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The effect of wave baffles inclination angle on the behavior of a packed bed operating under liquid up-flow was experimentally investigated. The system has been widely used in biotechnology due to the large surface area available for the microorganisms attachment. The results of different flow rates showed that the reactor “e” at $$\theta = 180^{\circ }$$ behaves as a plug flow distorted by a constant axial dispersion. At low flow rates, the mean residence time (MRT) and variance residence time (VRT) are high. However, both parameters increase with increasing the height of the sand bed for all reactors “a”, “b”, “c”, “d” and “e” (i.e. $$\theta = 0^{\circ }, 15^{\circ }, 30^{\circ }, 45^{\circ }$$ and $$180^{\circ }$$ ), respectively, and the flow patterns lie between plug flow and perfectly mixed. Other results of residence time distribution (RTD) obtained from all reactors showed that these reactors do not have segregations or dead volumes and the reactor “c” at $$\theta = 30^{\circ }$$ presents a uniform dispersion, high N-tanks number and a low MRT compared with the reference reactor at flat baffles.

Background: School closure is often considered as an option to mitigate influenza epidemics because of its potential to reduce transmission in children and then in the community. The policy is still however highly debated because of controversial evidence. Moreover, the specific mechanisms leading to mitigation are not clearly identified. Methods: We introduced a stochastic spatial age-specific metapopulation model to assess the role of holiday-associated behavioral changes and how they affect seasonal influenza dynamics. The model is applied to Belgium, parameterized with country-specific data on social mixing and travel, and calibrated to the 2008/ 2009 influenza season. It includes behavioral changes occurring during weekend vs. weekday, and holiday vs. school-term. Several experimental scenarios are explored to identify the relevant social and behavioral mechanisms. Results: Stochastic numerical simulations show that holidays considerably delay the peak of the season and mitigate its impact. Changes in mixing patterns are responsible for the observed effects, whereas changes in travel behavior do not alter the epidemic. Weekends are important in slowing down the season by periodically dampening transmission. Christmas holidays have the largest impact on the epidemic, however later school breaks may help in reducing the epidemic size, stressing the importance of considering the full calendar. An extension of the Christmas holiday of 1 week may further mitigate the epidemic. Conclusion: Changes in the way individuals establish contacts during holidays are the key ingredient explaining the mitigating effect of regular school closure. Our findings highlight the need to quantify these changes in different demographic and epidemic contexts in order to provide accurate and reliable evaluations of closure effectiveness. They also suggest strategic policies in the distribution of holiday periods to minimize the epidemic impact. The present work was partially supported by the French ANR project HarMS-flu (ANR-12-MONU-0018) to GDL and VC; the EC-Health project PREDEMICS (Contract No. 278433) to VC; the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement 682540 - TransMID) to NH, PC; the University of Antwerp scientific chair in Evidence-Based Vaccinology to NH; the Antwerp Study centre for Infectious Diseases (ASCID) in 2009-2016 to NH; the IAP Research Network P7/06 of the Belgian State (Belgian Science Policy) to KVK, NH; the PHC Tournesol Flanders program no. 35686NE to GDL, KVK, CP, NH, VC.

Background Most infections are spread through social networks (detrimental effect). However, social networks may also lower infection acquisition (beneficial effect). This study aimed to examine associations between social network parameters and prevalence of self-reported upper and lower respiratory, gastrointestinal and urinary tract infections in a population aged 40–75. Methods In this population-based cross-sectional cohort study (N = 3004, mean age 60.0 ± 8.2 years, 49% women), infections within the past two months were assessed by self-administered questionnaires. Social network parameters were assessed using a name generator questionnaire. To examine the associated beneficial and detrimental network parameters, univariable and multivariable logistic regression was used. Results Participants reported an average of 10 people (alters) with whom they had 231 contacts per half year. Prevalences were 31.1% for upper respiratory, 11.5% for lower respiratory, 12.5% for gastrointestinal, and 5.7% for urinary tract infections. Larger network size, and a higher percentage of alters that were friends or acquaintances were associated with higher odds of upper respiratory, lower respiratory and/or gastrointestinal infections (detrimental). A higher total number of contacts, higher percentages of alters of the same age, and higher percentages of family members/acquaintances were associated with lower odds of upper respiratory, lower respiratory and/or gastrointestinal infections (beneficial). Conclusion We identified both detrimental and beneficial associations of social network parameters with the prevalence of infections. Our findings can be used to complement mathematical models on infection spread, as well as to optimize current infectious disease control. Electronic supplementary material The online version of this article (10.1186/s12879-018-3197-3) contains supplementary material, which is available to authorized users.

Objectives The dominant mode of HIV transmission in China has changed from injection drug use to sexual contact. The objectives of this study were to describe the disassortative and assortative mixing patterns of drug-using and sex networks among young drug users in China. Study design Cross-sectional study. Methods Respondent-driven sampling (RDS) was used to recruit young drug users in an egocentric network study in Yunnan, China. Egos were categorized as having disassortative mixing network patterns if they reported both sex and drug-using networks. Egos who only had a sex network (no drug-using network), or only a drug-using network (no sex network) were categorized as having assortative mixing network patterns. Multiple logistic regression was performed to analyze the relationships between disassortative patterns with risky sexual behaviour and drug-using practices. Results A total of 426 participants were recruited into the study. Two hundred forty-two egos reported disassortative mixing patterns and 139 egos had assortative patterns. The RDS-adjusted proportion of having a disassortative pattern was 53.2%. Participants with disassortative patterns were more likely to engage in HIV risk behaviour compared to those with assortative patterns. Specifically, drug users with disassortative patterns reported more multiple sex partners (31.4% vs 19.6%), concurrent partnerships (52.1% vs 39.0%), non-regular sex partners (12.0% vs 4.3%), and sex partners who were IDUs (24.9% vs 12.5%). Consistent condom use with regular or non-regular partners was low (between 18.9% and 47.2%) regardless of the mixing pattern. However, parenteral risk for HIV transmission was relatively low in both groups. Conclusions The transition of the HIV epidemic in China from injection drug use to sexual contact may be attributed to disassortative mixing in drug-use and sexual networks. HIV programs should consider disassortative mixing patterns when designing new behavioural interventions.

The plane folded plate reactor (PFPR) and opposite folded plate reactor (OFPR) are two types of anaerobic baffled reactor (ABR) with similar design concepts and principles. Residence time distribution (RTD) analysis on the PFPR and OFPR under clean and working conditions at the same hydraulic residence time (HRT) of 4, 6, 8 and 10 h were performed to investigate mixing patterns and dead space. The results under all test conditions showed that the mixing pattern for both reactors fell within the “intermediate state”, that was, between plug flow and completely mixed. The mixing pattern of the OFPR, however, was closer to plug flow. Thus, the dead space of the OFPR was less than that of PFPR, regardless of whether the reactors were inoculated, and the chemical oxygen demand (COD) removal of the OFPR was better compared with that of the PFPR under the same HRT. The experimental results revealed that the OFPR was a potential reactor for wastewater treatment.

In first part of the talk we survey the experimental results on neutrino mixing, review phenomenological mixing patterns and discuss interpretations in terms of deviations from tri-bimaximal mixing, including mixing sum rules. In the second part of the talk we introduce theoretical approaches to neutrino mixing. We first consider the see-saw mechanism with right-handed neutrinos and sequential dominance. We then discuss approaches based on symmetry, in particular both GUT symmetry and discrete family symmetry, in constructing unified models of quark and lepton masses and mixing. Various different approaches to model building are described, denoted as direct, semi-direct and indirect, and the pros and cons of each approach is discussed.

The term assortativity indicates the tendency, for a network node, to be directly connected to other nodes that are someway similar. In more technical terms, a given feature is assortative in a network if the probability that an arc exists between two nodes having this feature is greater than the probability that an arc exists between two generic nodes. The role of assortativity in real-world and online social networks has been largely investigated in the literature, in which, starting from degree assortativity, several forms of assortativity have been analyzed. When moving from a single-social-network to a multiple-social-network perspective, new specific traits can be studied, also under the assortativity magnifying glass. This is the case of membership overlap among networks (i.e., the fact that people belong to more online social networks) as expression of different traits of users? personality. In this paper, we deal with the above issue, by defining two different measures of membership overlap assortativity, called Loose and Constrained Inter-social-network Assortativity, respectively and by observing that in two of the most representative online social networks, namely Facebook and Twitter, membership overlap is assortative. HighlightsIntroduction of two measures of membership overlap assortativity (MOA, for short).Experimental observation in Facebook and Twitter of membership overlap assortativity.MOA is source of privacy loss, helping the disclosure of implicit membership overlap.MOA opens a future issue on how information flow crossing OSNs is structured.

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

An efficient mixing system for a microfluidic platform that uses periodic sinusoidal characteristics in space and time is proposed in this work. A convergent–divergent channel with sinusoidal walls (space-periodic) represented the most effective coupling with pulsatile (time-periodic) flow among the five tested geometries. The effects of sinusoidal pulsing on mixing performance in the convergent–divergent microchannel were examined using unsteady Navier–Stokes equations. The mixing performance was analyzed using the Reynolds and Strouhal numbers, and the ratio of pulsing amplitude to steady flow velocity. The micromixer shows interesting mixing behaviors with these parameters in terms of instantaneous mixing patterns as well as overall mixing performance. The micromixer with pulsing inputs achieved mixing index, 0.92 within two periods of the sinusoidal walls.

Purpose – The purpose of this study was to provide quantitative indicators of intra-university assortative mixing patterns of scholars based on five parameters: degree of connections, faculty, professional position, gender and race. Design/methodology/approach – We conducted a case study of business and management scholars of University of Malaya, a research-intensive University in Malaysia, using co-authorship in papers indexed in the Digital Library Indexing System, Social Sciences Citation Index (SSCI) database of Web of Science, from 2006 to 2010. Background information of scholars was extracted from bibliometric records, online curriculum vitaes and other online sources. Assortativity coefficients were calculated for all parameters. Findings – The study found a degree assortativity coefficient of 0.195, which corresponds with other studies in the literature. Assortativity due to university faculty was strongly assortative at 0.649, whereas gender (0.28) and race (0.16) were weakly assortative. However, in contrast to the common belief that “similarity breeds connection”, the scholars were highly disassortative by professional position (−0.75). Practical implications – This study holds significance to policymakers in understanding the socio-academic factors that bring scholars together. It also adds to the body of knowledge in social network studies that are examining the various factors responsible in bringing the actors together. Originality/value – This is one of the first studies that empirically investigated mixing patterns of researchers at a prominent research-intensive university in Malaysia.

Mineralogical and elemental analyses of 20 ferromanganese (FeMn)-coated pumice samples from the Central Indian Ocean Basin (CIOB) indicate that todorokite is the major mineral phase, whereas vernadite occurs only rarely. Based on major, trace and rare earth elements (REEs) as well as Ce anomalies, the sources of the FeMn oxides were identified to be either hydrogenous, hydrothermal-plume fallout, diagenetic or a combination of these. Plots of Fe/Mn vs. Ce or Co reveal a distinct demarcation of the diagenetic, hydrogenous and plume fallout samples. Five samples are interpreted to be of hydrothermal origin because these show negative Ce anomalies and low Co/Zn ratios (0.5 to 1.1), and are masked by diagenesis. The relative contributions of hydrogenous, hydrothermal and diagenetic inputs were assessed in terms of ternary mixing patterns using REE mass balance equations. Furthermore, the hypothetical Ce anomaly (Ce/Ce*) was calculated using ternary mixing calculations for hydrogenous, hydrothermal and diagenetic end-members to ascertain the input to FeMn oxides on the pumice samples. This revealed a distinction between hydrogenous and hydrothermal components but diagenetic and plume fallout components could not be distinguished because this scheme comprises a three end-member calculation. A conservative estimate indicates the hydrothermal component to vary between 24% and 72%. The growth rates of the oxides, as estimated from published empirical methods, range between 3 and 47 mm/106 years. Fe/Mn ratios yielded a maximum age of 5–7 Ma and a minimum of 0.04–0.1 Ma. This suggests that the commencement of accretion of the FeMn oxides generally precedes the age of the Krakatau 1883 eruption, which is commonly considered as being the prime source of pumice to the CIOB. This is the first evidence of hydrothermal influence in the formation of FeMn oxides on CIOB pumice.

We perform a detailed study of lepton mixing patterns arising from a scenario with three Majorana neutrinos in which a discrete flavor group G f = Δ ( 3 n 2 ) or G f = Δ ( 6 n 2 ) and a CP symmetry are broken to residual symmetries G e = Z 3 and G ν = Z 2 × CP in the charged lepton and neutrino sectors, respectively. While we consider all possible Z 3 and Z 2 generating elements, we focus on a certain set of CP transformations. The resulting lepton mixing depends on group theoretical indices and one continuous parameter. In order to study the mixing patterns comprehensively for all admitted G e and G ν , it is sufficient to discuss only three types of combinations. One of them requires as flavor group Δ ( 6 n 2 ) . Two types of combinations lead to mixing patterns with a trimaximal column, while the third one allows for a much richer structure. For the first type of combinations the Dirac phase as well as one of the Majorana phases are trivial, whereas the other two types of combinations predict in general all CP phases to be non-trivial and also non-maximal. Already for small values of the index n of the group, n ≤ 11 , experimental data on lepton mixing can be accommodated well for particular choices of the parameters of the theory. We also comment on the relation of the used CP transformations to the automorphisms of Δ ( 3 n 2 ) and Δ ( 6 n 2 ) .

The present study concerns an efficient spectral analysis of advective–diffusive transport in periodic flows by the way of a compact version of the diffusive mapping method. Key to the compact approach is the representation of the scalar evolution by only a small subset of the eigenmodes of the mapping matrix, and capturing the relevant features of the transient towards the homogeneous state. This has been demonstrated for purely advective transport in an earlier study by Gorodetskyi et al. (2012). Here this ansatz is extended to advective–diffusive transport and more complex 3D flow fields, motivated primarily by the importance of molecular diffusion in many mixing processes. The study exposed an even greater potential for such transport problems due to the progressive widening of the spectral gaps in the eigenvalue spectrum of the mapping matrix with increasing diffusion. This facilitates substantially larger reductions of the eigenmode basis compared to the purely advective limit for a given approximation tolerance. The compact diffusive mapping method is demonstrated for a representative three-dimensional prototype micro-mixer. This revealed a reliable prediction of (transient) scalar evolutions and mixing patterns with reductions of the eigenmode basis by up to a factor 2000. The accurate estimation of the truncation error from the eigenvalue spectrum enables the systematic determination of the spectral cut-off for a desired degree of approximation. The validity and universality of the presumed correlation between spectral cut-off and truncation error have been established. This has the important practical consequence that the cut-off can a priori be chosen such that the truncation error remains within a preset tolerance. This offers a way to systematically (and reliably) employ the compact mapping method for an in-depth analysis of advective–diffusive transport.

The Wahiba Sand Sea is a large dune system composed of northern and southern zones. The dunes receive sand from multiple sources including two fluvial systems draining mountain basins, older underlying dunes, and a large coastline. Although the sand sea is distinctly divided into geomorphic regions with different dunes types, ages, and bulk mineral compositions, the ubiquitous presence of carbonate grains throughout the dune field has led to models that suggest the coast and shallow shelf is the direct and primary source of sediment for the entire sand sea. This study uses a novel method which couples selective, grain-by-grain analysis using laser-induced breakdown spectroscopy (LIBS) of a single mineral species with the classification method of Soft Independent Modeling of Class Analogy (SIMCA). The analysis of carbonate grains using the LIBS method reveals that the carbonates are comprised of several sub-populations that are well mixed throughout the dune field. Individual sources of carbonate grains are also composed of multiple sub-populations creating further complexity. Sand in the Northern Wahiba is predominantly, and directly, derived from wadi systems that lie on the west and northeast sides of the dunes and once bordered the southern end of the dunes. The Southern Wahiba is composed of a more complex mixture of sand derived from the coast; however, the coastal sediments themselves were dominantly derived from the fluvial systems in the region, along with sediment of unknown original source. The new LIBS/SIMCA method of grain-by-grain analysis shows promise for unraveling complex mixing patterns in sedimentary deposits.

To characterize the transitional region from the near-field to far-field of a river plume entering coastal waters, we conducted four surveys using an autonomous underwater vehicle (AUV) to target the outflow of the New River Inlet, North Carolina, during maximum ebb tide. The utilization of a mobile sensor to synoptically observe current velocity data in tandem with natural river plume tracers (e.g., colored dissolved organic matter, salinity) was essential in understanding the mechanisms driving the observed circulation and mixing patterns within these waters. We find that this region is regularly impacted by two primary processes: (1) the interaction of an old dredged channel plume with the main discharge and (2) the recirculation of the discharge plume by an eddy that persistently forms between the old channel and main discharge location. Wind-driven processes in the nearshore can enhance the interaction of these two plumes resulting in unstable regions where mixing of the merged plume with the receiving waters is accelerated. We also conduct comparisons between AUV velocity observations from two surveys and their corresponding velocity outputs from a parallelized quasi-3-D model. We conclude that the ability to observe the estuarine outflow transitional region at near-synoptic temporal scales and resolutions discussed in this paper is key in providing the mechanisms driving local circulation which is essential for proper parameterization of high-resolution numerical coastal models.

A new in situ technique is introduced and tested for the field tracer study in meandering rivers. Real-time position data from a global positioning system were integrated with in situ fluorometer data, thereby providing a 2D spatial distribution of the tracer concentration. The method was used in an intensive tracer field survey over an 83 km reach of the North Saskatchewan River downstream of the capital region wastewater treatment plant. Hydrodynamics data were also collected simultaneously by measuring streamwise water velocity and depth using an acoustic Doppler current profiler. The full mixing length for this surface bank outfall at the observed low flow condition was inferred to be 130 km. The employed technique effectively improved the understanding of mixing patterns in complex flows by providing tracer and hydrodynamic data with high spatial and temporal resolution.

This work focuses on the mixing between basalt and granite in a deep plutonic environment. The description of mixing patterns and measurements of fractal dimensions, and the evaluation of geochemical data from a Cambro–Ordovician granitic pluton are summarized and discussed. Different morphologic domains within the pluton reveal concentric fragmented and/or folded layers of granite in a gabbro/granite mixed matrix. This stands in contrast to two predominantly regular gabbroic regions. These regular regions are separated by tightly stretched filament areas, in which mixing is enhanced. Sharp and gradational contacts between granitic and gabbroic domains depict the interplay among frozen flows (mingling) and convection-enhanced diffusion processes (mixing). Measurements of fractal dimensions at different scales and analysis of normalized concentration variance for major elements point towards magma mixing: the compositional variability and flow patterns of the studied pluton have been greatly controlled by a natural chaotic mixing process between a granitic and a basaltic end-member. During the mixing process, coeval fractional crystallization no doubt contributed to increasing the complexity of the system. However, since flow, and therefore mixing, stops with temperature decrease, flow patterns must have retained the predominant morphology and composition of the moment at which both contrasting magmas came together and froze. Flow patterns have been preserved. With further temperature decrease, fractional crystallization took over and hybrid rocks were generated from the fractionation of magmas previously mixed in different proportions.

The temporal and spatial variability of the upper ocean hydrochemistry in the Black Sea is analysed using data originating from profiling floats with oxygen sensors and carried out with a coupled three-dimensional circulation-biogeochemical model including 24 biochemical state variables. Major focus is on the dynamics of suboxic zone which is the interface separating oxygenated and anoxic waters. The scatter of oxygen data seen when plotted in density coordinates is larger than those for temperature, salinity and passive tracers. This scatter is indicative of vigorous biogeochemical reactions in the suboxic zone, which acts as a boundary layer or internal sink for oxygen. This internal sink affects the mixing patterns of oxygen compared to the ones of conservative tracers. Two different regimes of ventilation of pycnocline were clearly identified: a gyre-dominated (cyclonic) regime in winter and a coastal boundary layer (anticyclonic eddy)-dominated regime in summer. These contrasting states are characterized by very different pathways of oxygen intrusions along the isopycnals and vertical oxygen conveyor belt organized in multiple-layered cells formed in each gyre. The contribution of the three-dimensional modelling to the understanding of the Black Sea hydro-chemistry, and in particular the coast-to-open-sea mixing, is also demonstrated. Evidence is given that the formation of oxic waters and of cold intermediate waters, although triggered by the same physical process, each follow a different evolution. The difference in the depths of the temperature minimum and the oxygen maximum indicates that the variability of oxygen is not only just a response to physical forcing and changes in the surface conditions, but undergoes its own evolution.

Heterogeneities in contact networks have a major effect in determining whether a pathogen can become epidemic or persist at endemic levels. Epidemic models that determine which interventions can successfully prevent an outbreak need to account for social structure and mixing patterns. Contact patterns vary across age and locations (e.g. home, work, and school), and including them as predictors in transmission dynamic models of pathogens that spread socially will improve the models’ realism. Data from population-based contact diaries in eight European countries from the POLYMOD study were projected to 144 other countries using a Bayesian hierarchical model that estimated the proclivity of age-and-location-specific contact patterns for the countries, using Markov chain Monte Carlo simulation. Household level data from the Demographic and Health Surveys for nine lower-income countries and socio-demographic factors from several on-line databases for 152 countries were used to quantify similarity of countries to estimate contact patterns in the home, work, school and other locations for countries for which no contact data are available, accounting for demographic structure, household structure where known, and a variety of metrics including workforce participation and school enrolment. Contacts are highly assortative with age across all countries considered, but pronounced regional differences in the age-specific contacts at home were noticeable, with more inter-generational contacts in Asian countries than in other settings. Moreover, there were variations in contact patterns by location, with work-place contacts being least assortative. These variations led to differences in the effect of social distancing measures in an age structured epidemic model. Contacts have an important role in transmission dynamic models that use contact rates to characterize the spread of contact-transmissible diseases. This study provides estimates of mixing patterns for societies for which contact data such as POLYMOD are not yet available., Author summary The risk of infectious disease transmission varies in different settings, for instance at home, at work or in the community, as a result of the different social structures and mixing patterns in those locations. These social structures vary across countries in different stages of development and with different demographics. Social contact patterns have been measured in a small number of countries, but in large swathes of the world, contact patterns are unmeasured, which makes it challenging to build mathematical or computer models of disease spread and control. In this work, we developed a modelling framework to combine social contact data from the past studies of contact patterns within eight countries in the EU with data from multiple data sources including the Demographic Household Surveys, World Bank and UN Statistics Division, to provide validated approximations to age-and-location-specific contact rates for 152 countries covering 95.9% of the world’s population.

Background Mixing patterns of human populations play a crucial role in shaping the spreading paths of infectious diseases. The diffusion of mobile and wearable devices able to record close proximity interactions represents a great opportunity for gathering detailed data on social interactions and mixing patterns in human populations. The aim of this study is to investigate how social interactions are affected by the onset of symptomatic conditions and to what extent the heterogeneity in human behavior can reflect a different risk of infection. Methods We study the relation between individuals’ social behavior and the onset of different symptoms, by making use of data collected in 2009 among students sharing a dormitory in a North America university campus. The dataset combines Bluetooth proximity records between study participants with self-reported daily records on their health state. Specifically, we investigate whether individuals’ social activity significantly changes during different symptomatic conditions, including those defining Influenza-like illness, and highlight to what extent possible heterogeneities in social behaviors among individuals with similar age and daily routines may be responsible for a different risk of infection for influenza. Results Our results suggest that symptoms associated with Influenza-like illness can be responsible of a reduction of about 40% in the average duration of contacts and of 30% in the daily time spent in social interactions, possibly driven by the onset of fever. However, differences in the number of daily contacts were found to be not statistically significant. In addition, we found that individuals who experienced clinical influenza during the study period were characterized by a significantly higher social activity. In particular, both the number of person-to-person contacts and the time spent in social interactions emerged as significant risk factors for influenza infection. Conclusions Our findings highlight that Influenza-like illness can remarkably reduce the social activity of individuals and strengthen the idea that the heterogeneity in social habits among individuals can significantly contribute in shaping differences among the individuals’ risk of infection. Electronic supplementary material The online version of this article (doi:10.1186/s12879-017-2623-2) contains supplementary material, which is available to authorized users.

This work focuses on the study of bulk flows accompanying the coalescence of two aqueous drops, one containing surfactant and the other surfactant-free, in silicone oils of various viscosities. It is observed that the surfactant-free drop intrudes into the surfactant-laden drop in the form of a penetrating jet whose speed increases and average radius decreases with increasing outer phase viscosity. Mixing patterns within the coalescing drops are due to the force imbalance caused by capillary pressure difference and surfactant-induced Marangoni stresses. The driving force for mixing associated with the difference in interfacial tension between the drops is considerably stronger than that related to the drop size. The long timescale mixing of the drops is driven by rapid interior convection, and the subsequent, slow, diffusive process. Three-dimensional numerical simulations show excellent qualitative and quantitative agreement with the experimental results. The implications of our results to formulation strategies of complex microstructures in practical applications are also discussed.

Introduction The consequences of mixing between sexual partners of different ages on the transmission and prevalence of sexually transmitted infections (STI) are still not well understood. Using sexual behaviour data, we obtained a detailed quantitative description of sexual mixing by age. We then investigated the impact of age mixing on the age- and sex-specific prevalence and incidence of Chlamydia trachomatis ( Ct ) using a dynamic transmission model. Methods First, we used age- and sex-specific data about the proportion of individuals who are sexually active, sexual partner change rates, and the ages of the three most recent partners at first episode of sexual intercourse from the second and third British National Surveys of Sexual Attitudes and Lifestyles (Natsal-2 and Natsal-3). We used a parametric description of the partner ages using skew-normal distributions and combined the data to reconstruct age mixing between heterosexual partners. Second, we incorporated the mixing patterns into a compartmental transmission model to investigate the age groups amongst which Ct is most likely to be transmitted and in which direction. Results On average, males reported sex with younger female partners (median age difference −5.3; IQR [−1.6,–8.9] years) and females reported having male partners of similar age (median age difference −0.4; IQR [−2.7, 1.9] years). The median and the skewness of partner age distributions depend heavily on the age of the respondent. Ct -transmitting partnerships are typically between an older male and a younger female partner. In 60% of Ct -transmitting partnerships, at least one partner was >25 years old. Conclusion Our study illustrates the importance of sexual mixing patterns on Ct spread and indicates that a majority of transmitted infections are in age groups outside of those included in typical Ct screening programs. Our method for the incorporating sexual behaviour data into dynamic transmission models can be used to study the transmission of any STI and to understand the potential impact of control strategies that target specific age groups.

The group Σ(36×3) with the generalized CP transformation is introduced to predict the mixing pattern of leptons. Various combinations of Abelian residual flavor symmetries with CP transformations are surveyed. Six mixing patterns could accommodate the fit data of neutrinos oscillation at the 3σ level. Among them, two patterns predict the nontrivial Dirac CP phase, around ±57° or ±123°, which is in accordance with the result of the literature and the recent fit data. Furthermore, one pattern could satisfy the experimental constraints at the 1σ level.

Degree ssortativity is the tendency for nodes of high degree (resp.low degree) in a graph to be connected to high degree nodes (resp. to low degree ones). It is sually quantified by the Pearson correlation coefficient of the degree-degree correlation. Here we extend this concept to account for the effect of second neighbours to a given node in a graph. That is, we consider the two-walks degree of a node as the sum of all the degrees of its adjacent nodes. The two-walks degree assortativity of a graph is then the Pearson correlation coefficient of the two-walks degree-degree correlation. We found here analytical expression for this two-walks degree assortativity index as a function of contributing subgraphs. We then study all the 261,000 connected graphs with 9 nodes and observe the existence of assortative-assortative and disassortative-disassortative graphs according to degree and two-walks degree, respectively. More surprinsingly, we observe a class of graphs which are degree disassortative and two-walks degree assortative. We explain the existence of some of these graphs due to the presence of certain topological features, such as a node of low-degree connected to high-degree ones. More importantly, we study a series of 49 real-world networks, where we observe the existence of the disassortative-assortative class in several of them. In particular, all biological networks studied here were in this class. We also conclude that no graphs/networks are possible with assortative-disassortative structure., 15 pages, 5 figures, 2 tables

In most European countries, data regarding movements of live animals are routinely collected and can greatly aid predictive epidemic modeling. However, the use of complete movements' dataset to conduct policy-relevant predictions has been so far limited by the massive amount of data that have to be processed (e.g., in intensive commercial systems) or the restricted availability of timely and updated records on animal movements (e.g., in areas where small-scale or extensive production is predominant). The aim of this study was to use exponential random graph models (ERGMs) to reproduce, understand, and predict pig trade networks in different European production systems. Three trade networks were built by aggregating movements of pig batches among premises (farms and trade operators) over 2011 in Bulgaria, Extremadura (Spain), and Cotes-d'Armor (France), where small-scale, extensive, and intensive pig production are predominant, respectively. Three ERGMs were fitted to each network with various demographic and geographic attributes of the nodes as well as six internal network configurations. Several statistical and graphical diagnostic methods were applied to assess the goodness of fit of the models. For all systems, both exogenous (attribute-based) and endogenous (network-based) processes appeared to govern the structure of pig trade network, and neither alone were capable of capturing all aspects of the network structure. Geographic mixing patterns strongly structured pig trade organization in the small-scale production system, whereas belonging to the same company or keeping pigs in the same housing system appeared to be key drivers of pig trade, in intensive and extensive production systems, respectively. Heterogeneous mixing between types of production also explained a part of network structure, whichever production system considered. Limited information is thus needed to capture most of the global structure of pig trade networks. Such findings will be useful to simplify trade networks analysis and better inform European policy makers on risk-based and more cost-effective prevention and control against swine diseases such as African swine fever, classical swine fever, or porcine reproductive and respiratory syndrome.

Biphasic calcium phosphate (BCP) bioceramics, the mixture of hydroxyapatite (HA) and beta- tricalcium phosphate (β-TCP), are widely used as bone repair materials. Optimization of its composition and mixing pattern is crucial for its design and preparation. A series of BCP structures with a HA/β-TCP mass ratio of 0/100, 30/70, 50/50, 70/30, and 100/0 were constructed and studied with a simulated annealing molecular dynamics method. On the basis of equilibrated BCP structures, their elastic constants and moduli were computed and analyzed. With increasing HA content, the elastic moduli of BCP increase. Under the same mass ratio (50/50), the elastic moduli have no distinct changes for different mixing patterns. Calculations on the uniaxial extension of BCP reveal a sophisticated nonlinear and loading-path dependent behavior. The maximum stress decreases with increasing β-TCP content and mixing level.

Background Patterns of person-to-person contacts relevant for infectious diseases transmission are still poorly quantified in Sub-Saharan Africa (SSA), where socio-demographic structures and behavioral attitudes are expected to be different from those of more developed countries. Methods and Findings We conducted a diary-based survey on daily contacts and time-use of individuals of different ages in one rural and one peri-urban site of Manicaland, Zimbabwe. A total of 2,490 diaries were collected and used to derive age-structured contact matrices, to analyze time spent by individuals in different settings, and to identify the key determinants of individuals’ mixing patterns. Overall 10.8 contacts per person/day were reported, with a significant difference between the peri-urban and the rural site (11.6 versus 10.2). A strong age-assortativeness characterized contacts of school-aged children, whereas the high proportion of extended families and the young population age-structure led to a significant intergenerational mixing at older ages. Individuals spent on average 67% of daytime at home, 2% at work, and 9% at school. Active participation in school and work resulted the key drivers of the number of contacts and, similarly, household size, class size, and time spent at work influenced the number of home, school, and work contacts, respectively. We found that the heterogeneous nature of home contacts is critical for an epidemic transmission chain. In particular, our results suggest that, during the initial phase of an epidemic, about 50% of infections are expected to occur among individuals younger than 12 years and less than 20% among individuals older than 35 years. Conclusions With the current work, we have gathered data and information on the ways through which individuals in SSA interact, and on the factors that mostly facilitate this interaction. Monitoring these processes is critical to realistically predict the effects of interventions on infectious diseases dynamics.

This article presented the effect of mixing patterns for the bio-cement in two different soils (Kaolin clay and Bangkok sand). Bio-cementation process initiated the crystal forms of calcium carbonate (CaCO3) to bind the soil particles. Soil samples were mixed with the solution containing 250 mM of CO(NH2)2, 250 mM of Ca2+ (by CaCl2) and 20% (v/v) of urease. In simulated deep mixing of Kaolin clay, the research found that blades used in solution mixing affected the strength development of Kaolin clay after bio-cementation. The V s of 210 m s−1 was found in comb blade mixer. In simulated deep mixing of Bangkok sand, the research found that solution injecting method affected the V s of Bangkok sand. The period drop and the period injecting methods provided better V s results than the one time pouring and the continuous injecting methods.

A simple experiment designed to study mixing of a material of complex rheology in a stirred tank is described. Non-Newtonian suspensions of blue maize flour that naturally contain anthocyanins have been chosen as a model fluid. These anthocyanins act as a native, wide spectrum pH indicator exhibiting greenish colors in alkaline environments, blue tones in neutral conditions, and pink–violet colors in acid environments. Students used a continuous injection of a basic solution in an initially acidic environment to reveal mixing patterns and flow structures and to follow their evolution over time in a typical stirred tank configuration. These experiments aim to demonstrate, in a laboratory setting, basic concepts related to mixing: (i) the existence of mixing pathologies in laminar-stirred tanks; (ii) the complex rheology of some real suspensions; (iii) the effect of tank geometry on mixing performance; and (iv) the quantitation of mixedness and mixing evolution using digital color analysis.

Mixing patterns within sexual networks have been shown to have an effect on HIV transmission, both within and across groups. This study examined sexual mixing patterns involving HIV-unknown status and risky sexual behavior conditioned on assortative/dissortative mixing by race/ethnicity. The sample used for this study consisted of drug-using male sex workers and their male sex partners. A log-linear analysis of 257 most at-risk MSM and 3,072 sex partners was conducted. The analysis found two significant patterns. HIV-positive most at-risk Black MSM had a strong tendency to have HIV-unknown Black partners (relative risk, RR = 2.91, p

Through experiment and numerical modeling, this study investigated the establishment of moderate or intense low-oxygen dilution (MILD) combustion in a laboratory-scale furnace when fuel and air are fully premixed (FP), partially premixed (PP), or non-premixed (NP). Experiments were carried out at firing rates from 7.5 to 15 kW and equivalence ratios (Φ) ranging from 0.5 to 1. The furnace thermal fields and exhaust NOx emissions for the three mixing patterns were compared. Validated computational fluid dynamics was used to aid in better understanding the flow and compositional structures in the furnace. Natural gas was used as the fuel. The eddy dissipation concept (EDC) model and the GRI-Mech 3.0 mechanism were used. Additional chemical kinetics calculations were also performed to examine reaction pathways under the MILD combustion regime. Moreover, the characteristics of the reaction regime of MILD combustion were examined and are discussed in detail. Estimation of the initial jet momentum rate (J) showe...

Measurements of trace elements leached from host rocks can indicate the source of flowing groundwater and provide the host rock's fingerprint information that may be useful in understanding the mixing patterns of different groundwaters and flowpaths. In this study, the leaching characteristics of three widely-distributed aquifer host rocks in Southern Nevada were investigated through leaching experiments of 13 trace elements under different experimental conditions (leaching time, pH, grain size, and rock mineralogy). The fraction of leached trace elements from different aquifer host rocks was calculated for examining the water-rock interaction in different conditions. The effect of host rock mineralogy on leachate composition was examined, which could provide useful information about groundwater source. Solute speciation and saturation indices were simulated using geochemical modeling to further explore the redistribution and leaching process of trace elements.

In this paper, a thermodynamic analysis of non-isothermal mixing's influence on the energy target of water-using network is presented. Firstly, water streams in the network are divided into two categories, and then based on the classification all the non-isothermal mixing patterns between two streams are defined. Through thermodynamic analysis from energy composite curve of hot and cold water streams, the influences of non-isothermal mixing on the energy target of water-using network are explored and some mixing rules are obtained, which can be used to simplify the heat exchanger network of a given water-using system and improve the system's energy performance through identifying the beneficial non-isothermal mixings. The applicability of these rules is illustrated by an example in the paper and the result is very encouraging.

It has been shown that both humanly constructed and natural networks are often characterized by small-world phenomenon and assortative mixing. In this paper, we propose a geometrically growing model for small-world networks. The model displays both tunable small-world phenomenon and tunable assortativity. We obtain analytical solutions of relevant topological properties such as order, size, degree distribution, degree correlation, clustering, transitivity, and diameter. It is also worth noting that the model can be viewed as a generalization for an iterative construction of Farey graphs.

Compressive sensing is an effective way to reconstruct the network structure. In this paper, we investigate the effect of the mixing patterns, measured by the assortative coefficient, on the performance of network reconstruction. First, we present a model to generate networks with different assortativity coefficients, then we reconstruct the network structure by using the compressive sensing method. The experimental results show that when the assortativity coefficient $r=0.2$, the accuracy of the network reconstruction reaches the maximum value, which suggests that the compressive sensing is more effective for uncovering the links of social networks. Moreover, the accuracy of the network reconstruction will be higher as the network size increases.

Including the generalized CP symmetry, we have performed a comprehensive scan of leptonic mixing patterns which can be obtained from finite discrete groups with order less than 2000. Both the semidirect approach and its variant are considered. The lepton mixing matrices which can admit a good agreement with experimental data can be organized into eight different categories up to possible row and column permutations. These viable mixing patterns can be completely obtained from the discrete flavor groups $\Delta(6n^2)$, $D^{(1)}_{9n,3n}$, $A_5$ and $\Sigma(168)$ combined with CP symmetry. We perform a detailed analytical and numerical analysis for each possible mixing pattern. The resulting predictions for lepton mixing parameter, neutrinoless double decay and flavored leptogenesis are studied., Comment: 50 pages, 19 figures

This study was conducted to build up the inventories of Pb isotopic compositions of major Pb pollution sources in South Korea. Since non-ferrous metal smelters are one of major anthropogenic sources, two smelters for zinc, each one of smelter for lead and copper were selected for the study. The Pb concentrations and isotopic compositions of metal ores, wastewater, sludge, metal rod and produced sulfuric acid were analysed to understand the Pb isotopic patterns in environment. The isotopic ratio, , of zinc ores from zinc smelter were in the range of 1.179~1.198 and the ratio of waste, flue gas and products samples were 1.105~1.147. This results implied that the isotopic patterns of output samples showed mixing patterns between two distinct metal ore soerces. In 2011, major importing countries of zinc ore were Australia, Peru and Mexico. Thus Pb isotopic patterns from zinc smelter is originated from the mixing patterns between less radiogenic Australian ores and more radiogenic South America`s ores. Lead smelters also showed the same mixing patterns with those of zinc smelters. However copper smelter showed same Pb isotopic patterns with more radiogenic South America`s ores.

This study introduces integrated approach on detection of a leakage in a sea wall based on remote sensing, electric resistivity survey, electromagnetic survey, and borehole survey for the Seosan A-Region sea wall. The satellite temperature distribution from Landsat ETM+ data identifies water leakage distribution and period by analyzing temperature mixing patterns between sea water and fresh water. Electric resistivity survey provides both horizontal and vertical anomaly distributions over the sea wall showing below average electric resistivity. Electromagnetic survey(electrical conductivity survey) reveals the potential possible leakage areas with minimal background impact by comparing electrical conductivity values between high and low tides. Borehole image processing system confirmed the locations of anomalies identified from the other survey methods and distributions of vertical fracture zones. The integrated approach identified 41.7% of the sea wall being the most probable area vulnerable to water leakage and effectively approximated both horizontal and vertical distribution of water leakage. The integrated analysis of remote sensing, electric resistivity survey, electromagnetic survey and borehole survey is considered to be an optimal method in identifying water leakage distribution, period, and extent of fractures knowledged from the boreholes.

Human populations are interconnected through a variety of different networks. The complex interactions of diverse populations of individuals and their interconnected network structures affect the diffusion of processes through the population. For example, the different modes of transmission of HIV and TB mean that they are transmitted along very different contact networks: HIV via sexual contact and TB via respiratory contact. In addition, co-infection with HIV raises the risk of progressing to active TB and reduces the response to TB treatment, potentially causing increasing incidence of TB. Here we extend existing network theory to find the effect of multiple networks and multiple host types on epidemic thresholds. We first analyse how transmission of a pathogen via an additional network affects its epidemic threshold. We then use the theory behind branching processes to study how multiple host types in a population affect its threshold. The formulation we obtain enables modellers to determine how multiple networks and host heterogeneity (i.e. vaccination, behavioural change, mixing patterns, etc.) affect the epidemic threshold. We apply the results to the example of HIV and TB to illustrate how the interactions of the diseases can substantially alter the epidemic threshold of TB.

Many social, biological or technological systems are recognized as complex networks with assortative or disassortative mixing pattern, which is lacking in typical theorical network models, such as, Watts-Strogatz small-world model or Barabasi-Albert scale-free network. In this paper, we propose a mechanism which models the emergence of the degree correlation property of complex networks. Numerical simulations indicate that this correlation-adjustable network model can exhibit fundamentally different degree correlation mixing patterns with a scale-free degree sequence. Moreover, the structural properties of networks, such as the average path length and clustering property are also investigated.

Mechanical properties and material mixing patterns of friction stir spot welded (FSSW) joints of dissimilar aluminum alloys were investigated. Two aluminum alloys typically used in automotive applications, 5052-H32 and 6061-T6, were selected. During the experiment, the process parameters including the z-axis force and torque histories were measured as a function of the tool displacement. The mechanical properties were investigated by microhardness measurements of the joint, and the material mixing in the stir zone was investigated by EPMA. The experimental results illustrate different process parameter histories, material mixing in the stir zone and material properties including microhardness distributions for FSSW joints of dissimilar aluminum alloys, likely due to different mechanical behaviors of the selected aluminum alloys in the FSSW process temperature range.

Recently, the attention to the ice season in lakes has been growing remarkably amongst limnological communities, in particular, due to interest in the response of mid- and high-latitude lakes to global warming. We review the present advances in understanding the governing physical processes in seasonally ice-covered lakes. Emphasis is placed on the general description of the main physical mechanisms that distinguish the ice-covered season from open water conditions. Physical properties of both ice cover and ice-covered water column are considered. For the former, growth and decay of the seasonal ice, its structure, mechanical and optical properties are discussed. The latter subject deals with circulation and mixing under ice. The relative contribution of the two major circulation drivers, namely heat release from sediment and solar heating, is used for classifying the typical circulation and mixing patterns under ice. In order to provide a physical basis for lake ice phenology, the heat transfer processes related to formation and melting of the seasonal ice cover are discussed in a separate section. Since the ice-covered period in lakes remains poorly investigated to date, this review aims at elaborating an effective strategy for future research based on modern field and modeling methods.

In light of the latest neutrino oscillation data, we examine whether the leptonic flavor mixing matrix can take on an exact form of tri-bimaximal (TBM), golden-ratio (GR) or bimaximal (BM) mixing pattern at a superhigh-energy scale, where such a mixing pattern could be realized by a flavor symmetry, and become compatible with experimental data at the low-energy scale. Within the framework of the Minimal Supersymmetric Standard Model (MSSM), the only hope for realizing such a possibility is to count on the corrections from the renomalization-group (RG) running. In this work we focus on these radiative corrections, and fully explore the allowed parameter space for each of these mixing patterns. We find that when the upper bound on the sum of neutrino masses $\Sigma^{}_\nu \equiv m^{}_1 + m^{}_2 + m^{}_3 < 0.23~\text{eV}$ at the $95\%$ confidence level from Planck 2015 is taken into account, none of these mixing patterns can be identified as the leptonic mixing matrix below the seesaw threshold. If this cosmological upper bound on the sum of neutrino masses were relaxed, the TBM and GR mixing patterns would still be compatible with the latest neutrino oscillation data at the $3\sigma$ level, but not at the $1\sigma$ level. Even in this case, no such a possibility exists for the BM mixing., Comment: 22 pages, 5 figures; minor changes, references added, version to appear in JHEP

A comparison of the performance of four full-scale aerated horizontal flow constructed wetlands was conducted to determine the efficacy of the technology on sites receiving high and variable ammonia loading rates not yet reported in the literature. Performance was assessed in terms of ammonia and solids removal, hydraulic conductivity and mixing patterns. The capability of systems to produce ammonium effluent concentrations

We study a second CP symmetry compatible with the $A_4$ flavor group, which interchanges the representations $\mathbf{1}'$ and $\mathbf{1}"$. We analyze the lepton mixing patterns arising from the $A_4$ and CP symmetry broken to residual subgroups $Z_3$ and $Z_2\times CP$ in the charged lepton and neutrino sectors respectively. One phenomenologically viable mixing pattern is found, and it predicts maximal atmospheric mixing angle as well as maximal Dirac CP phase, trivial Majorana phase and the correlation $\sin^2\theta_{12}\cos^2\theta_{13}=1/3$. We construct a concrete model based on the $A_4$ and CP symmetry, the above interesting mixing pattern is achieved, the observed charged lepton mass hierarchy is reproduced, and the reactor mixing angle $\theta_{13}$ is of the correct order., Comment: 22 pages, 1 figure

A numerical model has been developed employing an orthogonal stream-tube gridding system for the investigation of mixing patterns in meandering rivers. The proposed model couples field data and modeling. It uses a measured velocity field to solve the advection-diffusion equation. This equation provides a practical simulation with greater accuracy and lower computational cost for estimation of mixing in meandering channels with a long, full mixing length. The model has been used to estimate the transverse mixing coefficient in surveyed subreaches of the North Saskatchewan River in Canada. Good agreement was observed between the numerical and measured tracer concentrations using reasonable values for the transverse mixing coefficient. The average dimensionless transverse mixing coefficient from the calibrated numerical model for the surveyed reach was 0.39, which was consistent with values estimated using empirical formulas for transverse mixing coefficients in natural meandering rivers. The estimat...

We have performed a comprehensive analysis of the type D group $D^{(1)}_{9n, 3n}$ as flavor symmetry and the generalized CP symmetry. All possible residual symmetries and their consequences for the prediction of the mixing parameters are studied. We find that only one type of mixing pattern is able to accommodate the measured values of the mixing angles in both "direct" and "variant of semidirect" approaches, and four types of mixing patterns are phenomenologically viable in the "semidirect" approach. The admissible values of the mixing angles as well as CP violating phases are studied in detail for each case. It is remarkable that the first two smallest $D^{(1)}_{9n,3n}$ groups with $n=1, 2$ can fits the experimental data very well. The phenomenological predictions for neutrinoless double beta decay are discussed.