emotional responses of browsing Facebook: Happiness, envy, and the role of tie strength.

    Science.gov (United States)

    Lin, Ruoyun; Utz, Sonja

    2015-11-01

    On Facebook, users are exposed to posts from both strong and weak ties. Even though several studies have examined the emotional consequences of using Facebook, less attention has been paid to the role of tie strength. This paper aims to explore the emotional outcomes of reading a post on Facebook and examine the role of tie strength in predicting happiness and envy. Two studies - one correlational, based on a sample of 207 American participants and the other experimental, based on a sample of 194 German participants - were conducted in 2014. In Study 2, envy was further distinguished into benign and malicious envy. Based on a multi-method approach, the results showed that positive emotions are more prevalent than negative emotions while browsing Facebook. Moreover, tie strength is positively associated with the feeling of happiness and benign envy, whereas malicious envy is independent of tie strength after reading a (positive) post on Facebook.

  16. Influence of ties on the behavior of short reinforced concrete columns strengthened by external CFRP

    Directory of Open Access Journals (Sweden)

    Sarsam Kaiss

    2018-01-01

    Full Text Available An experimental study was carried out to investigate the behavior of normal strength reinforce concret (RC circular short column strengthned with “carbon fiber reinforced polymer (CFRP sheets”. Three series comprising totally of (15 specimens loaded until failure under concentric compresion load. Strengthening was varied by changing the number of CFRP strips, spacing and wrapping methods. The findings of this research can be summarized as follows: for the columns without CFRP, the influence of the tie spacing was significant: compared with 130 mm tie spacing, dropping the spacing to 100 mm and 70 mm increased the load carrying capacity by 18% and 26%, respectively. The columns with less internal confinement (lesser amount of ties were strengthened more significantly by the CFRP than the ones with greater amount of internal ties. As an example of the varying effectiveness of the fully wrapped CFRP, the column with ties at 130 mm was strengthened by 90% with the CFRP. In contrast, the ones with 70 mm spaced ties only increased in strength with CFRP by 66%. Compared with the control specimen (no CFRP, the same amount of CFRP when used as hoop strips led to more strengthening than using CFRP as a spiral strip- the former led to nearly 9% more strengthening than the latter in the case of 130 mm spaced internal steel ties. In the case of 100 mm internal steel ties, the difference (between the hoops & spiral CFRP strengthening is close to 4%. In contrast, there is no difference between the two methods of strengthening in the heavily tied columns (70 mm tied spacing.

  17. Detecting false positive sequence homology: a machine learning approach.

    Science.gov (United States)

    Fujimoto, M Stanley; Suvorov, Anton; Jensen, Nicholas O; Clement, Mark J; Bybee, Seth M

    2016-02-24

    Accurate detection of homologous relationships of biological sequences (DNA or amino acid) amongst organisms is an important and often difficult task that is essential to various evolutionary studies, ranging from building phylogenies to predicting functional gene annotations. There are many existing heuristic tools, most commonly based on bidirectional BLAST searches that are used to identify homologous genes and combine them into two fundamentally distinct classes: orthologs and paralogs. Due to only using heuristic filtering based on significance score cutoffs and having no cluster post-processing tools available, these methods can often produce multiple clusters constituting unrelated (non-homologous) sequences. Therefore sequencing data extracted from incomplete genome/transcriptome assemblies originated from low coverage sequencing or produced by de novo processes without a reference genome are susceptible to high false positive rates of homology detection. In this paper we develop biologically informative features that can be extracted from multiple sequence alignments of putative homologous genes (orthologs and paralogs) and further utilized in context of guided experimentation to verify false positive outcomes. We demonstrate that our machine learning method trained on both known homology clusters obtained from OrthoDB and randomly generated sequence alignments (non-homologs), successfully determines apparent false positives inferred by heuristic algorithms especially among proteomes recovered from low-coverage RNA-seq data. Almost ~42 % and ~25 % of predicted putative homologies by InParanoid and HaMStR respectively were classified as false positives on experimental data set. Our process increases the quality of output from other clustering algorithms by providing a novel post-processing method that is both fast and efficient at removing low quality clusters of putative homologous genes recovered by heuristic-based approaches.

  18. Exploring the significance of human mobility patterns in social link prediction

    KAUST Repository

    Alharbi, Basma Mohammed; Zhang, Xiangliang

    2014-01-01

    Link prediction is a fundamental task in social networks. Recently, emphasis has been placed on forecasting new social ties using user mobility patterns, e.g., investigating physical and semantic co-locations for new proximity measure. This paper

  19. Strut elaboration in strut-and-tie model

    Directory of Open Access Journals (Sweden)

    Mohammad PANJEHPOUR

    2012-12-01

    Full Text Available The Strut-and-Tie Model (STM has been incorporated into the codes and standards because of its consistency and rationality since last decade. However, it has encountered few challenges whilst its implementation. The effective compressive strength of strut has been a complex issue among researchers since emergence of STM. This review serves as a base for future developments of STM. It addresses several ways towards enhancing our understanding of strut performance in the STM. It also throws up questions for further investigation of effective compressive strength of strut in the STM. This review is confined to the evaluation of strut effectiveness factor based on the available codes and standards particularly AASHTO LRFD and ACI 318-08. According to the example given in this paper, there is sometimes a marked difference of approximately 50% between strut effectiveness factor recommended by AASHTO LRFD and ACI 318-08. More broadly, research is needed to determine which of the complicated strut effectiveness factor recommended by AASHTO LRFD and the simple one recommended by ACI 318-08 is optimum.

  20. Ties that bind: revisiting context, identity, and attitudes

    Directory of Open Access Journals (Sweden)

    James S. Krueger

    2015-07-01

    Full Text Available The article focuses on group-based features of issue publics and advances the concept of residual group saliency as a way to organize members of issue publics. We accord veterans exemplar or prototype status, and civilians as periphery members of this issue public. As issue public exemplars, veterans anchor the “right” attitudes and behaviors for the veteran issue public, and civilians, especially those with family ties to veterans, gravitate toward those exemplar attitudes. We argue that pressure to conform to these “right” attitudes among civilians who are connected to a veteran is greater when there are more veterans in their environment. However, veterans and civilians who are not connected to a veteran are not responsive to such contextual effects, the former because they are already exemplars, and the latter because there is no motivation to evaluate the self in relation to veterans. We test and find support for these claims using data from the 2010 Cooperative Congressional Election Study. We conclude with an evaluative discussion and suggestions for future research.

  1. Tying dark matter to baryons with self-interactions.

    Science.gov (United States)

    Kaplinghat, Manoj; Keeley, Ryan E; Linden, Tim; Yu, Hai-Bo

    2014-07-11

    Self-interacting dark matter (SIDM) models have been proposed to solve the small-scale issues with the collisionless cold dark matter paradigm. We derive equilibrium solutions in these SIDM models for the dark matter halo density profile including the gravitational potential of both baryons and dark matter. Self-interactions drive dark matter to be isothermal and this ties the core sizes and shapes of dark matter halos to the spatial distribution of the stars, a radical departure from previous expectations and from cold dark matter predictions. Compared to predictions of SIDM-only simulations, the core sizes are smaller and the core densities are higher, with the largest effects in baryon-dominated galaxies. As an example, we find a core size around 0.3 kpc for dark matter in the Milky Way, more than an order of magnitude smaller than the core size from SIDM-only simulations, which has important implications for indirect searches of SIDM candidates.

  2. Tie Points Extraction for SAR Images Based on Differential Constraints

    Science.gov (United States)

    Xiong, X.; Jin, G.; Xu, Q.; Zhang, H.

    2018-04-01

    Automatically extracting tie points (TPs) on large-size synthetic aperture radar (SAR) images is still challenging because the efficiency and correct ratio of the image matching need to be improved. This paper proposes an automatic TPs extraction method based on differential constraints for large-size SAR images obtained from approximately parallel tracks, between which the relative geometric distortions are small in azimuth direction and large in range direction. Image pyramids are built firstly, and then corresponding layers of pyramids are matched from the top to the bottom. In the process, the similarity is measured by the normalized cross correlation (NCC) algorithm, which is calculated from a rectangular window with the long side parallel to the azimuth direction. False matches are removed by the differential constrained random sample consensus (DC-RANSAC) algorithm, which appends strong constraints in azimuth direction and weak constraints in range direction. Matching points in the lower pyramid images are predicted with the local bilinear transformation model in range direction. Experiments performed on ENVISAT ASAR and Chinese airborne SAR images validated the efficiency, correct ratio and accuracy of the proposed method.

  3. TIE POINTS EXTRACTION FOR SAR IMAGES BASED ON DIFFERENTIAL CONSTRAINTS

    Directory of Open Access Journals (Sweden)

    X. Xiong

    2018-04-01

    Full Text Available Automatically extracting tie points (TPs on large-size synthetic aperture radar (SAR images is still challenging because the efficiency and correct ratio of the image matching need to be improved. This paper proposes an automatic TPs extraction method based on differential constraints for large-size SAR images obtained from approximately parallel tracks, between which the relative geometric distortions are small in azimuth direction and large in range direction. Image pyramids are built firstly, and then corresponding layers of pyramids are matched from the top to the bottom. In the process, the similarity is measured by the normalized cross correlation (NCC algorithm, which is calculated from a rectangular window with the long side parallel to the azimuth direction. False matches are removed by the differential constrained random sample consensus (DC-RANSAC algorithm, which appends strong constraints in azimuth direction and weak constraints in range direction. Matching points in the lower pyramid images are predicted with the local bilinear transformation model in range direction. Experiments performed on ENVISAT ASAR and Chinese airborne SAR images validated the efficiency, correct ratio and accuracy of the proposed method.

  4. Dzimuma stereotipizācija tiešsaistes laikrakstos

    OpenAIRE

    Tirzīte, Asne

    2015-01-01

    Pētnieciskā darba mērķis ir atrast un analizēt stereotipus britu tiešsaites avīžu The Guardian un Daily Mail rakstos par biznesu, lai uzzinātu no kādiem valodas elementiem sastāv stereotipu atspoguļojums un kā mediju diskursā tiek atspoguļotas dzimuma un profesionālās identitātes. Darba teorētiskā daļa apskata pašreizējā pētījuma metodi un iepriekšējo pētnieku darbus par šo tēmu. Izmantotā kvalitatīvā pētījuma metode ir Normana Fērklova (1992) trīsdimensionālais kritiskās diskursa analīzes mo...

  5. Social group utility maximization

    CERN Document Server

    Gong, Xiaowen; Yang, Lei; Zhang, Junshan

    2014-01-01

    This SpringerBrief explains how to leverage mobile users' social relationships to improve the interactions of mobile devices in mobile networks. It develops a social group utility maximization (SGUM) framework that captures diverse social ties of mobile users and diverse physical coupling of mobile devices. Key topics include random access control, power control, spectrum access, and location privacy.This brief also investigates SGUM-based power control game and random access control game, for which it establishes the socially-aware Nash equilibrium (SNE). It then examines the critical SGUM-b

  6. The K-homology of nets of C∗-algebras

    Science.gov (United States)

    Ruzzi, Giuseppe; Vasselli, Ezio

    2014-12-01

    Let X be a space, intended as a possibly curved space-time, and A a precosheaf of C∗-algebras on X. Motivated by algebraic quantum field theory, we study the Kasparov and Θ-summable K-homology of A interpreting them in terms of the holonomy equivariant K-homology of the associated C∗-dynamical system. This yields a characteristic class for K-homology cycles of A with values in the odd cohomology of X, that we interpret as a generalized statistical dimension.

  7. Can space ties on board GNSS satellites replace terrestrial ties in the implementation of Terrestrial Reference Frames?

    Science.gov (United States)

    Bruni, Sara; Zerbini, Susanna; Altamimi, Zuheir; Rebischung, Paul; Errico, Maddalena; Santi, Efisio

    2016-04-01

    SLR techniques via the so-called space ties, instead of relying on the terrestrial ties evaluated with ground measurement campaigns at co-located ITRF sites.

  8. Neural correlates of dynamically evolving interpersonal ties predict prosocial behavior

    NARCIS (Netherlands)

    J.J. Fahrenfort (Johannes J.); F.A.A.M. Winden, van (Frans); B. Pelloux (Benjamin); M. Stallen (Mirre); K.R. Ridderinkhof (Richard)

    2012-01-01

    textabstractThere is a growing interest for the determinants of human choice behavior in social settings. Upon initial contact, investment choices in social settings can be inherently risky, as the degree to which the other person will reciprocate is unknown. Nevertheless, people have been shown to

  9. Neural correlates of dynamically evolving interpersonal ties predict prosocial behavior

    NARCIS (Netherlands)

    Fahrenfort, J.J.; van Winden, F.A.A.M.; Pelloux, B.; Stallen, M.; Ridderinkhof, K.R.

    2012-01-01

    There is a growing interest for the determinants of human choice behavior in social settings. Upon initial contact, investment choices in social settings can be inherently risky, as the degree to which the other person will reciprocate is unknown. Nevertheless, people have been shown to exhibit

  10. Welfare assessment of dairy cows housed in a tie-stall system

    Directory of Open Access Journals (Sweden)

    Marija Vučemilo

    2012-03-01

    Full Text Available Welfare assessment methods and techniques developed as a result of great interest of scientific and consumer populations regarding the welfare of animals housed in farms. In view of the fact that welfare by definition includes both physical and mental health, the welfare quality assessment includes an extensive number of measures. Welfare assessment was performed in two stables in which cows are kept in tie-stall by using the specific method described in the Welfare Quality® Assessment Protocol for Cattle. The measures included body condition score, qualitative behaviour assessment and body hygiene. The welfare assessment confirmed the importance of quality housing for ensuring better performance from animals, thus also affecting their health and productivity. It also pointed out the necessity of freeing animals by providing them with the possibility of free movement, whereat they can exhibit their physiological behaviour. It is definitely important to continue research, expand the number of researched measures in order to confirm the most useful indicators for welfare assessment and to identify the factors that within the animals’ physical and social environment affect the increase of their welfare.

  11. High strength-of-ties and low mobility enable the evolution of third-party punishment

    Science.gov (United States)

    Roos, Patrick; Gelfand, Michele; Nau, Dana; Carr, Ryan

    2014-01-01

    As punishment can be essential to cooperation and norm maintenance but costly to the punisher, many evolutionary game-theoretic studies have explored how direct punishment can evolve in populations. Compared to direct punishment, in which an agent acts to punish another for an interaction in which both parties were involved, the evolution of third-party punishment (3PP) is even more puzzling, because the punishing agent itself was not involved in the original interaction. Despite significant empirical studies of 3PP, little is known about the conditions under which it can evolve. We find that punishment reputation is not, by itself, sufficient for the evolution of 3PP. Drawing on research streams in sociology and psychology, we implement a structured population model and show that high strength-of-ties and low mobility are critical for the evolution of responsible 3PP. Only in such settings of high social-structural constraint are punishers able to induce self-interested agents toward cooperation, making responsible 3PP ultimately beneficial to individuals as well as the collective. Our results illuminate the conditions under which 3PP is evolutionarily adaptive in populations. Responsible 3PP can evolve and induce cooperation in cases where other mechanisms alone fail to do so. PMID:24335985

  12. Homology of normal chains and cohomology of charges

    CERN Document Server

    Pauw, Th De; Pfeffer, W F

    2017-01-01

    The authors consider a category of pairs of compact metric spaces and Lipschitz maps where the pairs satisfy a linearly isoperimetric condition related to the solvability of the Plateau problem with partially free boundary. It includes properly all pairs of compact Lipschitz neighborhood retracts of a large class of Banach spaces. On this category the authors define homology and cohomology functors with real coefficients which satisfy the Eilenberg-Steenrod axioms, but reflect the metric properties of the underlying spaces. As an example they show that the zero-dimensional homology of a space in our category is trivial if and only if the space is path connected by arcs of finite length. The homology and cohomology of a pair are, respectively, locally convex and Banach spaces that are in duality. Ignoring the topological structures, the homology and cohomology extend to all pairs of compact metric spaces. For locally acyclic spaces, the authors establish a natural isomorphism between their cohomology and the �...

  13. Generalized local homology and cohomology for linearly compact modules

    International Nuclear Information System (INIS)

    Tran Tuan Nam

    2006-07-01

    We study generalized local homology for linearly compact modules. By duality, we get some properties of generalized local cohomology modules and extend well-known properties of local cohomology of A. Grothendieck. (author)

  14. On the homology and the cohomology of certain polycyclic groups

    International Nuclear Information System (INIS)

    Majumdar, S.

    1987-10-01

    The homology and the cohomology of infinite non-abelian split extensions of cyclic groups by cyclic groups have been computed through construction of nice free resolutions for these groups. (author). 16 refs

  15. Inhibitory Effect of Berberine on Zeste Homolog 2 (Ezh2 ...

    African Journals Online (AJOL)

    homolog 2 (Ezh2) expressions in KYSE450 human esophageal cancer cells. Methods: ... of the AXL receptor kinase. The results of ... effects of estrogen receptor antagonists on ..... protein EZH2 is involved in progression of prostate cancer.

  16. Faith, Social Activism and Politics : Role of Faith Based ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... the project methodology and findings will be used in similar explorations in Egypt, ... and religious organizations in the Lebanese social policies [Arabic language] ... There is no doubt that Canada is tying its future growth prospects to Asia.

  17. Learning from Low Income Market-driven Innovations and Social ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    A social enterprise is one that uses innovation, finance and business acumen in a ... their capacity for innovation and the performance of their business models. ... There is no doubt that Canada is tying its future growth prospects to Asia.

  18. Recovery From Radiation-induced Bone Marrow Damage by HSP25 Through Tie2 Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hae-June [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Kwon, Hee-Chung [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Chung, Hee-Yong [College of Medicine, Hanyang University, Seoul (Korea, Republic of); Lee, Yoon-Jin [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Lee, Yun-Sil, E-mail: yslee0425@ewha.ac.kr [College of Pharmacy and Division of Life and Pharmaceutical Sciences, Ewha Woman' s University, Seoul (Korea, Republic of)

    2012-09-01

    Purpose: Whole-body radiation therapy can cause severe injury to the hematopoietic system, and therefore it is necessary to identify a novel strategy for overcoming this injury. Methods and Materials: Mice were irradiated with 4.5 Gy after heat shock protein 25 (HSP25) gene transfer using an adenoviral vector. Then, peripheral blood cell counts, histopathological analysis, and Western blotting on bone marrow (BM) cells were performed. The interaction of HSP25 with Tie2 was investigated with mouse OP9 and human BM-derived mesenchymal stem cells to determine the mechanism of HSP25 in the hematopoietic system. Results: HSP25 transfer increased BM regeneration and reduced apoptosis following whole-body exposure to ionizing radiation (IR). The decrease in Tie2 protein expression that followed irradiation of the BM was blocked by HSP25 transfer, and Tie2-positive cells were more abundant among the BM cells of HSP25-transferred mice, even after IR exposure. Following systemic RNA interference of Tie2 before IR, HSP25-mediated radioprotective effects were partially blocked in both mice and cell line systems. Stability of Tie2 was increased by HSP25, a response mediated by the interaction of HSP25 with Tie2. IR-induced tyrosine phosphorylation of Tie2 was augmented by HSP25 overexpression; downstream events in the Tie2 signaling pathway, including phosphorylation of AKT and EKR1/2, were also activated. Conclusions: HSP25 protects against radiation-induced BM damage by interacting with and stabilizing Tie2. This may be a novel strategy for HSP25-mediated radioprotection in BM.

  19. Matrix factorizations and homological mirror symmetry on the torus

    International Nuclear Information System (INIS)

    Knapp, Johanna; Omer, Harun

    2007-01-01

    We consider matrix factorizations and homological mirror symmetry on the torus T 2 using a Landau-Ginzburg description. We identify the basic matrix factorizations of the Landau-Ginzburg superpotential and compute the full spectrum taking into account the explicit dependence on bulk and boundary moduli. We verify homological mirror symmetry by comparing three-point functions in the A-model and the B-model

  20. Regulation of homologous recombination at telomeres in budding yeast

    DEFF Research Database (Denmark)

    Eckert-Boulet, Nadine; Lisby, Michael

    2010-01-01

    Homologous recombination is suppressed at normal length telomere sequences. In contrast, telomere recombination is allowed when telomeres erode in the absence of telomerase activity or as a consequence of nucleolytic degradation or incomplete replication. Here, we review the mechanisms that contr...... that contribute to regulating mitotic homologous recombination at telomeres and the role of these mechanisms in signalling short telomeres in the budding yeast Saccharomyces cerevisiae....

  1. Zeroth Poisson Homology, Foliated Cohomology and Perfect Poisson Manifolds

    Science.gov (United States)

    Martínez-Torres, David; Miranda, Eva

    2018-01-01

    We prove that, for compact regular Poisson manifolds, the zeroth homology group is isomorphic to the top foliated cohomology group, and we give some applications. In particular, we show that, for regular unimodular Poisson manifolds, top Poisson and foliated cohomology groups are isomorphic. Inspired by the symplectic setting, we define what a perfect Poisson manifold is. We use these Poisson homology computations to provide families of perfect Poisson manifolds.

  2. Mobile communication and network privatism: A literature review of the implications for diverse, weak, and new ties

    Directory of Open Access Journals (Sweden)

    Scott W. Campbell

    2015-01-01

    Full Text Available Most of the research on the implications of mobile communication for social networks has focused on its uses and consequences in the intimate realm of close friends, family, and loved ones. A number of scholars have also become interested in ways that mobile communication helps and hinders the broader realm of network connectivity, including diverse, weak, and new ties. A collection of theoretical perspectives on mobile communication and diverse, weak, and new ties proposes that heightened connectivity in the intimate realm can come at the expense of being engaged more broadly – a scenario I characterize as network privatism. At the same time, the available empirical research in the literature tends to tell a different story, or rather stories. This analysis brings theory and empirical findings into closer conversation with one another by reviewing and synthesizing the literature in this area. Observed patterns in the literature offer new insight into questions of mobile communication and network privatism, while also pointing to opportunities for refinement of theory, analysis, and measurement as this line of inquiry further develops.

  3. Les maisons bâties au village d’origine dans les représentations des migrants roumains

    Directory of Open Access Journals (Sweden)

    Andra Larionescu

    2013-06-01

    Full Text Available Les maisons des migrants bâties dans le pays d’origine revêtent de significations différentes: certains migrants les perçoivent comme un moyen de valider leur statut social au sein de la communauté d’origine, tandis que d’autres les conçoivent comme un investissement ou comme une « sécurité » à la retraite, ou bien comme un abri en cas d’échec. Néanmoins, pour la majorité des migrants, la maison reste un « chez soi» lié soit au pays d’origine, soit au pays de destination, le sentiment d’appartenance étant déterminé par l’âge du sujet, le gendre, le niveau d’éducation, les liens familiaux, l’expérience de la migration et les caractéristiques du marché du travail. En utilisant un travail de terrain mené entre 2009 et 2011 dans le village de Marginea, au nord de la Roumanie, l’article examine les facteurs qui influent sur la sémantique de la maison bâtie au village d’origine.

  4. Mental health of sub-saharan african migrants: The gendered role of migration paths and transnational ties

    Directory of Open Access Journals (Sweden)

    Julie Pannetier

    2017-12-01

    Full Text Available In Europe, migrants are at higher risk of common mental disorders or psychological distress than are natives. Little is known regarding the social determinants of migrant mental health, particularly the roles played by migration conditions and transnational practices, which may manifest themselves in different ways for men and for women. The goal of this paper was to understand the gendered roles of migration paths and transnational ties in mental health among sub-Saharan African migrants residing in the Paris, France, metropolitan area. This study used data from the Parcours study conducted in 2012–2013, which employed a life-event approach to collect data from a representative sample of migrants who visited healthcare facilities (n = 2468. We measured anxiety and depressive symptoms at the time of data collection with the Patient Health Questionnaire-4 (PHQ-4. Reasons for migration, the living conditions in the host country and transnational ties after migration were taken into account by sex and after adjustment. Our study demonstrates that among sub-Saharan African migrants, mental health is related to the migratory path and the migrant’s situation in the host country but differently for women and men. Among women, anxiety and depressive symptoms were strongly related to having left one’s home country because of threats to one’s life. Among men, residing illegally in the host country was related to impaired mental health. For both women and men, cross-border separation from a child less than 18 years old was not independently associated with anxiety and depressive symptoms. In addition, social and emotional support from relatives and friends—both from the society of origin and of destination—were associated with lower anxiety and depressive symptoms. Migrant mental health may be impaired in the current context of anti-migrant policies and an anti-immigrant social environment in Europe.

  5. Goal specific social capital and job satisfaction Effects of different types of networks on instrumental and social aspects of work

    NARCIS (Netherlands)

    Flap, Henk; Völker, Beate

    2001-01-01

    This paper addresses the question “To what extent can job satisfaction be explained as the revenue of social capital?” By conceiving someone’s social network as social capital we specify conditions under which social ties do lead to job satisfaction. We inquire into the idea of goal specificity of

  6. IVF, same-sex couples and the value of biological ties

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2016-01-01

    Ought parents, in general, to value being biologically tied to their children? Is it important, in particular, that both parents be biologically tied to their children? I will address these fundamental questions by looking at a fairly new practice within IVF treatments, so-called IVF......-with-ROPA (Reception of Oocytes from Partner), which allows lesbian couples to 'share motherhood', with one partner providing the eggs while the other becomes pregnant. I believe that IVF-with-ROPA is, just like other IVF treatments, morally permissible, but here I argue that the increased biological ties which IVF...

  7. Hanging Together, Together Hung? Career Implications of Interpersonal Ties Between CEOs and Top Managers

    Directory of Open Access Journals (Sweden)

    Stefan Hilger

    2013-05-01

    Full Text Available Is it good or bad for senior executives to have strong interpersonal ties to the CEO? We argue that a strong relationship with the CEO raises the likelihood that a top manager stays in office or makes an upward career move when the CEO leaves office voluntarily. At the same time, such interpersonal ties also reinforce the negative spillover effects of a dismissal of the CEO on the career prospects of the manager concerned. Our empirical analysis lends support to both arguments. We contribute to managerial succession research by underlining the ambivalence of interpersonal ties within top management teams.

  8. Square and bow-tie configurations in the cyclic evasion problem

    Science.gov (United States)

    Arnold, M. D.; Golich, M.; Grim, A.; Vargas, L.; Zharnitsky, V.

    2017-05-01

    Cyclic evasion of four agents on the plane is considered. There are two stationary shapes of configurations: square and degenerate bow-tie. The bow-tie is asymptotically attracting while the square is of focus-center type. Normal form analysis shows that square is nonlinearly unstable. The stable manifold consists of parallelograms that all converge to the square configuration. Based on these observations and numerical simulations, it is conjectured that any non-parallelogram non-degenerate configuration converges to the bow-tie.

  9. 78 FR 57619 - Prestressed Concrete Steel Rail Tie Wire From Mexico, Thailand, and the People's Republic of...

    Science.gov (United States)

    2013-09-19

    ...] Prestressed Concrete Steel Rail Tie Wire From Mexico, Thailand, and the People's Republic of China... prestressed concrete steel rail tie wire from Mexico, Thailand, and the People's Republic of China. See Prestressed Concrete Steel Rail Tie Wire From Mexico, the People's Republic of China, and Thailand: Initiation...

  10. Between-group behaviour in health care: gaps, edges, boundaries, disconnections, weak ties, spaces and holes. A systematic review

    Directory of Open Access Journals (Sweden)

    Braithwaite Jeffrey

    2010-12-01

    Full Text Available Abstract Background Gaps are typically regarded as a problem to be solved. People are stimulated to close or plug them. Researchers are moved to fill deficits in the literature in order to realise a more complete knowledge base, health authorities want to bridge policy-practice disconnections, managers to secure resources to remedy shortfalls between poor and idealised care, and clinicians to provide services to patients across the divides of organisational silos. Despite practical and policy work in many health systems to bridge gaps, it is valuable to study research examining them for the insights provided. Structural holes, spaces between social clusters and weak or absent ties represent fissures in networks, located in less densely populated parts of otherwise closely connected social structures. Such gaps are useful as they illustrate how communication potentially breaks down or interactivity fails. This paper discusses empirical and theoretical work on this phenomenon with the aim of analysing a specific exemplar, the structures of silos within health care organisations. Methods The research literature on social spaces, holes, gaps, boundaries and edges was searched systematically, and separated into health [n = 13] and non-health [n = 55] samples. The health literature was reviewed and synthesised in order to understand the circumstances between stakeholders and stakeholder groups that both provide threats to networked interactions and opportunities to strengthen the fabric of organisational and institutional inter-relationships. Results The research examples illuminate various network structure characteristics and group interactions. They explicate a range of opportunities for improved social and professional relations that understanding structural holes, social spaces and absent ties affords. A principal finding is that these kinds of gaps illustrate the conditions under which connections are strained or have been severed, where the

  11. The strength of friendship ties in proximity sensor data.

    Directory of Open Access Journals (Sweden)

    Vedran Sekara

    Full Text Available Understanding how people interact and socialize is important in many contexts from disease control to urban planning. Datasets that capture this specific aspect of human life have increased in size and availability over the last few years. We have yet to understand, however, to what extent such electronic datasets may serve as a valid proxy for real life social interactions. For an observational dataset, gathered using mobile phones, we analyze the problem of identifying transient and non-important links, as well as how to highlight important social interactions. Applying the Bluetooth signal strength parameter to distinguish between observations, we demonstrate that weak links, compared to strong links, have a lower probability of being observed at later times, while such links-on average-also have lower link-weights and probability of sharing an online friendship. Further, the role of link-strength is investigated in relation to social network properties.

  12. The strength of friendship ties in proximity sensor data.

    Science.gov (United States)

    Sekara, Vedran; Lehmann, Sune

    2014-01-01

    Understanding how people interact and socialize is important in many contexts from disease control to urban planning. Datasets that capture this specific aspect of human life have increased in size and availability over the last few years. We have yet to understand, however, to what extent such electronic datasets may serve as a valid proxy for real life social interactions. For an observational dataset, gathered using mobile phones, we analyze the problem of identifying transient and non-important links, as well as how to highlight important social interactions. Applying the Bluetooth signal strength parameter to distinguish between observations, we demonstrate that weak links, compared to strong links, have a lower probability of being observed at later times, while such links-on average-also have lower link-weights and probability of sharing an online friendship. Further, the role of link-strength is investigated in relation to social network properties.

  13. Moving with the Military: Race, Class, and Gender Differences in the Employment Consequences of Tied Migration

    National Research Council Canada - National Science Library

    Cooney, Richard

    2003-01-01

    .... Previous research demonstrates negative employment and earnings consequences for tied migrants, but little is known about how the impact of such mobility differs by the gender, race, and class of the trailing spouse. The U.S...

  14. The effects of emitter-tied field plates on lateral PNP ionizing radiation response

    International Nuclear Information System (INIS)

    Barnaby, H.J.; Schrimpf, R.D.; Cirba, C.R.; Pease, R.L.; Fleetwood, D.M.; Kosier, S.L.

    1998-03-01

    Radiation response comparisons of lateral PNP bipolar technologies reveal that device hardening may be achieved by extending the emitter contact over the active base. The emitter-tied field plate suppresses recombination of carriers with interface traps

  15. ParTIES: a toolbox for Paramecium interspersed DNA elimination studies.

    Science.gov (United States)

    Denby Wilkes, Cyril; Arnaiz, Olivier; Sperling, Linda

    2016-02-15

    Developmental DNA elimination occurs in a wide variety of multicellular organisms, but ciliates are the only single-celled eukaryotes in which this phenomenon has been reported. Despite considerable interest in ciliates as models for DNA elimination, no standard methods for identification and characterization of the eliminated sequences are currently available. We present the Paramecium Toolbox for Interspersed DNA Elimination Studies (ParTIES), designed for Paramecium species, that (i) identifies eliminated sequences, (ii) measures their presence in a sequencing sample and (iii) detects rare elimination polymorphisms. ParTIES is multi-threaded Perl software available at https://github.com/oarnaiz/ParTIES. ParTIES is distributed under the GNU General Public Licence v3. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  16. One long tie bar broken after 3 days because of hydrogen contamination.

    CERN Multimedia

    H. Gerwig

    2000-01-01

    The tie bars have been produced with a high yield strength. As known for these type of high strength bolts, and hydrogen contamination during manufacture or heat treatment could lead to rupture under stress after several days.

  17. Multi-area economic dispatch with tie-line constraints employing ...

    African Journals Online (AJOL)

    user

    The economic dispatch problem is frequently solved without considering ... programming algorithm was proposed for the MAED solution with tie-line constraints ..... are the difference between two randomly chosen parameter vectors, a concept.

  18. Fiber Optic Tamper Indicating Enclosure (TIE); A Case Study in Authentication

    Energy Technology Data Exchange (ETDEWEB)

    Anheier, Norman C.; Benz, Jacob M.; Tanner, Jennifer E.; Westman, Matthew P.

    2015-07-15

    A robust fiber optic-based tamper-indicating enclosure (TIE) has been developed by PNNL through funding by the National Nuclear Security Administration Office of Nuclear Verification over the past few years. The objective of this work is to allow monitors to have confidence in both the authenticity and integrity of the TIE and the monitoring equipment inside, throughout the time it may be located at a host facility. Incorporating authentication features into the design were the focus of fiscal year 2014 development efforts. Throughout the development process, modifications have been made to the physical TIE design based on lessons learned via exercises and expert elicitation. The end result is a robust and passive TIE which can be utilized to protect monitoring party equipment left in a host facility.

  19. Statistical Models for Social Networks

    NARCIS (Netherlands)

    Snijders, Tom A. B.; Cook, KS; Massey, DS

    2011-01-01

    Statistical models for social networks as dependent variables must represent the typical network dependencies between tie variables such as reciprocity, homophily, transitivity, etc. This review first treats models for single (cross-sectionally observed) networks and then for network dynamics. For

  20. Ties that bind: multiple relationships between clinical researchers and the pharmaceutical industry.

    Science.gov (United States)

    Henry, David; Doran, Evan; Kerridge, Ian; Hill, Suzanne; McNeill, Paul M; Day, Richard

    2005-11-28

    It is believed that pharmaceutical industry sponsorship of clinical research leads to the development of multiple ties between clinicians and the pharmaceutical industry. To quantify this relationship we conducted a survey of medical specialists listed in the Medical Directory of Australia in 2002 and 2003. A questionnaire was mailed that elicited information about all aspects of research relationships between clinicians and pharmaceutical companies. The odds of reporting multiple additional ties (financial and professional) with pharmaceutical companies by clinicians who had an active research relationship were compared with those who did not. All clinicians who returned a completed questionnaire about their research activities were included in the study. A questionnaire was mailed to 2120 medical specialists; 823 (39%) responded. Of these, 338 (41%) reported involvement in industry-sponsored research in the previous year. They were more likely than others to have been offered industry-sponsored items or activities valued at more than 500 AU dollars (>382 US dollars; odds ratio [OR], 3.5; 95% confidence interval [CI], 2.6-4.7) and support for attending international conferences (OR, 5.4; 95% CI, 3.9-7.4). The strongest associations were seen for acting as a paid consultant to industry (OR, 9.0; 95% CI, 3.9-20.4) and for membership on advisory boards (OR, 6.9; 95% CI, 5.1-9.6). There was a strong relationship between research collaboration and accumulation of industry ties. For 1 additional tie the OR was 2.2 (95% CI, 1.2-3.8) and rose to 6.3 (95% CI, 3.5-11.1) with 3 ties and 41.8 (95% CI, 14.5-143.4) with 6 or more ties. Medical specialists who have research relationships with the pharmaceutical industry are much more likely to have multiple additional ties than those who do not have research relationships. Institutional review should discourage clinical researchers from developing multiple ties.

  1. Reducing Electromagnetic Interference in a Grid Tied Single Phase Power Inverter

    Science.gov (United States)

    2016-09-01

    With the growing demand for a reliable electrical grid, backup power supplies and energy management systems are a necessity. Systems such as server...ELECTROMAGNETIC INTERFERENCE IN A GRID TIED SINGLE PHASE POWER INVERTER by Jason Hassan Valiani September 2016 Thesis Advisor: Giovanna Oriti...3. REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE REDUCING ELECTROMAGNETIC INTERFERENCE IN A GRID TIED SINGLE PHASE POWER

  2. Division of tongue tie: review of practice through a tertiary paediatric otorhinolaryngology service.

    LENUS (Irish Health Repository)

    Glynn, R W

    2012-10-01

    Recent NICE guidance declared that evidence regarding surgical division of tongue tie was adequate to support the use of the procedure, provided that normal arrangements are in place for consent, audit and clinical governance. This work aimed to carry out a retrospective review of those patients who have previously undergone tongue tie division through a tertiary paediatric otorhinolaryngology service. We further aimed to identify the referral patterns, indications for, and outcomes following, division.

  3. Identification of proangiogenic TIE2-expressing monocytes (TEMs) in human peripheral blood and cancer

    OpenAIRE

    Venneri, Mary Anna; De Palma, Michele; Ponzoni, Maurilio; Pucci, Ferdinando; Scielzo, Cristina; Zonari, Erika; Mazzieri, Roberta; Doglioni, Claudio; Naldini, Luigi

    2007-01-01

    Tumor-infiltrating myeloid cells, including tumor-associated macrophages (TAMs), have been implicated in tumor progression. We recently described a lineage of mouse monocytes characterized by expression of the Tie2 angiopoietin receptor and required for the vascularization and growth of several tumor models. Here, we report that TIE2 expression in human blood identifies a subset of monocytes distinct from classical inflammatory monocytes and comprised within the less abundant "resident" popul...

  4. Evaluation of Shear Tie Connectors for Use in Insulated Concrete Sandwich Panels

    Science.gov (United States)

    2009-12-01

    stainless steel, galvanized carbon steel, carbon fiber reinforced polymers (CFRP), glass fiber reinforced polymer (GFRP), and basalt fiber reinforced polymer...Glass Fiber Reinforced Polymer (GFRP) Delta Tie produced by Dayton Superior; • (B) THERMOMASS® composite GFRP pins; • (C) THERMOMASS® non-composite...GFRP pins; • (D) Altus Group CFRP Grid; • (E) Universal Building products GFRP Teplo Tie; and • (F) Universal Building products Basalt FRP

  5. Ipsilateral deficits in 1-handed shoe tying after left or right hemisphere stroke.

    Science.gov (United States)

    Poole, Janet L; Sadek, Joseph; Haaland, Kathleen Y

    2009-10-01

    Poole JL, Sadek J, Haaland KY. Ipsilateral deficits in 1-handed shoe tying after left or right hemisphere stroke. To examine 1-handed shoe tying performance and whether cognitive deficits more associated with left or right hemisphere damage differentially affect it after unilateral stroke. Observational cohort comparing ipsilesional shoe tying, spatial and language skills, and limb praxis. Primary care Veterans Affairs and private medical center. Not applicable. Volunteer right-handed sample of adults with left or right hemisphere damage and healthy demographically matched adults. The number of correct trials and the total time to complete 10 trials tying a shoe using the 1-handed method. Both stroke groups had fewer correct trials and were significantly slower tying the shoe than the control group. Spatial skills predicted accuracy and speed after right hemisphere damage. After left hemisphere damage, accuracy was predicted by spatial skills and limb praxis, while speed was predicted by limb praxis only. Ipsilesional shoe tying is similarly impaired after left or right hemisphere damage, but for different reasons. Spatial deficits had a greater influence after right hemisphere damage, and limb apraxia had a greater influence after left hemisphere damage. Language deficits did not affect performance, indicating that aphasia does not preclude using this therapy approach. These results suggest that rehabilitation professionals should consider assessment of limb apraxia and ipsilesional skill training in the performance of everyday tasks.

  6. Relationships between authorship contributions and authors' industry financial ties among oncology clinical trials.

    Science.gov (United States)

    Rose, Susannah L; Krzyzanowska, Monika K; Joffe, Steven

    2010-03-10

    PURPOSE To test the hypothesis that authors who play key scientific roles in oncology clinical trials, and who therefore have increased influence over the design, analysis, interpretation or reporting of trials, are more likely than those who do not play such roles to have financial ties to industry. METHODS Data were abstracted from all trials (n = 235) of drugs or biologic agents published in the Journal of Clinical Oncology between January 1, 2006 and June 30, 2007. Article-level data included sponsorship, age group (adult v pediatric), phase, single versus multicenter, country (United States v other), and number of authors. Author-level data (n = 2,927) included financial ties (eg, employment, consulting) and performance of key scientific roles (ie, conception/design, analysis/interpretation, or manuscript writing). Associations between performance of key roles and financial ties, adjusting for article-level covariates, were examined using generalized linear mixed models. Results One thousand eight hundred eighty-one authors (64%) reported performing at least one key role, and 842 authors (29%) reported at least one financial tie. Authors who reported performing a key role were more likely than other authors to report financial ties to industry (adjusted odds ratio [OR], 4.3; 99% CI, 3.0 to 6.0; P analysis, and interpretation, or reporting of oncology clinical trials are more likely than authors who do not perform such roles to have financial ties to industry.

  7. [Medical equipment companies and their ties with technology development centers in Mexico].

    Science.gov (United States)

    Hernández, B; Arredondo, A; Cruz, C; Sánchez, E; Damián, T

    1993-10-01

    The purpose of this study was to determine the characteristics of the companies that produce, distribute, and service medical equipment in Mexico and the factors related to whether or not they had established ties with research and technology development centers. The data analyzed came from a survey of such companies carried out in Mexico City and environs in 1989. The information was updated in 1991. Multivariate analyses were carried out in order to identify the characteristics of companies that had established ties or wished to do so and the areas of interest of those companies. Of 208 companies surveyed, only 23% had ties with research centers. The companies that had such ties or were interested in establishing them tended to invest in research and to have made plans for expansion. The establishment of ties appeared to be a two-way process, with positive consequences for the companies involved, the research centers, and the health sector. It was concluded that it would be advantageous to design programs to promote ties with companies having the characteristics mentioned.

  8. Multipronged regulatory functions of a novel endonuclease (TieA) from Helicobacter pylori.

    Science.gov (United States)

    Devi, Savita; Ansari, Suhail A; Tenguria, Shivendra; Kumar, Naveen; Ahmed, Niyaz

    2016-11-02

    Helicobacter pylori portrays a classical paradigm of persistent bacterial infections. A well balanced homeostasis of bacterial effector functions and host responses is purported to be the key in achieving long term colonization in specific hosts. H. pylori nucleases have been shown to assist in natural transformation, but their role in virulence and colonization remains elusive. Therefore, it is imperative to understand the involvement of these nucleases in the pathogenesis of H. pylori Here, we report the multifaceted role of a TNFR-1 interacting endonuclease A (TieA) from H. pylori. tieA expression is differentially regulated in response to environmental stress and post adherence to gastric epithelial cells. Studies with isogenic knockouts of tieA revealed it to be a secretory protein which translocates into the host gastric epithelial cells independent of a type IV secretion system, gets phosphorylated by DNA-PK kinase and auto-phosphorylates as serine kinase. Furthermore, TieA binds to and cleaves DNA in a non-specific manner and promotes Fas mediated apoptosis in AGS cells. Additionally, TieA induced pro-inflammatory cytokine secretion via activation of transcription factor AP-1 and signaled through MAP kinase pathway. Collectively, TieA with its multipronged and moonlighting functions could facilitate H. pylori in maintaining a balance of bacterial adaptation, and elimination by the host responses. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  9. Multiscale analysis of nonlinear systems using computational homology

    Energy Technology Data Exchange (ETDEWEB)

    Konstantin Mischaikow; Michael Schatz; William Kalies; Thomas Wanner

    2010-05-24

    This is a collaborative project between the principal investigators. However, as is to be expected, different PIs have greater focus on different aspects of the project. This report lists these major directions of research which were pursued during the funding period: (1) Computational Homology in Fluids - For the computational homology effort in thermal convection, the focus of the work during the first two years of the funding period included: (1) A clear demonstration that homology can sensitively detect the presence or absence of an important flow symmetry, (2) An investigation of homology as a probe for flow dynamics, and (3) The construction of a new convection apparatus for probing the effects of large-aspect-ratio. (2) Computational Homology in Cardiac Dynamics - We have initiated an effort to test the use of homology in characterizing data from both laboratory experiments and numerical simulations of arrhythmia in the heart. Recently, the use of high speed, high sensitivity digital imaging in conjunction with voltage sensitive fluorescent dyes has enabled researchers to visualize electrical activity on the surface of cardiac tissue, both in vitro and in vivo. (3) Magnetohydrodynamics - A new research direction is to use computational homology to analyze results of large scale simulations of 2D turbulence in the presence of magnetic fields. Such simulations are relevant to the dynamics of black hole accretion disks. The complex flow patterns from simulations exhibit strong qualitative changes as a function of magnetic field strength. Efforts to characterize the pattern changes using Fourier methods and wavelet analysis have been unsuccessful. (4) Granular Flow - two experts in the area of granular media are studying 2D model experiments of earthquake dynamics where the stress fields can be measured; these stress fields from complex patterns of 'force chains' that may be amenable to analysis using computational homology. (5) Microstructure

  10. Multiscale analysis of nonlinear systems using computational homology

    Energy Technology Data Exchange (ETDEWEB)

    Konstantin Mischaikow, Rutgers University/Georgia Institute of Technology, Michael Schatz, Georgia Institute of Technology, William Kalies, Florida Atlantic University, Thomas Wanner,George Mason University

    2010-05-19

    This is a collaborative project between the principal investigators. However, as is to be expected, different PIs have greater focus on different aspects of the project. This report lists these major directions of research which were pursued during the funding period: (1) Computational Homology in Fluids - For the computational homology effort in thermal convection, the focus of the work during the first two years of the funding period included: (1) A clear demonstration that homology can sensitively detect the presence or absence of an important flow symmetry, (2) An investigation of homology as a probe for flow dynamics, and (3) The construction of a new convection apparatus for probing the effects of large-aspect-ratio. (2) Computational Homology in Cardiac Dynamics - We have initiated an effort to test the use of homology in characterizing data from both laboratory experiments and numerical simulations of arrhythmia in the heart. Recently, the use of high speed, high sensitivity digital imaging in conjunction with voltage sensitive fluorescent dyes has enabled researchers to visualize electrical activity on the surface of cardiac tissue, both in vitro and in vivo. (3) Magnetohydrodynamics - A new research direction is to use computational homology to analyze results of large scale simulations of 2D turbulence in the presence of magnetic fields. Such simulations are relevant to the dynamics of black hole accretion disks. The complex flow patterns from simulations exhibit strong qualitative changes as a function of magnetic field strength. Efforts to characterize the pattern changes using Fourier methods and wavelet analysis have been unsuccessful. (4) Granular Flow - two experts in the area of granular media are studying 2D model experiments of earthquake dynamics where the stress fields can be measured; these stress fields from complex patterns of 'force chains' that may be amenable to analysis using computational homology. (5) Microstructure

  11. RPA homologs and ssDNA processing during meiotic recombination.

    Science.gov (United States)

    Ribeiro, Jonathan; Abby, Emilie; Livera, Gabriel; Martini, Emmanuelle

    2016-06-01

    Meiotic homologous recombination is a specialized process that involves homologous chromosome pairing and strand exchange to guarantee proper chromosome segregation and genetic diversity. The formation and repair of DNA double-strand breaks (DSBs) during meiotic recombination differs from those during mitotic recombination in that the homologous chromosome rather than the sister chromatid is the preferred repair template. The processing of single-stranded DNA (ssDNA) formed on intermediate recombination structures is central to driving the specific outcomes of DSB repair during meiosis. Replication protein A (RPA) is the main ssDNA-binding protein complex involved in DNA metabolism. However, the existence of RPA orthologs in plants and the recent discovery of meiosis specific with OB domains (MEIOB), a widely conserved meiosis-specific RPA1 paralog, strongly suggest that multiple RPA complexes evolved and specialized to subdivide their roles during DNA metabolism. Here we review ssDNA formation and maturation during mitotic and meiotic recombination underlying the meiotic specific features. We describe and discuss the existence and properties of MEIOB and multiple RPA subunits in plants and highlight how they can provide meiosis-specific fates to ssDNA processing during homologous recombination. Understanding the functions of these RPA homologs and how they interact with the canonical RPA subunits is of major interest in the fields of meiosis and DNA repair.

  12. The OGCleaner: filtering false-positive homology clusters.

    Science.gov (United States)

    Fujimoto, M Stanley; Suvorov, Anton; Jensen, Nicholas O; Clement, Mark J; Snell, Quinn; Bybee, Seth M

    2017-01-01

    Detecting homologous sequences in organisms is an essential step in protein structure and function prediction, gene annotation and phylogenetic tree construction. Heuristic methods are often employed for quality control of putative homology clusters. These heuristics, however, usually only apply to pairwise sequence comparison and do not examine clusters as a whole. We present the Orthology Group Cleaner (the OGCleaner), a tool designed for filtering putative orthology groups as homology or non-homology clusters by considering all sequences in a cluster. The OGCleaner relies on high-quality orthologous groups identified in OrthoDB to train machine learning algorithms that are able to distinguish between true-positive and false-positive homology groups. This package aims to improve the quality of phylogenetic tree construction especially in instances of lower-quality transcriptome assemblies. https://github.com/byucsl/ogcleaner CONTACT: sfujimoto@gmail.comSupplementary information: Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  13. Primary homologies of the circumorbital bones of snakes.

    Science.gov (United States)

    Palci, Alessandro; Caldwell, Michael W

    2013-09-01

    Some snakes have two circumorbital ossifications that in the current literature are usually referred to as the postorbital and supraorbital. We review the arguments that have been proposed to justify this interpretation and provide counter-arguments that reject those conjectures of primary homology based on the observation of 32 species of lizards and 81 species of snakes (both extant and fossil). We present similarity arguments, both topological and structural, for reinterpretation of the primary homologies of the dorsal and posterior orbital ossifications of snakes. Applying the test of similarity, we conclude that the posterior orbital ossification of snakes is topologically consistent as the homolog of the lacertilian jugal, and that the dorsal orbital ossification present in some snakes (e.g., pythons, Loxocemus, and Calabaria) is the homolog of the lacertilian postfrontal. We therefore propose that the terms postorbital and supraorbital should be abandoned as reference language for the circumorbital bones of snakes, and be replaced with the terms jugal and postfrontal, respectively. The primary homology claim for the snake "postorbital" fails the test of similarity, while the term "supraorbital" is an unnecessary and inaccurate application of the concept of a neomorphic ossification, for an element that passes the test of similarity as a postfrontal. This reinterpretation of the circumorbital bones of snakes is bound to have important repercussions for future phylogenetic analyses and consequently for our understanding of the origin and evolution of snakes. Copyright © 2013 Wiley Periodicals, Inc.

  14. Goal specific social capital and job satisfaction Effects of different types of networks on instrumental and social aspects of work

    OpenAIRE

    Flap, Henk; Völker, Beate

    2001-01-01

    This paper addresses the question “To what extent can job satisfaction be explained as the revenue of social capital?” By conceiving someone’s social network as social capital we specify conditions under which social ties do lead to job satisfaction. We inquire into the idea of goal specificity of social capital, which implies that a network with a given structure and content will have different impacts on various aspects of job satisfaction. If the content of the ties and the structure of th...

  15. [Construction of recombinant lentiviral vector of Tie2-RNAi and its influence on malignant melanoma cells in vitro].

    Science.gov (United States)

    Shan, Xiu-ying; Liu, Zhao-liang; Wang, Biao; Guo, Guo-xiang; Wang, Mei-shui; Zhuang, Fu-lian; Cai, Chuan-shu; Zhang, Ming-feng; Zhang, Yan-ding

    2011-07-01

    To construct lentivector carrying Tie2-Small interfering RNA (SiRNA), so as to study its influence on malignant melanoma cells. Recombinant plasmid pSilencer 1.0-U6-Tie2-siRNA and plasmid pNL-EGFP were digested with XbaI, ligated a target lentiviral transfer plasmid of pNL-EGFP-U6-Tie2-I or pNL-EGFP-U6-Tie2-II, and then the electrophoresis clones was sequenced. Plasmids of pNL-EGFP-U6-Tie2-I and pNL-EGFP-U6-Tie2-II were constructed and combined with pVSVG and pHelper, respectively, to constitute lentiviral vector system of three plasmids. The Lentiviral vector system was transfected into 293T cell to produce pNL-EGFP-U6-Tie2- I and pNL-EGFP-U6-Tie2-II lentivirus. Then the supernatant was collected to determine the titer. Malignant melanoma cells were infected by both lentiviruses and identified by Realtime RT-PCR to assess inhibitory efficiency. The recombinant lentiviral vectors of Tie2-RNAi were constructed successfully which were analyzed with restriction enzyme digestion and identified by sequencing. And the titer of lentiviral vector was 8.8 x 10(3)/ml, which was determined by 293T cell. The results of Realtime RT-PCR demonstrated that the lentiviral vectors of Tie2-RNAi could infect malignant melanoma cells and inhibit the expression of Tie2 genes in malignant melanoma cells (P0.05) between the two lentiviral vectors of Tie2-RNAi. Lentivector carrying Tie2-SiRNA can be constructed successfully and inhibit the expression of Tie2 gene in vitro significantly. The study will supply the theory basis for the further research on the inhibition of tumor growth in vivo.

  16. 'Ties that Bind and Differences that Divide': Exploring the ...

    African Journals Online (AJOL)

    This article investigates the resurgence of ethno-cultural identity in contemporary Nigeria. The article shows that contestations associated with ethno-cultural identity are not recent, but date back to the creation of the modern state called Nigeria. The article also demonstrates how colonialism fostered various social, ...

  17. Reconnecting with the past on social network sites

    DEFF Research Database (Denmark)

    Shklovski, Irina

    we do not know why people seek out such ties and whether they benefit from them. This paper presents findings from a qualitative study of how people in Russia and Kazakhstan used SNSs for communication and relational maintenance. For many of the participants SNSs had offered an opportunity...... for reconnection with lapsed ties that brought about deeply emotional experiences of nostalgic remembrances and intimate exchanges of current status. In this process of reconnecting, they established connections not only with each other but also with a kind of past that was long gone. These ties were not expected...... to function as social resources or as active providers of support. In many ways, these ties explicitly lacked a purpose beyond emotional remembrance, as they were rarely re-integrated into daily life. Nevertheless, these ties remained connections to a past even as they at times became digital connections...

  18. Financial ties of principal investigators and randomized controlled trial outcomes: cross sectional study.

    Science.gov (United States)

    Ahn, Rosa; Woodbridge, Alexandra; Abraham, Ann; Saba, Susan; Korenstein, Deborah; Madden, Erin; Boscardin, W John; Keyhani, Salomeh

    2017-01-17

     To examine the association between the presence of individual principal investigators' financial ties to the manufacturer of the study drug and the trial's outcomes after accounting for source of research funding.  Cross sectional study of randomized controlled trials (RCTs).  Studies published in "core clinical" journals, as identified by Medline, between 1 January 2013 and 31 December 2013.  Random sample of RCTs focused on drug efficacy.  Association between financial ties of principal investigators and study outcome.  A total of 190 papers describing 195 studies met inclusion criteria. Financial ties between principal investigators and the pharmaceutical industry were present in 132 (67.7%) studies. Of 397 principal investigators, 231 (58%) had financial ties and 166 (42%) did not. Of all principal investigators, 156 (39%) reported advisor/consultancy payments, 81 (20%) reported speakers' fees, 81 (20%) reported unspecified financial ties, 52 (13%) reported honorariums, 52 (13%) reported employee relationships, 52 (13%) reported travel fees, 41 (10%) reported stock ownership, and 20 (5%) reported having a patent related to the study drug. The prevalence of financial ties of principal investigators was 76% (103/136) among positive studies and 49% (29/59) among negative studies. In unadjusted analyses, the presence of a financial tie was associated with a positive study outcome (odds ratio 3.23, 95% confidence interval 1.7 to 6.1). In the primary multivariate analysis, a financial tie was significantly associated with positive RCT outcome after adjustment for the study funding source (odds ratio 3.57 (1.7 to 7.7). The secondary analysis controlled for additional RCT characteristics such as study phase, sample size, country of first authors, specialty, trial registration, study design, type of analysis, comparator, and outcome measure. These characteristics did not appreciably affect the relation between financial ties and study outcomes (odds ratio 3.37, 1

  19. [Analysis of DNA-DNA homologies in obligate methylotrophic bacteria].

    Science.gov (United States)

    Doronina, N V; Govorukhina, N I; Lysenko, A M; Trotsenko, Iu A

    1988-01-01

    The genotypic affinity of 19 bacterial strains obligately dependent on methanol or methylamine as carbon and energy sources was studied by techniques of molecular DNA hybridization. The high homology level (35-88%) between motile strain Methylophilus methanolovorus V-1447D and nonmotile strain Methylobacillus sp. VSB-792 as well as other motile strains (Pseudomonas methanolica ATCC 21704, Methylomonas methanolica NRRL 5458, Pseudomonas sp. W6, strain A3) indicates that all of them belong to one genus. Rather high level of homology (62-63%) was found between Methylobacillus glycogenes ATCC 29475 and Pseudomonas insueta ATCC 21276 and strain G-10. The motile strain Methylophilus methylotrophus NCIB 10515 has a low homology (below 20%) to other of the studied obligate methylobacteria. Therefore, at least two genetically different genera of obligate methylobacteria can be distinguished, namely Methylophilus and Methylobacillus, the latter being represented by both motile and nonmotile forms.

  20. Induction of intrachromosomal homologous recombination in whole plants

    International Nuclear Information System (INIS)

    Puchta, H.; Swoboda, P.; Hohn, B.

    1995-01-01

    The influence of different factors on frequencies of intrachromosomal homologous recombination in whole Arabidopsis thaliana and tobacco plants was analyzed using a disrupted β-glucuronidase marker gene. Recombination frequencies were enhanced several fold by DNA damaging agents like UV-light or MMS (methyl methanesulfonate). Applying 3-methoxybenzamide (3-MB), an inhibitor of poly(ADP)ribose polymerase (PARP), an enzyme that is postulated to be involved in DNA repair, enhanced homologous recombination frequencies strongly. These findings indicate that homologous recombination is involved in DNA repair and can (at least partially) compensate for other DNA repair pathways. Indications that recombination in plants can be induced by environmental stress factors that are not likely to be involved in DNA metabolism were also found; Arabidopsis plants growing in a medium containing 0.1 M NaCl exhibited elevated recombination frequencies. The possible general effects of ‘environmental’ challenges on genome flexibility are discussed. (author)

  1. Khovanov homology for virtual knots with arbitrary coefficients

    International Nuclear Information System (INIS)

    Manturov, Vassily O

    2007-01-01

    The Khovanov homology theory over an arbitrary coefficient ring is extended to the case of virtual knots. We introduce a complex which is well-defined in the virtual case and is homotopy equivalent to the original Khovanov complex in the classical case. Unlike Khovanov's original construction, our definition of the complex does not use any additional prescription of signs to the edges of a cube. Moreover, our method enables us to construct a Khovanov homology theory for 'twisted virtual knots' in the sense of Bourgoin and Viro (including knots in three-dimensional projective space). We generalize a number of results of Khovanov homology theory (the Wehrli complex, minimality problems, Frobenius extensions) to virtual knots with non-orientable atoms

  2. Homology groups for particles on one-connected graphs

    Science.gov (United States)

    MaciÄ Żek, Tomasz; Sawicki, Adam

    2017-06-01

    We present a mathematical framework for describing the topology of configuration spaces for particles on one-connected graphs. In particular, we compute the homology groups over integers for different classes of one-connected graphs. Our approach is based on some fundamental combinatorial properties of the configuration spaces, Mayer-Vietoris sequences for different parts of configuration spaces, and some limited use of discrete Morse theory. As one of the results, we derive the closed-form formulae for ranks of the homology groups for indistinguishable particles on tree graphs. We also give a detailed discussion of the second homology group of the configuration space of both distinguishable and indistinguishable particles. Our motivation is the search for new kinds of quantum statistics.

  3. Ties that bind: implications of social support for rural, partnered African American women's health functioning.

    Science.gov (United States)

    Black, Angela R; Cook, Jennifer L; Murry, Velma McBride; Cutrona, Carolyn E

    2005-01-01

    Ecological theory was used to explore the pathways through which intimate relationship quality influenced health functioning among rural, partnered African American women. Structural equation modeling was used to analyze data from 349 women in Georgia and Iowa. Women's intimate relationship quality was positively associated with their psychological and physical health functioning. Support from community residents moderated this link, which was strongest for women who felt most connected with their neighbors and for women who believed their neighborhood to have a sense of communal responsibility. Future research should identify other factors salient to health functioning among members of this population.

  4. Social Capital and the Trade Unions: Reciprocity, or Understanding the Ties that Bind Us?

    Science.gov (United States)

    Whaites, Michael

    2005-01-01

    Australia once enjoyed the highest union density in the world but is now facing a "crisis of membership". Trade union membership and density have been in decline in Australia since the late 1970s with a 50 percent decrease in density since 1990. The Australian Bureau of Statistics currently puts trade union density at around 25 percent…

  5. Gift Giving in Hong Kong and the Continuum of Social Ties.

    OpenAIRE

    Joy, Annamma

    2001-01-01

    This article explores gift-giving practices using data collected through interviews in Hong Kong. I argue that Chinese culture promotes the familial over the private self and that the attainment of family-oriented goals represents an important measure of self-realization and self-fulfillment. Although each individual also has a private or inner self (chi), it is also subject to the collective will. This idea is in keeping with Confucian ideals that encourage the individual to focus on develop...

  6. Social Embeddedness and Late-Life Parenthood : Community Activity, Close Ties, and Support Networks

    NARCIS (Netherlands)

    Wenger, G. Clare; Dykstra, Pearl A.; Melkas, Tuula; Knipscheer, Kees C.P.M.

    2007-01-01

    This article focuses on the ways in which patterns of marriage and fertility shape older people’s involvement in community groups and their support networks. The data are from Australia, Finland, Germany, Israel, Japan, the Netherlands, Spain, the United Kingdom, and the United States. Findings show

  7. Social embeddedness and late-life parenthood: community activity, close ties and support networks

    NARCIS (Netherlands)

    Wenger, G.; Dykstra, P.A.; Melkas, T.; Knipscheer, K.

    2007-01-01

    This article focuses on the ways in which patterns of marriage and fertility shape older people’s involvement in community groups and their support networks. The data are from Australia, Finland, Germany, Israel, Japan, the Netherlands, Spain, the United Kingdom, and the United States. Findings show

  8. Social embeddedness and late-life parenthood: Community activity, close ties, and support networks

    NARCIS (Netherlands)

    Wenger, G.C.; Dykstra, P.A.; Melkas, T.; Knipscheer, C.P.M.

    2007-01-01

    This article focuses on the ways in which patterns of marriage and fertility shape older people's involvement in community groups and their support networks. The data are from Australia, Finland, Germany, Israel, Japan, the Netherlands, Spain, the United Kingdom, and the United States. Findings show

  9. Social Embeddedness and Late-Life Parenthood: Community Activity, Close Ties, and Support Networks

    Science.gov (United States)

    Wenger, G. Clare; Dykstra, Pearl A.; Melkas, Tuula; Knipscheer, Kees C. P. M.

    2007-01-01

    This article focuses on the ways in which patterns of marriage and fertility shape older people's involvement in community groups and their support networks. The data are from Australia, Finland, Germany, Israel, Japan, the Netherlands, Spain, the United Kingdom, and the United States. Findings show that childless older adults, regardless of…

  10. From social ties to embedded competencies: The case of business groups

    NARCIS (Netherlands)

    P.P.M.A.R. Heugens (Pursey); S.C. Zyglidopoulos (Stelios)

    2008-01-01

    textabstractOur current views of economic competition are still rooted in the imagery of the isolated firm that transacts with its buyers, suppliers, and competitors via largely anonymous factor and product markets. Yet this view is fundamentally at odds with the growing importance of business

  11. Governing the league : Opportunism, credible threats ans social ties in football competition licensing

    NARCIS (Netherlands)

    Speklé, R.F.; Smittenaar, T.G.

    2008-01-01

    We examine the comparative effectiveness of three alternative licensing systems in professional football. The three systems’ main concern is with the promulgation of responsible financial behaviour among football clubs. To that effect, all three systems rely on entry control and ex ante budget

  12. Khovanov-Rozansky Graph Homology and Composition Product

    DEFF Research Database (Denmark)

    Wagner, Emmanuel

    2008-01-01

    In analogy with a recursive formula for the HOMFLY-PT polynomial of links given by Jaeger, we give a recursive formula for the graph polynomial introduced by Kauffman and Vogel. We show how this formula extends to the Khovanov–Rozansky graph homology.......In analogy with a recursive formula for the HOMFLY-PT polynomial of links given by Jaeger, we give a recursive formula for the graph polynomial introduced by Kauffman and Vogel. We show how this formula extends to the Khovanov–Rozansky graph homology....

  13. Macdonald operators and homological invariants of the colored Hopf link

    International Nuclear Information System (INIS)

    Awata, Hidetoshi; Kanno, Hiroaki

    2011-01-01

    Using a power sum (boson) realization for the Macdonald operators, we investigate the Gukov, Iqbal, Kozcaz and Vafa (GIKV) proposal for the homological invariants of the colored Hopf link, which include Khovanov-Rozansky homology as a special case. We prove the polynomiality of the invariants obtained by GIKV's proposal for arbitrary representations. We derive a closed formula of the invariants of the colored Hopf link for antisymmetric representations. We argue that a little amendment of GIKV's proposal is required to make all the coefficients of the polynomial non-negative integers. (paper)

  14. Clinical evaluation of the endothelial tie-2 crossmatch in ABO compatible and ABO incompatible renal transplants.

    Science.gov (United States)

    Kafetzi, Maria L; Boletis, John N; Melexopoulou, Christine A; Tsakris, Athanassios; Iniotaki, Aliki G; Doxiadis, Ilias I N

    2013-11-01

    The necessity of detection of other than the classical major histocompatibility complex (MHC) and MHC class I-related chain A (MICA) directed antibodies prior to organ transplantation has already been repeatedly reported. A commercial flow cytometric endothelial crossmatch (CM) using isolated peripheral blood tie-2 positive cells provides a tool to detect non-MHC antibodies in addition to antibodies directed to MHC class I and II. The vast majority of circulating tie-2 positive cells expresses HLA-DR but not the A, B blood group antigens. Tie-2 cells are circulating surrogate endothelial cells. In this retrospective study we evaluated the endothelial CM in 51 renal transplantations, 30 with ABO compatible grafts and 21 with ABO incompatible grafts. Fifteen of the ABO compatible recipients (group A) developed unexplained rejection episodes (RE) while the remaining 15 had no RE (group B). Five cases of group A and none of group B had a positive tie-2 CM before transplantation (p=0.042). A positive tie-2 CM was also correlated with graft failure in ABO compatible transplants (p=0.02). No significant correlation was found between a positive pre-transplant tie-2 CM and RE in the ABO incompatible group. This study strongly suggest that a positive tie-2 CM may predict post-transplantation complications in ABO compatible grafts while negative reactions are not predictive. The test is not significantly correlated with RE in ABO incompatible grafts possibly due to applied desensitization. Copyright © 2013 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.

  15. Tie2 Expressing Monocytes in the Spleen of Patients with Primary Myelofibrosis.

    Directory of Open Access Journals (Sweden)

    Rita Campanelli

    Full Text Available Primary myelofibrosis (PMF is a Philadelphia-negative (Ph- myeloproliferative disorder, showing abnormal CD34+ progenitor cell trafficking, splenomegaly, marrow fibrosis leading to extensive extramedullary haematopoiesis, and abnormal neoangiogenesis in either the bone marrow or the spleen. Monocytes expressing the angiopoietin-2 receptor (Tie2 have been shown to support abnormal angiogenic processes in solid tumors through a paracrine action that takes place in proximity to the vessels. In this study we investigated the frequency of Tie2 expressing monocytes in the spleen tissue samples of patients with PMF, and healthy subjects (CTRLs, and evaluated their possible role in favouring spleen angiogenesis. We show by confocal microscopy that in the spleen tissue of patients with PMF, but not of CTRLs, the most of the CD14+ cells are Tie2+ and are close to vessels; by flow cytometry, we found that Tie2 expressing monocytes were Tie2+CD14lowCD16brightCDL62-CCR2- (TEMs and their frequency was higher (p = 0.008 in spleen tissue-derived mononuclear cells (MNCs of patients with PMF than in spleen tissue-derived MNCs from CTRLs undergoing splenectomy for abdominal trauma. By in vitro angiogenesis assay we evidenced that conditioned medium of immunomagnetically selected spleen tissue derived CD14+ cells of patients with PMF induced a denser tube like net than that of CTRLs; in addition, CD14+Tie2+ cells sorted from spleen tissue derived single cell suspension of patients with PMF show a higher expression of genes involved in angiogenesis than that found in CTRLs. Our results document the enrichment of Tie2+ monocytes expressing angiogenic genes in the spleen of patients with PMF, suggesting a role for these cells in starting/maintaining the pathological angiogenesis in this organ.

  16. Soluble Tie2 overrides the heightened invasion induced by anti-angiogenesis therapies in gliomas.

    Science.gov (United States)

    Cortes-Santiago, Nahir; Hossain, Mohammad B; Gabrusiewicz, Konrad; Fan, Xuejun; Gumin, Joy; Marini, Frank C; Alonso, Marta M; Lang, Frederick; Yung, W K; Fueyo, Juan; Gomez-Manzano, Candelaria

    2016-03-29

    Glioblastoma recurrence after treatment with the anti-vascular endothelial growth factor (VEGF) agent bevacizumab is characterized by a highly infiltrative and malignant behavior that renders surgical excision and chemotherapy ineffective. Our group has previously reported that Tie2-expressing monocytes (TEMs) are aberrantly present at the tumor/normal brain interface after anti-VEGF therapies and their significant role in the invasive outgrowth of these tumors. Here, we aimed to further understand the mechanisms leading to this pro-invasive tumor microenvironment. Examination of a U87MG xenogeneic glioma model and a GL261 murine syngeneic model showed increased tumor expression of angiopoietin 2 (Ang2), a natural ligand of Tie2, after anti-angiogenesis therapies targeting VEGF or VEGF receptor (VEGFR), as assessed by immunohistochemical analysis, immunofluorescence analysis, and enzyme-linked immunosorbent assays of tumor lysates. Migration and gelatinolytic assays showed that Ang2 acts as both a chemoattractant of TEMs and an enhancing signal for their tumor-remodeling properties. Accordingly, in vivo transduction of Ang2 into intracranial gliomas increased recruitment of TEMs into the tumor. To reduce invasive tumor outgrowth after anti-angiogenesis therapy, we targeted the Ang-Tie2 axis using a Tie2 decoy receptor. Using syngeneic models, we observed that overexpression of soluble Tie2 within the tumor prevented the recruitment of TEMs to the tumor and the development of invasion after anti-angiogenesis treatment. Taken together, these data indicate an active role for the Ang2-Tie2 pathway in invasive glioma recurrence after anti-angiogenesis treatment and provide a rationale for testing the combined targeting of VEGF and Ang-Tie2 pathways in patients with glioblastoma.

  17. The political responsibility of Social Work

    Directory of Open Access Journals (Sweden)

    Teresa Zamanillo Peral

    2011-06-01

    Full Text Available The intention of this article is to try to recover a critical dialog between the politics and the social work. In this paper it argued that the politics is a dimension of the identity of the social work of which we cannot avoid. In this way, the politics and the social work, are doubly tied. On the one hand, the political power exercise corresponds to every citizen of the polis. And, on the other hand, the social work is narrowly tied to the social politics by means of its object of study. Our arguments it’s construct from a diagnosis of the social reality and professional that is held in this specific relationship. We claim to contribute with elements of analyses that help, not only to understand, but also answering politically as professionals of the social work and as citizen in the society.

  18. Women and Development in Urban Senegal: Microcredit and Social ...

    African Journals Online (AJOL)

    The study finds that the impact and success of microcredit are intimately tied to the female borrowers' social capital. Household members, kin groups, communities, social and business networks, formal education, training, professional and business experience are all important sources of social capital for female borrowers.

  19. Fluid Centrality: A Social Network Analysis of Social-Technical Relations in Computer-Mediated Communication

    Science.gov (United States)

    Enriquez, Judith Guevarra

    2010-01-01

    In this article, centrality is explored as a measure of computer-mediated communication (CMC) in networked learning. Centrality measure is quite common in performing social network analysis (SNA) and in analysing social cohesion, strength of ties and influence in CMC, and computer-supported collaborative learning research. It argues that measuring…

  20. "The Path of Social Justice": A Human Rights History of Social Justice Education

    Science.gov (United States)

    Grant, Carl A.; Gibson, Melissa Leigh

    2013-01-01

    Although not often recognized, social justice education in the U.S. is historically and philosophically tied to the twentieth century's human rights initiatives. The efforts of human rights pioneers, such as those who authored the Universal Declaration of Human Rights, have indelibly shaped social justice efforts, including within education, in…

  1. Platelet-rich plasma extract prevents pulmonary edema through angiopoietin-Tie2 signaling.

    Science.gov (United States)

    Mammoto, Tadanori; Jiang, Amanda; Jiang, Elisabeth; Mammoto, Akiko

    2015-01-01

    Increased vascular permeability contributes to life-threatening pathological conditions, such as acute respiratory distress syndrome. Current treatments for sepsis-induced pulmonary edema rely on low-tidal volume mechanical ventilation, fluid management, and pharmacological use of a single angiogenic or chemical factor with antipermeability activity. However, it is becoming clear that a combination of multiple angiogenic/chemical factors rather than a single factor is required for maintaining stable and functional blood vessels. We have demonstrated that mouse platelet-rich plasma (PRP) extract contains abundant angiopoietin (Ang) 1 and multiple other factors (e.g., platelet-derived growth factor), which potentially stabilize vascular integrity. Here, we show that PRP extract increases tyrosine phosphorylation levels of Tunica internal endothelial cell kinase (Tie2) and attenuates disruption of cell-cell junctional integrity induced by inflammatory cytokine in cultured human microvascular endothelial cells. Systemic injection of PRP extract also increases Tie2 phosphorylation in mouse lung and prevents endotoxin-induced pulmonary edema and the consequent decreases in lung compliance and exercise intolerance resulting from endotoxin challenge. Soluble Tie2 receptor, which inhibits Ang-Tie2 signaling, suppresses the ability of PRP extract to inhibit pulmonary edema in mouse lung. These results suggest that PRP extract prevents endotoxin-induced pulmonary edema mainly through Ang-Tie2 signaling, and PRP extract could be a potential therapeutic strategy for sepsis-induced pulmonary edema and various lung diseases caused by abnormal vascular permeability.

  2. IVF, same-sex couples and the value of biological ties.

    Science.gov (United States)

    Di Nucci, Ezio

    2016-12-01

    Ought parents, in general, to value being biologically tied to their children? Is it important, in particular, that both parents be biologically tied to their children? I will address these fundamental questions by looking at a fairly new practice within IVF treatments, so-called IVF-with-ROPA (Reception of Oocytes from Partner), which allows lesbian couples to 'share motherhood', with one partner providing the eggs while the other becomes pregnant. I believe that IVF-with-ROPA is, just like other IVF treatments, morally permissible, but here I argue that the increased biological ties which IVF-with-ROPA allows for do not have any particular value beside the satisfaction of a legitimate wish, because there is no intrinsic value in a biological tie between parents and children; further, I argue that equality within parental projects cannot be achieved by redistributing biological ties. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  3. Topological Hochschild homology and the Bass trace conjecture

    DEFF Research Database (Denmark)

    Berrick, A. J.; Hesselholt, Lars

    2015-01-01

    We use the methods of topological Hochschild homology to shed new light on groups satisfying the Bass trace conjecture. Factorization of the Hattori–Stallings rank map through the Bökstedt–Hsiang–Madsen cyclotomic trace map leads to Linnell's restriction on such groups. As a new consequence...

  4. The homological content of the Jones representations at $q = -1$

    DEFF Research Database (Denmark)

    Egsgaard, Jens Kristian; Fuglede Jørgensen, Søren

    We generalize a discovery of Kasahara and show that the Jones representations of braid groups, when evaluated at $q = -1$, are related to the action on homology of a branched double cover of the underlying punctured disk. As an application, we prove for a large family of pseudo-Anosov mapping...

  5. Topological quantum information, virtual Jones polynomials and Khovanov homology

    International Nuclear Information System (INIS)

    Kauffman, Louis H

    2011-01-01

    In this paper, we give a quantum statistical interpretation of the bracket polynomial state sum 〈K〉, the Jones polynomial V K (t) and virtual knot theory versions of the Jones polynomial, including the arrow polynomial. We use these quantum mechanical interpretations to give new quantum algorithms for these Jones polynomials. In those cases where the Khovanov homology is defined, the Hilbert space C(K) of our model is isomorphic with the chain complex for Khovanov homology with coefficients in the complex numbers. There is a natural unitary transformation U:C(K) → C(K) such that 〈K〉 = Trace(U), where 〈K〉 denotes the evaluation of the state sum model for the corresponding polynomial. We show that for the Khovanov boundary operator ∂:C(K) → C(K), we have the relationship ∂U + U∂ = 0. Consequently, the operator U acts on the Khovanov homology, and we obtain a direct relationship between the Khovanov homology and this quantum algorithm for the Jones polynomial. (paper)

  6. Homology of the open moduli space of curves

    DEFF Research Database (Denmark)

    Madsen, Ib Henning

    2012-01-01

    This is a survey on the proof of a generalized version of the Mumford conjecture obtained in joint work with M. Weiss stating that a certain map between some classifying spaces which a priori have different natures induces an isomorphism at the level of integral homology. We also discuss our proo...

  7. On the Cogosvili functor generated by a homology

    International Nuclear Information System (INIS)

    Abd El-Satter, A. Dabbour; Mahmoud, S.

    1991-09-01

    In the present work we discuss the Cogosvili functor generated by a homology, and study the construction of the corresponding groups and their induced homomorphisms. Moreover, we investigate the properties of this functor and prove that the set of such functors are isomorphic to the Bauer homotopy theory. (author). 19 refs

  8. Human Fanconi anemia monoubiquitination pathway promotes homologous DNA repair.

    Science.gov (United States)

    Nakanishi, Koji; Yang, Yun-Gui; Pierce, Andrew J; Taniguchi, Toshiyasu; Digweed, Martin; D'Andrea, Alan D; Wang, Zhao-Qi; Jasin, Maria

    2005-01-25

    Fanconi anemia (FA) is a recessive disorder characterized by congenital abnormalities, progressive bone-marrow failure, and cancer susceptibility. Cells from FA patients are hypersensitive to agents that produce DNA crosslinks and, after treatment with these agents, have pronounced chromosome breakage and other cytogenetic abnormalities. Eight FANC genes have been cloned, and the encoded proteins interact in a common cellular pathway. DNA-damaging agents activate the monoubiquitination of FANCD2, resulting in its targeting to nuclear foci that also contain BRCA1 and BRCA2/FANCD1, proteins involved in homology-directed DNA repair. Given the interaction of the FANC proteins with BRCA1 and BRCA2, we tested whether cells from FA patients (groups A, G, and D2) and mouse Fanca-/- cells with a targeted mutation are impaired for this repair pathway. We find that both the upstream (FANCA and FANCG) and downstream (FANCD2) FA pathway components promote homology-directed repair of chromosomal double-strand breaks (DSBs). The FANCD2 monoubiquitination site is critical for normal levels of repair, whereas the ATM phosphorylation site is not. The defect in these cells, however, is mild, differentiating them from BRCA1 and BRCA2 mutant cells. Surprisingly, we provide evidence that these proteins, like BRCA1 but unlike BRCA2, promote a second DSB repair pathway involving homology, i.e., single-strand annealing. These results suggest an early role for the FANC proteins in homologous DSB repair pathway choice.

  9. The Strength of Family Ties: Perceptions of Network Relationship Quality and Levels of C-Reactive Proteins in the North Texas Heart Study.

    Science.gov (United States)

    Uchino, Bert N; Ruiz, John M; Smith, Timothy W; Smyth, Joshua M; Taylor, Daniel J; Allison, Matthew; Ahn, Chul

    2015-10-01

    Although the quality of one's social relationships has been linked to important physical health outcomes, less work has been conducted examining family and friends that differ in their underlying positivity and negativity. The main aim of this study was to examine the association between supportive, aversive, and ambivalent family/friends with levels of C-reactive proteins. Three hundred participants from the North Texas Heart Study completed the social relationships index and a blood draw to assess high-sensitivity C-reactive proteins (hs-CRPs). After standard controls, the number of supportive family members predicted lower hs-CRP levels, whereas the number of ambivalent family members predicted higher hs-CRP levels. These links were independent of depressive symptoms and perceived stress. These data highlight the importance of considering specific types of relationships and their underlying positive and negative aspects in research on social ties and physical health.

  10. Analysis and design of type b package tie-down systems

    International Nuclear Information System (INIS)

    Phalippou, C.; Tombini, C.; Tanguy, L.

    1993-01-01

    In order to analyse the incidence of tie-down conditions as a cause of road accidents and to advise carriers on methods of calculating the risk, the French Atomic Energy Commission (CEA), within the framework of a research contract financed by the European Community, conducted a survey into road accidents in which B type packages were involved. After analysis of the survey results, the CEA then conducted reduced scale tests on representative models to establish design rules for tie-down systems. These rules have been the subject of various publications and have at last resulted in the production of a software aid to the design and monitoring of tie-down systems. This document states the various stages involved in this work and the way in which the ARRIMAGE software is arranged. (J.P.N.)

  11. A matched Bow-tie antenna at 433MHz for use in underwater wireless sensor networks

    International Nuclear Information System (INIS)

    Abdou, A A; Shaw, A; Mason, A; Al-Shamma'a, A; Cullen, J; Wylie, S; Diallo, M

    2013-01-01

    Electromagnetic (EM) wave propagation underwater is been disregarded because of attenuation at high frequencies, however the theory predicts that propagation is possible at some useful distance in the lower Industrial, Scientific and Medical (ISM) band. Common transceivers rely on narrowband antennas and matching circuit. The aim of this paper is to design a broadband 433MHz bow-tie antenna and experiment it in air and water without a matching circuit. This antenna could be attached to wireless transceivers and form a Wireless Sensor Network for deployment in various underwater applications. The bow-tie antennas were designed, simulated and constructed in laboratory. Experiments were setup carefully by using a completely isolated transmitter from electronics to avoid airborne transmission. The 433MHz. bow-tie proved its suitability for use in Underwater.

  12. The effects of integration and transnational ties on international return migration intentions

    Directory of Open Access Journals (Sweden)

    Hein de Haas

    2011-12-01

    Full Text Available While return migration is receiving increasing attention, there is still insufficient insight into the factors which determine migrants' intentions and decisions to return. It is often assumed that integration in receiving countries and the concomitant weakening of transnational ties decreases the likelihood of returning. However, according to alternative theoretical interpretations, return migration can also be the outflow of successful integration in receiving countries. Drawing on a data set of four African immigrant groups in Spain and Italy, this articlereviews these conflicting hypotheses by assessing the effects of integration and transnational ties on return migration intentions. The results of the analysis suggest that socio-cultural integration has a negative effect on return migration intentions, while economic integration and transnational ties have more ambiguous and sometimes positive effects. The results provide mixed support for the different hypotheses but question theoretical perspectives that unequivocally conceptualizereturn migration and transnationalism as causes and/or consequences of "integration failure".

  13. An LLCL Power Filter for Single-Phase Grid-Tied Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; He, Yuanbin; Blaabjerg, Frede

    2012-01-01

    This paper presents a new topology of higher order power filter for grid-tied voltage-source inverters, named the LLCL filter, which inserts a small inductor in the branch loop of the capacitor in the traditional LCL filter to compose a series resonant circuit at the switching frequency. Particul......This paper presents a new topology of higher order power filter for grid-tied voltage-source inverters, named the LLCL filter, which inserts a small inductor in the branch loop of the capacitor in the traditional LCL filter to compose a series resonant circuit at the switching frequency...... to the inverter system control. The parameter design criteria of the proposed LLCL filter is also introduced. The comparative analysis and discussions regarding the traditional LCL filter and the proposed LLCL filter have been presented and evaluated through experiment on a 1.8-kW-single-phase grid-tied inverter...

  14. A Synchronization Method for Single-Phase Grid-Tied Inverters

    DEFF Research Database (Denmark)

    Hadjidemetriou, Lenos; Kyriakides, Elias; Yang, Yongheng

    2016-01-01

    The controllers of single-phase grid-tied inverters require improvements to enable distribution generation systems to meet the grid codes/standards with respect to power quality and the fault ride through capability. In that case, the response of the selected synchronization technique is crucial...... for the performance of the entire grid-tied inverter. In this paper, a new synchronization method with good dynamics and high accuracy under a highly distorted voltage is proposed. This method uses a Multi-Harmonic Decoupling Cell (MHDC), which thus can cancel out the oscillations on the synchronization signals due...... to the harmonic voltage distortion while maintaining the dynamic response of the synchronization. Therefore, the accurate and dynamic response of the proposed MHDC-PLL can be beneficial for the performance of the whole single-phase grid-tied inverter....

  15. Taiwan-China: The Gordian Knot Stays Tied

    Directory of Open Access Journals (Sweden)

    Saša Istenič

    2014-12-01

    Full Text Available Separated historical, geographical, economic, political, and social processes on the two sides of the Taiwan Strait have formed two entirely different political, economic and cultural entities. However, up to now, the governments in Beijing and Taipei have not yet found a common language regarding the questions related to Taiwan’s sovereignty. Whereas for the government in Beijing, Taiwan is an inalienable part of the People’s Republic of China, the government of the Republic of China who has actually been ruling Taiwan for almost 70 years, regards it as a sovereign, independent country. How to find a manageable political consensus that would please both parties remains a key question. The present article will outline the recent dynamics and illuminate the obstacles on the road toward long-term peace and stability in the Taiwan Strait.

  16. REGISTRATION OF LASER SCANNING POINT CLOUDS AND AERIAL IMAGES USING EITHER ARTIFICIAL OR NATURAL TIE FEATURES

    Directory of Open Access Journals (Sweden)

    P. Rönnholm

    2012-07-01

    Full Text Available Integration of laser scanning data and photographs is an excellent combination regarding both redundancy and complementary. Applications of integration vary from sensor and data calibration to advanced classification and scene understanding. In this research, only airborne laser scanning and aerial images are considered. Currently, the initial registration is solved using direct orientation sensors GPS and inertial measurements. However, the accuracy is not usually sufficient for reliable integration of data sets, and thus the initial registration needs to be improved. A registration of data from different sources requires searching and measuring of accurate tie features. Usually, points, lines or planes are preferred as tie features. Therefore, the majority of resent methods rely highly on artificial objects, such as buildings, targets or road paintings. However, in many areas no such objects are available. For example in forestry areas, it would be advantageous to be able to improve registration between laser data and images without making additional ground measurements. Therefore, there is a need to solve registration using only natural features, such as vegetation and ground surfaces. Using vegetation as tie features is challenging, because the shape and even location of vegetation can change because of wind, for example. The aim of this article was to compare registration accuracies derived by using either artificial or natural tie features. The test area included urban objects as well as trees and other vegetation. In this area, two registrations were performed, firstly, using mainly built objects and, secondly, using only vegetation and ground surface. The registrations were solved applying the interactive orientation method. As a result, using artificial tie features leaded to a successful registration in all directions of the coordinate system axes. In the case of using natural tie features, however, the detection of correct heights was

  17. FEATURES OF DESIGN OF TIED-ARCH BRIDGES WITH FLEXIBLE INCLINED SUSPENSION HANGERS

    Directory of Open Access Journals (Sweden)

    V. O. Samosvat

    2017-10-01

    Full Text Available Purpose. Investigation and analysis of the hanger arrangement and the structural stability of a Network arch bridge – a tied-arch bridge with inclined hangers that cross each other at least twice. It is also necessary to make a comparative analysis with other types of hanger arrangements. Methodology. The authors in their research investigated a large number of parameters to determine their influence in the force distribution in the arch. Eventually they determined optimal values for all parameters. These optimal values allowed developing a design guide that leads to optimal arch design. When solving this problem, the authors used three-dimensional finite element models and the objective was to determine the most suitable solution for a road bridge, with a span of 100 meters, consisting of two inclined steel arches, located on a road with two traffic lanes, subjected to medium traffic. The virtual prototype of the model is performed by finite element simulator Midas Civil. Findings. In this study, for the bridge deck, a concrete tie appears to be the best solution considering the structural behavior of network arches, but economic advantages caused by easier erection may lead to steel or a composite bridge deck as better alternatives. Design requirements and local conditions of each particular bridge project will decide the most economic deck design.Originality. To ensure passenger comfort and the stability and continuity of the track, deformations of bridges are constricted. A network arch is a stiff structure with small deflections and therefore suitable to comply with such demands even for high speed railway traffic.
A network arch bridge with a concrete tie usually saves more than half the steel required for tied arches with vertical hangers and concrete ties. Practical value. Following the study design advice given in this article leads to savings of about 60 % of structural steel compared with conventional tied arch bridges with

  18. Artifacts in magnetic spirals retrieved by transport of intensity equation (TIE)

    Science.gov (United States)

    Cui, J.; Yao, Y.; Shen, X.; Wang, Y. G.; Yu, R. C.

    2018-05-01

    The artifacts in the magnetic structures reconstructed from Lorentz transmission electron microscopy (LTEM) images with TIE method have been analyzed in detail. The processing for the simulated images of Bloch and Neel spirals indicated that the improper parameters in TIE may overestimate the high frequency information and induce some false features in the retrieved images. The specimen tilting will further complicate the analysis of the images because the LTEM image contrast is not the result of the magnetization distribution within the specimen but the integral projection pattern of the magnetic induction filling the entire space including the specimen.

  19. United States, Europe and Poland Different Stages of Antitrust Tying War in the New Economy

    Directory of Open Access Journals (Sweden)

    Mariusz SWORA

    2006-06-01

    Full Text Available Microsoft’s case has led to heated debates, both in Europe and the United States of America, on the abuse of the dominant position and on the prohibition of tying. This discussion, both in Europe and the United States, is not finished. In this article the author presents legal implications of tying products in Europe and Poland and confronts them with the American approach to tying. In Poland, a country with a fast developing economy, with the growing level of foreign investments, discussion on monopolist practices under the conditions of a fast technological development1 has not really commenced yet. The problems of innovation and development of New Economy undertakings has gained new impetus following Poland’s accession to the European Union. It is a matter of time when the anti-trust law begins to show interest in them. There are some indications that this has already taken place. In the first part of this article the author briefly presents the discussion related to Microsoft III case in the United States insofar as it pertains to New Economy issues. The second and third parts address legal and political aspects of the Microsoft case in the European Union. In the fourth part legal aspects related to tying practices in Poland are presented. The article aims to show that instrumental and mechanical treatment of tying practices used by firms having the market power under conditions of technological progress is not proper. The problem of antitrust analysis of such practices is universal, as universal as these practices are. However, the problem is solved differently in the United States and in Europe and the reasons for such a different approach are rooted in the legal system and policy enforcement. Microsoft antitrust is global. After US and European cases, Korean competition authority has found Microsoft guilty of tying practices2. Regarding Microsoft problems with tying it is necessary to ask the question whether tying practices are

  20. Do recruitment ties affect wages? An analysis using matched employer-employee data from Vietnam

    DEFF Research Database (Denmark)

    Larsen, Anna Folke; Rand, John; Torm, Nina Elisabeth

    2011-01-01

    This paper examines the extent to which recruitment ties affect individual wage outcomes in small and medium scale manufacturing firms. Based on a unique matched employer–employee dataset from Vietnam the authors find that there is a significant positive wage premium associated with obtaining a job...... through an informal contact, when controlling for standard determinants of wage compensation. Moreover, they show that the mechanism through which informal contacts affect wages depends on the type of recruitment tie used. The findings are robust across location, firm size categories, and different worker...

  1. Frequency Adaptive Repetitive Control of Grid-Tied Three-Phase PV Inverters

    DEFF Research Database (Denmark)

    Zhou, Keliang; Yang, Yongheng; Blaabjerg, Frede

    2016-01-01

    Repetitive control offers an accurate current control scheme for grid-tied converters to feed high quality sinusoidal current into the grid. However, with grid frequency being treated as a constant value, conventional repetitive controller fail to produce high quality feeding current in the prese......Repetitive control offers an accurate current control scheme for grid-tied converters to feed high quality sinusoidal current into the grid. However, with grid frequency being treated as a constant value, conventional repetitive controller fail to produce high quality feeding current...

  2. Exploring the Relationship Between Mobile Facebook and Social Capital: What Is the “Mobile Difference” for Parents of Young Children?

    OpenAIRE

    Andrew R. Schrock

    2016-01-01

    Mobile media have generally been found to reinforce close ties. Many have predicted this will bring about an onerous social insularity or “network privatism.” However, mobile media now enable frequent communication and multimedia activities with larger, more diffuse social networks. Might we be at a tipping point where certain groups benefit from weak tie connections on mobile social media? To answer this question, this study considers how mobile media altered social capital outcomes on Faceb...

  3. Forging ties between young People from CERN and ESA

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    The CERN Student Club (CSC) is the official club for the community of young people at CERN. In addition to organizing regular activities for its members, the club serves as a platform for young people to come together and meet people from other backgrounds. On 11 and 12 April, the network for young people from the European Space Agency (YoungESA) organized an excursion to CERN, in which more than 30 young researchers participated. The CERN Student Club was happy to host several activities for the members of the two communities.   Some of the participants in the first meeting of the ESA-CERN student clubs. “One of the most amazing things about being a young researcher is the boundless opportunities for meeting people from all around the world, whether for the exchange of research ideas or for social purposes”, says Yi Ling Hwong, a member of the CMS experiment and Vice-president of the CERN Student Club. “In a place like CERN such occasions are abundant but t...

  4. Optimal decision making and matching are tied through diminishing returns.

    Science.gov (United States)

    Kubanek, Jan

    2017-08-08

    How individuals make decisions has been a matter of long-standing debate among economists and researchers in the life sciences. In economics, subjects are viewed as optimal decision makers who maximize their overall reward income. This framework has been widely influential, but requires a complete knowledge of the reward contingencies associated with a given choice situation. Psychologists and ecologists have observed that individuals tend to use a simpler "matching" strategy, distributing their behavior in proportion to relative rewards associated with their options. This article demonstrates that the two dominant frameworks of choice behavior are linked through the law of diminishing returns. The relatively simple matching can in fact provide maximal reward when the rewards associated with decision makers' options saturate with the invested effort. Such saturating relationships between reward and effort are hallmarks of the law of diminishing returns. Given the prevalence of diminishing returns in nature and social settings, this finding can explain why humans and animals so commonly behave according to the matching law. The article underscores the importance of the law of diminishing returns in choice behavior.

  5. Loving transgressions: Queer of color bodies, affective ties, transformative community.

    Science.gov (United States)

    Carrillo Rowe, Aimee; Royster, Francesca T

    2017-07-03

    This introductory article considers the importance of queer woman of color theorizations of affect in thinking more fully the recent interdisciplinary turn to affect. The affective turn has vitally invited culture and feminist critics to interrogate emotion beyond the individual to examine the political and cultural production of emotion. Even as women of color are often associated with excessive affect, the theoretical contributions women of color make to the field of affect studies are often overlooked. Our introduction and this special issue more broadly examine how this solipsism shapes projects invested in critical knowledge production, as well as the stakes of centering a queer woman of color genealogy. For instance, we argue for the importance of retaining U.S. third-world feminist concepts-like interpellation, oppositional consciousness, and the generative force of negative affects-even as they fall out of favor within affect studies. Centering theory that emerges from the vexed spaces of queer women of color lived experiences generates a vital interdisciplinary conversation that contributes to the ongoing political task of mobilizing affect for social action as a critical praxis. In the articles that follow we see this critical praxis at work in the form of community organizing, music, poetry, and performance art.

  6. The differential impact of subjective and objective aspects of social engagement on cardiovascular risk factors.

    LENUS (Irish Health Repository)

    Kamiya, Yumiko

    2010-01-01

    This article provides new insights into the impact of social engagement on CVD risk factors in older adults. We hypothesized that objective (social participation, social ties and marital status) and subjective (emotional support) aspects of social engagement are independently associated with objective measures of cardiovascular risk.

  7. The ties that bind: Maternal kin bias in a multilevel primate society despite natal dispersal by both sexes.

    Science.gov (United States)

    Städele, Veronika; Pines, Mathew; Swedell, Larissa; Vigilant, Linda

    2016-07-01

    In many social animals, individuals derive fitness benefits from close social bonds, which are often formed among kin of the philopatric sex. Hamadryas baboons, however, exhibit a hierarchical, multilevel social system where both sexes disperse from their natal one-male-unit (OMU). Although this would seem to hinder maintenance of kin ties, both sexes appear largely philopatric at the higher order band and clan levels, possibly allowing for bonds with same sex kin by both males and females. In order to investigate the possibility of kin bonds in hamadryas baboons, we identified kin dyads in a band without known pedigree information using a large panel of genetic markers: 1 Y-linked, 4 X-linked, and 23 autosomal microsatellites and part of the mitochondrial hypervariable region I. With these data, we performed a kinship analysis while accounting for misclassification rates through simulations and determined kinship among two types of dyads: leader and follower males and female dyads within OMUs. Leader and follower males were maternal relatives more often than expected by chance, suggesting that kinship plays a role in the formation of these relationships. Moreover, maternal female relatives were found in the same OMU more often than expected by chance, indicating that females may be motivated to maintain post-dispersal contact with maternal female kin. Our results suggest that hamadryas baboons can recognize maternal kin and that kin selection has contributed to shaping their complex social system. This implies that an ancestral maternal kin bias has been retained in hamadryas society. Am. J. Primatol. 78:731-744, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  8. Intersection spaces, spatial homology truncation, and string theory

    CERN Document Server

    Banagl, Markus

    2010-01-01

    Intersection cohomology assigns groups which satisfy a generalized form of Poincaré duality over the rationals to a stratified singular space. The present monograph introduces a method that assigns to certain classes of stratified spaces cell complexes, called intersection spaces, whose ordinary rational homology satisfies generalized Poincaré duality. The cornerstone of the method is a process of spatial homology truncation, whose functoriality properties are analyzed in detail. The material on truncation is autonomous and may be of independent interest to homotopy theorists. The cohomology of intersection spaces is not isomorphic to intersection cohomology and possesses algebraic features such as perversity-internal cup-products and cohomology operations that are not generally available for intersection cohomology. A mirror-symmetric interpretation, as well as applications to string theory concerning massless D-branes arising in type IIB theory during a Calabi-Yau conifold transition, are discussed.

  9. A homology sound-based algorithm for speech signal interference

    Science.gov (United States)

    Jiang, Yi-jiao; Chen, Hou-jin; Li, Ju-peng; Zhang, Zhan-song

    2015-12-01

    Aiming at secure analog speech communication, a homology sound-based algorithm for speech signal interference is proposed in this paper. We first split speech signal into phonetic fragments by a short-term energy method and establish an interference noise cache library with the phonetic fragments. Then we implement the homology sound interference by mixing the randomly selected interferential fragments and the original speech in real time. The computer simulation results indicated that the interference produced by this algorithm has advantages of real time, randomness, and high correlation with the original signal, comparing with the traditional noise interference methods such as white noise interference. After further studies, the proposed algorithm may be readily used in secure speech communication.

  10. The endless tale of non-homologous end-joining.

    Science.gov (United States)

    Weterings, Eric; Chen, David J

    2008-01-01

    DNA double-strand breaks (DSBs) are introduced in cells by ionizing radiation and reactive oxygen species. In addition, they are commonly generated during V(D)J recombination, an essential aspect of the developing immune system. Failure to effectively repair these DSBs can result in chromosome breakage, cell death, onset of cancer, and defects in the immune system of higher vertebrates. Fortunately, all mammalian cells possess two enzymatic pathways that mediate the repair of DSBs: homologous recombination and non-homologous end-joining (NHEJ). The NHEJ process utilizes enzymes that capture both ends of the broken DNA molecule, bring them together in a synaptic DNA-protein complex, and finally repair the DNA break. In this review, all the known enzymes that play a role in the NHEJ process are discussed and a working model for the co-operation of these enzymes during DSB repair is presented.

  11. RTEL1 maintains genomic stability by suppressing homologous recombination.

    Science.gov (United States)

    Barber, Louise J; Youds, Jillian L; Ward, Jordan D; McIlwraith, Michael J; O'Neil, Nigel J; Petalcorin, Mark I R; Martin, Julie S; Collis, Spencer J; Cantor, Sharon B; Auclair, Melissa; Tissenbaum, Heidi; West, Stephen C; Rose, Ann M; Boulton, Simon J

    2008-10-17

    Homologous recombination (HR) is an important conserved process for DNA repair and ensures maintenance of genome integrity. Inappropriate HR causes gross chromosomal rearrangements and tumorigenesis in mammals. In yeast, the Srs2 helicase eliminates inappropriate recombination events, but the functional equivalent of Srs2 in higher eukaryotes has been elusive. Here, we identify C. elegans RTEL-1 as a functional analog of Srs2 and describe its vertebrate counterpart, RTEL1, which is required for genome stability and tumor avoidance. We find that rtel-1 mutant worms and RTEL1-depleted human cells share characteristic phenotypes with yeast srs2 mutants: lethality upon deletion of the sgs1/BLM homolog, hyperrecombination, and DNA damage sensitivity. In vitro, purified human RTEL1 antagonizes HR by promoting the disassembly of D loop recombination intermediates in a reaction dependent upon ATP hydrolysis. We propose that loss of HR control after deregulation of RTEL1 may be a critical event that drives genome instability and cancer.

  12. Cultural heritage and memory: untangling the ties that bind

    Directory of Open Access Journals (Sweden)

    Viejo-Rose, Dacia

    2015-12-01

    Full Text Available Today in heritage studies memory looms larger than ever, there are memory parks, memory politics, and memory wars, there is discussion of ‘dissonant’, ‘dark’, and ‘difficult’ heritage linked to memories of traumatic past events. But what to we mean when we use the word ‘memory’ in the field of heritage? How is the divide between its social and individual realms bridged? This article theorizes the intimate relationship between heritage and memory by focusing on three areas. First, it maps out the vocabulary that has emerged from the heritage-memory dyad including how notions of collective memory and lieux de mémoire have been used, and occasionally misused, as well as the metaphors employed in the process. Second, the emergence of memory studies is considered, providing a brief overview of its foundations as well as assessing how it differs from, overlaps with, and contributes to heritage research. A third section offers a brief review of recent developments in cognitive psychology, neuroscience, and evolutionary biology relating to memory and how this might inform heritage studies. The concluding discussion provides a synthesis of the theoretical and empirical contribution of memory research to furthering out understanding of cultural heritage and proposes directions for future work on the area of confluence between the two.La memoria impregna hoy como nunca antes los estudios del patrimonio. Hay parques, políticas y guerras de la memoria. Se habla de un patrimonio “disonante”, “oscuro” o “difícil” vinculado al recuerdo de pasados sucesos traumáticos. Pero, ¿a qué nos referimos cuando usamos la palabra “memoria” en el campo del patrimonio? ¿Cómo se cruza el abismo que separa sus dimensiones social e individual? Este artículo teoriza sobre la íntima relación entre patrimonio y memoria, centrándose en tres áreas. La primera cartografía el vocabulario generado por la díada patrimonio-memoria, incluido

  13. Peer Influence, Peer Selection and Adolescent Alcohol Use: a Simulation Study Using a Dynamic Network Model of Friendship Ties and Alcohol Use.

    Science.gov (United States)

    Wang, Cheng; Hipp, John R; Butts, Carter T; Jose, Rupa; Lakon, Cynthia M

    2017-05-01

    While studies suggest that peer influence can in some cases encourage adolescent substance use, recent work demonstrates that peer influence may be on average protective for cigarette smoking, raising questions about whether this effect occurs for other substance use behaviors. Herein, we focus on adolescent drinking, which may follow different social dynamics than smoking. We use a data-calibrated Stochastic Actor-Based (SAB) Model of adolescent friendship tie choice and drinking behavior to explore the impact of manipulating the size of peer influence and selection effects on drinking in two school-based networks. We first fit a SAB Model to data on friendship tie choice and adolescent drinking behavior within two large schools (n = 2178 and n = 976) over three time points using data from the National Longitudinal Study of Adolescent to Adult Health. We then alter the size of the peer influence and selection parameters with all other effects fixed at their estimated values and simulate the social systems forward 1000 times under varying conditions. Whereas peer selection appears to contribute to drinking behavior similarity among adolescents, there is no evidence that it leads to higher levels of drinking at the school level. A stronger peer influence effect lowers the overall level of drinking in both schools. There are many similarities in the patterning of findings between this study of drinking and previous work on smoking, suggesting that peer influence and selection may function similarly with respect to these substances.

  14. FastBLAST: homology relationships for millions of proteins.

    Directory of Open Access Journals (Sweden)

    Morgan N Price

    Full Text Available BACKGROUND: All-versus-all BLAST, which searches for homologous pairs of sequences in a database of proteins, is used to identify potential orthologs, to find new protein families, and to provide rapid access to these homology relationships. As DNA sequencing accelerates and data sets grow, all-versus-all BLAST has become computationally demanding. METHODOLOGY/PRINCIPAL FINDINGS: We present FastBLAST, a heuristic replacement for all-versus-all BLAST that relies on alignments of proteins to known families, obtained from tools such as PSI-BLAST and HMMer. FastBLAST avoids most of the work of all-versus-all BLAST by taking advantage of these alignments and by clustering similar sequences. FastBLAST runs in two stages: the first stage identifies additional families and aligns them, and the second stage quickly identifies the homologs of a query sequence, based on the alignments of the families, before generating pairwise alignments. On 6.53 million proteins from the non-redundant Genbank database ("NR", FastBLAST identifies new families 25 times faster than all-versus-all BLAST. Once the first stage is completed, FastBLAST identifies homologs for the average query in less than 5 seconds (8.6 times faster than BLAST and gives nearly identical results. For hits above 70 bits, FastBLAST identifies 98% of the top 3,250 hits per query. CONCLUSIONS/SIGNIFICANCE: FastBLAST enables research groups that do not have supercomputers to analyze large protein sequence data sets. FastBLAST is open source software and is available at http://microbesonline.org/fastblast.

  15. Social Network Analysis and informal trade

    DEFF Research Database (Denmark)

    Walther, Olivier

    networks can be applied to better understand informal trade in developing countries, with a particular focus on Africa. The paper starts by discussing some of the fundamental concepts developed by social network analysis. Through a number of case studies, we show how social network analysis can...... illuminate the relevant causes of social patterns, the impact of social ties on economic performance, the diffusion of resources and information, and the exercise of power. The paper then examines some of the methodological challenges of social network analysis and how it can be combined with other...... approaches. The paper finally highlights some of the applications of social network analysis and their implications for trade policies....

  16. Homologous Recombination in Protozoan Parasites and Recombinase Inhibitors

    Directory of Open Access Journals (Sweden)

    Andrew A. Kelso

    2017-09-01

    Full Text Available Homologous recombination (HR is a DNA double-strand break (DSB repair pathway that utilizes a homologous template to fully repair the damaged DNA. HR is critical to maintain genome stability and to ensure genetic diversity during meiosis. A specialized class of enzymes known as recombinases facilitate the exchange of genetic information between sister chromatids or homologous chromosomes with the help of numerous protein accessory factors. The majority of the HR machinery is highly conserved among eukaryotes. In many protozoan parasites, HR is an essential DSB repair pathway that allows these organisms to adapt to environmental conditions and evade host immune systems through genetic recombination. Therefore, small molecule inhibitors, capable of disrupting HR in protozoan parasites, represent potential therapeutic options. A number of small molecule inhibitors were identified that disrupt the activities of the human recombinase RAD51. Recent studies have examined the effect of two of these molecules on the Entamoeba recombinases. Here, we discuss the current understandings of HR in the protozoan parasites Trypanosoma, Leishmania, Plasmodium, and Entamoeba, and we review the small molecule inhibitors known to disrupt human RAD51 activity.

  17. Phenylbutyrate inhibits homologous recombination induced by camptothecin and methyl methanesulfonate.

    Science.gov (United States)

    Kaiser, Gitte S; Germann, Susanne M; Westergaard, Tine; Lisby, Michael

    2011-08-01

    Homologous recombination is accompanied by extensive changes to chromatin organization at the site of DNA damage. Some of these changes are mediated through acetylation/deacetylation of histones. Here, we show that recombinational repair of DNA damage induced by the anti-cancer drug camptothecin (CPT) and the alkylating agent methyl methanesulfonate (MMS) is blocked by sodium phenylbutyrate (PBA) in the budding yeast Saccharomyces cerevisiae. In particular, PBA suppresses CPT- and MMS-induced genetic recombination as well as DNA double-strand break repair during mating-type interconversion. Treatment with PBA is accompanied by a dramatic reduction in histone H4 lysine 8 acetylation. Live cell imaging of homologous recombination proteins indicates that repair of CPT-induced DNA damage is redirected to a non-recombinogenic pathway in the presence of PBA without loss in cell viability. In contrast, the suppression of MMS-induced recombination by PBA is accompanied by a dramatic loss in cell viability. Taken together, our results demonstrate that PBA inhibits DNA damage-induced homologous recombination likely by mediating changes in chromatin acetylation. Moreover, the combination of PBA with genotoxic agents can lead to different cell fates depending on the type of DNA damage inflicted. 2011 Elsevier B.V. All rights reserved.

  18. Membrane and Protein Interactions of the Pleckstrin Homology Domain Superfamily

    Directory of Open Access Journals (Sweden)

    Marc Lenoir

    2015-10-01

    Full Text Available The human genome encodes about 285 proteins that contain at least one annotated pleckstrin homology (PH domain. As the first phosphoinositide binding module domain to be discovered, the PH domain recruits diverse protein architectures to cellular membranes. PH domains constitute one of the largest protein superfamilies, and have diverged to regulate many different signaling proteins and modules such as Dbl homology (DH and Tec homology (TH domains. The ligands of approximately 70 PH domains have been validated by binding assays and complexed structures, allowing meaningful extrapolation across the entire superfamily. Here the Membrane Optimal Docking Area (MODA program is used at a genome-wide level to identify all membrane docking PH structures and map their lipid-binding determinants. In addition to the linear sequence motifs which are employed for phosphoinositide recognition, the three dimensional structural features that allow peripheral membrane domains to approach and insert into the bilayer are pinpointed and can be predicted ab initio. The analysis shows that conserved structural surfaces distinguish which PH domains associate with membrane from those that do not. Moreover, the results indicate that lipid-binding PH domains can be classified into different functional subgroups based on the type of membrane insertion elements they project towards the bilayer.

  19. Prefiltering Model for Homology Detection Algorithms on GPU.

    Science.gov (United States)

    Retamosa, Germán; de Pedro, Luis; González, Ivan; Tamames, Javier

    2016-01-01

    Homology detection has evolved over the time from heavy algorithms based on dynamic programming approaches to lightweight alternatives based on different heuristic models. However, the main problem with these algorithms is that they use complex statistical models, which makes it difficult to achieve a relevant speedup and find exact matches with the original results. Thus, their acceleration is essential. The aim of this article was to prefilter a sequence database. To make this work, we have implemented a groundbreaking heuristic model based on NVIDIA's graphics processing units (GPUs) and multicore processors. Depending on the sensitivity settings, this makes it possible to quickly reduce the sequence database by factors between 50% and 95%, while rejecting no significant sequences. Furthermore, this prefiltering application can be used together with multiple homology detection algorithms as a part of a next-generation sequencing system. Extensive performance and accuracy tests have been carried out in the Spanish National Centre for Biotechnology (NCB). The results show that GPU hardware can accelerate the execution times of former homology detection applications, such as National Centre for Biotechnology Information (NCBI), Basic Local Alignment Search Tool for Proteins (BLASTP), up to a factor of 4.

  20. Membrane and Protein Interactions of the Pleckstrin Homology Domain Superfamily.

    Science.gov (United States)

    Lenoir, Marc; Kufareva, Irina; Abagyan, Ruben; Overduin, Michael

    2015-10-23

    The human genome encodes about 285 proteins that contain at least one annotated pleckstrin homology (PH) domain. As the first phosphoinositide binding module domain to be discovered, the PH domain recruits diverse protein architectures to cellular membranes. PH domains constitute one of the largest protein superfamilies, and have diverged to regulate many different signaling proteins and modules such as Dbl homology (DH) and Tec homology (TH) domains. The ligands of approximately 70 PH domains have been validated by binding assays and complexed structures, allowing meaningful extrapolation across the entire superfamily. Here the Membrane Optimal Docking Area (MODA) program is used at a genome-wide level to identify all membrane docking PH structures and map their lipid-binding determinants. In addition to the linear sequence motifs which are employed for phosphoinositide recognition, the three dimensional structural features that allow peripheral membrane domains to approach and insert into the bilayer are pinpointed and can be predicted ab initio. The analysis shows that conserved structural surfaces distinguish which PH domains associate with membrane from those that do not. Moreover, the results indicate that lipid-binding PH domains can be classified into different functional subgroups based on the type of membrane insertion elements they project towards the bilayer.