Influence fast or later:Two types of influencers in social networks

In real-world networks,there usually exist a small set of nodes that play an important role in the structure and function of networks.Those vital nodes can influence most of other nodes in the network via a spreading process.While most of the existing works focused on vital nodes that can maximize the spreading size in the final stage,which we call final influencers,recent work proposed the idea of fast influencers,which emphasizes nodes’spreading capacity at the early stage.Despite the recent surge of efforts in identifying these two types of influencers in networks,there remained limited research on untangling the differences between the fast influencers and final influencers.In this paper,we firstly distinguish the two types of influencers:fast-only influencers and final-only influencers.The former is defined as individuals who can achieve a high spreading effect at the early stage but lose their superiority in the final stage,and the latter are those individuals that fail to exhibit a prominent spreading performance at the early stage but influence a large fraction of nodes at the final stage.Further experiments are based on eight empirical datasets,and we reveal the key differences between the two types of influencers concerning their spreading capacity and the local structures.We also analyze how network degree assortativity influences the fraction of the proposed two types of influencers.The results demonstrate that with the increase of degree assortativity,the fraction of the fast-only influencers decreases,which indicates that more fast influencers tend to keep their superiority at the final stage.Our study provides insights into the differences and evolution of different types of influencers and has important implications for various empirical applications,such as advertisement marketing and epidemic suppressing.

Dynamics and interactions of blog-based science communication:A case study of blogging activities in China related to 2011 Japanese seismic and nuclear power crisis

Purpose: This paper tries to understand the dynamics of scientific communication systems during crises by investigating as a case study the blogging activities that took place during the period of the 2011 earthquake and related events in Japan. Interactions between bloggers and registered users are studied quantitatively and qualitatively at Sciencenet.cn, an influential science-related blogosphere in China.Design/methodology/approach: The editors of Sciencenet.cn compiled a special issue of science blog articles under the title Analysis of the Japanese Earthquake. We developed a spider program and downloaded from this special issue the metadata about title, content,publishing time, total read count, reply count and recommendation count, and further collected information about bloggers and recommenders. We then sent a short message to the bloggers who wrote articles on these emergencies, asking for their educational and professional background.Findings: We found that knowledge reflected in the blog articles is strongly related to the educational and professional background of bloggers. Knowledge diffusion is facilitated by interactions, such as recommendations, comments and answers. Interactions via comments and recommendations are of an assortative nature: A blog article is more likelyto be commented on and recommended by those bloggers who write on the same or similar topics than by those writing on a different one. Registered users tend to give comments on articles dealing with the topic that they recommend, and vice versa.Interaction in the intersection of two or three topics is more intense than that within one topic. The impact of blog articles is also influenced by other factors, such as the reputation of the blogger and the type of information they contain.Implications and limitations: It is confirmed that studying blogs is a valid approach within informetric studies. Yet, we only studied one triple(earthquake, tsunami, nuclear disaster) event based on data originating from one Chinese blog website. More events should be studied.Originality/value: Informetric studies based on blogs are still relatively few. Using science blogs and combining comments on a triple event with the knowledge background of bloggers in China is even less common. As such this contribution enhances our knowledge on this new form of science communication activity.

ESTIMATES OF THE DOUBLE DETERMINANTS OF QUATERNION MATRICES

An estimate of the upper bound is given for the double determinant of the sum of two arbitrary quaternion matrices, and meanwhile the lower bound on the double determinant is established especially for the sum of two quaternion matrices which form an assortive pair. As applications, some known results are obtained as corollaries and a question in the matrix determinant theory is answered completely.

Folding rate prediction using complex network analysis for proteins with two- and three-state folding kinetics

It is a challenging task to investigate the different in- fluence of long-range and short-range interactions on two-state and three-state folding kinetics of protein. The networks of the 30 two-state proteins and 15 three-state proteins were constructed by complex networks analysis at three length scales: Protein Contact Networks, Long-range Interaction Networks and Short-range Interaction Networks. To uncover the relationship between structural properties and folding kinetics of the proteins, the correlations of protein network parameters with protein folding rate and topology parameters contact order were analyzed. The results show that Protein Contact Networks and Short-range Interaction Networks (for both two-state and three-state proteins) exhibit the “small-world” property and Long-range Interaction networks indicate “scale-free” behavior. Our results further indicate that all Protein Contact Networks and Short- range Interaction networks are assortative type. While some of Long-range Interaction Networks are of assortative type, the others are of disassortative type. For two-state proteins, the clustering coefficients of Short-range Interaction Networks show prominent correlation with folding rate and contact order. The assortativity coefficients of Short-range Interaction Networks also show remarkable correlation with folding rate and contact order. Similar correlations exist in Protein Contact Networks of three-state proteins. For two-state proteins, the correlation between contact order and folding rate is determined by the numbers of local contacts. Short- range interactions play a key role in determining the connecting trend among amino acids and they impact the folding rate of two-state proteins directly. For three-state proteins, the folding rate is determined by short-range and long-range interactions among residues together.

<i>Wolbachia</i>induces sexual isolation in <i>Drosophila melanogaster</i>and <i>Drosophila simulans</i>

Wolbachia are a group of intracellular bacteria, ma-ternally transmitted from infected females to their offspring, which affect a wide range of arthropods. Their presence is associated with Cytoplasmic Incompatibility (CI) in crosses between infected males and uninfected females and between populations carrying different strains of Wolbachia. The negative influence of Wolbachia a infection on progeny fitness in incompatible crosses can be considered a first step in the appearance of reproductive isolation between infected and uninfected individuals. In this work, we examined the possibility of assortative mating in response to Wolbachia infection, a response that evolved as an incipient mechanism of sexual isolation in the species D. melanogaster and D. simulans. We found that the females of each species could detect the presence of the bacterium in the other sex and chose to mate with males who had the same state of infection, whereas the males randomly attempted to mate with both infected and uninfected females. Thus, Wolbachia may act as an additive factor influencing sexual isolation in Drosophila populations and may play a role in speciation events.

Sexual dichromatism and assortative mating by multiple plumage color traits in wild Chestnut Thrush

Sex differences in plumage color are common in bird species.Some bird species are regarded as sexually monochromatic in human visual systems,and in recent years,some species are found to be of cryptic(to human)sexual dichromatism by spectrophotometric techniques.However,the functions of plumage color are still less understood in these species.Here,we focused on plumage color traits in the Chestnut Thrush(Turdus rubrocanus),which is considered as a sexually monochromatic bird by human observers.We used spectrometer analyses and avian visual modeling to investigate the color traits of males and females,and whether these color traits are involved in assortative mating.We found that Chestnut Thrush showed sexual dichromatism in bill,throat and wing,and pairs mated assortatively with colorations of throat,chest,crown and wing.We also found that color of tarsus was different between two consecutive years.These results revealed that Chestnut Thrush is sexually dichromatic in the avian visual system,and plumage color traits play important roles in mate choice.

Assortment of Deep Mantle Fluids and Their Products in Kimberlites from China

Based on studies of petrography, mineralogy and mineral chemistry, deep mantle fluids and their products in kimberlites and diamonds can be assorted into the ultradeep fluid-transmitted minerals with an oxygen-free feature, the deep fluid metasomatized-minerals characterized by enrichment in TiO2, K2O, BaO, REE and Fe3+, and the deep fluid-reformed minerals. The three types show a successive descent in fluid origin depth and metasomatism strength, and they have brought forth a series of corresponding metasomatic products.

Reproductive isolation in the Elegans-Group of Caenorhabditis

Reproductive isolation is the basis of the Biological Species Definition and can be a driving force of speciation. Theoretical studies have provided models of how reproductive isolation can arise within individual species. Genetic tests of these models are limited to populations in which reproductive isolation is present but not complete. Here, reproductive isolation in the Elgans-Group of the nematode genus Caenorhabditis is reviewed. Pre-mating barriers, assortative fertilization and post-zygotic barriers all have been observed in this clade. In some combinations of species, fertile F1 hybrids can be obtained. Therefore, the Elegans-Group of Caenorhabditis is poised to become an important experimental system for the study of reproductive isolation.

Analysis and Improvement Measures for the Current Situation of Spare Parts Management (SPM)

Based on an investigation on the current situation of SPM in some enterprises, this paper presents the common probletns and poor fields existing in SPM in enterprise; analyzes the reasons which resulted in the situation, and then puts forward some feasible measures to improve it. Lastly, some fields that should be paid more attention in SPM are provided.

DEMAND ESTIMATION AND ASSORTMENT PLANNING IN WIRELESS COMMUNICATIONS

This paper provides an efficient and useful approach for demand estimation and assortment planning of cell phone cards in wireless communication industry. We use maximum likelihood estimation to estimate the primary demand and substitution probability of each cell phone card based on historical sales data. This estimation model is nonlinear, so we transform it to a mixed integer linear programming model by logarithmic transformations and piecewise＇linear approximation. On the basis of the estimation results, we can make assortment planning. Considering the resource of cell phone cards is limited, we jointly optimize the assortment and quantity planning of cell phone cards. In numerical study, we apply our approach to a large mobile service provider in China and frod our approach can increase the revenue of this mobile service provider by 23.69%. Sensitivity analysis shows the mobile service provider should provide more assortments to increase revenue when the types of cell phone cards that can be assigned to each store are limited.

Bidirectional impact of imperfect mask use on reproduction number of COVID-19:A next generation matrix approach

The use of masks as a means of reducing transmission of COVID-19 outside healthcare settings has proved controversial.Masks are thought to have two modes of effect:they prevent infection with COVID-19 in wearers;and prevent transmission by individuals with subclinical infection.We used a simple next-generation matrix approach to estimate the conditions under which masks would reduce the reproduction number of COVID-19 under a threshold of 1.Our model takes into account the possibility of assortative mixing,where mask users interact preferentially with other mask users.We make 3 key observations:1.Masks,even with suboptimal efficacy in both prevention of acquisition and transmission of infection,could substantially decrease the reproduction number for COVID-19 if widely used.2.Widespread masking may be sufficient to suppress epidemics where R has been brought close to 1 via other measures(e.g.,distancing).3.“Assortment”within populations(the tendency for interactions between masked individuals to be more likely than interactions between masked and unmasked individuals)would rapidly erode the impact of masks.As such,mask uptake needs to be fairly universal to have an effect.This simple model suggests that widespread uptake of masking could be determinative in suppressing COVID-19 epidemics in regions with R(t)at or near 1.

Adaptive associations between total body color dimorphism and climatic stress-related traits in a stenothermal circumtropical Drosophila species

Low desiccation resistance of Drosophila ananassae reflects its rarity outside the humid tropics. However, the ability of this sensitive species to evolve under seasonally varying subtropical areas is largely unknown. D. ananassae flies are mostly lighter during the rainy season but darker and lighter flies occur in the autumn season in northern India. We tested the hypothesis whether seasonally varying alternative body color phenotypes of D. ananassae vary in their levels of environmental stress tolerances and mating behavior. Thus, we investigated D. ananassae flies collected during rainy and autumn seasons for changes in body melanization and their genetic basis, desiccation-related traits, cold tolerance and mating propensity. On the basis of genetic crosses, we found total body color dimorphism consistent with a single gene model in both sexes olD. ananassae. A significant increase in the frequency of the dark morph was observed during the drier autumn season, and body color phenotypes showed significant deviations from Hardy-Weinberg equilibrium, which suggests climatic selection plays a role. Resistance to desiccation as well as cold stress were two- to three-fold higher in the dark body color strain as compared with the light strain. On the basis of no-choice mating experiments, we observed significantly higher assortative matings between dark morphs under desiccation or cold stress, and between light morphs under hot or higher humidity conditions. To the best of our knowledge, this is the first report on the ecological significance of seasonally varying total body color dimorphism in a tropical species, D. ananassae.

Data mining-based algorithm for assortment planning

With increasing varieties and products,management of limited shelf space becomes quite difficult for retailers.Hence,an efficient product assortment,which in turn helps to plan the organization of various products across limited shelf space,is extremely important for retailers.Products can be distinguished based on quality,price,brand,and other attributes,and decision needs to be made about an assortment of the products based on these attributes.An efficient assortment planning improves the financial performance of the retailer by increasing profits and reducing operational costs.Clustering techniques can be very effective in grouping products,stores,etc.and help managers solve the problem of assortment planning.This paper proposes data mining approaches for assortment planning for profit maximization with space,and cost constraints by mapping it into well-known knapsack problem.

Differentiation and pricing power of online retailers

This study aims to contribute to marketing theory by applying monopolistic competition theory to investigate how differentiation affects online retailers7 pricing power. We examine the intermediary effect of customer loyalty on the relationship between differentiation and pricing power of online retailers. We assume that customers have different preferences for the differentiated characteristics of online retailers, and thus different degrees of willingness to pay premiums, which gives online retailers pricing power. Structural equation modeling (SEM) is employed to test the hypothesized relati on ships between differentiation, customer loyalty, and pricing power. The statistical results of the empirical data indicate that some of the differentiation characteristics of online retailers can cultivate their pricing power indirectly. Logistics quality followed by commodity assortment and transaction security produces profound effects on the buildup of pricing power with customer loyalty as an intermediary factor. Results further reveal that commodity quality is positively related to pricing power. This study expands the definition of differentiation by combining corporate strategic positioning with commodity pricing. Implications for practice and di recti ons for future research are provided.