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

Inspired by the analysis of several empirical online social networks, we propose a simple reaction-diffusion-like coevolving model, in which individuals are activated to create links based on their states, influenced by local dynamics and their own intention. It is shown that the model can reproduce the remarkable properties observed in empirical online social networks; in particular, the assortative coefficients are neutral or negative, and the power law exponents are smaller than 2. Moreover, we demonstrate that, under appropriate conditions, the model network naturally makes transition(s) from assortative to disassortative, and from sparse to dense in their characteristics. The model is useful in understanding the formation and evolution of online social networks.Comment: 10 pages, 7 figures and 2 table

Lactation and neonatal nutrition: defining and refining the critical questions.

This paper resulted from a conference entitled "Lactation and Milk: Defining and refining the critical questions" held at the University of Colorado School of Medicine from January 18-20, 2012. The mission of the conference was to identify unresolved questions and set future goals for research into human milk composition, mammary development and lactation. We first outline the unanswered questions regarding the composition of human milk (Section I) and the mechanisms by which milk components affect neonatal development, growth and health and recommend models for future research. Emerging questions about how milk components affect cognitive development and behavioral phenotype of the offspring are presented in Section II. In Section III we outline the important unanswered questions about regulation of mammary gland development, the heritability of defects, the effects of maternal nutrition, disease, metabolic status, and therapeutic drugs upon the subsequent lactation. Questions surrounding breastfeeding practice are also highlighted. In Section IV we describe the specific nutritional challenges faced by three different populations, namely preterm infants, infants born to obese mothers who may or may not have gestational diabetes, and infants born to undernourished mothers. The recognition that multidisciplinary training is critical to advancing the field led us to formulate specific training recommendations in Section V. Our recommendations for research emphasis are summarized in Section VI. In sum, we present a roadmap for multidisciplinary research into all aspects of human lactation, milk and its role in infant nutrition for the next decade and beyond

Nitrides as ammonia synthesis catalysts and as potential nitrogen transfer reagents

In this article, an overview of the application of selected metal nitrides as ammonia synthesis catalysts is presented. The potential development of some systems into nitrogen transfer reagents is also described

Trends of sex differences in outcomes of cardiac electronic device implantations in the United States

Background The disparity in outcomes of CIED implantations between sexes has been previously demonstrated in device-specific cohorts (e.g. implantable cardioverter defibrillators (ICD)). However, it is unclear whether sex differences are present with all types of CIED and, if so, what the trends of such differences were in recent years. Methods Using the National Inpatient Sample, all hospitalizations between 2004 and 2014 for de novo implantation of permanent pacemakers (PPM), cardiac resynchronization therapy with or without a defibrillator (CRT-D and CRT-P, respectively) and ICD were analyzed to examine the association between sex and in-hospital acute complications of CIED implantation. Results Out of 2,815,613 hospitalizations for de novo CIED implantation, 41.9% were performed on women. Women were associated with increased adjusted odds of adverse procedural complications (major adverse cardiovascular complications: 1.17 [1.16, 1.19], bleeding: 1.13 [1.12, 1.15], thoracic: 1.42 [1.40, 1.44], cardiac: 1.44 [1.38, 1.50]), while the adjusted odds of in-hospital all-cause mortality compared to men was 0.96 [0.94, 1.00]. The odds of adverse complications in the overall CIED cohort were persistently raised in women throughout the study period, whereas similar odds of all-cause mortality across the sexes were observed throughout the study period. Conclusion In a national cohort of CIED implantations we demonstrate that women are at an overall higher risk of procedure-related adverse events compared to men, but no increased risk of all-cause mortality. Further studies are required to identify procedural techniques that would improve outcomes amongst women undergoing such procedures

Predicting language diversity with complex network

Evolution and propagation of the world's languages is a complex phenomenon, driven, to a large extent, by social interactions. Multilingual society can be seen as a system of interacting agents, where the interaction leads to a modification of the language spoken by the individuals. Two people can reach the state of full linguistic compatibility due to the positive interactions, like transfer of loanwords. But, on the other hand, if they speak entirely different languages, they will separate from each other. These simple observations make the network science the most suitable framework to describe and analyze dynamics of language change. Although many mechanisms have been explained, we lack a qualitative description of the scaling behavior for different sizes of a population. Here we address the issue of the language diversity in societies of different sizes, and we show that local interactions are crucial to capture characteristics of the empirical data. We propose a model of social interactions, extending the idea from, that explains the growth of the language diversity with the size of a population of country or society. We argue that high clustering and network disintegration are the most important characteristics of models properly describing empirical data. Furthermore, we cancel the contradiction between previous models and the Solomon Islands case. Our results demonstrate the importance of the topology of the network, and the rewiring mechanism in the process of language change

A perspective on multinational enterprise’s national identity dilemma

This conceptual paper identifies gaps and contributes to the literature on ‘identity’ dilemmas faced by multinational enterprises operating in a globalised world. Various characteristics and business strategies of multinational enterprises are delineated and analysed through the lens of social identity theory and international business concepts such as market and institutional logic. Our analysis, based on multiple cases, and derived from a variety of industries and countries, associates the identity dilemma to informed business strategy. Our findings suggest that while multinational enterprises face identity dilemmas that they sometimes use to their advantage, it also poses several challenges. Through our conceptualisation, we derive five distinct propositions to shape future research directions